HUMAN 


PHYSIOLOGY. 


BY 


HOBLEY  DUKGLISON,  M.D.,  LL.D., 

PROFESSOR    OF   THE    INSTITUTES    OF    MEDICINR   IN   JEFFERSOIf   MEDICAL  COLLEGE,    PHILADELPHIA  ; 
VIOK-PRESLDEST   OF   THE   AMERICAN   PHILOSOPHICAL  SOCIETY,  ETC.  ETC. 


'Vastissimi  studii  primas  quasi  lineas  circumscripsi." — Haller. 


FIVE   HUNDRED   AND    THTRTY-TV/0   ILLUSTRATIONS 


EIGHTH  edition:, 

REVISED,  MODIFIED,  AND  ENLARGED. 

IN    TWO    YOLUMES. 

YOL.  I. 


PHILADELPHIA: 

B  L  A  N  C  H  A  Pv  D    AND    LEA 
78  6         -"  ^  ^^^.^- 


Entered  according  to  tlie  Act  of  Congress,  in  the  year  1841,  by 

ROBLEY  DUNGLISON, 

in  tlie  Clerk's  Office  of  the  District  Court  for  the  Eastern  District  of  Pennsylvania. 


PHILADELPHIA  : 
T.   K.   AND  P.  G.  COLLIXS,  PRINTERS. 


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TO 

JAMBS    MADISON, 

EX-PRESIDENT  OF  THE  UNITED  STATES,  ETC.,  ETC., 

ALIKE    DISTINGUISHED   AS   AN    ILLUSTRIOUS    BENEFACTOR   OF    HIS   COUNTRY, 
A  ZEALOUS  PROMOTER  OF  SCIENCE  AND  LITERATURE, 
AND  THE  FRIEND  OF  MANKIND, 

Q  ' 

INTENDED  TO  ILLUSTRATE  THE  FUNCTIONS  EXECUTED  BY  THAT  BEING, 

WHOSE    MORAL   AND    POLITICAL   CONDITION    HAS    BEEN    WITH    HIM    AN    OBJECT    OP 

ARDENT  AND  SUCCESSFUL  STUDY, 

IS,    WITH    HIS   PERMISSION,    INSCRIBED, 

IN  TESTIMONY  OF  UNFEIGNED  RESPECT  FOR  HIS  TALENTS  AND  PHILANTHROPY, 

AND  OF  GRATITUDE  FOR  NUMEROUS  EVIDENCES  OF  FRIENDSHIP, 

BY  HIS  OBEDIENT  AND  OBLIGED  SERVANT, 

THE   AUTHOR. 


PRErACE  TO  THE  EIGHTH  EDITION. 


The  demand  for  another  edition  of  this  work  has  given  occasion  to 
a  thorough  revision  of  it  by  the  author. 

There  is  no  department,  perhaps,  of  medicine,  to  which  the  atten- 
tion of  so  many  investigators  has  been,  and  is,  directed  as  to  that 
of  physiology ;  and,  as  remarked  in  the  preface  to  the  last  edition, 
perhaps  at  no  time  in  the  history  of  the  science  have  observers  been 
more  energetic,  and  discriminating.  Many  modifications  of  fact  and 
inference  have  consequently' taken  place,  which  it  has  been  neces- 
^  sary  for  the  author  to  record,  and  to  express  his  views  in  I'elation 
thereto.  Especially  has  he  endeavoured  to  note  the  phenomena  that 
have  presented  themselves  to  the  most  accurate  observers,  and  to 
deduce  from  them  laws  which  may  tend  to  enlarge  the  boundaries  of 
the  science :  he  has  not,  however,  felt  himself  at  liberty  to  discard  the 
results  of  the  observations  of  all  former  anthropologists,  or  the  opinions 
they  had  embraced  in  regard  to  the  various  functions.  It  not  unfre- 
ijuently,  indeed,  happens,  that  in  ignorance  of  the  history  of  the  science, 
views  are  esteemed  new,  which  had  been  promulged  by  earlier  inves- 
tigators. He  has,  therefore,  in  an  encyclopaediac  work  like  the  pre- 
sent, retained  many  of  those  opinions,  whilst  he  has  laboured  to  do 
especial  justice  to  such  as  have  emanated  from  more  recent  inquirers. 
In  this  respect,  his  work  differs  from  valuable  physiological  treatises 
that  are  before  the  public.  Whilst,  too,  he  has  inserted  the  main 
results  of  the  labours  of  recent  histologists,  especially  such  as  are 
directly  applicable  to  physiology,  he  has  not  considered  it  advisable 
to  pursue  the  subject  to  such  an  extent  as  if  the  work  were  on  general 
anatomy,  to  which  histology  properly  belongs. 


vi  PREFACE. 

On  the  wliole  subject  of  physiology  proper,  as  it  applies  to  the  fuuc- 
tious  executed  by  the  different  organs,  the  present  edition,  the  author 
flatters  himself,  will  be  found  to  contain  the  views  of  the  most  distin- 
guished physiologists  of  all  periods.  The  contributions  to  the  science 
of  life  have,  of  late  years,  been  rich  and  varied ;  and  to  collate  and 
weigh  them,  and  to  separate  the  most  trustworthy  and  valued,  has  been 
a  work  of  no  little  discriminating  labour, — but  to  the  author  a  labour 
of  love,  inasmuch  as  they  are  subjects  which  he  has  been  long  accus- 
tomed to  investigate ;  and  on  which  he  has  annually  to  treat  before 
the  class  of  Institutes  of  Medicine  in  the  Jefferson  Medical  College. 

The  rich  collection  of  materials  in  the  possession  of  his  publishers 
has  enabled  him  to  increase  greatly  the  list  of  illustrations,  and  to  sub- 
stitute in  many  cases  better ;  whilst  new  cuts  have  been  added,  so  as 
to  make  the  Avhole  number  five  hundred  and  thirty-two,  in  place  of 
four  hundred  and  seventy-four,  as  in  the  last  edition.  It  has  been  diiR- 
cult  in  all  cases  to  assign  these  to  the  original  projectors ;  but  an  effort 
has  been  made  so  to  do. 

The  author  need  scarcely  add,  that  no  pains  have  been  spared  by 
him  to  make  the  work  a  complete  expression  of  the  science  of  the  day. 
The  list  of  ex  professo  publications^  will  indicate  most  of  the  numerous 

'  Atlee,  Walter  F.,  M.  D.     Notes  of  M.  Bernard's  Lectures  on  tlie  Blood  ;  witli  an 

appendix,  Pkilad.,  1S54. 
Bain,  Alexander,  A.  M.     The  Senses  and  the  Intellect,  London,  1855. 
Beale,  Lionel  John.     The  Laws  of  Health  in  relation  to  Mind  and  Body :  A  series  of 

Letters  from  an  old  Practitioner  to  a  Patient,  Amer.  edit.,  Philad.,  1851. 
Beclard,  J.     Traite  Elementaire  de  Physiologie  Humaine  comprenant  les  Principales 

Notions  de  la  Physiologie  Comparee,  Ouvrage  accompagne  de  144  Gravures  iuterca- 

lees  dans  le  Texte,  Paris,  1855. 
Becquerel,  M.  Alf.  and  Rodier,  M.  A.     Traite  de  Chimie  Pathologique  appliquee  S,  la 

Medecine  Pratique,  Paris,  1854. 
Berard,  P.     Cours  de  Physiologie,  fait  a  la  Faculte  de  Medecine  de  Paris.     Tome  Seme 

et  2  livraisons  du  Tome  4eme,  1851-1855. 
Beraud,  M.  J.  B.     Manuel  de  Physiologie  de  PHomme  et  des  Principaux  Vertebres ; 

repondant  ^  toutes  les  Questions  Physiologiques  du  Programme  des  Exameus  de  Fin 

d'Annee,  revu  par  M.  Ch.  Robin,  &c.,  Paris,  1853. 
Bernard,  M.  Claude.     Lemons  de  Physiologie  Experimentale  appliqut-e  a  la  Mi'decine, 

faites  au  College  de  France,  avec  22  figures  intercalees  dans  le  Texte,  Paris,  1855. 

,  see  Atlee. 

Bidder,  Dr.  F.,and  Schmidt,  Dr.  C.     Die  Verdauungssafte  und  der  Stoffwechsel.  Eine 

Physiologisch-Chemische  Untersuchung.    Mit  fiiuf  Tafeln  graphischer  Darstellungen, 

Mitau  und  Leipzig,  1852. 
Bishop,  John,  F.  R.  S.     On  Articulate  Sounds  ;  and  on  the  Causes  and  Cure  of  Impedi- 
ments of  Speech,  London,  1851. 


& 


PREFACE.  Vll 

distinct  treatises,  connected  with  biology,  whicli  he  has  had  to  consult  in 
the  preparation  of  the  present  edition.    He  has,  moreover,  industriously 

Bock,  Dr.  Carl  Ernst.  Lelirbucli  der  Pathologisclien  Anatomie  und  Diagnostik, 
2  Bd.,  Leipzig,  1852-1S53. 

Bowman,  John  E.,  F.  C.  S.  A  Practical  Handbook  of  Medical  Chemistry  ;  2d  Ameri- 
can from  the  third  and  revised  London  edition,  with  illustrations,  Philad.,  1855. 

Brachet,  J.  L.  Physiologic  Elementaire  de  I'Homme,  2de  edit.,  2  vols.,  Paris  et  Lyon, 
1855. 

Brodie,  Sir  Benjamin,  Bart.,  D.  C.  L.,  &:c.     Physiological  Researches,  London,  1851. 

Brown-Sequard,  Experimental  Researches  applied  to  Physiology  and  Pathology,  New 
York, 1853. 

,  Sur  les  Resultats  de  la  Section  et  de  la  Galvanisation  dn  Nerf  Grand 

Sympathique  au  Cou.     (Extrait  de  la  Gazette  Medicale  de  Paris,  Annee,  1854.) 

,  Experimental  and  Clinical  Researches  on  the  Physiology  and  Pathology 


of  the  Spinal  Cord,  and  some  other  parts  of  the  Nervous  Centres,  Richmond,  1855. 
,  Recherches  Experimentales  sur  la  Transmission  Croisee  des  Impressions 


Sensitives  dans  la  Moelle  Epiniere.     (Extrait  de  la  Gazette  Hebdomadaire  de  Mede- 
ciue  et  de  Chirurgie.     Tome  ii.,  Nos.  31  and  36),  Paris,  1855. 
,  Proprietes  et  Fonctions  de  la  Moelle  Epiniere,  Rapport  sur  quelques  Ex- 


periences de  M.  Brown-Sequard,  lu  a  la  Societe  de  Biologic,  le  21  Juillet,  1855,  par 
M.  Paul  Broca,  Professeur  Agrege,  &c.,  Paris,  1855. 
,  Deux  Memoires  sur  la  Physiologic  de  la  Moelle  Epiniere  lus  a  I'Academie 


des  Sciences  le  27  Aoiit  et  le  24  Septembre,  1855. 

1.  Recherches  sur  la  Voie  de  Transmission  des  Impressions  Sensitives  dans  la 
Moelle  Epiniere. 

2.  Recherches  Experimentales  sur  la  Distribution  des  Fibres  des  Racines  Posteri- 
eures  dans  la  Moulle  i-piuiere,  et  sur  la  Voie  de  Transmission  des  Impressions  Sen- 
sitives dans  cet  Organe.    (Extraits  de  la  Gazette  Medicale  de  Paris,  Annee,  1855). 

[The  last  four  memoirs — the  gift  of  Dr.  Browu-Sequard — reached  the  author  whilst 
he  was  preparing  the  present  list.  The  results  at  which  he  has  arrived  from  his  ex- 
periments on  living  animals,  and  published  in  the  two  memoirs  presented  before  the 
Academie  des  Sciences,  of  Paris,  conflict  greatly  with  those  hitherto  received  by  phy- 
siologists, in  regard  to  the  functions  of  the  vesicular  and  tubular  portions  of  the  spi- 
nal marrow.  In  the  first  of  the  two  memoirs  he  concludes, — that  it  is  not  by  the 
posterior  cords  of  the  spinal  marrow,  as  is  generally  admitted  in  France,  that  the  trans- 
mission to  the  encephalon  of  sensory  impressions,  received  by  the  trunk  and  the  limbs, 
is  finally  effected  ;  that  such  transmission  is  finally  eflected  by  the  gray  substance  of  the 
medulla  spinalis,  and  especially  by  its  central  portion  ; — and  in  the  latter  memoir  he 
concludes,  that  sensory  impressions  on  their  arrival  at  the  medulla  spinalis,  pass  by 
the  posterior  cords,  the  posterior  gray  cornua,  and  probably  also  by  the  lateral  cords  ; 
and  that  in  these  different  portions  of  the  medulla  they  ascend  or  descend ;  and  after 
a  short  course  towards  the  encephalon,  or  in  the  opposite  direction,  quit  those  parts  to 
enter  into  the  gray  central  matter,  in  which,  or  by  which,  they  are  finally  transmitted 
to  the  encephalon. 

The  brilliant  vivisections  made  by  this  dexterous  experimenter  and  able  physiolo- 
gist, in  the  presence  of  a  Committee  of  the  Societe  de  Biologic,  composed  of  MM. 
Claude  Bernard,  Bouley,  Broca,  Giraldes,  Goubaux  and  Vulpian,  have  led  M.  Broca — 
the  reporter — to  the  sweeping  conclusion,  that  "  no  known  doctrine  or  system  can  live 
alongside  the  experiments  of  M.  Brown-Sequard  ;  and  that  we  must  submit  to  make  a 
tabula  rasa  of  everything  that  has  been  hitherto  said  on  the  physiology  of  the  medulla 
spinalis." 


VIU  PREFACE. 

availed  himself  of  multitudinous  contributions  to  medical  encyclopcedias, 
dictionaries,  and  journals,  published  at  home  and  abroad;  and,  for  the 

The  Committee  considered,  that  the  experiments,  performed  in  their  presence,  satis- 
factorily demonstrated — that  exposure  of  the  dura  mater  and  of  the  medulla  permitted 
sensibility  and  motion  to  persist  in  the  posterior  train ; — that  such  sensibility  still 
persisted  after  the  section  of  the  posterior  cords — called  the  sensitive  cords  of  the  me- 
dulla ;  and  that,  consequently,  these  cords  are  not  indispensable  for  the  transmission 
of  sensory  impressions  ; — that  far  from  abolishing  sensibility,  the  section  of  the  sup- 
posed sensitive  cords  was  accompanied  by  hypersesthesia  of  the  lower  limbs ;  that  after 
such  section,  the  caudal  segment  of  the  medulla  was  more  sensible  than  the  cei^halic 
segment,  and  that  the  vesicular  matter  of  the  cord  was  of  itself  insensible. 

Other  experiments  showed,  that  the  separate  and  complete  section  of  the  posterior 
cords  neither  destroyed  sensibility  nor  motion ;  but  that  both  were  destroyed  when 
the  vesicular  matter  was  cut  across  ;  that  the  integrity  of  the  antero-lateral  cords  did 
not  prevent  the  loss  of  movement,  nor  did  that  of  the  posterior  cords  prevent  the  loss 
of  feeling. 

A  work  on  the  physiology  of  the  spinal  marrow,  from  the  pen  of  Dr.  Brown-Sequard, 
is  announced.     It  will,  doubtless,  contain  all  the  facts  observed  by  him,  as  well  as  the 
important  deductions  to  which  his  ample  knowledge  of  the  whole  subject  cannot  fail 
to  have  led  him.] 
Budd,  Geo.,  M.  D.,  F.  R.  S.     On  Diseases  of  the  Liver,  2d  Amer.  from  the  last  and 

improved  London  edition,  with  colored  plates  and  wood-cuts,  Philad.,  1853. 
,  On  the  Organic  Diseases  and  Functional  Disorders  of  the  Stomach,  Amer. 

edit.,  Philad.,  1856. 
Budge,  Julius.     Memoranda  der  Speciellen  Physiologie  des  Meuschen  ;  ein  Leitfaden 

fiir  Vorlesungen  und  zum  Selbststudium,  5te  verbesserte  tind  vermehrte  Aiiflage. 

Mit  10  Kupfertafeln,  Weimar,  1853. 
Bushnan,  J.  Stevenson,  M.  D.     The  Principles  of  Animal  and  Vegetable  Physiology  ; 

a  Popular  Treatise  on  the  Functions  and  Phenomena  of  Organic  Life ;  to  which  is 

prefixed  a  general  view  of  the  great  Departments  of  Human  Knowledge,  with  one 

hundred  and  two  Illustrations  on  wood.      [Reprinted  from  vol.  1  of  Orr's  Circle  of 

the  Sciences,  London,  1854.]     Philadelphia,  1854. 
Carpenter,  William  B.,  M.  D.,  F.  R.  S.,  &c.     Pi-inciples  of  Human  Physiology,  with 

their  Chief  Applications  to  Psychology,  Pathologj'-,  Therapeutics,  Hygiene,  and  Fo- 
rensic Medicine.     A  new  American  from  the  last  London  edition,  with  two  hundred 

and  sixty-one  Illustrations.    Edited,  with  additions,  by  Francis  Gurney  Smith,  M.  D., 

Professor  of  the  Institutes  of  Medicine  in  the  Medical  Department  of  Pennsylvania 

College,  &c.,  Philad.,  1855. 
,  Principles  of  Comparative  Physiology,  with  three  hundred  and  nine  wood 

engravings.     A  new  American  from  the  fourth  and  revised  London  edition,  Philad., 

1854. 
Chambers,  Thomas  K.     Digestion  and  its  Derangements.     The  Principles  of  Rational 

Medicine  applied  to  Disorders  of  the  Alimentary  Canal,  London,  1856. 
Coste,  M.     Histoire  Gt'nerale  et  Particuliere  du  Developpement  des  Corps  Organises, 

Publie  sous  les  Auspices  de  M.  Villemain,  Ministre  de  I'lnstruction  Piibllque,  Paris, 

1847-1854. 
Eschricht,  Dr.  Daniel  Friedrich.     Das  Physische  Leben  in  Poi^ularen  Vortriigen.     Mit 

208  Abbildungen,  meist  in  Holz  geschnitten,  Kopenhagen,  1852. 
Fabius  and  Buys-Ballot.     De  Spirometro  ejusque  Usu.     Dissertatio  Inauguralis,  Am- 

stelodam.,  1853. 


PREFACE.  IX 

eighth  time,  he  ventures  to  place  the  work  before  a  profession,  which, 
he  is  proud  in  being  permitted  again  to  state,  has  already  done  too 

Fleiiry,  Louis.     Cours  d'Hygiene  fait  a  la  Faculte  de  Medecine  de  Paris,  Paris,  1852. 

Flourens,  Prof.  P.     Histoire  de  la  Decouverte  de  la  Circulation  du  Sang,  Paris,  1854. 

,  De  la  Longevite  Huniaine  et  de  la  Quantite  de  Vie  sur  le  Globe,  2enie  Edi- 
tion, Paris,  1855. 

Funke,  Dr.  Otto.  Atlas  der  Physiologisclien  Cliemie,  zugleich  als  Supplement  zu  C.  G. 
Lehmann's  Lehrbuclx  der  Physiologisclien  Chemie.  Funfzelm  Tafeln  enthaltend  90 
Abbildungen  siimmtlicli  nacli  dem  Mikroscop  gezeichnet  und  erlautert,  Leipzig, 
1853. 

,  See  Giinther. 

,  See  Wagner. 

Gavarret,  J.  Physique  Medicale.  De  la  Chaleur  produite  par  les  Etres  Vivants,  Avec 
41  figures  dans  le  Texte,  Paris,  1855. 

Gluge,  Dr.  Gottlieb.  Pathologische  Histologie.  Mit  12  Kupfertafeln  und  fabellen, 
Jena,  1850 ;  Translated,  under  the  Title,  Atlas  of  Pathological  Histology,  by  Dr. 
Gottlieb  Gluge,  &c.,  &c.,  from  the  German,  by  Joseph  Leidy,  M.  D.,  &c.  &c.,  Philad.j 
1853. 

Giinther,  Dr.  August  Friedrich.  Lehrbuch  der  Physiologie  des  Menschen  fiir  Aerzte 
und  Studirende.  Fortgesetzt  von  Dr.  Otto  Funke,  &c.  II  Band.  2,  3,  und  4 
Abtheilung,  Leipzig,  1853. 

Holland,  (Sir;  Henry,  M.  D.,  F.  R.  S.     Chapters  on  Mental  Physiology,  London,  1852. 

Jochman,  Dr.  Paul  Alex.,  Beobachtungen  tiber  die  Koi-perwarme  in  chronischen 
fieberhaften  Krankheiten.     Mit  zwei  lithograiihirten  Tafeln,  Berlin,  1853. 

Jones,  C.  Handfield,  M.  B.  F.  R.  S.,  and  Edward  H.  Sieveking,  M.  D.  A  Manual  of  Pa- 
thological Anatomy.  First  American  edition,  revised,  with  three  hundred  and  ninety- 
seven  Illustrations,  Philad.,  1854. 

Keber,  G.  A.  F.     De  Sjiermatozoorum  Introitu  in  Ovula,  Konigsberg,  1853. 

Kirkes,  W.  S.,  M.  D.,  and  Paget,  James,  F.  R.  S.  Manual  of  Physiology,  2d  Amer. 
edit.,  Philad.,  1853. 

Kitto,  John,  D.  D.,  F.  S.  A.  The  Lost  Senses.  Series  1.  Deafness,  London,  1853.  Series 
2.  Blindness,  London,  1845. 

Kobelt,  Dr,  De  I'Appareil  du  Sens  Genital  des  deux  Sexes  dans  I'Espece  Humaine  et 
dans  quelques  Mammiferes,  au  point  de  Vue  Anatomique  et  Physiologique.  Traduit 
de  I'AUemand  par  H.  Kaula,  D.  M.  Avec  cinq  Planches  lithographiees,  Strasbourg 
et  Paris,  1851. 

Kolliker,  Dr.  A.  Mikroskoi^ische  Anatomic  oder  Gewebelehre  des  Menschen,  2ter  Band., 
Leipzig,  1850-1854. 

,  Manual  of  Human  Histology,  translated  and  edited  by  George  Busk,  F. 

R.  S.,  and  Thomas  Huxley,  F.  R.  S.  Sydenham  Society's  edition,  2  vols.,  London, 
1853-1854.  American  edition  under  the  title.  Manual  of  Human  Microscopical 
Anatomy,  edited  with  notes  and  additions  by  J.  Da  Costa,  M.  D.,  illustrated  by 
three  hundred  and  thirteen  Engravings  on  wood,  Philad.,  1854. 

Lehmann,  Prof.  C.  G.  Lehrbuch  der  Physiologisclien  Chemie,  2te  giinzlich  neu  um- 
gearbeite  Auflage,3  Bd.  Leipz.,  1850-1852.  Translated  for  the  Cavendish  Society,  by 
Dr.  Geo.  E.  Day,  M.  D.,  F.  R.  S.  Amer.  edition  by  Prof.  R.  E.  Rogers,  M.  D.,  with 
Illustrations  selected  from  Funke's  Atlas  of  Physiological  Chemistry,  and  an  Appendix 
of  Plates,  2  vols,  Philad.,  1855. 

,  Handbuch  der  Physiologischen  Chemie,  Leipzig,  1854,  translated  under 


X  PREFACE. 

much  honor  to  his  efforts  to  be  useful.     His  crowning  desire,  in  all 
his  literary  undertakings  connected  with  his  profession,  has  been  to 

the  following  Title,  Manual  of  Cliemical  Physiology,  from   the    German   of   Prof. 

C.  G.  Lelimann,  M.  D.,  translated  with  notes  and  additions  by  J.  Cheston  Morris,  M.D., 

with  an  Introductory  Essay  ou  Vital  Force,  by  Samuel  Jackson,  M.  D.,  Professor  of 

Institutes  of  Medicine  in  the  University  of  Pennsylvania,  and  illustrated  with  forty 

Woodcuts,  Philad.,  1856. 
Liebig,  Justus  Von.     Familiar  Letters  on  Chemistry,  in  its  relations  to  Physiology, 

Dietetics,  Agriculture,  Commerce,  and  Political  Economy,  3d  edition,  revised  and 

miuch  enlarged,  London,  1851. 
Longet,  F.  A.     Traite  de  Physiologic,  Ouvrage  accompagne  de  figures  dans  le  teste  et 

de  planches  en  taille-douce,  Tom.  ler,  Fascicul.  3,  Paris,  1852. 
Ludwig,  C.     Lehrbuch  der  Physiologie  des  Meuschen,  Iste  Band,  Heidelberg,  1852- 

1853  ;  und  2ter  Band,  Iste  Abtheilung,  Leipzig  und  Heidelberg,  1855,  2te  Abth.  1856. 
Mialhe,  Dr.     Chemie  Appliquee  a  la  Physiologie  et  k  la  Therapeutique,  Paris,  1856. 
Moleschott,  Dr.  Jac.     Physiologie  des   Stoffswechsels   in  Pflanzen   und  Thieren,  ein 

Handbuch  fiir  Naturforscher,  Landwirthe,  und  Aerzte,  Erlangen,  1851. 
Moser,  Dr.  A.,  and  Dr.  J.  C.  Strahl.     Handbuch  der  Physiologischen  und  Pathologis- 

chen  Chemie,  nach  den  neusten  Quellen  bearbeitet,  Leipzig,  1851. 
Noble,  Daniel,  M.  D.,  Elements  of  Psychological  Medicine:  An  Introduction  to  the  Prac- 
tical Study  of  Insanity,  adapted  for  Students  and  Junior  Practitioners,  London,  1853. 
Oesterlen,  Dr.  Fr.     Handbuch  der  Hygieine  fiir  den  Einzelnen  wie  fiir  eine  Bevolke- 

rung,  Tubingen,  1851. 

Paget,  James,  F.  R.  S.  Lectures  on  Surgical  Pathology,  delivered  at  the  Eoyal  College 
of  Surgeons  of  England;  Hypertrophy,  Atrophy,  Repaii-,  Inflammation,  Mortification, 
Specific  Diseases,  and  Tumors,  Amer.  edit.,  Philad.,  1854. 

Prochaska.     See  Unzer  and  Prochaska. 

Robin,  Charles.     See  Atlee,  Walter  F. 

' ,  et  F.  Verdeil.     Traite  de  Chimie  Anatomique  et  Physiologique  Normale 

et  Pathologique  ou  des  Principes  Immediats  Normaux  et  Morbides  qui  constituent  le 
Coii^s  de  I'Homme  et  des  Mammiferes,  accompagne  d'un  Atlas  de  45  Planches  gra- 
vees,  en  partie  coloriees,  3  vols.,  Paris,  1853. 

Segond,  L.  A.  Traite  d'Anatomie  Generale :  Theorie  de  la  Structure,  embrassant  les 
Substances  Organiques  et  les  Elements,  les  Tissus,  les  Jlembraues  et  les  Parenchymes, 
Paris,  1854. 

Sieveking,  Edward  H.     See  Jones,  C.  Handfield. 

Strahl,  Dr.  J.  C.     See  Moser,  Dr.  A. 

Tardieu,  Ambroise.  Dictionnaire  d'Hygiene  Publique  et  de  Salubrite  ou  Repertoire  de 
toutes  les  Questions  relatives  a  la  Saute  Publique,  considerees  dans  leurs  Rapports 
avec  les  Substances,  les  Epidemies,  les  Professions,  les  Etablissements  et  Institutions 
d'Hygiene  et  de  Salubrite,  complete  par  le  Texte  des  Lois,  Decrets,  Arretes,  Ordounances 
et  Instructions  qui  s'y  rattacheut,  3  vols.,  Paris,  1852-1854. 

Thomas,  Dr.  E.     Die  Physiologie  des  Menschen,  Leipzig,  1853. 

Todd,  Robert  Bentley,  M.  D.,  F.  R.  S.,  and  Bowman,  Wm.,  F.  R.  S.  Tlie  Physiological 
Anatomy  and  Physiology  of  Man,  Pt.  iv..  Sect.  1,  London,  1852,  Amer.  edit.,  Philad., 
1853. 

Unzer  and  Prochaska.  Tlie  Principles  of  Physiology,  by  John  Augustus  Unzer,  and  A 
Dissertation  on  the  Functions  of  the  Nervous  System,  by  George  Prochaska,  trans- 
lated and  edited  by  Thomas  Laycock,  M.  D.  (Sydenham  Society's  edit.),  London,  1851. 


PREFACE.  XI 


facilitate  the  onward  course  of  those,  who  are  pressing  forward  for  dis- 
tinction in  a  truly  learned  and  difficult  avocation  ;  and  the  reception, 
which  his  undertakings  have  met  with,  has  abundantly  satisfied  him 
that  his  labours  have  been  far  from  fruitless. 


ROBLEY  DUNGLISOK 


IS  GiEAED  St. 
May,  1856. 


Wagner,  Rudolph.  Lelirbuch  der  Speciellen  Pliysiologie,  vierte  durchgehends  neu 
bearbeitete  Aiiflage,  von  Dr.  Otto  Funke  ;  also  under  tlie  title — Lelirbuch  der  Physi- 
ologic, von  Dr.  Otto  Funke,  Leipzig,  1854. 

Wedl,  Carl,  M.  D.  Rudiments  of  Pathological  Histology,  with  172  Illustrations  on 
wood,  translated  from  the  German,  and  edited  by  George  Busk,  F.  R.  S.  (Sydenham 
Society's  edition),  London,  1855. 

Wilson,  Erasmus,  F.  R.  S.  Healthy  Skin :  A  Popular  Treatise  on  the  Skin  and  Hnir, 
their  Preservation  and  Management,  2d  Amer.,  from  the  4th  and  revised  London  edi- 
tion, with  niustrations,  Philad.,  1854. 


CONTENTS  OF  YOL  I 


PRELIMINARY  OBSERVATIONS. 


Prolegomena. 

I.  Natural  Bodies     ..... 

1.  Difference  between  Inorganic  and  Organized  Bodies 

2,  Difference  between  Animals  and  Vegetables 

II.  General  Physiology  of  Man  ... 

1 .  Material  Composition  of  Man 

a.  Organic  Elements  that  contain  nitrogen 

b.  Organic  Elements  that  do  not  contain  Nitrogen 

c.  Of  tlie  Solid  parts  of  the  Human  Body  . 

d.  Of  the  Fluids  of  the  Human  Body 

e.  Physical  Properties  of  the  Tissues 

2.  Functions  of  Man        .... 


'33 
34 
39 
43 
43 
47 
53 
57 
62 
64 
69 


BOOK  I. 


NUTRITIVE  FUNCTIONS, 


Chap.  I. 


Chap.  II. 


Digestion    ..... 

73 

1.  Anatomy  of  the  Digestive  Organs 

.      73 

2.  Food  of  Man     .... 

106 

3.  Physiology  of  Digestion 

.     120 

4.  Digestion  of  Solid  Food 

121 

a.  Hunger         .... 

121 

b.  Prehension  of  Food 

127 

c.  Oral  or  Buccal  Digestion 

130 

d.  Deglutition .... 

135 

e.  Chymification 

139 

f.    Action  of  the  Small  Intestine 

176 

g.  Action  of  the  Large  Intestine 

185 

5.  Digestion  of  Liquids     . 

194 

6.  Of  Eructation,  Regurgitation,  and  Rumination 

197 

Absorption              .              .              .              .              . 

206 

I.  Digestive  Absorption  .             .             .             , 

207 

a.  Absorption  of  Chyle  or  Chylosis     . 

207 

1.  Anatomy  of  the  Chyliferous  Apparatus 

207 

2.  Chyle 

215 

3.  Physiology  of  Chylosis  . 

221 

b.  Absorption  of  Drinks 

230 

XIV 


CONTENTS. 


II.  Absorption  of  Lymph  or  Lympliosis   . 

1.  Anatomy  of  tlie  Lymphatic  Apparatus 

2.  Lymph         .... 

3.  Physiology  of  Lymphosis    . 

III.  Venous  Absorption 
1.  Physiology  of  Venous  Absorption  . 

IV.  Internal  Absoi-ption    . 
V.  Accidental  Absorption  .  . 

a.  Cutaneous  Absorption 

b.  Other  Accidental  Absorptions 
Chap.  III.  Respiration  .... 

1.  Anatomy  of  the  Respiratory  Organs  . 

2.  Atmospheric  Air 

3.  Physiology  of  Respiration     . 

a.  Mechanical  Phenomena  of  Respiration 
(1.)  Inspiration 
(2.)  Expiration 
(3.)  Respiratory  Phenomena  concerned  in  certain  Functions 
(4.)  Respiratory  Phenomena  connected  with  Expression 

b.  Chemical  Phenomena  of  Respiration 

c.  Cutaneous  Respiration,  &c. 

d.  Effects  of  Section  of  the  Cerebral  Nerves 

e.  Respiration  of  Animals 
Chap.  IV.    Circulation  .... 


on  Respiration 


Chap.  V. 
VI. 


1.  Anatomy  of  the  Circulatory  Organs  . 

a.  Heart  .... 

b.  Arteries      .... 

c.  Intermediate,  Peripheral  or  Capillary  System 

d.  Veins  .... 

2.  Blood  .... 

3.  Physiology  of  the  Circulation 

a.  Circulation  in  the  heart     . 

b.  Circulation  in  the  Arteries 

c.  Circulation  through  the  Capillaries 

d.  Circulation  in  the  Veins   . 

e.  Forces  that  Propel  the  Blood 

f.  Accelerating  and  Retarding  Forces 

g.  The  Pulse  .... 
h.  Uses  of  the  Circulation 
i.   Transfusion  and  Infusion  . 

4.  Circulatory  apparatus  in  animals 
Nutrition  ..... 
Secretion ..... 

1.  Anatomy  of  the  Secretory  Apparatus 

2.  Physiology  of  Secretion 
Exhalations,  or  Simple  Secretions 
A.  Internal  Exhalations  . 

1.  Areolar  Exhalation 

2.  Serous  Exhalation — General  and  Vascular 

a.  General 

b.  Vascular 

3.  Synovial  Exhalation 


CONTENTS. 


XV 


4.  Adipous  Exhalation  . 

a.  Fat 

b.  Marrow 

5.  Pigmental  Exhalation 

6.  Ca]3sular  Exhalation . 
B.  External  Exhalations 

1.  Exhalations  of  the  Skin  and  Mncous 

2.  Menstrual  Exhalation 

3.  Gaseous  Exhalation   . 
II.  Follicular  Secretions 

1.  Follicular  Secretion  of  Mucoits  Membranes 

2.  Follicular  Secretion  of  the  Skin 

3.  Secretion  of  the  Ovaries 

III.  Glandular  Secretions     . 

1.  Transpiratory  Secretion  of  the  Skin 

2.  Secretion  of  the  Lachrymal  Gland 

3.  Secretion  of  the  Salivary  Glands 

4.  Secretion  of  the  Pancreas 
6.  Secretion  of  the  Liver 

6.  Secretion  of  the  Kidneys 
a.  Connection  between  the  Stomach 

7.  Secretion  of  the  Testes 

8.  Secretion  of  the  Manimse 

IV.  Vascular  or  Ductless  Glands 

o.  The  Sj^leen 
Chap.  VII.    Calorification     . 


Membranes — Dermic 


and  the  Kidneys 


BOOK  II. 


ANIMAL  FUNCTIONS. 

Chap.  I.   Sensibility  .... 

1.  Nervous  System 

2.  Physiology  of  Sensibility 
a.  Sensations . 
a.  External  Sensations 

A.  Sense  of  Tact  or  Touch — Palpation 

1.  Anatomy  of  the  Skin,  Hair,  Nails,  &c 

2.  Physiology  of  Tact  and  Touch 
^     B.  Sense  of  Taste  or  Gustation 

1.  Anatomy  of  the  Organs  of  Taste 

2.  Savours 

3.  Physiology  of  Taste    . 
C.  Sense  of  Smell  or  Olfaction 

1.  Anatomy  of  tlie  Organ  of  Smell 

2.  Odours 

3.  Physiology  of  Olfaction 


LIST  OF  ILLUSTRATIONS  IN  VOL.  L 


FIG. 

1.  Endosmometer,  ...... 

2.  Diagram  of  the  stomach  and  intestines  to  show  their  course, 

3.  Skull  of  the  Polar  bear,  ..... 

4.  Skull  of  the  cow,        ...... 

5.  Salivary  glands  in  situ,  ..... 

6.  Cavity  of  the  mouth,  as  sliown  by  dividing  the  angles  and  turning  off  the 

lips,  ........ 

7.  Pharynx  seen  from  behind,  ...... 

8.  Longitudinal  section  of  oesophagus,  near  the  pharynx,  seen  on  its  inside, 

9.  Section  of  the  cesophagus,      ...... 

10.  A  view  of  the  muscles  of  the  tongue,  palate,  &c., 

11.  Stomach  seen  externally,       ...... 

12.  Vei'tical  and  longitudinal  section  of  stomach  and  duodenum, 

13.  Section  of  a  piece  of  stomach  not  far  from  pylorus, 

14.  A  portion  of  the  mucous  membrane  of  the  stomach,  after  Wilson, 

15.  Tubular  follicle  of  pig's  stomach,  after  Wasmann,    . 

16.  Peptic  gastric  gland,  after  Kolliker,  .... 

17.  Portions  of  one  of  the  cseca  more  highly  magnified,  after  Kolliker,  . 

18.  Mucous  gastric  gland,  with  cylinder  epithelium,  after  Kolliker, 

19.  Capillary  network  of  lining  membrane  of  stomach,  after  Kolliker,  . 

20.  Vertical  section  of  a  stomach  cell  with  its  tubes,  after  Todd  and  Bowman 

21.  Mucous  membrane  of  the  stomach,  Todd  and  Bowman, 

22.  Appearance  of  living  membrane  of  stomach  injected,  Carpenter,     . 

23.  Front  view  of  stomach,  distended  by  flatus,  with  peritoneal  coat  turned  off, 

24.  Distribution  of  the  glosso-pharyngeal,  pneumogastric  and  spinal  accessory 

nerves,  or  the  eighth  pair, 

25.  Stomach  of  the  ox,     ..... 

26.  Section  of  part  of  the  stomach  of  the  sheep,  Flourens, 

27.  Digestive  ajiparatus  of  common  fowl,  Edwards, 

28.  Gastric  apparatus  of  the  turkey, 

29.  Interior  of  the  gastric  apparatus  of  the  turkey, 

30.  Portion  of  the  stomach  and  duodenum  laid  open  to  show  their  interior, 

31.  Longitudinal  section  of  the  upper  part  of  the  jejunum  extended  under 

water,  ........ 

82.  Muscular  coat  of  the  ileum,  ...... 

33.  Distribution  of  capillaries  in  the  villi  of  the  intestine,  after  Berres, 

34.  Arrangement  of  capillaries  in  mucoiis  membrane  of  large  intestine,  after 

Todd  and  Bowman,  ....... 

VOL.  I.— 2 


PAGE 

G7 
74 
75 

76 
78 

79 
79 
79 
79 
80 
81 
82 
82 
83 
83 
84 
84 
84 
84 
85 
85 
86 
86 

87 
88 
89 
89 
90 
91 
93 

.^3 
94 
94 

94 


XVlll 


LIST   OF   ILLUSTKATIOXS, 


35.  Distribution  of  capillaries  around  follicles  of  mucous  membrane,  after 

Berres,        .........         94 

36.  Bloodvessels  of  villi  of  the  hare,  after  DoUiuger,      .  .  .  .95 

37.  One  of  the  glandule  majores  simplices  of  the  large  intestine,  as  seen  from 

above,  and  also  in  a  section,  after  Boelim,  .  .  .  .95 

38.  Vertical  section  of  the  mucous  membrane  of  the  duodenum  in  the  horse, 

after  Todd  and  Bowman,    .......         95 

39.  Portion  of  one  of  Brunner's  glands  from  the  human  duodenum,  after  Allen 

Thomson,   .........         96 

40.  Section  of  the  mucous  membrane  of  the  small  intestine  in  the  dog,  after 

Todd  and  Bowman,  .  .  .  .  .  .  .96 

41.  Transverse  section  of  Lieberkiihn's  tubes  or  follicles,  after  Todd  and  Bow- 

man, .........         97 

42.  Horizontal  section  through  the  middle  plane  of  three  Peyerian  glands,  after 

Kolliker,      .........         97 

43.  Vertical  section  of  two  of  the  Peyerian  glandulre,  after  Allen  Thompson,    .         98 

44.  A  patch  of  Peyer's  glands  of  the  adult  human  subject,  after  Boehm,  .         98 

45.  Section  of  small  intestine,  containing  some  of  the  glands  of  Peyer,  as  shown 

under  the  microscope,        .......         98 

46.  Side  view  of  intestinal  mucous  membrane  of  a  cat,  after  Bendz,      .  .         99 

47.  Vertical  section  through  a  patch  of  Peyer's  glands  in  the  dog,  after  Todd 

and  Bowman,  ........         99 

4S.  Muscular  coat  of  the  colon,  as  seen  after  the  removal  of  the  peritoneum,    .       101 

49.  Longitudinal  section  of  the  end  of  the  ileum,  and  of  the  beginning  of  the 

large  intestine,        ........       101 

50.  View  of  external  parietes  of  abdomen,  with  the  position  of  the  lines  drawn 

to  mark  off  its  regions,        .......       103 

51.  Reflections  of  the  peritoneum,  as  shown  in  a  vertical  section  of  the  body,         105 

52.  Action  of  the  lower  jaw  in  prehension,  .....       129 

53.  Gastric  glands  of  the  oesophagus  magnified  fifteen  times,  after  Sir  E.  Home,       159 

54.  Chyliferous  vessels,  ........       207 

55.  Chyliferous  apparatus,  .......       209 

56.  Section  of  intestinal  villus,  after  Gerlach,     ...•*.       210 

57.  Intestinal  villus  with  the  commencement  of  a  lacteal,  after  Krause,  .       210 

58.  Extremity  of  intestinal  villus,  after  Goodsir,  ....       211 

59.  Extremity  of  an  intestinal  villus  during  absorption,  after  Kijlliker,  .       211 

60.  Thoracic  duct,  after  Wilson,  .  .  .  .  .  .213 

61.  Diagram  of  a  lymphatic  gland,  showing  the  intra-glandular  network,  and 

the  transition  from  the  scale-like  epithelia  of  the  extra-glandular  lym- 
phatics, to  the  nucleated  cells  of  the  intra-glandular,  after  Goodsir,         .       213 

62.  Portion  of  the  intra-glandular  lymphatics,  showing  along  the  lower  edge 

the  thickness  of  the  germinal  membrane,  and  upon  it,  the  thick  layer  of 
glandular  epithelial  cells,  after  Goodsir,  .  .  .  .213 

63.  Section  of  lymphatic  gland,  after  Kolliker,    .....       214 

64.  Fluid  from  a  mesenteric  gland  of  a  rabbit  when  white  chyle  was  present  in 

the  lacteals,  after  Todd  and  Bowman,       .  .  .  .  .217 

65.  Chyle  corpuscles  in  various  phases,  after  Kolliker,  .  .  .       217 

66.  Villi  of  the  human  intestine,  with  their  capillary  plexus  injected,  after  Kol- 

liker, .........       230 

67.  Capillary  plexus  of  the  villi  of  the  human  small  intestine,  after  Todd  and 

Bowman,    .........       231 

68.  Vertical  section  of  the  coats  of  the  small  intestine  of  a  dog,  after  Todd  and 

Bowman,    .........       231 


LIST   OF   ILLUSTRATIONS. 


XIX 


FIG.  PAGE 

69.  Vessels  and  lymphatic  glands  of  axilla,        .....  238 

70.  Lymphatic  vessels  and  glands  of  the  groin  of  the  right  side,            .             .  239 

71.  Bloodvessels  and  lymphatics  from  the  tail  of  the  tadpole,    .             .             .  242 

72.  Lymphatic  glands  injected  with  mercury,  after  Mascagni,  .             .             .  243 

73.  Group  of  blood  vesicles  fi-om  the  thyroid  gland  of  a  child,  after  KoUiker,   .  243 

74.  Termination  of  thoracic  duct,              ......  249 

75.  Lymph  heart  of  python  bivittatus,  after  Weber,       ....  251 

76.  Anterior  view  of  thorax,         .......  269 

77.  Anterior  view  of  the  thoracic  viscera  in  situ,  as  shown  by  the  removal  of 

the  anterior  parietes  of  the  thorax,             .....  270 

78.  Posterior  view  of  the  thoracic  viscera,  showing  their  relative  positions  by 

the  removal  of  the  posterior  portion  of  the  parietes  of  the  thorax,             .  271 

79.  A  shaded  diagram,  representing  the  heart  and  great  vessels,  injected  and 

in  connexion  with  the  lungs  :  the  pericardium  is  removed,  after  Quain,  272 

80.  Arrangement  of  the  capillaries  of  the  air-cells  of  the  human  lung,  after 

Carpenter,               .             .             .             .             .             .             .             .  273 

81.  Air-cells  from  an  emphysematous  lung,  after  Leidy,             .             .             .  275 

82.  Transverse  section  of  a  portion  of  the  pulmonary  parenchyma,  after  Leidy,  276 

83.  Longitudinal  section  of  the  termination  of  a  bronchus,  after  Leidy,             .  276 

84.  Thin  slice  from  the  pleural  surface  of  a  cat's  lung,  after  Rossignol,              .  277 

85.  Bronchial  termination  in  the  lung  of  the  dog,  after  Rossignol,          .             .  277 

86.  Air-cells  of  human  lung,  with  intervening  tissues,  after  Kolliker,                 .  277 

87.  Outline  of  a  transverse  section  of  the  chest,  showing  the  relative  position 

of  the  pleurae  to  the  thorax  and  its  contents,         ....  279 

88.  The  changes  of  the  thoracic  and  abdominal  walls  of  the  male  during  respi- 

ration, after  Hutchinson,                 ......  287 

89.  The  respiratory  movements  in  the  female,  after  Hutchinson,             .             .  287 

90.  Small  bronchial  tube  laid  open,  after  Todd  and  Bowman,     .             .             .  290 

91.  Heart  of  the  dugong,               .......  331 

92.  Diagram  of  the  circulatory  apparatus  in  mammals  and  birds,  after  M.  Ed- 

wards,        .........  331 

93.  Heart  placed  with  its  anterior  surface  upwards,  and  its  apex  turned  to  the 

right  hand  of  the  spectator.     The  right  auricle  and  right  ventricle  are 

both  opened,  after  Quain,               ......  332 

94.  Semilunar  valves  closed,        .......  333 

95.  Diagram  of  the  semilunar  valves  of  the  aorta,  after  Morgagni,          .             .  333 

96.  Sections  of  aorta,  to  show  the  action  of  the  semilunar  valves,           .              .  334 

97.  Heart  seen  from  behind,  and  having  the  left  auricle  and  ventricle  opened, 

after  Quain,             ........  335 

98.  Anterior  view  of  external  muscular  lnyer  of  the  heart  after  removal  of  its 

serous  coat,  &c.,      .  .  .  .  .  .  .  .336 

99.  Posterior  view  of  the  same,                 ......  336 

100.  View  of  the  heart  in  situ,  after  Pennook,       .....  338 

101.  Circulation  in  the  web  of  the  frog's  foot,  after  Wagner,        .              .              .  344 

102.  Portion  of  the  web  of  the  frog's  foot,  after  Wagner,               .             .             .  345 

103.  Circulation  in  the  under  surface  of  the  tongue  of  the  frog,  after  Donne,      .  345 

104.  Capillary  network  of  nervous  centres,           .....  346 

105.  Cajjillary  network  of  fungiform  papilla  of  tongue,  after  Berres,         .             .  346 

106.  Capillaries  of  the  web  of  the  frog's  foot,  after  Wagner,         .             .             .  349 

107.  Splenic  vein  with  its  branches  and  ramifications,      ....  350 

108.  Diagrams  showing  valves  of  veins,  after  Quain,        ....  352 


XX 


LIST   OF    ILLUSTRATIONS. 


FIG. 

109. 
110. 
111. 
112. 
113. 
114. 
115. 
IIG. 

117. 

118. 

119. 

120. 
121. 
122. 

123. 
124. 
125. 
126. 
127. 
128. 
129. 
130. 
131. 
132. 
133. 

134. 

135. 
136. 
137. 
138. 

139. 

140. 


141. 
142. 
143. 

144. 

145. 
146. 


Roots,  trunk,  and  divisions  of  the  vena  jwrta. 

Portal  system,  after  Wilson,  ..... 

Red  corpuscles  of  liuman  blood,  after  Donne, 

Blood  corpuscles  of  rana  esculenta,  after  Wagner, 

Red  corpuscles  of  pigeon's  blood,  after  Todd  and  Bowman, 

Red  corpuscles  of  fishes,  after  Wharton  Jones, 

White  corpuscles  of  the  blood,  after  Paget, 

Developement  of  human  lymph  and  chyle  corpuscles  into  red  corpuscles  of 
blood,  after  Paget,  ...... 

Blood  crystals,  after  Otto  Funke,       ..... 

Coagulation  of  normal  human  blood  under  the  microscope,  after  Otto 
Funke,        ........ 

Aggregation  of  corpuscles  in  healthy  and  in  inflamed  blood,  after  T.  W 
Jones,  ........ 

Hsemadynamometer,  after  Poigeuille,  .... 

Section  of  a  forcing  pump,     ...... 

Small  venous  branch,  from  the  web  of  a  frog's  foot,  magnified  350  diame 
ters,  after  Wagner,  ...... 

Large  vein  of  frog's  foot,  magnified  600  diameters,  after  Wagner, 

Vena  contracta,  ....... 

Do.  do.  ....... 

Circulation  in  the  frog,  ...... 

Circulation  in  fishes,  ...... 

Interior  of  the  leech,  ...... 

Areolar  tissue,  after  Edwards,  ..... 

Muscular  tissue,  after  Edwards,         ..... 

Nei-vous  tissue,  after  Edwards,  ..... 

Cellules  of  brain,  after  Dutrochet,     ..... 

Primary  organic  cell,  showing  the  germinal  cell,  nucleus,  and  nucleolus 
after  Todd  and  Bowman,  ..... 

Plan  representing  the  formation  of  a  nucleus,  and  of  a  cell  on  the  nucleus 
according  to  Schleiden's  view,        ..... 

Endogenous  cell-growth  in  cells  of  a  meliceritous  tumour,  after  Goodsir, 

Tattooed  head  of  a  New  Zealand  chief,  .... 

Plan  of  secreting  membrane,  after  Sharpey  and  Quain, 

Plan  to  show  augmentation  of  surface  by  formation  of  processes,  after 
Sliarpey  and  Quain,  ...... 

Plans  of  extension  of  secreting  membrane  by  inversion  or  recession  in  form 
of  cavities,  after  Sharpey  and  Quain,       .... 

Portion  of  areolar  tissue  inflated  and  dried,  showing  the  general  character 
of  its  larger  meshes  ;  magnified  twenty  diameters,  after  Todd  and  Bow- 
man. ......... 

Arrangement  of  fibres  in  areolar  tissue,  magnified  135  diameters,  after  Car- 
penter,       ......... 

White  fibrous  tissue,  from  ligament,  magnified  65  diameters,  after  Car- 
penter,      ......... 

Yellow  fibrous  tissue,  from  ligamentum  nuchae  of  calf,  magnified  65  diame- 
ters, after  Carpenter,         ....... 

A  small  cluster  of  fat-cells,  magnified  150  diameters, 

Bloodvessels  of  fat  vesicles,  after  Todd  and  Bowman, 

Fat  vesicles  from  an  emaciated  subject,  alter  Todd  and  Bowman, 


485 

485 

486 

486 
490 
490 
492 


LIST   OF   ILLUSTRATIONS. 


XXI 


FIG. 

147.  Sebaceous  or  oil  glands  and  ceruminous  glands,  after  Wagner, 

148.  Cutaneous   follicles   or   glands   of  the   axilla,  magnified   one-third,  after 

Horner,       ........ 

149.  Entozoa  from  the  sebaceous  follicles,  after  Todd  and  Bowman, 

150.  Vertical  section  of  the  sole,  after  Todd  and  Bowman, 

151.  Vertical  section  of  epidermis  from  palm  of  the  hand,  after  Todd  and  Bow 

man,  ........ 

152.  Surface  of  the  skin  of  the  palm,  after  Todd  and  Bowman, 

153.  Lobules  of  the  parotid  gland,  in  the  embryo  of  the  sheep,  in  a  more  ad 

vanced  condition,  after  Miiller,      ..... 

154.  Distribution  of  capillaries  around  the  follicles  of  parotid  gland,  after  Berres, 

155.  Figure,  altered  from  Tiedemann,  in  which  the  liver   and  stomach   are 

turned  up  to  show  the  duodenum,  the  pancreas,  and  the  siJleen,  after 
Quain,         ........ 

156.  Lobules  of  liver,  after  Kiernan,  ..... 

157.  Connexion  of  lobules  of  liver  with  hepatic  vein,  after  Kiernan, 

158.  Transverse  section  of  lobules  of  the  liver,  after  Kiernan, 

159.  Horizontal  section  of  three  superficial  lobules,  showing  the  two  principal 

systems  of  bloodvessels,  after  Kiernan,     .... 

160.  Horizontal  section  of  two  superficial  lobules,  showing  interlobular  plexus 

of  biliary  ducts,  after  Kiernan,      ..... 

161.  A  small  portion  of  a  lobule  highly  magnified,  after  Leidy,   . 

162.  Portion  of  a  biliary  tube,  from  a  fresh  human  liver,  very  highly  magnified 

after  Leidy,  ....... 

163.  Transverse  section  of  a  lobule  of  tlie  human  liver,  after  Leidy, 

164.  Hepatic  cells  gorged  with  fat,  after  Bowman, 

165.  Minute  portal  and  hepatic  veins  and  capillaries,  after  Budd, 

166.  Diagram  of  the  arrangement  of  the  cellular  parenchyma  of  the  liver,  after 

Kijlliker,      ........ 

167.  Lobules  of  the  liver  magnified,  after  Budd,  .... 

168.  First  stage  of  hepatic  venous  congestion,  after  Kiernan, 

169.  Second  stage  of  hepatic  venous  congestion,  after  Kiernan,    . 

170.  Portal  venous  congestion,  after  Kiernan,       .... 

171.  The  three  coats  of  gall-bladder  separated  from  each  other,  . 

172.  Gall-bladder  distended  with  air,  and  with  its  vessels  injected, 

173.  Crystals  of  cholesterin,  &c.,  after  Otto  Funke, 

174.  Right  kidney  with  its  renal  capsule,  .... 

175.  Plan  of  a  longitudinal  section  of  the  kidney  and  upper  part  of  the  ureter, 

through  the  hilus,  copied  from  an  enlarged  model, 

176.  Portion  of  kidney  of  new-born  infant,  after  Wagner, 

177.  Small  portion  of  kidney  magnified  60  diameters,  after  Wagner, 

178.  Section  of  the  cortical  substance  of  the  human  kidney,  after  Ecker, 

1 79.  Tubuli  uriniferi,  after  Baly,  ...... 

180.  Plan  of  the  renal  circulation,  after  Bowman, 

181.  Part  of  the  ossa  pubis  and  ischia,  with  the  root  of  the  penis  attached,  after 

Kobelt,        ........ 

182    Section  of  the  spleen,  ...... 

183.  Branch  of  splenic  artery,  the  ramifications  studded  with  Mali^ighian  cor- 

puscles, after  KiJlliker,        ...... 

184.  Anterior  view  of  the  brain  and  spinal  marrow, 

185.  Falx  cerebri  and  sinuses  of  upper  and  back  part  of  skull, 


PAGE 

505 


xxu 


LIST   OF   ILLUSTRATIONS. 


FIG. 

186.  Longitudinal  section  of  the  brain  on  the  mesial  line, 

187.  Convolutions  of  one  side  of  the  cerebrum,  as  seen  from  above, 

188.  Superior  part  of  the  lateral  ventricles,  coi-pora  striata,  septum  lucidum, 

fornix,  &c.,  as  given  by  a  transverse  section  of  the  cerebrum, 

189.  Section  of  the  cerebrum,  displaying  the  surfaces  of  the  coqwra  striata,  and 

optic  thalami,  the  cavity  of  the  third  ventricle,  and  the  upper  surface  of 
the  cerebellum,       ....... 

190.  An  under  view  of  the  cerebellum,  seen  from  behind, 

191.  Posterior  superior  view  of  the  pons  Varolii,  cerebellum,  and  medulla  ob 

longata  and  M.  spinalis,     ...... 

192.  Analytical  diagram  of  the  encephalon — in  a  vertical  section,  after  Mayo, 

193.  Anterior  view  of  the  medulla  oblongata,  showing  the  decussation  of  the 

pyramids,  and  of  the  upper  part  of  the  spinal  cord,  after  Mayo, 
194  Posterior  view  of  the  medulla  oblongata,       .... 
]  95  Transverse  sections  of  the  spinal  cord,  Todd  and  Bowman, 
196  Shows  the  under  surface  or  base  of  the  encephalon  freed  from  its  mem 

branes,        ........ 

107    I 

-,qo    j  Pacinian  corpuscles,  after  Todd  and  Bowman,        .  . 

199.  Tactile  corpuscles  from  the  skin,  after  Ecker, 

200.  A  nerve  consisting  of  many  smaller  cords  or  funiculi  wrapped  up  in 

common  cellular  sheath,    ...... 

201.  A  portion  of  the  spinal  marrow,  showing  the  origin  of  some  of  the  sfnnal 

nerves,        ......... 

202.  Plans  in  outline,  showing  the  front  a,  and  the  sides  b,  of  the  spinal  cord, 

with  the  fissures  upon  it ;  also  sections  of  the  gray  and  white  matter, 
and  the  roots  of  the  spinal  nerves,  .  .  .  .  . 

203.  Pioots  of  a  dorsal  sjnnal  nerve,  and  its  union  with  sympathetic,  Todd  and 

Bowman,     ...... 

204.  Great  sympathetic  nerve,       .... 

205.  Structure  of  the  spinal  cord,  according  to  Stilling,    . 

206.  Transverse  section  of  the  medulla,  after  Stilling,     . 

207.  Tubular  nerve-fibres,  .... 

208.  Gelatinous  nerve-fibres,         .... 

209.  Ganglion  corpuscles,  after  Valentin, 

210.  Stellate  or  caudate  nerve-corpuscles,  after  Hannover, 

211.  Microscopic  ganglion  from  heart  of  frog,  after  Ecker, 

212.  Bipolar  ganglionic  cells,  &c.,  after  Ecker,      . 

213.  Connection  between  nerve-fibres  and  nerve-corpuscles, 

214.  Circle  of  Willis,  ..... 

215.  Sinuses  of  the  base  of  the  skull, 

216.  Capillary  network  of  nervous  centres,  after  Berres, 

217.  Distribution  of  capillaries  at  the  surface  of  the  skin  of  the  finger,  after 

Berres,         ••.... 

218.  Brain  of  squirrel,  laid  open,  after  Solly, 

219.  Brain  of  turtle,  after  Solly,    .... 
220-21.  Brains  of  fishes,  after  Leuret, 

222.  Vertical  section  of  epidermis,  from  the  palm  of  the  hand,  after  Wilson 

223.  Section  of  the  skin,   ..... 

224.  Papilla-  of  the  palm,  the  cuticle  being  detached,  magnified  35  diameters, 

225.  Sections  of  hair,         ..... 


PAGE 

631 
631 

632 


LIST    OF    ILLUSTKATIONS. 


XSlll 


FIG.  PAGE 

2-16.  Thin  layer  from  tlie  scalp,      .......  G81 

227.  Magnified  view  of  the  root  of  the  hair,  Kohlrausch,  .  .  .  681 

228.  Section  of  the  skin  on  the  end  of  the  finger,  Todd  and  Bowman,     .  .  684 

229.  Transverse  section  of  a  finger-nail,  after  Wilson,      ....  684 

230.  A.  Separated  epithelium  cells  from  mucous  membrane  of  the  mouth,     b. 

Pavement-epithelium  of  the  mucous  membrane  of  the  smaller  bronchial 

tubes,  .........  685 

231.  Tesselated  epithelium,  .......  686 

232.  Scales  of  tesselated  epithelium,  after  Henle,  ....  687 

233.  Cylinders  of  intestinal  epithelium,  after  Henle,        ....  687 

234.  Hand  of  man  compared  with  anterior  extremity  of  orang,  after  Gervais,  693 

235.  Capillary  network  at  margin  of  lips,  after  Berres,    ....  694 

236.  Front  view  of  the  upper  surface  of  the  tongue,  as  well  as  of  the  palatine 

arch,  Wilson,  ........       699 

237.  View  of  a  papilla  of  the  smallest  class,  magnified  25  diameters,  Todd  and 

Bowman,    .........       699 

238.  Vei'tical  section  of  one  of  the  gustatory  papilL-e  of  the  largest  class,  show- 

ing its  conical  form,  its  sides,  and  the  fissure  between  the   diflerent 
papillas,  Todd  and  Bowman,  ......       700 

239.  The  hypoglossal  ;  lingual  branch  of  fifth  pair ;  glosso-pharyngeal  and  deep- 

seated  nerves  of  the  neck,  ......       700 

240.  Vertical  section  of  the  middle  part  of  the  nasal  fossae,  giving  a  posterior 

view  of  the  arrangement  of  the  ethmoidal  cells,  &c.,         .  .  .       713 

241.  Outer  wall  of  the  nasal  fossfe  with  the  three  spongy  bones  and  meatus, 

after  Sommering,   .  .  .  .  .  .  .  .714 

242.  Nerves  of  the  septum  of  the  nose,  after  Arnold,         ....       714 

243.  A  portion  of  the  pituitary  membrane  of  the  nasal  septum,  magnified  9  times, 

showing  the  number,  size,  and  arrangement  of  the  mucous  crypts,  .       715 

244.  A  portion  of  the  pituitary  membrane,  with  its  arteries  and  veins  injected, 

magnified  15  diameters,     .......       715 

245.  Olfactory  filaments  of  the  dog,  Todd  and  Bowman,  .  .  .       715 


HUMAN 
PHYSIOLOGY. 


PROLEGOMENA. 


I.  NATURAL  BODIES. 


The  extensive  domain  of  Nature  is  divisible  into  tliree  great  classes : 
— Minerals^  Vegetables,  and  Anviaals.  This  division  was  universally 
adopted  by  the  ancients,  and  still  prevails,  especially  amongst  the 
unscientific.  When,  however,  we  carefully  examine  their  respective 
characteristics,  we  discover,  that  the  animal  and  the  vegetable  resemble 
each  other  in  many  essential  particulars.  This  resemblance  has  given 
occasion  to  the  partition  of  all  bodies  into  two  classes :  the  Inorganic, 
or  those  not  possessing  organs  or  instruments  adapted  for  the  perform- 
ance of  special  actions  or  functions,  and  the  Organized,  or  such  as 
possess  this  arrangement. 

In  all  ages,  philosophers  have  attempted  to  point  out  a 

"  Vast  chain  of  being,  which  from  God  began, 
Nature's  ethereal,  human,  angel,  man. 
Beast,  bird,  fish,  insect,  what  no  eye  can  see, 
No  glass  can  reach — " 

the  links  of  which  chain  they  have  considered  to  be  constituted  of  all 
natural  bodies;  passing  by  insensible  gradations  through  the  inorganic 
and  the  organized,  and  forming  a  rigid  and  unbroken  series ;  and  in 
which,  they  have  conceived, 

" Each  moss, 

Each  shell,  each  crawling  insect,  holds  a  rank, 
Important  in  the  plan  of  Him  wlio  framed 
This  scale  of  beings — holds  a  rank  which,  lost, 
Would  break  the  chain,  and  leave  behind  a  gap 
Which  Nature's  self  would  rue." 

Crystallization  has  been  esteemed  by  them  as  the  highest  link  of  the 
inorganic  kingdom ;  the  lichen,  which  encrusts  the  stone,  as  but  one 
link  higher  than  the  stone  itself;  the  mushroom  and  the  coral  as  the 
connecting  links  between  the  vegetable  and  the  animal ;  and  the  im- 
mense space,  which  separates  man — the  highest  of  the  mammalia — 
from  his  Maker,  they  have  conceived  to  be  occupied  in  succession  by 
beings  of  gradually  increasing  intelligence.  If,  however,  we  investi- 
gate the  matter  minutely,  we  discover  that  many  links  of  the  chain 
appear  widely  separated  from  each  other;  and  that,  in  the  existing 
VOL.  I. — 3 


34:  NATURAL   BODIES. 

State  of  our  knowledge,  the  catenation  cannot  be  esteemed  rigidly 
maintained.'  Let  us  inquire  into  the  great  characteristics  of  the  dif- 
ferent kingdoms,  and  endeavour  to  describe  the  chief  points  in  which 
living  bodies  differ  from  those  that  have  never  possessed  vitality,  and 
into  the  distinctions  between  organized  bodies  themselves. 

1.   DIFFERENCE  BETWEEN  INORGANIC  AND  ORGANIZED  BODIES. 

Inorganic  bodies  possess  the  common  properties  of  matter.  Their 
elements  are  fixed  under  ordinary  circumstances.  Their  study  con- 
stitutes Physics,  in  its  enlarged  sense,  or  Natural  Science.  Organized 
bodies  have  properties  in  common  with  inorganic,  but  they  have  like- 
wise others  superadded,  which  control  the  first  in  a  singular  manner. 
They  are  beings,  whose  elements  are  undergoing  constant  mutation, 
and  the  sciences  treating  of  their  structure  and  functions  are  Anatomy 
and  Physiology. 

They  differ  from  each  other  in — 

1.  Origin. — Inorganic  bodies  are  not  born :  they  do  not  arise  from  a 
parent :  they  spring  from  the  general  forces  of  matter, — the  particles 
being  merely  in  a  state  of  aggregation,  and  their  motions  regulated  by 
certain  fixed  and  invariable  laws.  The  animal  and  the  vegetable,  on 
the  other  hand,  are  products  of  generation ;  they  must  spring  from 
beings  similar  to  themselves:  and  they  possess  the  force  of  life,  which 
controls  the  ordinary  forces  of  matter.  Yet  it  has  been  supposed,  that 
they  are  capable  of  creating  life;  in  other  words,  that  a  particular 
organization  presupposes  life.  This  is  not  the  place  for  entering  into 
the  question  of  generation.  It  will  be  sufficient  at  present  to  remark, 
that  in  the  upper  classes  of  animals,  the  necessity  of  a  parent  cannot 
be  contested ;  the  only  difficulty  that  can  possibly  arise  regards  the 
very  lowest  classes ;  and  analogy  warrants  the  conclusion,  that  every 
living  being  must  spring  from  an  egg  or  a  seed. 

2.  Sliape. — The  shape  of  inorganic  bodies  is  not  fixed  in  a  deter- 
minate manner.  It  is  true,  that  by  proper  management  every  mineral 
can  be  reduced  to  a  primitive  nucleus,  which  is  the  same  in  all  minerals 
of  like  composition  ;  still,  the  shape  of  the  mineral,  as  it  presents  itself 
to  us,  differs.  Carbonate  of  lime,  for  example,  although  it  may  always 
be  reduced  to  the  same  primitive  nucleus,  assumes  various  appear- 
ances ; — being  sometimes  rhoraboidal ;  at  others,  in  regular  hexahedral 
})risms; — in  solids,  terminated  by  twelve  scalene  triangles,  or  in  dode- 
cahedrons, whose  surfaces  are  pentagons.  In  organized  bodies,  on  the 
contrary,  the  shape  is  constant.  Each  animal  and  vegetable  has  the 
one  that  characterizes  its  species,  so  that  no  possible  mistake  can  be 
indulged ;  and  this  applies  not  only  to  the  whole  body,  but  to  every 
one  of  its  parts,  numerous  as  they  are. 

3.  Size. — The  size  of  an  inorganic  body  is  by  no  means  fixed.  It 
may  be  great,  or  small,  according  to  the  quantity  present  of  the  parti- 
cles that  have  to  form  it.  A  crystal,  for  example,  may  be  minute,  or 
the  contrary,  according  to  the  number  of  saline  particles  in  the  solu- 
tion. On  the  other  hand,  organized  bodies  attain  a  certain  size, — at 
times  by  a  slow,  at  others  by  a  more  rapid  growth, — but  in  all  cases 

'  Fleming's  Philosophy  of  Zoology,  i.  4.     Edinburgh,  1822. 


INORGANIC   AND   ORGANIZED.  35 

tlie  due  proportion  is  preserved  between  the  various  parts, — between 
the  stem  and  the  root,  the  limb  and  the  trunk.  Each  vegetable  and 
each  animal  has  its  own  size,  by  which  it  is  known;  and  although  we 
occasionally  meet  with  dwarf  or  gigantic  varieties,  these  are  unfre- 
quent,  and  mere  exceptions  establishing  the  position. 

4.  Chendcal  character. — Great  difference  exists  between  inorganic 
and  organized  bodies  in  this  respect.  In  the  mineral  kingdom  are 
found  all  the  elementary  substances,  or  those  which  chemistry,  at 
present,  considers  simph ;  amounting  to  at  least  sixty-two.  They  are 
as  follows : — Noyi-metullic  ladies.  Oxygen,  hydrogen,  nitrogen,  sulphur, 
selenium,  phosphorus,  chlorine,  iodine,  bromine,  fluorine,  carbon,  boron, 
silicon.  Metals.  Potassium,  sodium,  lithium,  calcium,  magnesium, 
barium,  strontium,  aluminium,  glucinium,  zirconium,  yttrium,  thorium, 
iron,  manganese,  zinc,  cadmium,  lead,  tin,  copper,  bismuth,  mercury, 
silver,  gold,  platinum,  rhodium,  palladium,  osmium,  iridium,  nickel, 
cobalt,  uranium,  cerium,  antimony,  arsenic,  chromium,  molybdenum, 
tungsten,  columbium,  tellurium,  titanium,  vanadium,  lautanium,  didy- 
mium,  erbium,  terbium,  niobium,  ruthenium,  norium,  ilmenium, 
aridium  (?),  and  donarium  (?).  In  the  organized,  a  few  only  of  these 
elements  of  matter  are  met  with,  viz.,  oxygen,  hydrogen,  nitrogen, 
and  carbon,  which  are  always  present;  and  sulphur,  phosphorus,  chlo- 
rine, iodine,  bromine,  fluorine,  potassium,  sodium,  calcium,  magnesium, 
silicon,  aluminium,  iron,  manganese,  titanium,  and  arsenic,  which  are 
usually  in  small  proportion. 

The  composition  of  inorganic  bodies  is  more  simple :  several  con- 
sist of  but  one  element ;  and,  when  composed  of  more,  the  combina- 
tion is  rarely  higher  than  ternary.  Organized  bodies,  on  the  other 
hand,  are  never  simple,  nor  even  binary.  They  are  always  at  least 
ternary  or  quaternary.  The  simplest  vegetable  consists  of  a  union  of 
oxygen,  carbon,  and  hydrogen ;  the  simplest  animal,  of  oxygen, 
hydrogen,  carbon,  and  nitrogen. 

The  composition  of  the  mineral,  again,  is  constant.  Its  elements 
have  entirely  satisfied  their  affinities  ;  and  all  remains  at  rest.  In  the 
organized  kingdom,  the  affinities  are  not  satisfied  ;  compounds  are 
formed  to  be  again  decomposed,  and  this  happens  from  the  earliest 
period  of  foetal  formation  till  the  cessation  of  life ;  all  is  in  commo- 
tion, and  the  chemical  character  of  the  corporeal  fabric  is  incessantly 
undergoing  modification.  This  applies  to  every  organized  body;  and, 
accordingly,  change  of  some  kind  is  essential  to  our  idea  of  active 
life.  In  the  case  of  the  seed,  which  has  remained  unaltered  for  cen- 
turies, and  subsequently  vegetates  under  favorable  circumstances,  life 
may  be  considered  to  be  dormant  or  suspended.  It  possesses  vitality, 
or  the  power  of  being  excited  to  active  life  under  favoring  influences. 

In  chemical  nomenclature,  the  term  element  has  a  different  accepta- 
tion, according  as  it  is  applied  to  inorganic  or  organic  chemistry.  In 
the  former,  it  means  a  substance,  whicli,  in  the  present  state  of  science, 
does  not  admit  of  decomposition.  We  say,  "  in  the  present  state  of 
the  science,"  for  several  bodies,  now  esteemed  compound,  were,  not 
many  years  ago,  classed  amongst  the  simple  or  elementary.  It  is  not 
much  more  than  forty  years  since  the  alkalies  were  found  to  be  com- 
posed of  two  elements.     Previously,  they  were  considered  simple.     In 


36  NATURAL   BODIES. 

the  animal  and  the  vegetable,  we  find  substances,  also  called  elements, 
but  with  the  epithet  organic  prefixed,  because  they  are  only  found  in 
organized  bodies;  and  are  therefore  the  exclusive  products  of  organi- 
zation and  life.  For  example,  in  both  animals  and  vegetables  we  meet 
with  oxygen,  hydrogen,  carbon,  nitrogen,  and  diSerent  metallic  sub- 
stances :  these  are  chemical  or  inorganic  elements.  We  further  meet 
with  albumen,  gelatin,  fibrin,  casein,  &c.,  substances  which  constitute 
the  various  organs,  and  have,  therefore,  been  termed  organic  elements 
or  compowub  of  organization ;  yet  they  are  capable  of  decomposition ; 
and  in  one  sense,  therefore,  not  elementary. 

In  the  inorganic  body,  all  the  elements  that  constitute  it  are  formed 
by  the  agency  of  general  chemical  affinities ;  but,  in  the  organized, 
the  formation  is  produced  by  the  force  that  presides  over  the  formation 
of  the  organic  elements  themselves — the  force  of  life.  Hence,  the 
chemist  is  able  to  recompose  many  inorganic  bodies  ;  whilst  the  pro- 
ducts of  organization  and  life  set  his  art  at  defiance. 

The  different  parts  of  an  inorganic  body  enjoy  an  existence  inde- 
pendent of  each  other ;  whilst  those  of  the  organized  are  materially 
dependent.  No  part  can,  indeed,  be  injured  without  the  mass  and  the 
separated  portion  being  more  or  less  affected.  If  Ave  take  a  piece  of 
marble,  which  is  composed  of  carbonic  acid  and  lime,  and  break  it 
into  a  thousand  fragments,  each  portion  will  be  found  to  consist  of 
carbonic  acid  and  lime.  The  mass  will  be  destroyed;  but  the  pieces 
will  not  suffer  from  the  disjunction.  They  will  continue  as  fixed  and 
unmodified  as  at  first.  Not  so  with  an  organized  body.  If  we  tear 
the  branch  from  a  tree,  the  stem  itself  participates  more  or  less  in  the 
injury;  the  detached  branch  speedily  undergoes  striking  changes;  it 
withers ;  becomes  shrivelled ;  and,  in  the  case  of  the  succulent  vege- 
table, undergoes  decomposition ;  certain  of  its  constituents,  no  longer 
lield  in  control  by  vital  agency,  enter  into  new  combinations,  are  given 
off"  in  the  form  of  gas,  and  the  remainder  sinks  to  earth. 

Changes,  no  less  impressive,  occur  in  the  animal  when  a  limb  is 
separated  from  the  body.  The  parent  trunk  suffers ;  the  system  recoils 
at  the  first  infiiction  of  the  injury,  but  subsequently  arouses  itself  to  a 
re])aratory  effort— at  times  with  such  energy  as  to  destroy  its  own 
vitality.  The  separated  limb,  like  the  branch,  is  given  up,  uncontrolled, 
to  new  affinities  ;  and  putrefaction  soon  reduces  the  mass  to  a  state  in 
which  its  previously  admirable  organization  is  no  longer  perceptible. 
Some  of  the  lower  classes  of  animals  may,  indeed,  be  divided  with 
im|)unity ;  and  with  no  other  effect  than  that  of  multiplying  the  ani- 
mal in  proportion  to  the  number  of  sections;  but  these  cases  are  ex- 
ceptions ;  and  we  may  regard  the  destructive  process— set  up  when 
parts  of  organized  bodies  are  separated— as  one  of  the  best  modes  of 
distinction  between  the  inorganic  and  the  organized  classes. 

5.  Textnre. — In  this  respect  the  inorganic  and  the  organized  differ 
considerably— a  difference  which  has  given  rise  to  their  respective  ap- 
pellations. To  the  structure  of  the  latter  class  only  can  the  term  texture 
be  with  propriety  applied.  If  we  examine  a  vegetable  or  animal  sub- 
stance with  attention,  we  find  that  it  has  a  regular  and  determinate 
arrangement  or  structure ;  and  readily  discover  that  it  consists  of  va- 
rious parts ;— in  the  vegetable,  of  wood,  bark,  leaves,  roots,  flowers, 


INORGANIC   AND   ORGANIZED.  37 

Sec. ;  and  in  the  animal,  of  muscles,  nerves,  vessels,  &c. ;  all  of  whicli 
appear  to  be  instruments  or  orrjansfov  special  purposes  in  the  economy. 
Hence,  tlie  body  is  said  to  be  organized,  and  the  result,  as  well  as  the 
process,  is  often  called  organization.  Properly,  organization  means  the 
process  by  which  an  organized  being  is  formed  ;  organism,  the  result 
of  such  process,  or  organic  structure. 

The  particles  of  matter  in  an  organized  body,  in  many  instances, 
constitute  fibres,  which  interlace  and  intersect  each  other  in  all  direc- 
tions, and  form  a  spongy  areolar  texture  or  tissue,  of  which  the  various 
organs  of  the  body  are  composed.  These  fibres,  and  indeed  every 
organized  structure,  are  considered  by  modern  histologists  to  be  formed 
originally  from  cellgerms  or  cytoblasts :  the  resulting  cells  assuming 
an  arrangement  appropriate  to  the  particular  tissue.  "A  texture," 
says  Mr.  Goodsir,'  "may  be  considered  either  by  itself,  or  in  connexion 
with  the  parts  which  usually  accompany  it.  These  subsidiary  parts 
may  be  entirely  removed  without  interfering  with  the  anatomical 
constitution  of  the  texture.  It  is  essentially  non-vascular; — neither 
vessels  nor  nerves  entering  into  its  intimate  structure.  It  possesses 
in  itself  those  powers  by  which  it  is  nourished,  produces  its  kind,  and 
performs  the  actions  for  which  it  is  destined,  the  subsidiary  or  super- 
added parts  supplying  it  with  materials,  which  it  appropriates  by  its 
own  inherent  powers,  or  connecting  it  in  sympathetic  and  harmonious 
action  with  other  parts  of  the  organism  to  which  it  belongs.  In  none 
of  the  textures  are  these  characters  more  distinctly  seen  than  in  the 
osseous.  A  well-macerated  bone  is  one  of  the  most  easily  made,  and 
at  the  same  time  one  of  the  most  curious  of  anatomical  preparations. 
It  is  a  perfect  example  of  a  texture  completely  isolated ;  the  vessels, 
nerves,  membranes,  and  fat,  are  all  separated;  and  nothing  is  left  but 
the  non-vascular  osseous  substance." 

In  the  inorganic  substance  the  mass  is  homogeneous ;  the  smallest 
particle  of  marble  consists  of  carbonic  acid  and  lime ;  and  all  the  par- 
ticles concur  alike  in  its  formation  and  preservation. 

Lastly,  while  an  inorganic  body,  of  a  determinate  species,  has  always 
a  fixed  composition,  the  living  being,  although  constituting  a  particular 
species,  may  present  individual  differences,  which  give  rise,  in  the  ani- 
mal, to  various  tempei-aments,  constitutions,  &c. 

6.  Mode  of  preservation. — Preservation  of  the  species  is,  in  organized 
bodies,  the  effect  of  reproduction.  As  regards  individual  preservation, 
that  of  the  mineral  is  dependent  upon  the  same  actions  that  eftected 
its  formation;  on  the  persistence  of  the  affinities  of  cohesion  and  com- 
bination that  united  its  various  particles.  The  animal  and  the  vege- 
table, on  the  other  hand,  are  maintained  by  a  mechanism  peculiar  to 
themselves.  From  the  bodies  surrounding  them  they  lay  hold  of  nu- 
tritious matter,  which,  by  a  process  of  elaboration,  they  assimilate  to 
their  own  composition ;  at  the  same  time,  they  are  constantly  absorbing 
or  taking  up  particles  of  their  own  structure,  and  throwing  them  off. 
The  actions  of  composition  and  decomposition  are  constant  whilst  life 

'  Anatomical  and  Pathological  Observations,  p.  64,  Edinburgh,  1845.  See  also 
Schwann,  Microscopical  Researches  into  the  Accordance  in  the  Structure  and  Growth 
of  Animals  and  Plants  ;  translated  by  Henry  Smith.  Sydenham  Society  edit.  Loud. 
1847. 

'      S550V 


38  NATURAL   BODIES. 

persists ;  althougli  subject  to  particular  modifications  at  different  pe- 
riods of  existence,  and  under  different  circumstances. 

Again : — the  inorganic  and  organized  are  alike  subject  to  changes 
during  their  existence;  but  the  character  of  these  changes,  in  the  two 
classes,  differs  essentially.  The  mineral  retains  its  form,  unless  acted 
upon  by  some  mechanical  or  chemical  force.  Within,  all  the  particles 
are  at  rest,  and  no  internal  force  exists,  which  can  subject  them  to 
modification.  There  is  no  succession  of  conditions  tliat  can  be  termed 
ages.  How  different  is  the  case  with  organized  bodies!  Internally, 
there  is  no  rest ;  from  birth  till  death  all  is  in  a  state  of  activity.  The 
plant  and  the  animal  are  subject  to  incessant  changes.  Each  runs 
through  a  succession  of  conditions  or  ages.  We  see  it  successively  de- 
velope  its  structure  and  functions,  attain  maturity,  and  finall}''  decay. 

Characteristic  differences  likewise  exist  in  the  external  conformation 
of  the  beings  of  the  two  divisions,  as  well  as  in  their  mode  of  increase. 
Inorganic  bodies  have  no  covering  to  defend  them ;  no  exterior  enve- 
lope to  preserve  their  form ;  a  stone  is  the  same  at  its  centre  as  at  its 
circumference ;  whilst  organized  bodies  are  protected  by  an  elastic  and 
extensible  covering,  differing  from  the  parts  beneath,  and  iuservient  to 
valuable  purposes  in  the  economy. 

Every  change  to  which  an  inorganic  body  is  liable  must  occur  at 
its  surface.  It  is  there  that  the  particles  are  added  or  abstracted  when 
it  experiences  increase  or  diminution.  Increase — for  growth  it  can 
scarcely  be  termed — takes  place  by  accretion  or  juxtaposition^  that  is, 
by  the  successive  application  of  fresh  particles  upon  those  that  form 
the  nucleus ;  and  diminution  in  bulk  is  produced  by  the  removal  of 
the  external  layers  or  particles.  In  organized  substances,  increase  or 
growth  is  caused  by  particles  deposited  internally,  and  diminution  by 
particles  subtracted  from  within.  We  see  them,  likewise,  under  two 
conditions,  to  which  there  is  nothing  similar  in  the  mineral  kingdom — 
healthy  and  disease.  In  the  former,  the  functions  are  executed  with 
freedom  and  energy ;  in  the  latter,  with  oppression  and  restraint. 

7.  Termination. — Every  bod}-,  inorganic  or  organized,  may  cease  to 
exist,  but  the  mode  of  cessation  varies  greatly  in  the  two  classes.  The 
mineral  is  broken  down  by  mechanical  violence ;  or  it  ceases  to  exist 
in  consequence  of  modifications  in  the  affinities,  which  held  it  concrete. 
It  has  no  fixed  duration ;  and  its  existence  may  be  terminated  at  any 
moment,  when  the  circumstances,  that  retained  it  in  aggregation,  are 
destroyed.  The  vegetable  and  the  animal,  on  the  other  hand,  carry 
on  their  functions  for  a  period  only  which  is  fixed  and  determinate  for 
each  species.  For  a  time,  new  particles  are  deposited  internally.  The 
bulk  is  augmented,  and  the  external  envelope  distended,  until  maturity 
or  full  developement  is  attained ;  but,  after  this,  decay  commences ;  the 
functions^  are  exerted  with  gradually  diminishing  energy ;  the  fluids 
decrease  in  quantity;  and  the  solids  become  more  rigid — circumstances 
premonitory  of  the  cessation  of  vitality.  This  term  of  duration  is 
different  in  different  species.  Whilst  many  of  the  lower  classes  of 
animals  and  vegetables  have  but  an  ephemeral  existence,  some  of  the 
more  elevated  individuals  of  the  two  kingdoms  outlive  a  century. 

8.  Motive  forces. — Lastly,  observation  has  satisfactorily  proved,  that 
there  are  certain  forces,  which  affect  matter  in  general,  inorganic  as  well 


ANIMALS   AND   VEGETABLES.  89 

as  organized;  and  tliat,  in  addition  to  these,  organized  bodies  possess  a 
peculiar  force  or  forces,  which  modify  them  in  a  remarkable  manner. 
Hence,  we  have  general  forces  ;  and  special  or  vital;  the  first  acting  upon 
all  matter,  the  dead  and  the  living,  and  including  the  forces  of  gravi- 
tation, cohesion,  cJtemical  affinity,  &c. ;  the  latter  appertaining  exclusively 
to  liviug  beings. 

Such  are  the  chief  distinctions  to  be  drawn  between  the  two  great 
divisions  of  natural  bodies;  the  inorganic  and  the  organized.  By  the 
comparison  which  has  been  instituted,  the  objects  of  physiology  have 
been  indicated.  To  inquire  into  the  mode  in  which  a  living  being  is 
lorn,  nourished,  reproduced,  and  dies,  is  the  legitimate  object  of  the  science. 
We  have,  however,  entered  only  into  a  comparison  between  the  inor- 
ganic and  the  organized.  The  two  divisions  constituting  the  latter  class 
difter  also  materially  from  each  other.  Into  these  difi'erences  we  shall 
now  inquire. 

2.   DIFFEEENCE  BETWEEN  ANIMALS  AND  VEGETABLES. 

The  distinctions  between  the  divisions  of  organized  bodies  are  not 
so  rigidly  fixed,  or  so  readily  appreciated,  as  those  between  the  inor- 
ganic and  the  organized.  There  are  certain  functions  possessed  by 
both ;  hence  called  vegetative,  'plastic,  or  organic, — nutrition  and  repro- 
duction, for  example;  but  vegetables  are  endowed  with  these  only. 
All  organized  bodies  must  have  the  power  of  assimilating  foreign  mat- 
ters to  their  own  substance,  and  of  producing  a  living  being  similar  to 
themselves;  otherwise,  the  species,  having  a  limited  duration,  would 
perish.  In  addition  to  these  common  functions,  animals  have  sensation 
and  voluntary  motion ;  by  the  possession  of  which  they  are  said  to  be 
animated.  Hence,  they  are  termed  animals,  and  the  condition  is  called 
animality.  This  division  of  the  functions  into  animal  and  organic  has 
been  adopted,  with  more  or  less  modification,  by  most  physiologists. 

Between  animals  and  vegetables,  situate  high  in  their  respective 
scales,  no  confusion  can  exist.  The  characters  are  obvious  at  sight. 
No  one  can  confound  the  horse  with  the  oak;  the  butterfly  with  the 
potato.  It  is  on  the  lower  confines  of  the  two  kingdoms  that  we  are 
liable  to  be  deceived.  Many  of  the  zoophytes  have  alternately  been 
considered  vegetable  and  animal;  *but  we  are  generally  able  to  classify 
any  doubtful  substance  with  accuracy ;  and  the  following  are  the  prin- 
cipal points  of  difference. 

1.  Composition. — It  was  long  supposed,  that  the  essential  difference 
between  animal  and  vegetable  substances  consists  in  the  former  con- 
taining nitrogen;  whilst  the  latter  do  not.'  Modern  researches  have, 
however,  satisfactorily  shown,  that  the  organized  portions  of  animals 
and  vegetables  are  essentially  alike ;  and  consist  of  the  four  elements, 
— carbon,  oxygen,  hydrogen,  and  nitrogen ;  whilst  the  unorganized — 
as  the  fat  of  the  animal,  and  the  starch  of  the  vegetable — are  composed 
of  three  elements  only — carbon,  oxygen,  and  hj'-drogen.  Still,  their 
intimate  composition  must  vary  greatly;  for,  when  burning,  the  animal 
substance  is  readily  known  from  the  vegetable; — a  fact,  which,  as  Dr. 
Fleming^  has  remarked,  is  interesting  to  the  young  naturalist,  if  uncer- 

'  Braehet  still  adheres  to  this  distinction.  Pliysiologie  Llemeutaire  de  I'llomme, 
2de  edit.,  i.  21.     Paris  et  Lj'on,  185.5. 

2  Philosophy  of  Zoology,  i.  41,     Edinburgh,  1822. 


40  NATURAL   BODIES. 

tcain  to  which  kingdom  to  refer  any  substance  met  with  in  his  researches. 
The  smell  of  a  burnt  sponge,  of  coral,  or  other  zoophytic  animal,  is  so 
peculiar,  that  it  can  scarcely  be  mistaken  for  that  of  a  vegetable  body 
in  combustion.  According  to  Mulder,'  there  is  this  real  difference 
between  plants  and  animals  in  composition,  that  cellulose  (C^''H^^O^^) 
forms  the  principal  part  of  the  cellular  mass  in  plants ;  whilst  in  ani- 
mals the  primary  material  is  gelatin  (C'^H'°N^O^);  and  to  this  rule,  he 
says,  no  exception  has  yet  been  discovered  either  among  animals  or 
plants.  Yet  amylaceous  or  amyloid  bodies — corpora  sen  corpiiscula 
amylacea — of  microscopic  size,  are  found  in  the  animal  body;  chiefly 
in  the  human  brain  and  spinal  marrow,  in  the  ependyma  ventriculorum 
and  its  prolongations,  mingled  with  the  proper  nerve  elements,  and 
having  most  of  the  chemical  characters  of  cellulose  ;^  Mr.  Busk  indeed 
affirms,  that  they  are  absolutely  identical  in  every  property,  whether 
optical,  physical,  or  chemical,  with  starch.^ 

2.  'Texture. — In  this  respect,  important  differences  are  observable. 
Both  animals  and  vegetables  consist  of  solid  and  fluid  parts.  In  the 
former,  however,  the  fluids  bear  a  large  proportion  :  in  the  latter,  the 
solids.  This  is  the  cause,  why  decomposition  occurs  so  much  more 
rapidly  in  the  animal  than  in  the  vegetable;  and  in  the  succulent  more 
than  in  the  dry  vegetable.  If  we  analyze  the  structure  of  the  vege- 
table, we  cannot  succeed  in  detecting  more  than  one  elementary  tissue, 
which  is  vesicular  or  areolar^  or  arranged  in  vesicles  or  areolae,  and 
appears  to  form  every  organ  of  the  body;  whilst,  in  the  animal,  we 
■  discover  at  least  three  of  these  anatomical  elements,  the  areolar — analo- 
gous to  that  of  the  vegetable; — the  muscular^  and  the  nervoxis.  The 
vegetable  again  has  no  great  splanchnic  cavities  containing  the  chief 
organs  of  the  body.  It  has  a  smaller  number  of  organs,  and  none  that 
are  destined  for  sensation  or  volition ;  in  other  words,  no  brain,  no 
nerves,  no  muscular  sj'stem;  and  the  organs  of  which  it  consists  are 
simple,  and  readily  convertible  into  each  other. 

But  these  differences  in  organization,  striking  as  they  may  appear, 
are  not  sufficient  for  rigid  discrimination,  as  they  are  applicable  only 
to  the  upper  classes  of  each  kingdom.  In  many  vegetables,  the  fluids 
appear  to  preponderate  over  the  solids ;  numerous  animals  are  devoid 
of  muscular  and  nervous  tissues,  and  ajiparently  of  vessels  and  distinct 
organs;  whilst  ]\[^[.  Datrochet,'*  Brachet,^  and  others,®  admit  the  exist- 
ence of  a  rudimental  nervous  system  even  in  vegetables. 

'  Tlio  Chemistry  of  Animal  and  Vegetable  Physiology ;  translated  by  Fromberg,  p. 
91.      Kdinburgh  and  Ij(in(b)n,  lS4t). 

^  Yirchow,  Arcliiv.  fiir  i)athnl.  Anat.,  &c.  Leipzig,  1853.  Translated  in  Quarterly  Jour- 
nal of  Microscopic  Science,. July,  1855,  p.  284. — KiilUkor,  Mikroskopische  Anatomic,  ii.  501. 
Leipzig,  1850.  And  tlie  translation  of  the  same  by  Messrs.  Busk  and  Huxley,  Sydenham 
Society  edition,  i.  458.  London,  1853.  And  American  edition,  the  same,  by  J.  Da  Costa, 
M.  D.,  p.  402.  I'hilailelphia,  1854.— Thos.  Albert  Carter,  Edinb.  Med.  Journ.,  August, 
1853,  y.  130,  On  tlie  Dill'usion  of  Starch-corpuscles  in  the  Animal  Tissues. 

'  Oiiarterly  .Ji)unial  of  Microscopical  Science,  January  1854. 

♦  Kecherches  Anat<)nu(iues  t>t  Physiologiques  sur  la  Structure  Intime  des  Animaux, 
et  des  Vegetaux,  et  sur  leur  Motilite.     Paris,  1824. 

*  Recherches  Experimontales  sur  les  Fonctions  du  Systdme  Nerveux  Ganglionnaire, 
&c.,  2de  edit.  Paris  et  Lyon.  1837.  And  Physioloirie  l.lenunitaire  de  I'Ho'mme,  2de 
6dit.,  i.  (j4.     Paris  et  Lyon,  1855. 

6  Sir  J.  E.  Smith,  Introduction  to  Botany,  7th  edit.,  by  Sir  W.  J.  Hooker,  p.  40. 
London,  1833. 


ANIMALS   AND  VEGETABLES.  41 

3.  Sensation  and  voluntary  motion. — There  is  one  manifest  distinction 
lietween  animals  and  vegetables.  Whilst  the  latter  receive  their  nutri- 
tion from  the  objects  around  them — irresistibly  and  without  volition, 
or  the  participation  of  mind;  and  whilst  the  function  of  reproduction 
is  effected  Avithout  the  union  of  the  sexes,  both  volition  and  sensation 
are  necessary  for  the  nutrition  of  the  former,  and  for  acts  that  are 
requisite  for  the  reproduction  of  the  species.  Hence,  the  necessity  of 
two  faculties  or  functions  in  the  animal,  that  are  wanting  in  the  vege- 
table,— sensibility^  or  the  faculty  of  consciousness  and  feeling;  and 
motility,  or  the  pow0r  of  moving  at  will  the  whole  body  or  any  of  its 
parts.  Vegetables  are  possessed  of  spontaneous,  but  not  of  voluntary 
motion.  Of  the  former  we  have  numerous  examples  in  the  direction 
of  the  branches  and  upper  surfaces  of  the  leaves,  although  repeatedly 
disturbed,  to  the  light;  and  in  the  unfolding  and  closing  of  flowers  at 
stated  periods  of  the  day.  This,  however,  is  distinct  from  the  sensi- 
Ijility  and  motility  that  characterize  the  animal.  By  sensibility  man 
feels  his  own  existence — becomes  acquainted  with  the  universe — 
appreciates  the  bodies  that  compose  it;  and  experiences  all  the  desires 
and  inward  feelings  that  solicit  him  to  the  performance  of  those  ex- 
ternal actions,  which  are  requisite  for  his  preservation  as  an  individual, 
and  as  a  species ;  and  by  motility  he  executes  those  external  actions 
which  his  sensibility  may  suggest  to  him. 

By  some  naturalists  it  has  been  maintained,  that  those  plants, 
which  are  borne  about  on  the  waves,  and  fructify  in  that  situation, 
exhibit  examples  of  the  locomotility,  which  is  described  as  charac-  ■ 
teristic  of  the  animal.  One  of  the  most  interesting  novelties  in  the 
monotonous  occurrences  of  a  voyage  across  the  Atlantic  towards  the 
Gulf  of  Florida  is  the  almost  interminable  quantity  of  Fucus  natans, 
Florida  iveed  or  Oulf  weed,  with  which  the  surftice  of  the  ocean  is 
covered.  But  how  different  is  this  from  the  locomotion  of  animals ! 
It  is  a  subtlety  to  conceive  them  identical.  The  weed  is  passively 
and  unconsciously  borne  whithersoever  the  winds  and  the  waves  may 
urge  it ;  whilst  animal  locomotion  requires  the  direct  agency  of  voli- 
tion, of  a  nervous  system  that  can  excite,  and  of  muscles  that  can  act 
under  sucli  excitement. 

The  spontaneity  and  percejAivity  of  plants  must  also  be  explained  in 
a  different  manner  from  the  elevated  function  of  sensibility  on  which 
we  shall  have  to  dwell.  These  properties  must  be  referred  to  the  fact 
of  certain  vegetables  being  possessed  of  the  faculty  of  contracting  on 
the  application  of  a  stimulus,  independently  of  sensation  or  conscious- 
ness. If  we  touch  the  leaf  of  the  sensitive  plant,  Mimosa  pudica,  the 
various  leaflets  collapse  in  rapid  succession.  In  the  barberry  bush, 
Berber  is  vulgar  is,  we  have  another  example  of  the  possession  of  this 
faculty.  In  the  flower,  the  six  stamens,  spreading  moderately,  are 
sheltered  under  the  concave  tips  of  the  petals,  till  some  extraneous 
body,  as  the  feet  or  trunk  of  an  insect  in  search  of  honey,  touches  the 
inner  part  of  each  filament,  near  the  bottom.  The  susceptibility  of 
this  part  is  such,  that  the  filament  immediately  contracts,  and  strikes 
its  anther,  full  of  pollen,  against  the  stigma.  Any  other  part  of  the 
filament  may  be  touched  without  this  result,  provided  no  concussion 
be  given  to  the  whole.     After  a  while,  the  filament  retires  gradually, 


42  NATURAL   BODIES. 

and  may  be  again  stimulated  ;  and  when  each  petal,  with  its  annexed 
filament,  has  fallen  to  the  ground,  the  latter,  on  being  touched,  shows 
as  much  sensibility  as  ever.' 

These  singular  effects  are  produced  by  the  power  of  contractility  or 
irritability,  the  nature  of  which  will  fall  under  consideration  hereafter. 
It  is  possessed  equally  by  animals  and  vegetables,  and  is  essentially 
organic  and  vital.  This  power,  we  shall  see,  needs  not  the  interven- 
tion of  volition ;  it  is  constantly  exerted  in  the  animal  without  con- 
sciousness, and  therefore  necessarily  without  volition.  Its  existence 
in  vegetables  does  not,  consequently,  demonstraH  that  they  are  pos- 
sessed of  consciousness, 

4.  Nutrition. — A  great  difference  exists  between  plants  and  animals 
in  this  respect.  The  plant,  being  fixed  to  the  soil,  cannot  search  after 
food.  It  must  be  passive  ;  and  obtain  its  supplies  from  the  materials 
around,  and  in  contact  with  it ;  and  the  absorbing  vessels  of  nutrition 
must  necessarily  open  on  its  exterior.  In  the  animal,  on  the  other 
hand,  the  aliment  is  scarcely  ever  found  in  a  state  fit  for  absorption  ; 
it  is  crude,  and  in  general — Ehrenberg^  thinks  always — requires  to  be 
received  into  a  central  organ  or  stomach,  for  the  purpose  of  under- 
going changes,  by  a  process  termed  digestion,  which  adapts  it  for  the 
nutrition  of  the  individual.  The  absorbing  vessels  of  nutrition  arise, 
in  this  case,  from  the  internal  or  lining  membrane  of  the  alimentary 
tube.  The  analogy  that  exists  between  these  two  kinds  of  absorption 
is  great,  and  had  not  escaped  the  attention  of  the  ancients  : —  Qaem- 
admochim  terra  arhoribus,  ita  animalihus  ventriculus  sicut  humus''^  was 
an  aphoristic  expression  of  universal  reception.  With  similar  feel- 
ings, Boerhaave  asserts,  that  animals  have  their  roots  of  nutrition  in 
their  intestines ;  and  Dr.  Alston*  has  fancifully  termed  a  plant  an 
inverted  animal. 

After  all,  however,  the  most  essential  difference  consists  in  the  steps 
that  are  preliminary  to  the  reception  of  food.  These,  in  the  animal, 
are  voluntary — requiring  prehension ;  often  locomotion  ;  and  always 
consciousness. 

5.  Reproduction. — In  this  functi(Mi  we  find  a  striking  analogy  be- 
tween animals  and  vegetables ;  but  differences  exist,  which  must  be 
referred  to  the  same  cause  that  produced  many  of  the  distinctions 
already  pointed  out, — the  possession,  by  the  animal,  of  sensibility  and 
locomotility.  For  example,  every  part  of  the  generative  act,  as  before 
remarked,  is,  in  the  vegetable,  without  the  perception  or  volition  of 
the  being :— the  union  of  the  sexes,  fecundation,  and  the  birth  of  the 
new  individual  are  alike  automatic.  In  the  animal,  on  the  other  hand, 
the  approximation  of  the  sexes  is  always  voluntary,  and  effected  con- 
sciously :— the  birth  of  the  new  individual  being  not  only  perceived, 
but  somewhat  aided  by  volition.  Fecundation  alone  is  involuntary 
and  irresistible. 

Again,  in  the  vegetable  the  sexual  organs  do  not  exist  at  an  early 
period;  and  are  not  developed  until  reproduction  is  practicable.    They 

'  Sir  J.  E.  Smith's  Introduction  to  Botany,  p.  325. 

2  Edinb.  New  I'liilosojihifal  Journal,  for  Sept.,  18S1  ;  and  Jan.,  183S,  p.  232. 

»  Tirocinium  Botauicum  Edinburgun^^e,  Svo.,  Edinli.,  1753. 


MATEEIAL   COMPOSITION   OF   MAN".  43 

are  capable  of  acting  for  once  only,  and  perish  after  fecundation  ;  and 
if  the  plant  be  vivacious,  they  fall  off  after  each  reproduction,  and  are 
annually  renewed.  In  the  animal,  on- the"  contrary,  they  exist  from 
the  earliest  period  of  foetal  development,  survive  repeated  fecundations, 
and  continue  during  the  life  of  the  individual. 

Lastly,  the  possession  of  sensibility  and  locomotility  leads  to  other 
characteristics  of  animated  beings.  These  functions  are  incapable  of 
constant,  unremitting  exertion.  Sleep^  therefore,  becomes  necessary. 
The  animal  is  also  capable  of  exjiression,  or  of  language,  in  a  degree 
proportionate  to  the  extent  of  his  sensibility,  and  of  his  power  over  the 
beings  that  surround  him. 

But  these  differences  in  function  are  not  so  discriminate  as  they  may 
appear  at  first.  There  are  many  animals,  that  are  as  irresistibly  at- 
tached to  the  soil  as  the  vegetables  themselves.  Like  the  latter,  they 
must,  of  necessity,  be  compelled  to  absorb  their  food  in  the  state  in 
which  it  is  presented  to  them.  Sensibility  and  locomotility  appear,  in 
the  zoophyte,  to  be  no  more  necessary  than  in  the  vegetable.  No 
nervous,  no  muscular  system  is  required ;  and,  accordingly,  none  can 
be  traced  in  them ;  whilst  many  of  those  spontaneous  motions  of  the 
vegetable,  to  which  allusion  has  been  made,  have  been  considered  by 
some  to  indicate  the  first  rudiments  of  sensibility  and  locomotility ;  and 
Linnaeus'  has  regarded  the  closure  of  the  flowers  towards  night  as  the 
sleep,  and  the  movements  of  vegetables,  for  the  approximation  of  the 
sexual  organs,  as  the  marriage,  of  plants. 

II.  GENERAL  PHYSIOLOGY  OF  MAN.2 

The  observations  made  on  the  differences  between  animals  and  vege- 
tables have  anticipated  many  topics,  that  would  require  consideration 
under  this  head.  The  general  properties,  which  man  possesses  along 
with  other  animals,  have  been  referred  to  in  a  cursory  manner.  They 
will  now  demand  a  more  special  investigation. 

1.   MATERIAL  COMPOSITION  OF  MAN. 

The  detailed  study  of  human  organization  is  the  province  of  the 
anatomist — of  its  intimate  composition,  that  of  the  chemist.  In  ex- 
plaining the  functions  executed  by  the  various  organs,  the  physiologist 
will  frequently  have  occasion  to  trench  upon  both. 

The  bones,  in  the  aggregate,  form  the  skeleton.  The  base  of  the 
skeleton  is  a  series  of  vertehrce,  with  the  skull  as  a  capital — itself  re- 
garded as  a  vertebra.  This  base  is  situate  on  the  median  line  through 
the  whole  trunk,  and  contains  a  cavity,  in  which  are  lodged  the  brain 
and  spinal  marrow.  On  each  side  of  this,  other  bones,  which  by  some 
have  been  called  ajipendices,  are  arranged  in  pairs.  Upon  the  skeleton 
are  placed  muscles,  for  moving  the  different  parts  of  the  body;  and  for 
changing  its  situation  w^ith  regard  to  the  soil.  The  body  is  divided 
into  trunk  and  limbs.  The  trunk,  which  is  the  principal  portion,  is 
composed  of  three  splanchnic  cavities,  the  abdomen,  tliorax,  and  head, 

'  Amccnit.  Academ.,  torn.  iv. 

'  See,  on  all  this  suhjedt,  Robiu  and  Vordeil,  Traite  do  Chimie  Anatomiquc  et  Pliy- 
siologi(iue,  &c.     Paris  1853. 


44  MATEEIAL   COMPOSITION   OF   MAN. 

situate  one  above  the  other.  They  contain  the  most  important  organs 
of  the  body — those  that  effect  the  functions  of  sensibility,  digestion, 
respiration,  circuhition,  &;c.  The  liead  comprises  the /ace,  in  which  are 
the  organs  of  four  of  the  senses — sight,  hearing,  smell,  and  taste, — 
and  the  cranium^  which  lodges  the  brain — the  organ  of  the  mental 
manifestations,  and  the  most  elevated  part  of  the  nervous  system.  The 
thorax  or  chest  contains  the  lungs — organs  of  respiration — and  the 
heart,  the  central  organ  of  the  circulation.  The  abdomen  contains  the 
principal  organs  of  digestion,  and  (if  we  include  in  it  the  pelvis),  those 
of  the  urinary  secretion  and  of  generation.  Of  the  limbs,  the  upjjer, 
suspended  on  each  side  of  the  thorax,  are  instruments  of  prehension ; 
and  are  terminated  by  the  hand,  the  great  organ  of  touch.  The  loiver 
are  beneath  the  trunk ;  and  are  agents  for  supporting  the  body,  and 
for  locomotion.  Vessels,  emanating  from  the  heart,  are  distributed  to 
every  part — conveying  to  them  the  blood  necessary  for  their  life  and 
nutrition :  these  are  the  arteries.  Other  vessels  communicate  with 
them,  and  convey  the  blood  back  to  the  heart — the  veins;  whilst  a  third 
set  arise  in  the  tissues,  and  convey  into  the  circulation,  by  a  particular 
channel,  a  fluid  called  lymp)h — whence  they  derive  the  name  lymphatics. 
Nerves,  communicating  with  the  great  central  masses  of  the  nervous 
system,  are  distributed  to  every  part;  and  lastly,  a  membrane  or  layer, 
possessed  of  acute  sensibility — the  skin — serves  as  an  outer  envelope 
to  the  whole  body. 

It  was  before  observed,  that  two  kinds  of  elements  enter  into  the 
composition  of  the  body — the  chemical  or  inorganic;  and  the  organic, 
which  are  compound,  and  formed  only  under  the  force  of  life. 

The  chief  Chemical  or  Inorganic  Elements  met  with  are:  oxygen, 
hydrogen,  carbon,  nitrogen,  phos|)horus,  calcium;  and,  in  smaller  quan- 
tity, sulphur,  iron,  manganese,  calcium,  silicium,  aluminium,  chlorine ; 
also,  sodium,  magnesium,  &c.  &c. 

1.  Oxygen. — This  is  widely  distributed  in  the  solids  and  fluids  ;  and 
a  constant  supply  of  it  from  the  atmosphere  is  indispensable  to  animal 
life.  It  is  almost  always  found  combined  with  other  bodies;  often  in 
the  form  of  carbonic  acid, — that  is,  united  with  carbon.  In  a  separate 
state  it  is  met  witli  in  the  air-bag  of  fishes,  in  which  it  is  found  varying 
in  quantity,  according  to  the  species,  and  the  depth  at  which  the  fish 
has  been  caught. 

2.  Hydrogen. — This  gas  occurs  universally  in  the  animal  kingdom. 
It  is  a  constituent  of  all  the  fluids,  and  of  many  of  the  solids ;  and  is 
generall}'  in  a  state  of  combination  with  carbon.  In  the  human  intes- 
tines it  has  been  fountl  pure,  as  well  as  combined  with  carbon  and  sul- 
phur. 

3.  Carbon. — This  substance  is  met  with  under  various  forms,  in  both 
fluids  and  solids.  It  is  most  frequently  found  under  that  of  carbonic 
acid.  Carbonic  acid  has  been  detected  in  an  uncorabined  state  in  urine 
by  Prout;  and  in  the  blood  by  Vogel.'  It  exists  in  the  intestines  of 
animals;  but  is  chiefly  met  with  in  animal  bodies,  in  combination  with 
the  alkalies  or  earths;  and  is  emitted  by  all  animals  in  the  act  of  re- 
spiration. 

'  Annals  of  Philosophy,  vii.  56. 


I 


MATERIAL   COMPOSITION   OF   MAN.  45 

4.  Nitrogen. — This  gas  is  likewise  widely  distributed  as  a  component 
of  animal  substances,  and  especially  of  the  tissues.  It  occurs  in  an 
uncorabined  state,  in  the  swimming-bladder  of  certain  fishes. 

5.  Phosphorus  is  an  essential  constituent  of  neurine ;  and  is  found 
united  with  oxygen,  in  the  state  of  phosphoric  acid,  in  many  of  the 
solids  and  fluids.  It  is  this  acid  that  is  combined  with  the  earthy  mat- 
ter of  bones ;  and  with  potassa,  soda,  ammonia,  and  magnesia,  in  other 
parts.  It  is  supposed  to  give  rise  to  the  luminousness  of  certain  ani- 
mals— as  of  the  fire-fly,  Pyrosoma  Atlanticurn,  &c. — but  nothing  pre- 
cise is  known  on  this  subject. 

6.  Calcium. — This  metal  is  found  in  the  animal  economy  in  the 
state  of  oxide — lime;  and  it  is  generally  united  with  phosphoric  or 
carbonic  acid.  It  is  the  earth,  of  which  the  hard  parts  of  animals  are 
constituted. 

7.  Sulphur  is  not  met  with  extensively  in  animal  solids  or  fluids; 
nor  is  it  often  found  free,  but  usually  in  combination  with  oxygen 
united  to  soda,  potassa,  or  lime.  It  seems  to  be  an  invariable  concomi- 
tant of  albumen;  and  is  found  in  the  intestines,  in  the  form  of  sulpha- 
retted  hydrogen ;  and  as  an  emanation  from  fetid  ulcers. 

8.  Iron. — This  metal  has  been  detected  in  the  colouring  matter  of 
the  blood ;  in  bile,  and  in  milk.  In  the  first  of  these  fluids  it  was,  for 
a  long  time,  considered  to  be  in  the  state  of  phosphate  or  sub-phos- 
phate. Berzelius^  showed,  that  this  was  not  the  case ;  that  the  ashes 
of  the  colouring  matter  always  yielded  oxide  of  iron  in  the  proportion 
of  1 -200th  of  the  original  mass.  That  distinguished  chemist  was,  how- 
ever, unable  to  detect  the  condition  in  which  the  metal  exists  in  the 
blood;  and  could  not  discover  its  pi'esence  by  any  of  the  liquid  tests. 
Subsequently,  Engelhart  showed,  that  the  fibrin  and  albumen  of  the 
blood,  when  carefully  separated  from  colouring  particles,  do  not  con- 
tain a  trace  of  iron ;  whilst  he  could  procure  it  from  the  red  corpuscles 
by  incineration.  lie  also  succeeded  in  proving  its  existence  in  the 
red  corpuscles  by  liquid  tests ;  and  his  experiments  were  repeated,  with 
the  same  results,  by  Eose  of  Berlin,^  In  milk,  iron  seems  to  be  in  the 
state  of  phosphate, 

9.  Manganesium  has  been  found  in  the  state  of  oxide,  along  with 
iron,  in  the  ashes  of  the  hair;  in  bones,  in  gall-stones,  and  in  the 
blood. 

10.  Copper  and  lead. — It  was  conceived  by  M.  Devergie,  that  copper 
and  lead  may  exist  naturally  in  the  tissues;'  but  MM,  Flandin  and 
Danger,  and  a  commission  of  the  Academic  Eoyale  de  Mcdecine  of 
Paris,  were  unable  to  confirm  the  existence  of  copper;  and  the  results 
of  the  investigations  of  Professor  F.  de  Cattanei  di  Momo,^  of  Pavia, 
seem  to  j)rove  the  non-existence  of  lead  also.  M.  Parse,  however,  in 
a  paper  read  before  the  Royal  Acadera}''  of  Sciences  of  Paris,  in 
August,  1843,  states,  that  he  found  both  metals  in  the  bodies  of  two 

'  Medico-Cliinirgical  Transact.,  vol.  iii, 
^  Turner's  Chemistry,  fifth  ed.,  p.  963.     London,  1834. 
3  Bullet,  de  I'Academ.  Royale  de  Medecine,  11)  Fevr.,  183J1, 

*  Annali  Universal!  di  Mediciua,  Aprile,  1H40;  cited  in  British  and  Foreign  Medical 
Review,  Jan.,  1841,  p.  220'. 


46  MATERIAL   COMPOSITIOX   OF   MAN. 

persons,  to  whom  they  could  not  have  been  given  for  poisons.  The 
researches  of  Signor  Cattanei  di  Momo  appeared  to  prove  that  these 
metals  do  not  exist  in  the  bodies  of  new-born  children  or  infants;  and 
M.  J.  Rossignon  has  offered  a  solution  as  to  the  probable  source  of  the 
copper,  which  he  found  not  onl}^  in  the  blood  and  muscles  of  the  dog, 
but  in  many  articles  of  vegetable  and  animal  food ;  in  gelatin  from 
bones,  for  example,  in  sorrel,  chocolate,  bread,  cofiee,  succory,  madder, 
and  sugar.  The  ashes  obtained  from  starch  sugar  yielded  4  per  cent. 
of  copper;  those  of  gelatin,  0"03  per  cent.;  and  those  of  bread,  O'OOo  to 
0"006  per  cent.'  It  is  now  generally  considered  to  be  present  in  the 
human  liver,^  and  M.  E.  Millon^  asserts,  that  human  blood  invariably 
contains  lead,  copper,  silica,  and  manganese. 

11.  Silicon. — Silica  is  found  in  the  hair,  bones,  blood,  urine,  and  in 
urinary  calculi. 

12.  Chlorine. — In  combination  with  hydrogen,  and  forming  chloro- 
hydric  acid^  chlorine  is  met  with  in  most  of  the  animal  fluids.  It  is 
generally  united  with  soda.  Free  chlorohydric  acid  has  also  been 
found  by  Dr.  Prouf  in  the  stomach  of  the  rabbit,  hare,  horse,  calf,  and 
dog;  and  he  has  discovered  the  same  acid  in  the  sour  matter  ejected 
from  the  stomachs  of  those  labouring  under  indigestion.  Mr.  Children, 
and  Messrs.  Tiedemann  and  Gmelin,*  made  similar  observations;  and 
Professor  Emmet  and  the  author^  found  it  in  considerable  quantity  in 
the  healthy  gastric  secretions  of  man. 

13.  Fluorine. — This  simple  substance  has  been  found  combined  with 
calcium — -Jluoride  of  calcium — in  the  enamel  of  the  teeth,  bones,  and 
urine. 

14.  Sodium. — Oxide  of  sodium,  soda^  forms  part  of  all  the  fluids. 
It  has  never  been  discovered  in  a  free  state ;  but  it  is  united  (without 
an  acid),  to  albumen.  Most  frequently,  it  is  combined  with  chlorine, 
and  phosphoric  acid ;  less  frequently,  with  lactic,  carbonic,  and  sulphuric 
acids.  Chloride  of  sodium  is  contained  in  most  of  the  animal  secre- 
tions; and  from  its  decomposition  may  result  the  chlorohydric  acid  of 
the  gastric  juice,  and  a  part  of  the  soda  of  the  bile  and  other  fluids. 

15.  Potassium. — The  oxide,  potassa,  is  found  in  many  animal  fluids, 
but  always  united  with  acids — sulphuric,  chlorohydric,  phosphoric,  &c. 
It  is  much  more  common  in  the  vegetable  kingdom;  and  hence  one  of 
its  names — vejeiahle  alkali. 

10.  Jfagnesium. — The  oxide,  viagnesia^  exists  sparingly  in  bones, 
and  in  some  other  parts;  but  always  in  combination  with  phosphoric 
acid,  and  appears  to  be  always  associated  with  calcium. 

17.  Aluminium. — Alumina  is  said  by  Morichini  to  exist  in  the  ena- 
mel of  the  teeth.     Fourcroy  and  Yauquelin  found  it  in  the  bones;  and 

'  Lou.l.  M.mI.  Traz.,  Dec.  1,  1843,  from  Gazette  M.^licale  de  Paris,  and  Mr.  Paget,  Rep. 
on  AnatoTiiy  and  Physiology,  1843-4,  in  Brit,  and  For.  Med.  Rev.,  Jan.,  1845,  p.  249. 

"  Kirk.-s  and  Patret,  Manual  of  Physiology,  2d  Amer.  edit.,  p.  29,  Philad.,  1853. 

'  Coniptes  Rcndiis,  Pans,  1848. 

*  Philiisuph.  Transact,  for  1824,  p.  45. 

6  Reelierehes  KxiH-rimentales,  &c.,  sur  la  Digestion,  trad,  par  A.  G.  L.  Jourdan.  Art. 
4,  p.  94,  Paris,  1S27. 

"  See  under  the  head  of  "  Digestion,''  and  tlie  author's  Human  Health,  p.  191,  Phila- 
delphia, 1844. 


ORGANIC   ELEMENTS.  47 

Jolin,  in  white  hairs.     According  to  Schlossberger,  it  is  in  the  flesh  of 
fishes.' 

18.  Titanium. — Dr.  Rees  affirms,  that  he  detected  it  in  salts  obtained 
from  the  supra-renal  capsules. 

19.  Arsenic. — It  was  asserted,  by  M.  Orfila,  that  arsenic  exists  natu- 
rally in  the  human  body  ;  and  that  it  is  a  normal  constituent  of  human 
bones.  Subsequent  experiments,  however,  performed  by  M,  Orfila 
himself,  have  shown  that  there  was  fallacy  in  his  first  observations.^ 

Organic  Elements,  proximate  principles  or  compounds  of  organiza- 
tion., are  combinations  of  two  or  more  of  the  elementary  substances,  in 
definite  proportions.  Formerly,  four  only  were  admitted — gelatin, 
fibrin,  albumen,  and  oil.  Of  late,  however,  organic  chemistry  has 
jtointed  out  others,  which  are  divided  into  two  classes — first,  those  that 
contain  nitrogen,  as  albumen,  gelatin,  fibrin,  osmazome,  mucus,  casein, 
urea,  uric  acid,  red  colouring  principle  of  the  blood,  yellow  colouring 
principle  of  the  bile,  &C. ;  and  secondly,  those  that  do  not  contain  nitro- 
gen— as  olein,  margarin,  stearin,  the  fatty  matter  of  the  brain  and 
nerves,  acetic,  oxalic,  benzoic,  and  lactic  acids,  sugar  of  milk,  sugar  of 
diabetes,  hepatic  sugar,  picromel,  colouring  principle  of  the  bile,  and 
that  of  other  solids  and  liquids,  &c. 

a.  Organic  Elements  that  contain  Nitrogen. 

1.  Protein. — Modern  researches  have  appeared  to  show,  that  the 
chief  proximate  principles  of  animal  tissues,  and  those  that  have  been 
regarded  as  highly  nutritious  among  vegetables,  have  almost  identi- 
cally the  same  composition ;  and  are  modifications  of  a  principle  to 
which  Mulder — its  discoverer — gave  the  name  Protein.  If  animal 
albumen,  fibrin,  or  casein,  be  dissolved  in  a  moderately  strong  solution 
of  caustic  potassa,  and  the  solution  be  exposed  for  some  time  to  a  high 
temperature,  these  substances  are  decomposed.  The  addition  of  acetic 
acid  to  the  solution  causes,  in  all  three,  the  separation  of  a  gelatinous 
translucent  precipitate,  which  has  exactly  the  same  character  and  com- 
position, from  whichsoever  of  the  solutions  it  is  obtained.  It  may  be 
procured,  too,  from  globulin  of  blood,  and  from  vegetable  albumen.' 

The  chemical  relations  of  protein,  especially  in  regard  to  oxygen, 
are  full  of  interest.  The  products  of  its  oxidation,  binoxide  and  trit- 
oxide  of  protein,  occur  constantly  in  the  blood.  They  arc  formed  in 
the  lungs  from  fibrin ;  which,  in  a  moist  state,  possesses  the  property 
of  absorbing  oxygen.  Fibrin,  oxidized  in  the  lungs,  is,  according  to 
Mulder,  the  principal — if  not  the  only—  carrier  of  the  oxygen  of  the 
air  in  the  blood  to  the  tissues ;  and  it  is  from  this  substance,  especially, 
that  the  secretions  are  formed.  In  inflammatory  conditions,  a  much 
larger  quantity  of  protein,  in  an  oxidized  state,  is  contained  in  the 

'  Henle,  AUgemeine  Anatomie,  s.  4.  Leipz.,  1841,  or  Jourdaii's  translation,  i.  2, 
Paris,  1843. 

^  Rapport  de  I'Academie  Royale  de  Medecine,  Juillet,  1841 ;  Taylor's  Medical  Juris- 
prudence, by  Dr.  Griffith,  p.  133,  Pliilada.,  1845  ;  and  Simon,  Animal  Chemistry,  Syden- 
ham Soc.  edit.,  p.  4,  Lond.,  1845,  or  Amer.  edit.,  Pliilad.,  1845. 

^  Liebig,  Animal  Chemistry,  Gregory's  and  Webster's  edit.,  p.  100.     Cambridge,  1842. 


/ 
48  MATERIAL   COMPOSITION    OF    MAX. 

T)lood  than  in  healtli ;  and  tliis,  according  to  Mulder,  gives  occasion  to 
the  bufty  coat.^ 

The  following  substances  may  be  regarded  as  modifications  or  com- 
binations of  protein.  They  are  composed  of  it  and  of  a  small  quan- 
tity of  phosphorus,  or  of  sulphur,  or  botli.^ 

a.  Albumen. — This  is  one  of  the  most  common  organic  constituents; 
and  appears  under  two  forms — liquid  and  concrete.  In  its  purest  state, 
the  former  is  met  with  in  white  of  egg — whence  its  name ;  in  the  serum 
of  the  blood  ;  the  lymph  of  the  absorbents ;  the  serous  fluid  of  the 
great  splanchnic  cavities  and  of  the  areolar  membrane ;  and  in  the 
synovial  secretion.  It  is  colorless  and  transparent ;  without  smell  or 
taste ;  and  is  coagulated  by  acids,  alcohol,  ether,  metallic  solutions, 
infusion  of  galls,  and  by  a  temperature  of  158°  Fahrenheit.  A  very 
dilute  solution,  however,  does  not  become  turbid  until  it  is  boiled.  It 
is  excreted  by  the  kidneys  in  large  quantities,  in  the  disease,  which, 
owing  to  its  presence  in  the  urine,  has  been  called  Albuminuria. 

Concrete,  coagulated,  or  solid  albumen,  is  white ;  tasteless ;  and  elastic ; 
insoluble  in  water,  alcohol,  or  oil ;  but  readily  soluble  in  alkalies. 

Albumen  is  always  combined  with  soda.  It  exists  in  abundance — 
both  the  liquid  and  concrete — in  different  parts  of  the  animal  body. 
Hair,  nails,  and  horn,  consist  of  it ;  and  it  is,  in  some  form  or  other,  a 
constituent  of  many  tumours. 

In  the  advanced  chyliferous  vessels  albumen  is  found  in  quantity  ; 
and  it  is  probable  that  every  proteinaceous  aliment,  and  perhaps  those 
that  are  not  proteinaceous,  is  reduced  to  the  form  of  albumen  in  the 
process  of  digestion,  so  that  it  becomes  the  nutritious  constituent  of 
whatever  fluid  is  absorbed  for  the  formation  of  tissue. 

Albuminose  or  2-)eptone  has  considerable  analogy  with  albumen  and 
casein.  Its  non-coagulation  by  heat  distinguishes  it  from  the  former ; 
the  precipitate  which  it  forms  with  acetic  acid,  and  which  redissolves  in 
an  excess  of  the  acid,  distinguishes  it  from  the  latter.  It  is  found  in 
the  chyme  from  the  digestion  of  nitrogenized  matters;  and  passes  into 
the  blood,  where  it  is  found  in  the  proportion  of  from  four  to  six  parts 
in  the  1,OOU.^ 

b.  Fibrin. — This  proximate  principle  exists  in  the  chyle ;  enters  into 
the  composition  of  the  blood  ;  forms  the  chief  part  of  muscular  flesh ; 
and  may  be  looked  upon  as  one  of  the  most  abundant  animal  substances. 
It  is  obtained  by  beating  the  blood  with  a  rod,  as  it  issues  from  a  vein. 
The  fibrin  attaches  itself  to  each  twig  in  the  form  of  red  filaments, 
which  may  ^be  deprived  of  their  colour  by  repeated  washing  with  cold 
water.  Fibrin  is  solid;  white;  flexible;  shghtly  elastic ;  insipid;  in- 
odorous ;  and  heavier  than  water.  It  is  neither  soluble  in  water,  alco- 
hol, nor  acids  ;  dissolves  in  liquid  potassa  or  soda,  in  the  cold,  without 
much  change ;  and,  when  warm,  becomes  decomposed. 

Fibrin  constitutes  the  buffy  coat  of  blood ;  it  is  thrown  out  from 
the  bloodvessels,  as  a  secretion,  in  many  cases  of  inflammation ;  and 
becomes  subsequently  organized. 

'  Simon,  Animal  Cliemistrj,  Sydeuliam  Soc.  edit.,  p.  12,  London,  1845  ;  or  Ameii.'an 
edit.,  Philadelphia,  1845. 
*  Henle,  op.  cit.,  p.  31. 
3  L.  A.  Segond,  Traite  d'Anatomie  GenSrale,  p.  49.     Paris,  1854. 


ORGANIC   ELEMENTS.  49 

There  is  no  mode  of  distinguishing  liquid  fibrin  from  liquid  albumen, 
except  by  the  spontaneous  coagulation  of  the  former.  Consequently, 
according  to  Henle,'  if  a  liquid  does  not  coagulate  of  itself,  it  does  not 
contain  fibrin.  A  very  small  quantity,  however,  of  fibrin  may  be  so 
dissolved  in  serous  fluid,  that  it  will  not  coagulate.^  The  change  of 
albumen  to  fibrin  has  generally  been  regarded  as  the  first  important 
step  in  the  process  of  assimilation,  fibrin  being  endowed  with  much 
higher  organizable  properties  than  albumen.  This  has  been  attributed 
to  some  influence  exerted  upon  albuminous  fluids  by  the  living  sur- 
faces over  which  they  pass,  but  reasons  have  been  brought  forward  for 
the  belief,  that  it  is  rather  in  a  state  of  transition  towards  the  fibro- 
gelatinous  textures  than  towards  those  of  the  cellulo-albuminous  tj^pe; 
and  Dr.  Carpenter,^  who  was  a  strenuous  supporter  of  the  former  doc- 
trine, now  maintains  the  latter:  and  thinks,  that  we  seem  to  be  justified 
in  regarding  fibrin  as  the  special  pabulum  of  those  connective  or 
gelatinous  tissues  whose  physical  offices  in  the  economy  are  so  import- 
ant, whilst  their  vital  endowments  are  so  low — a  view  which  the  author 
is,  as  yet,  b}''  no  means  prepared  to  adopt. 

More  probable  is  that  of  Mr.  Simon,**  that  the  fibrin  of  the  blood 
may  have  arisen  in  it  from  its  own  decay,  or  have  reverted  to  it  from 
the  waste  of  the  tissues ;  when,  amongst  other  reasons,  we  consider  the 
small  quantity  of  fibrin  in  the  blood,  so  inadequate,  apparently,  for 
the  purposes  of  nutrition,  and  that  its  amount  is  not  diminished  by 
bloodletting,  or  by  starvation ;  but,  on  the  contrary,  has  been  observed 
to  be  greatly  increased  under  such  circumstances. 

The  correspondence  of  fibrin  with  albumen  is  shown  by  the  circum- 
stance, that  it  may  be  wholly  dissolved  in  a  solution  of  nitrate  of  po- 
tassa,  and  that  this  solution  greatly  resembles  a  solution  of  albumen, 
and  is  coagulable  by  heat.  This  happens,  however,  only  to  the  ordi- 
nary fibrin  of  venous  blood.  That  which  is  obtained  from  arterial 
blood  or  from  the  buff'y  coat ;  or  which  has  been  exposed  for  some  time 
to  the  air,  is  not  thus  soluble,  the  difference  appearing  to  depend  upon 
the  larger  quantity  of  oxygen  contained  in  the  latter  ;  for  a  solution  of 
venous  fibrin  in  nitre,  contained  in  a  deep  cylindrical  jar,  allows  a  pre- 
cipitate in  fine  flocks  to  fall  gradually,  provided  the  air  has  access  to 
the  surface ;  but  not  if  its  access  be  prevented.  This  precipitate  is 
insoluble  in  the  solution  of  nitre,  and  possesses  the  properties  of  arterial 
fibrin.*  Hence,  Dr.  Carpenter*  has  remarked,  it  might  be  inferred, 
that  the  fibrin  of  venous  blood  most  nearly  resembles  albumen ;  whilst 
that  of  arterial  blood,  and  of  the  buffycoat,  contains  more  oxygen,  and 
is  more  highly  animalized  [?] ;  and  that  the  matter  of  the  red  corpuscles 
is  not  the  only  constituent  of  the  blood,  which  undergoes  a  change  in 
the  respiratory  process. 

c.   Casein,  Caseum,  Caseous  matter. — This  substance  exists  in  greatest 

'  Op.  cit.,p.  38. 

2  Dr.  Buchanan,  Lond.  Med.  Gaz.  for  1836,  pp.  52  and  90,  and  ibid,  for  1845,  p.  G17. 

3  Principles  of  Human  Physiology,  Amer.  edit.,  p.  21(5.     Philad.,  1855. 

*  Lectures  on  General  Pathology,  Amer.  edit.,  p.  45.     Philad.,  1852. 

*  Scherer,  Chemisch-physiologische  Untersucliungen,  Annalen  der  Chemie,  &c.,  Oct. 
1841,  cited  in  Graham's  Chemistry,  Amer.  edit.,  p.  692.    Philad.,  1843. 

«  Principles  of  Human  Physiology,  2d  edit.,  p.  479.     Philad.,  1845. 
VOL.  I.— 4 


I 


50  MATERIAL   COMPOSITIOISr   OF   MAN. 

abundance  in  milk;  and  is  the  basis  of  cheese.  It  is  found  also  in 
blood,  saliva,  bile,  pancreatic  juice ;  in  pus,  tubercular  matter,  &c.  To 
obtain  it,  milk  must  be  left  at  rest,  at  the  ordinary  temperature,  until 
it  is  coagulated ;  the  cream  that  collects  on  the  surface  must  be  taken 
off;  the  clot  well  washed  with  water,  drained  upon  a  filter,  and  dried. 
The  residuum  is  pure  casein.  It  is  a  white,  insipid,  inodorous  sub- 
stance, insoluble  in  water,  but  readily  soluble  in  the  alkalies,  especially 
in  ammonia.  It  possesses  considerable  analogy  with  albumen.  Prout 
ascribes  the  characteristic  flavor  of  cheese  to  the  presence  of  caseate 
of  ammonia. 

Until  recently  it  was  believed  that  vegetable  albumen  and  fibrin 
difier  from  animal  albumen  and  fibrin ;  but  Mulder  showed  that  this 
is  not  the  case  ;  and  casein,  which  agrees  with  the  others  in  composi- 
tion, has  been  found  by  Liebig  in  the  vegetable.  Legnmin  is  vegetable 
casein.  Of  late,  the  views  of  Mulder  as  to  the  very  existence  of  pro- 
tein have,  however,  been  combated  by  Liebig  and  Th.  Fleitmann  and 
others;'  but  still — as  Messrs. Kirkes  and  Paget^have  remarked — there 
seems  sufficient  probability  in  those  views  to  justify  the  received  use 
of  the  term  '■'■protein  comiwunds,''^  in  speaking  of  the  class,  including 
fibrin,  albumen,  and  others,  to  which  the  name  of  ^^  albuminous  com- 
2)ounds''^  was  formerly  applied. 

2.  Globulin. — The  globulin  of  Berzelius  consists  of  the  envelopes  of 
the  blood  corpuscles,  and  of  the  part  of  their  contents  that  remains 
after  the  extraction  of  the  hcematin.  The  two  constitute  hcemato- 
globulin.  M.  Lecanu  regards  globulin  as  identical  with  albumen; 
according  to  Mulder,  it  belongs  to  the  combinations  of  protein.  Simon 
terms  it  blood  casein,  and  Henle'  thinks  it  probable,  that  it  is  in  reality 
only  albumen  with  the  membranes  of  the  blood  corpuscles.  Berzelius 
considers  the  crystalline  lens  to  be  composed  of  the  same  substance. 

3.  Pepsin. — This  substance,  to  which  Eberle  gave  the  name,  was 
discovered  by  Schwann.  It  seems  to  be  a  modification  of  protein,  but 
has  not  been  much  examined.  It  is  contained  in  the  gastric  juice ; 
and  its  physiological  properties  will  be  described  under  the  head  of 
Digestion.  It  greatly  resembles  albumen ;  coagulates  by  heat  and 
alcohol ;  and  loses  its  solvent  virtues.  It  is  best  procured  by  digest- 
ing portions  of  the  mucous  membrane  of  the  stomach  in  cold  water, 
after  they  have  been  macerated  for  some  time  in  water  at  a  tempera- 
ture between  80°  and  100°  of  Fahrenheit.  The  warm  water  dissolves 
various  substances  as  well  as  some  of  the  pepsin;  but  the  cold  water 
takes  up  little  more  than  the  pepsin,  which  is  obtained,  by  evaporating 
the  cold  solution,  in  the  form  of  a  grayish-bro^\^l  viscid  fluid.  The 
addition  of  alcohol  throws  down  the  pepsin  in  grayish-white  flocculi ; 
and  one  part  of  the  principle  thus  prepared,  when  dissolved  in  even 
60,000  parts  of  water,  will  digest  meat  and  other  alimentary  substances. 
Liebig  doubts  the  existence  of  pepsin  as  a  distinct  compound.     Ac- 

'  Sclierer,  in  Canstatt  und  Eisenmann's  Jaliresbericlit  liber  die  Fortscliritte  in  der 
Biologie  im  Jahre,  1847,  s.  82.  Erlangen,  1848.  "  Cette  substance  generale,"  says 
Brachet,  "adoptee  en  Allemagne,  est  encore  tine  probleme."  Physiologie  Elementaire 
de  I'Homme,  2de  edit.,  Paris  et  Lyon,  1855. 

2  Manual  of  Physiology,  2d  Amer.  edit.,  p.  24,  Philad.,  1853. 

'  Op.  cit.,  p.  53. 


\ 


ORGANIC   ELEMENTS.  51 

cording  to  liim — as  explaiued  hereafter — the  solv^ent  power  of  the 
gastric  juice  is  owing  to  the  gradual  decomposition  of  a  matter  dis- 
solved from  the  lining  membrane  of  the  stomach,  aided  by  oxygen 
introduced  into  the  saliva. 

4.  Gelatin. — This  is  the  chief  constituent  of  areolar  tissue,  skin, 
tendons,  ligaments,  and  cartilages.  The  membranes  and  bones  also 
contain  a  large  quantity  of  it.  It  is  obtained  by  boiling  these  sub- 
stances for  some  time  in  water  ;  clarifying  the  concentrated  solution  ; 
allowing  it  to  cool,  and  drying  the  substance,  thus  obtained,  in  the 
air.  In  this  state  it  is  called  glue ;  in  a  more  liquid  form,  jelly. 
Gelatin  dissolves  readily  in  hot  water ;  is  soluble  in  acids  and  alkalies ; 
insoluble  in  alcohol,  ether,  and  in  fixed  and  volatile  oils.  Alcohol 
precipitates  it  from  its  solution  in  water.  It  is  not  a  compound  of 
protein  ;  hence  it  has  been  concluded,  that  it  cannot  yield  albumen, 
fibrin,  or  casein ;  and,  therefore,  that  blood  cannot  be  formed  of  it.  The 
animal  system,  it  has  been  maintained,  can  convert  one  form  of  protein 
into  another,  but  cannot  form  protein  from  compounds  that  do  not 
contain  it.  This  deduction — as  stated  hereafter — is  probably  too 
hast}^  It  is  admitted,  that  gelatin  may  be  produced  from  fibrin  and 
albumen ;  since,  in  animals  that  are  fed  on  these  alone,  the  nutrition 
of  the  gelatinous  tissues  does  not  seem  to  be  impaired ;  and  it  is  as  easy 
to  conceive  that  gelatin  may  go  to  the  formation  of  the  proteinaceous 
tissues. 

Gelatin,  nearly  in  a  pure  state,  forms  the  air-bag  of  different  fishes, 
and  is  well  known  under  the  name  of  isinglass.  It  is  used  extensively 
in  the  arts,  on  account  of  its  adhesive  quality,  under  the  forms  of  glue 
and  size.  What  is  called  portable  soup  is  dried  jelly,  seasoned  with 
various  spices. 

5.  Gliondrin. — This  was  first  discovered  by  J.  Miiller.  It  is  obtained 
by  boiling  the  cornea,  the  permanent  cartilages,  and  the  bones  before 
ossification.     It  is  a  variety  of  gelatin. 

6.  Osmazome. — This  is  the  matih-e  extractive  du  bouillon;  extractive^ 
and  scf.jjonaceous  extract  of  meat. — When  flesh,  cut  into  small  fragments, 
is  macerated  in  successive  portions  of  cold  water,  the  albumen,  osma- 
zome, and  salts  are  dissolved ;  and,  on  boiling  the  solution,  the  albu- 
men is  coagulated.  From  the  liquid  remaining,  the  osmazome  may 
be  procured  in  a  separate  state,  by  evaporating  to  the  consistence  of 
an  extract,  and  treating  with  cold  alcohol.  This  substance  is  of  a 
reddish-brown  colour ;  and  is  distinguished  from  the  other  animal 
principles  by  solubility  in  water  and  alcohol — whether  cold  or  at  the 
boiling  point — and  by  not  forming  a  jelly  when  its  solution  is  concen- 
trated by  evaporation. 

Osmazome  exists  in  the  muscles  of  animals,  the  blood,  and  the  brain. 
It  gives  the  peculiar  flavour  of  meat  to  soups ;  and,  according  to  Four- 
croy,  the  brown  crust  of  roast  meat  consists  of  it.  It  is  regarded  as  a 
mixture  of  different  crystallizable  and  uncrystallizable  principles  with 
empyreumatic  products.^ 

Kreatin  and  Kreatinin  are  two  principles  which  were  formerly  in- 
cluded among  the  extractive  or  ill-defined  matters  of  muscular  tissue. 

'  Robin  and  Verdeil,  Traite  de  Cliimie  auatomique,  &c.,  iii.  565,  Paris  1853. 


52  MATERIAL   COMPOSITION   OF   MAN". 

They  have  been  investigated  by  Liebig,'  who  discovered  them  also  in 
urine.  They  appear  to  be  like  urea,  mere  products  of  the  decomposi- 
tion of  muscle. 

7.  Mucus. — This  term  has  been  applied  to  various  substances ;  and 
hence  the  discordant  characters  ascribed  to  it.  Applying  it  to  the 
fluid  secreted  by  mucous  surfaces,  it  varies  somewhat  according  to  the 
source  whence  it  is  derived.  Its  leading  characters  may  be  exempli- 
fied in  that  deriv^ed  from  the  nostrils,  which  has  the  following  proper- 
ties. It  is  insoluble  in  alcohol  and  water,  but  imbibes  a  little  of  the 
latter,  and  becomes  transparent ;  it  is  neither  coagulated  by  heat,  nor 
rendered  horny ;  but  is  coagulated  by  tannic  acid. 

Mucus,  in  a  liquid  state,  serves  as  a  protecting  covering  to  different 
parts.  Hence  it  varies  somewhat  in  its  characters,  according  to  the 
office  it  has  to  fulfil.  When  inspissated,  it  forms,  according  to  some, 
the  minute  scales  that  are  detached  from  the  surface  of  the  body  by 
friction,  corns,  and  the  thick  layers  of  the  soles  of  the  feet,  nails,  and 
horny  parts;  and  it  is  contained  in  considerable  quantity  in  hair,  wool, 
feathers,  scales  of  fishes,  &c. 

8.  Urea. — This  proximate  principle  exists  in  the  urine  of  the  mam- 
malia when  they  are  in  a  state  of  health.  In  human  urine  it  is  less 
abundant  after  a  meal,  and  it  may  nearly  disappear  in  diabetes,  and 
aSeetions  of  the  liver.  It  is  obtained  by  evaporating  urine  to  the  con- 
sistence of  syrup.  The  syrup  is  then  treated  with  four  parts  of  alco- 
hol, which  are  afterwards  volatilized  by  heating  the  alcoholic  extract. 
The  mass  that  remains  is  dissolved  in  water,  or  rather  in  alcohol,  and 
crystallized. 

The  purest  urea  that  has  been  obtained,  assumes  the  shape  of  acicu- 
lar  prisms  similar  to  those  of  the  muriate  of  strontian.  It  is  colourless, 
devoid  of  smell,  or  of  action  on  blue  vegetable  colours,  transparent, 
and  somewhat  hard.  Its  taste  is  cool,  slightly  sharp,  and  its  specific 
gravity  is  greater  than  that  of  water. 

Urea  is  supposed  by  Dr.  Prout  to  be  chiefly  derived  from  the  de- 
composition of  the  gelatinous  tissues;  but,  as  Dr.  Carpenter  has  re- 
marked,^ there  seems  to  be  no  valid  reason  thus  to  limit  the  mode  of 
its  production. 

9.  Uric  or  litliic  acid. — This  acid  is  found  in  the  urine  of  man,  birds, 
serpents,  tortoises,  crocodiles,  lizards ;  in  the  excrements  of  the  silk- 
worm, and  very  frequently  in  urinary  calculi.  It  is  obtained  by  dis- 
solving any  urinary  calculus  which  contains  it,  or  the  sediment  of  hu- 
man urine,  in  warm  liquid  potassa,  and  precipitating  the  uric  acid  by 
the  chlorohydric.  Pure  uric  acid  is  white,  tasteless,  and  inodorous. 
It  is  insoluble  in  alcohol,  and  is  dissolved  very  sparingly  by  cold  or 
hot  water,  requiring  about  10,000  times  its  weight  of  that  fluid,  at  60° 
of  Fahrenheit,  for  solution.  According  to  Dr.  Prout,  this  acid  is  not 
free,  but  is  commonly  combined  with  ammonia;  the  reddening  of  lit- 
mus paper  being  not  altogether  owing  to  it,  but  to  the  super-phosphate 
of  ammonia,  which  is  likewise  present  in  urine. 

In  the  herbivora,  this  acid  is  replaced  by  the  hippuric.  Xanthic 
acid^  found  by  Marcet  in  urinary  calculi,  seems  to  have  been  uric  acid. 

'  Chemistry-  of  Food,  London,  1847. 

»  Human  Physiology,  §  673,  Lond.,  1842. 


OEGANIO   ELEMENTS.  53 

10.  Colouring  princijyles  of  the  blood. — It  has  been  already  observed 
that  Engelhart  and  Rose,  German  chemists,  had  detected  iron  in  the 
red  corpuscles  of  the  blood,  but  had  not  found  it  in  the  other  prin- 
ciples of  that  fluid.  It  has  been  considered  probable,  therefore,  that 
it  has  something  to  do  with  the  colour.  Engelhart's  experiments 
did  not,  however,  determine  the  manner  in  which  it  acts,  nor  in  what 
state  it  exists  in  the  blood.  The  sulphocjanic  acid  which  is  found  in 
the  saliva  forms,  with  peroxide  of  iron,  a  colour  exactl}''  like  that  of 
venous  blood ;  and  it  is  possible,  that  the  colouring  matter  may  be  a 
sulphocyanate  of  iron. 

To  obtain  the  red  colouring  matter,  hcematin  or  hcematosin,  allow 
the  crassamentum  or  clot,  cut  into  thin  pieces,  to  drain  as  much  as 
possible  on  bibulous  paper,  triturating  it  with  water,  and  then  evapo- 
rating the  solution  at  a  temperature  not  exceeding  122°  of  Fahren- 
heit. When  thus  prepared,  the  colouring  particles  are  no  longer  of 
a  bright  red  colour,  and  their  nature  is  somewhat  modified,  in  conse- 
quence of  which  they  are  insoluble  in  water.  When  half  dried,  they 
form  a  brownish-red,  granular,  friable  mass;  and  when  completely 
dried  at  a  temperature  between  167°  and  190°,  the  mass  is  tough, 
hard,  and  brilliant.  The  mode  in  which  the  haematin  is  concerned 
in  the  coloration  of  the  blood,  will  be  inquired  into  under  the  head  of 
Eespiration. 

A  brown  colouring  matter,  hceynaphcein,  and  a  blue  colouring  matter, 
hcemacyanin,  have  been  described.  The  former,  however,  it  has  been 
suggested,  is  nothing  more  than  hgematin  modified  by  an  alkali ;  and 
Simon^  never  succeeded  in  detecting  the  latter. 

11.  Yellow  colouring  princijyle  of  the  bile; — cholepyrrhin  of  Berze- 
lius,  biliphcein  of  Simon. — This  substance  is  present  in  the  bile  of 
nearly  all  animals.  It  enters  into  the  composition  of  almost  all  gall- 
stones, and  is  deposited  in  the  gall-bladder  under  the  form  of  magma. ' 
It  is  solid;  pulverulent;  when  dry,  insipid,  inodorous,  and  heayier 
than  water.  When  decomposed  by  heat,  it  yields  carbonate  of  am- 
monia, charcoal,  &c.  It  is  insoluble  in  water,  alcohol,  and  the  oils ; 
but  soluble  in  alkalies.  On  the  gradual  addition  of  nitric  acid  to  a 
fluid,  which  contains  this  substance  in  solution,  a  very  characteristic 
series  of  tints  is  evolved.  The  fluid  becomes  first  blue,  then  green, 
afterwards  violet  and  red,  and  ultimately  assumes  a  yellow  or  yellowish- 
brown  colour. 

On  adding  an  acid  to  a  solution  of  biliphcein,  a  precipitation  of  green 
flocculi  takes  place :  these  possess  all  the  properties  of  chlorophyll,  or 
the  green  colouring  matter  of  leaves.  In  this  state  it  is  termed  bili- 
verdin  by  Berzelius ;  and  is  a  product  of  the  metamorphosis  of  bili- 
phagin.^ 

These  are  the  chief  nitrogenized  organic  elements. 

b.  Organic  Elements  that  do  not  contain  Nitrogen. 

1.  Olein  and  Stearin. — Fixed  oils  and  fats  are  not  pure  proximate 
principles,  as  was  at  one  time  supposed.  They  were  long  presumed 
to  consist  of  two  substances,  one  of  which  is  solid  at  the  ordinary  tem- 
perature of  the  atmosphere,  and  the  other  fluid  :  the  former  of  these 

'  Op.  cit.,  p.  42.  *  Simon,  op.  cit.,  p.  44. 


5-i  MATERIAL   COMPOSITION   OF   MAX.  j 

was  called  Stearin,  from  attap,  suet ;  the  latter,  Elain  or  OJein,  from 
fXaiov,  oil.  Stearin  is  the  chief  ingredient  of  vegetable  and  animal 
suet ;  of  fat  and  butter ;  and  is  found,  although  in  small  quantity,  in 
fixed  oils.  In  suety  bodies,  it  is  the  cause  of  their  solidity.  Elain 
and  stearin  may  be  separated  from  each  other  by  exposing  fixed  oil  to 
a  low  temperature  ;  and  pressing  it,  when  congealed,  between  folds  of 
bibulous  paper.  The  stearin  is  thus  obtained  in  a  separate  form ;  and 
by  pressing  the  bibulous  paper  under  water,  an  oily  matter  is  procured, 
■which  is  elain  in  a  state  of  purity.  Modern  chemistry  has  shown, 
however,  that  fat  contained  in  the  cells  of  adipose  tissue  is- composed 
of  a  base  termed  glycerin — itself  hydrated  oxide  of  glyceryl — with 
stearic  and  margaric  acids.  Stearin  is  a  hi-stearate  of  glycerin  : — olein, 
or  elain,  an  oleate  of  glycerin. 

2.  Fatty  matter  of  the  Brain  and  Nerves. — Yauquelin^  found  two 
varieties  of  fatty  matter  in  the  brain — the  one  white,  the  other  red, 
the  pro]:)erties  of  which  have  not  been  fully  investigated.  Both  give 
rise  to  phosphoric  acid  by  calcination,  without  there  being  any  evidence 
of  an  acid  or  phosphate  in  their  composition.  They  may  be  obtained 
by  repeatedly  boiling  the  cerebral  substance  in  alcohol ;  filtering  each 
time  ;  mixing  the  various  liquors,  and  suffering  them  to  cool : — a  lamel- 
lated  substance  is  deposited,  w^hich  is  the  ivhite  fatty  matter.  By  eva- 
porating the  alcohol,  which  still  contains  red  fatty  matter  and  osmazome, 
to  the  consistence  of  bouillie ;  and  exposing  this,  when  cold,  to  the 
action  of  alcohol,  the  osmazome  is  entirely  dissolved,  whilst  the  alcohol 
takes  up  scarcely  any  red  fatty  matter. 

3.  Acetic  acid. — This  acid  exists  in  a  very  sensible  manner  in  sweat, 
urine,  and  milk — even  when  entirely  sweet.  It,  or  lactic  acid,  is  formed 
in  the  stomach  in  indigestion  ;  was  found  by  the  author  and  his  late 
friend.  Professor  Emmet,  contained  in  the  gastric  secretions  in  health, 

'  and  is  one  of  the  constant  products  of  the  putrid  fermentation  of  ani- 
mal or  vegetable  substances.  It  is  the  most  prevalent  of  the  vegetable 
acids,  and  most  easily  formed  artificially. 

4.  Oxalic  acid. — This  acid — which  exists  extensively  in  the  vege- 
table kingdom,  but  always  united  with  lime,  potassa,  soda,  or  oxide  of 
iron — is  only  found,  combined  with  lime,  as  an  animal  constituent  in 
certain  urinary  calculi. 

5.  Benzoic  acid. — Tliis  acid,  found  in  many  individuals  of  the  vege- 
table kingdom,  is  likewise  met  with  in  the  urine  of  the  horse,  cow, 
camel,  and  rhinoceros ;  and  sometimes  in  that  of  man,  especially  of 
children.  When  benzoic  acid  is  swallowed,  hippuric  acid  is  observed 
in  the  urine ;  and  it  was  supposed  by  Mr.  A.  Ure  and  others,  that  this 
was  owing  to  the  conversion  of  uric  acid  into  hippuric;  and  as  the 
hippuratcs  are  more  soluble,  it  was  suggested  by  liim,  that  benzoic  acid 
might  be  advantageously  exhibited  in  lithuria,  and  in  cases  of  gouty 
depositions  of  lithate  of  soda.  It  has  been  found,  however,  by  Drs. 
Keller  and  Garrod,^  and  by  Professors  Booth  and  Boye,  of  Phila- 
delphia,^ that  the  administration  of  benzoic  acid  exerts  no  influence 
on  the  amount  of  uric  acid  in  the  urine. 

>  Annales  de  Chim.,  Ixxxi.  37.  *  Liebig's  Animal  Chemistry,  p.  316. 

3  Proceedings  of  the  American  Philosophical  Society  at  the  Centennial  Celebration  in 
Philada.,  May,  1843,  and  Transactions  of  the  A.  P.  Society,  vol.  ix.  pt.  2,  Philadelphia, 
1845. 


OEGAXIC   ELEMENTS.  65 

6.  Lactic  acid. — Acid  of  milk  is  met  with  in  blood,  gastric  juice, 
urine,  milk,  marrow,  and  also  in  muscular  flesli.  At  times  it  is  in  a 
free  state,  but  is  usually  united  with  alkalies.  However  much  it  may 
be  concentrated,  it  does  not  crystallize,  but  remains  under  the  form  of 
syrup  or  extract.  AVhen  cold  it  is  tasteless,  but,  when  heated,  has  a 
sharp  acid  taste.  According  to  Dr.  Prout,  this  acid,  like  urea,  results 
from  the  decomposition  of  the  gelatinous  parts  of  the  system  ;  accord- 
ing to  Berzelius,  however,  it  is  a  general  product  of  the  spontaneous 
decomposition  of  animal  matters  within  the  body.  Liebig^  formerly 
denied  that  any  lactic  acid  is  formed  in  the  stomach  in  health ;  and 
affirmed,  that  the  property  possessed  by  many  substances,  such  as  starch, 
and  the.  varieties  of  sugar,  by  contact  with  animal  matters  in  a  state 
of  decomposition,  of  passing  into  lactic  acid,  had  induced  physiologists 
too  hastily  to  assume  the  fact  of  the  production  of  lactic  acid  during 
healthy  digestion: — yet  he  now  admits  its  presence. 

7.  Sugar  of  milk. — This  substance,  which  is  so  called  because  it  has 
a  saccharine  taste,  and  exists  chiefly,  if  not  solely,  in  milk,  differs  from 
ordinary  sugar  in  not  fermenting.  It  is  obtained  by  evaporating  whey, 
formed  during  the  making  of  cheese,  to  the  consistence  of  honey ;  al- 
lowing the  mass  to  cool ;  dissolving ;  clarifying  and  crystallizing.  It 
commonly  crystallizes  in  regular  parallelopipedons,  terminated  by 
pyramids  with  four  faces.  It  is  white ;  semitransparent ;  hard,  and  of 
a  slightly  saccharine  taste. 

8.  Sugar  of  diabetes. — In  diabetes  mellitus,  the  urine,  which  is  often 
passed  in  enormous  quantity,  contains,  at  the  expense  of  the  economy, 
a  large  amount  of  peculiar  saccharine  matter,  which,  when  properly 
purihed,  appears  identical  in  properties  and  composition  with  vegetable 
sugar,  and  approaches  nearer  to  the  sugar  of  grapes — glucose — than 
to  that  of  the  cane.  It  is  obtained  in  an  irregularly  crystalline  mass, 
by  evaporating  diabetic  urine  to  the  consistence  of  syrup,  and  keeping 
it  in  a  warm  place  for  several  days.  It  is  purified  by  washing  in  cold, 
or — at  the  most — gently  heated  alcohol,  till  the  liquor  comes  off  colour- 
less; and  then  dissolving  it  in  hot  alcohol.  By  repeated  crystallization 
it  is  thus  rendered  pure.^  In  the  notes  of  two  cases  of  diabetes  mel- 
litus now  before  the  author,  it  appears  that  sixteen  ounces  of  the  urine 
of  one  patient,  of  the  specific  gravity  of  l.OS-i,  afforded  a  straw-co- 
loured extract,  which,  when  cold  and  consolidated,  weighed  one  ounce 
and  five  drachms.  The  same  quantity  of  the  urine  of  the  other  patient, 
specific  gravity  1.040,  yielded  one  ounce  and  seven  drachms.  Neither 
extract  appeared  to  contain  urea  when  nitric  acid  was  added ;  but  when 
a  portion  was  dissolved  in  water,  and  subjected  to  a  temperature  of 
212°,  traces  of  ammonia  were  manifested  on  the  vapour  being  presented 
to  the  fumes  of  chlorohydric  acid.  From  this  a  conclusion  was  drawn, 
that  urea  was  present,  as  it  is  the  only  known  animal  matter  decom- 
posed by  the  heat  of  boiling  water.  In  a  little  more  than  a  month, 
the  subject  of  the  latter  case  passed  about  four  hundred  and  eighty 
pints  of  urine,  or  about  seventy -five  pounds  troy  of  diabetic  sugar ! 

9.  Hepatic  sugar.,  liver  sugar.,  found,  by  M.  Bernard,  to  be  produced 
in  the  liver,  appears  to  resemble  diabetic  sugar  more  than  it  does  glu- 

'  Op.  cit.,  p.  107.  ^  Prout,  Medico-Cliirui-g.  Trausact.,  viii.  538. 


56  MATERIAL   COMPOSITION   OF   MAN. 


1 


cose.  Little  is  known,  however,  of  its  precise  characters;  but  it 
is  much  more  assimilable  than  glucose ;  for,  when  injected  into  the 
veins,  but  little  of  it  is  detected  in  the  urine.^ 

10.  Bilin  or  Picromel. — M.  Thenard^  discovered  this  principle  in  the 
bile  of  the  ox,  sheep,  dog,  cat,  and  several  birds ;  Chevalier,  in  that  of 
man.  To  obtain  it,  the  acetate  of  lead  of  commerce  must  be  added  to 
bile  until  there  is  no  longer  any  precipitate.  By  this  means,  the  yellow 
matter  of  the  bile  and  the  whole  of  the  fatty  matter  are  thrown  down, 
united  with  the  oxide  of  lead ;  the  phosphoric  acid  of  the  phosphate  of 
soda,  and  the  sulphuric  acid  of  the  sulphate  of  soda,  are  likewise  pre- 
cipitated. The  picromel  may  then  be  thrown  down  from  the  filtered 
liquor  by  the  subacetate  of  lead.  The  precipitate,  which  is  a  combina- 
tion of  picromel  with  oxide  of  lead,  must  now  be  washed  and  dissolved 
in  acetic  acid.  Through  this  solution,  sulphuretted  hydrogen  is  passed 
to  separate  the  lead ;  the  solution  is  then  filtered,  and  the  acetic  acid 
driven  off  by  evaporation. 

Pure  picromel  is  devoid  of  colour,  and  has  the  same  appearance  and 
consistence  as  thick  turpentine.  Its  taste  is  at  first  acrid  and  bitter, 
but  afterwards  sweet.  Its  smell  is  nauseous,  and  specific  gravity 
greater  than  that  of  water.  When  digested  with  resin  of  bile,  a  por- 
tion of  the  latter  is  dissolved,  and  a  solution  obtained,  which  has  a 
bitter  and  a  sweet  taste,  and  yields  a  precipitate  with  the  subacetate  of 
lead  and  the  stronger  acids.  This  is  the  compound  that  causes  the 
peculiar  taste  of  the  bile. 

11.  Gholesterin. — This  is  a  constituent  principle  of  the  blood,  bile, 
medullary  neurine,  and  vernix  caseosa.  It  is  often  precipitated  from 
bile  in  a  crystalline  state :  and  forms  of  itself  concretions  which  have 
an  evidently  laminated  texture.  It  has  been  very  frequently  met  with 
in  morbid  secretions  and  tissues ;  in  the  fluid  of  dropsies ;  in  that  of 
cysts  and  hydatids ;  and  in  medullary  fungus  and  other  tumours.  At 
times,  it  is  dissolved;  at  others,  swims  upon  the  fluid  in  brilliant  plates, 
or  forms  solid  masses.  It  is  obtained  from  biliary  calculi  by  boiling 
in  water,  and  dissolving  them  afterwards  in  boiling  alcohol.  On  cool- 
ing, crystals  of  cholesterin  separate. 

These  inorganic  and  organic  elements — with  others  of  less  moment 
discovered  by  modern  chemists — variously  combined  and  modified  by 
the  vital  force,  constitute  the  different  parts  of  the  animal  fabric.^ 
Chemistry,  in  its  present  improved  condition,  enables  us  to  separate 
them,  and  to  investigate  their  properties ;  but  all  the  information  we 
derive  from  this  source  relates  to  bodies,  that  have  been  influenced  by 
the  vital  force,  but  are  no  longer  so ;  and  in  the  constant  mutations 
that  occur  in  the  system  whilst  life  exists,  and  under  its  controlling 
agency,  the  same  textures  might  exhibit  very  difterent  chemical  cha- 

'  Bernard,  Le(,'ons  de  Physiologie  Experimeutale,  &c.  &c.,  p.  209,  Paris,  1855. 

2  Memoir.  d'Arcueil,  i.  2:3,  and  Traite  de  Chimie,  torn.  iii. 

3  See,  on  all  this  subject,  Robin  and  Verdeil,  Traite  de  Chimie  Anatomique  at  Physio- 
logique,  &.C.,  Paris,  1853 ;  and  Lehmann,  Lehrbuch  der  Physiologischen  Chemie,  Leipz., 
1852,  or  translation  of  the  same,  by  Dr.  Geo.  E.  Day:  Amer.  edit.,  by  Dr.  Robt.  E. 
Rogers,  Phila.,  1855.  Also,  Report  on  the  Progress  of  Animal  Chemistry  during  the 
years  1852,  3  and  4,  by  Dr.  Geo.  E.  Day,  in  the  British  and  Foreign  Medico-Chirurgical 
Review  for  April  and  July,  1855. 


SOLID   PAKTS.  57 

racterisfcics,  could  our  researches  be  directed  to  tliem  under  tliose 
circumstances.  "Whenever,  therefore,  the  physiologist  has  to  apply 
chemical  elucidations  to  operations  of  the  living  machine,  he  must  re- 
collect that  all  his  analogies  are  drawn  from  dead  matter,  which  dif- 
fers so  widely  from  the  living  as  to  suggest  the  necessity  of  a  wise  and 
discriminating  caution. 

The  components  of  the  animal  body  are  invariably  found  under  two 
forms — solids  and  fluids.  Both  are  met  with  in  every  animal,  the  for- 
mer being  derived  from  the  latter;  for,  from  the  blood  every  part  of 
the  body  is  separated ;  yet  they  are  mutually  dependent,  for  every 
liquid  is  contained  in  a  solid.  The  blood  itself  circulates  in  solid 
vessels.  Both,  too,  possess  an  analogous  composition ;  are  in  constant 
motion,  and  incessantly  converted  from  one  into  the  other.  Every 
animal  consists  of  a  union  of  the  two ;  and  this  union  is  indispensable 
to  life.  Yet  certain  vague  notions  with  regard  to  their  relative  pre- 
];)onderance  in  the  economy,  and  to  their  agency  in  the  production  of 
disease,  have  led  to  discordant  doctrines  of  pathology, — the  solidists 
l)elieving,  that  the  cause  of  most  affections  is  resident  in  the  solids ; 
the  Juimorists,  that  we  are  to  look  for  it  in  the  fluids.  In  this,  as  in 
similar  cases,  the  mean  will  lead  to  the  most  satisfactory  result.  The 
causes  of  disease  ought  not  to  be  sought  in  the  one  or  the  other  exclu- 
sively. 

c.  Of  the  Solid  Parts  of  the  Human  Body. 

A  solid  is  a  body  whose  particles  adhere  to  each  other,  so  that  they 
do  not  separate  by  their  own  weight ;  but  require  the  agency  of  some 
extraneous  force  to  effect  the  disjunction.  Anatomists  reduce  all  the 
solids  of  the  human  body  to  twelve  varieties; — hone,  cartilage,  muscle, 
ligament,  vessel,  nerve,  ganglion,  follicle,  gland,  membrane,  areolar  mem- 
brane, and  viscus. 

1.  Bone  is  the  hardest  of  the  solids.  It  forms  the  skeleton ;  the 
levers  for  the  various  muscles  to  act  upon ;  and  serves  for  the  protec- 
tion of  important  organs. 

2.  Cartilage  is  of  a  white  colour,  formed  of  very  elastic  tissue ;  cover- 
ing the  articular  extremities  of  bones  to  facilitate  their  movements; 
sometimes  added  to  bones  to  prolong  them,  as  in  the  case  of  the  ribs ; 
at  others,  placed  within  the  articulations  to  act  as  elastic  cushions; 
and,  in  the  foetus,  forming  a  substitute  for  bone.  Hence,  cartilages 
are  divided  into  articular  or  incr'usting,  cartilages  ofjyrolongation,  interarti- 
cular  cartilages,  and  cartilages  of  ossification. 

3.  Muscles  constitute  the  flesh  of  animals.  They  consist  of  fasciculi 
of  contractile  fibres,  extending  generally  from  one  bone  to  another; 
and  are  the  agents  of  all  movements. 

4.  Ligaments  are  tough;  difficult  to  tear;  and  under  the  form  of 
cords  or  membranes,  serve  to  connect  different  parts  with  each  other, 
particularly  bones  and  muscles;  hence  their  division,  by  some  anato- 
mists, into  ligaments  of  hones — as  the  ligaments  of  the  joints ;  and  liga- 
ments  of  muscles — as  the  tendons  and  aponeuroses. 

5.  Vessels  are  solids,  having  the  form  of  canals,  in  which  the  fluids 


58  MATERIAL   COMPOSITION   OF   MAN. 

circulate.     They  are  called — according  to  the  fluid  they  convey — san- 
guineous (arterial  and  venous),  chyUferous,  lymphatic,  &c. 

6.  Nerves  are  cords,  consisting  of  numerous  tubular  fasciculi.  These 
are  connected  with  the  brain,  spinal  marrow,  or  great  sympathetic. 
They  are  the  organs  by  which  impressions  are  conveyed  to  the  nervous 
centres,  and  by  which  each  part  receives  from  these  its  nervous  influ- 
ence. There  are  three  great  divisions  of  the  nerves, — the  cerebro-sjnnal, 
true  spinal,  and  organic. 

7.  Ganglions  are  solid  knots  in  the  course  of  a  nerve  which  seem  to 
be  formed  of  an  inextricable  interlacing  of  nervous  filaments.  The 
term  is  likewise  apjilied,  by  many  modern  anatomists,  to  similar  inter- 
lacings  of  the  ramifications  of  lymphatic  vessels.  Ganglions  may,  con- 
sequently, either  be  nervous  or  vascular ;  and  the  latter,  again,  may  be 
divided  into  cliyliferous  or  lymphatic,  according  to  the  kind  of  vessel  on 
which  they  appear.  Chaussier,  a  distinguished  anatomist  and  physi- 
ologist, has  given  the  name  glandiform  ganglions  to  certain  organs 
whose  nature  and  functions  are  unknown,  but  which  appear  to  be  con- 
cerned in  lymphosis, — as  the  thjmius  gland,  the  thyroid  gland,  &c. 

8.  Follicles  or  crypts  are  secretory  organs,  shaped — when  simple — like 
membranous  ampullas  or  vesicles,  formed  by  an  inversion  of  the  outer 
membranes  of  the  body — the  skin  and  mucous  surfaces — and  secreting 
a  fluid  intended  to  lubricate  them.  They  are  often  divided  into  the 
simp)h  or  isolated;  the  conglomerate ;  and  the  conqwund,  according  to 
their  size,  or  the  manner  in  which  they  are  grouped  and  united  to- 
gether. 

9.  Glands  are  secretory  organs  not  differing  essentially  from  the  last. 
Their  organization  is  more  complex ;  and  the  fluid,  after  secretion,  is 
poured  out  by  means  of  one  or  more  excretory  ducts. 

10.  Ilemhrane. — This  is  one  of  the  most  extensive  and  important  of 
the  substances  formed  chiefly  of  areolar  tissue.  It  is  spread  out  in  the 
shape  of  a  web ;  and,  in  man,  serves  to  line  cavities  and  reservoirs ;  and 
to  form,  support,  and  envelope  organs. 

Bichat  divides  membranes  into  two  kinds,  simple  and  compound,  ac- 
cording as  they  are  formed  of  one  or  more  layers. 

Simp)le  membranes  are  of  three  kinds,  serous,  mucous,  and  fibrous. 

1st.  Serous  membranes  constitute  all  the  sacs  or  shut  cavities  of  the 
body, — those  of  the  chest  and  abdomen,  for  example. 

2dly.  Mucous  membrcmes  line  all  the  outlets  of  the  body, — the  air- 
passages,  alimentary  canal,  urinary  and  genital  organs,  &;c. 

Sdly.  Fibrous  membranes  form  tendon,  aponeurosis,  ligament,  &c. 

Compound  membranes  are  formed  by  the  union  of  the  simple,  and  are 
divided  into  fibro-serous,  as  the  pericardium;  sero-mucous,  as  the  gall- 
bladder, at  its  lower  part;  and fibro-mucous,  as  the  ureter. 

11.  Areolar,  cellular  or  laminated  tissue — to  be  described  presentl}^ — 
is  a  sort  of  spongy  or  areolar  structure,  which  forms  the  framework  of 
the  solids;  fills  up  the  spaces  between  them,  and  serves  at  once  as  a 
bond  of  union  and  of  separation. 

12.  A  viscus  is  the  most  complex  solid  of  the  body ;  not  only  as  re- 
gards intimate  organization,  but  use.  This  name  is  given  to  organs 
contained  in  the  splanchnic  cavities, — brain,  thorax,  and  abdomen, — 
and  hence  the  viscera  are  termed  cerebral,  thoracic,  and  abdominal. 


SOLID   PARTS.  -  59 

Every  animal  solid  is  either  amorphorts  or  fibrous;  that  is,  it  is  either 
without  apparent  arrangement,  like  jelly;  or  is  disposed  in  minute 
threads,  called  fibres.  The  disposition  of  these  threads,  in  different 
structures,  is  various.  Sometimes,  they  retain  the  form  of  threads;  at 
others,  they  have  that  of  laminte,  lamellas,  or  plates.  Accordingly, 
"when  we  examine  any  animal  solid,  where  the  organization  is  percep- 
tible, it  is  found  to  be  either  amorphous,  or  fibrous  and  laminated. 

This  circumstance  led  the  ancients  to  endeavour  to  discover  an  ele- 
mentary fibre  or  filament,  from  which  the  various  organs  might  be 
formed.  Haller^  embraced  the  idea,  and  endeavoured  to  unravel  every 
texture  to  this  ultimate  element, — which,  he  conceived,  is  to  the  physi- 
ologist what  the  line  is  to  the  geometer ;  and,  as  all  figures  can  be  con- 
structed from  the  line,  so  every  tissue  and  organ  of  the  body  may  be 
built  up  from  the  filament.  Haller,  however,  admitted  that  this  ele- 
mentary fibre  is  not  capable  of  demonstration,  and  that  it  is  visible 
only  to  the  "mind's  eye," — ^Hnvisibilis  ea  fibra,  qiuirn  sold  mentis  acie 
adtingiinusP  It  must  be  regarded,  indeed,  as  a  pure  abstraction ;  for, 
as  different  animal  substances  in  the  mass  have  different  proportions 
of  carbon,  hydrogen,  oxygen,  and  nitrogen,  it  is  fair  to  conclude  that 
the  elementary  fibre  must  equally  differ  in  the  different  substances. 

The  ancients  believed  that  the  first  product  of  the  elementary  fibre 
was  areolar  tissue ;  and  that  this  tissue  forms  every  organ  of  the  body, 
— the  difference  in  the  appearance  of  the  organs  arising  from  the  dif- 
ferent degrees  of  condensation  of  its  laminae.  Anatomists,  however, 
have  been  unable  to  reduce  all  animal  solids  to  areolar  tissue  only. 

In  the  upper  classes  of  animals,  three  primary  fibres  or  tissues  or 
anatomical  elements  are  usually  admitted, — the  areolar,  cellular  or 
laminated;  the  muscular;  and  the  nervous,  pulpy  or  medullary. 

1.  The,  areolar,  cellular,  mucous,  filamentous  or  laminated  fibre  or 
tissue  is  the  most  simple  and  abundant  of  animal  solids.  It  exists  in 
every  organized  being;  and  is  an  element  of  every  solid.  In  the  ena- 
mel of  the  teeth  only  it  has  not  been  detected.  It  is  formed  of  an 
assemblage  of  thin  laminae,  of  delicate,  whitish,  extensible  filaments, 
interlacing  and  leaving  between  each  other  areolae  or  spaces.  These 
filaments — although  possessed,  like  every  other  living  tissiie,  of  con- 
tractility or  the  power  of  feeling  an  appropriate  irritant  and  of  moving 
responsive  to  such  irritant — do  not  move  perceptibly  under  the  influ- 
ence of  mechanical  or  chemical  stimuli.  They  are  mainly  composed 
of  concrete  gelatin. — The  great  bulk  of  animal  solids  consists  of  areolar 
tissue,  arranged  as  membrane. 

2.  Muscular  fibre  or  tissue  is  a  substance  of  peculiar  nature;  ar- 
ranged in  fibres  of  extreme  delicacy.  The  fibres  are  linear,  soft,  gray- 
ish or  reddish,  and  manifestly  possessed  of  contractility  or  irritability ; 
that  is,  they  move  very  perceptibly  under  the  influence  of  mechanical 
or  chemical  stimuli.  They  are  composed,  essentially,  of  fibrin.  Their 
histology  will  be  described  hereafter. 

Muscular  fibres,  which  are  arranged  in  the  form  of  meml^ranous 
expansions  or  muscular  coats,  differ  from  proper  muscles  chiefly  in  the 
mechanical  disposition  of   the  fibres.      The  physical  and  chemical 

■  Elemonta  Physiologire,  vol.  i.  lib.  i.  sect.  i.  p.  7,  Lausan.,  1757. 


60  MATERIAL   COMPOSITION   OF   MAN. 

characters  of  both  are  identical.  The  fibres,  instead  of  being  collected 
into  fasciculi,  are  in  layers,  and,  instead  of  being  parallel,  interlace. 
This  tissue  does  not  exist  in  the  zoophyte. 

3.  Nervous^  imlpy^  or  medullary  fibre  or  tissue^  which  will  be  referred 
to  hereafter,  is  much  less  distributed  than  the  preceding.  It  is  of  a 
pulpy  consistence ;  is  composed  essentially  of  albumen  united  to  a 
phosphuretted  fatty  matter  ;  and  is  the  organ  for  receiving  and  trans- 
mitting impressions  to  and  from  the  nervous  centres.  Of  it,  brain, 
cerebellum,  medulla  spinalis,  nerves  and  their  ganglia  are  composed. 

Professor  Chaussier'  added  another  primary  fibre  or  tissue — the 
aTbugineous.  It  is  white ;  satiny  ;  resisting ;  of  a  gelatinous  nature ; 
and  constitutes  tendons  and  tendinous  structures.  He  is,  perhaps,  the 
only  anatomist  that  admits  this  tissue.  Others  properly  regard  it  as  a 
condensed  variet}^  of  the  areolar. 

These  various  fibres  or  tissues,  by  uniting  differently,  constitute  the 
first  order  of  solids ;  and  these  again,  by  union,  give  rise  to  compound 
solick,  from  which  the  different  organs  are  formed.  A  bone,  for  ex- 
ample, is  a  compound  of  various  tissues;  osseous  in  its  body;  medullary 
in  its  interior ;  and  cartilaginous  at  its  extremities. 

Bichat^  was  the  first  anatomist  who  possessed  clear  views  regarding 
the  constituent  tissues  of  the  animal  frame  ;  and  whatever  merit  may 
accrue  to  after  anatomists  and  physiologists,  he  is  entitled  to  the  credit 
of  having  pointed  out  the  path,  and  facilitated  the  labours  of  the  ana- 
tomical analyst. 

The  term  texture  can  only  apply  to  solids ;  but  inasmuch  as  there 
are  in  suspension  in  certain  fluids,  as  the  blood,  chyle  and  lymph, 
solid  corpuscles  of  determinate  form  and  organic  properties,  and  which 
are  not  mere  products  or  secretions  of  a  particular  organ,  or  confined 
to  a  particular  part,  such  corpuscles  have  been  looked  upon  as  organ- 
ized constituents  of  the  body,  and  therefore  considered  along  with  the 
solid  tissues ;  and,  accordingly,  the  textures  and  other  organized  con- 
stituents have  been  enumerated  as  follows  •? 

The  blood,  chyle  and  lymph.  Bone  or  osseous  tissue. 

Epidermic  tissue,  including  epi-     Muscular  tissue. 

thelium,    cuticle,     nails,  and     Nervous  tissue. 

hairs.  Bloodvessels.                              "*• 

Pigment.  Absorbent  vessels  and  glands. 

Adipose  tissue.  Serous  and  synovial  membranes. 

Cellular  (areolar)  tissue.  ]\[ucous  membranes. 

Fibrous  tissue.  Skin. 

Elastic  tissue.  Secreting  glands. 
Cartilage  and  its  varieties. 

Under  the  idea,  now  entertained,  that  all  organized  tissues  are 
essentially  composed  of  cells  having  plastic  or  formative  powers,  with 
an  intercellular  substance  or  blastema,  the  tissues  have  been  thus 
arranged  by  Schwann, •*  the  great  author  of  the  cell  doctrine. 

'  Table  Synoptique  des  Solides  Organiques. 
2  Anatomic  Gen.,  Paris,  1801,  torn.  i. 

'  Quain  and  Sharpey,  Hnman  Anatomy,  Amer.  edit.,  by  Dr.  Leidy,  i.  39,  Pliilad.,  1849. 

*  Microscopical    Researches  into  tlie  Accordance    in  "the  Structure  and  Gro-wth  of 

Animals  and  Plants.     Sydenham  Society's  edit.,  by  Henry  Smith,  p.  60,  London,  lS-i7. 


PRIMARY   AND   COMPOUND   TISSUES.  61 

1,  Isolated,  independent  cells.  To  this  class  the  cells  in  fluids  pre- 
eminently belong  : — lympli  globules ;  blood  corpuscles. 

2.  Independent  cells  united  into  continuous  tissues;  sucli  as  the 
horny  tissues  and  the  crystalline  lens. 

8.  Cells  in  which  only  the  cell  walls  have  coalesced — cartilage,  bone, 
and  the  substantia  'proinia  (ivory)  of  the  teeth. 

•i.  Fibre  cells — cellular  (areolar),  fibrous  and  elastic  tissue. 

5.  Cells  in  which  both  the  cell  walls  and  cell  cavities  have  coalesced, 
— muscle,  nerve  and  capillary  vessels. 

Dr.  Allen  Thomson^  has  proposed  the  following  tabular  view,  which 
— he  remarks — may  be  adopted  in  preference  to  the  foregoing  as  com- 
bining similar  theoretical  considerations  with  a  more  immediate  refer- 
ence to  the  actual  form  of  the  prevailing  structural  elements  in  the 
different  tissues.  He  properly  adds,  however,  that  this  classification 
is  open — as  he  might  have  said  every  arrangement  must  be — to  several 
objections;  inasmuch  as  it  brings  together,  under  the  same  head,  some 
parts  endowed  with  different  functions ;  and  separates  some  textures 
whose  functions  are  closely  related  ;  and  it  does  not  point  out  suffi- 
ciently the  usual  degree  of  complexity  of  the  several  textures. 

Some  part  of  it,  moreover,  is  founded  on  theoretical  considerations 
not  yet  fully  established ;  and  the  distinctions  on  which  it  rests  are 
based  on  a  structural  analysis  of  various  extent  in  the  different  tex- 
tures. On  the  whole,  however,  it  is  a  sufficient  exponent  of  the  exist- 
ing state  of  belief  on  the  subject. 

I.  Organized  textures  in  which  the  cellular  form  of  the  constituent 
elements  is  apparent ;  not  unfrequently  also  presenting  granules  of 
molecular  deposition. 

1.  Eounded  simple  cells,  floating  loose  in  fluid,  Bloody  Lymph^  Chyle 
and  Milk  Corpuscles,  &c. 

2.  Simple  cells  massed  together,  either  preserving  their  cellular 
form,  and  without  other  parts  intervening,  or  altered  in  form  and 
mixed  with  other  solid  elements : — Pigment,  Fat,  Cuticle,  Horny  tex- 
tures, JEJjntheUum,  Crystalline  lens.  Cartilage. 

3.  Simple  cells,  or  their  contents,  altered  in  form: — Ciliated  texture, 
Spermatozoa. 

4.  Compound  cells,  separate  or  mixed  with  other  textures: — Ovum, 
Ganglionic  corpuscles. 

II.  Textures  exhibiting  a  simply  fibrous  structure. 

1.  Filamentous  (areolar)  texture ;  formerl}^  Cellular  texture. 

2.  Fibrous  textures : — Tendon,  Ligament,  Fibrous  membranes.  Fibrous 
plates. 

8.  Elastic  fibrous  texture. 

III.  Textures  exhibiting  a  tubular  structure. 

1.  Containing  moving  fluids: — Bloodvessels  and  Absorbent  vessels. 

2.  Containing  muscular  substance  : — Striated  and  non-striated  mus- 
cular fibre. 

3.  Containing  nervous  matter : — Primitive  nerve  tubes. 

IV.  Textures  exhibiting  a  membranous  structure. 

1.  Principally  filamentous : — Serous  and  Synovial  membranes. 

'  Outlines  of  Physiology  for  tlio  U:=e  of  Students,  pt.  i.  p.  C8,  Edinb.,  1848. 


62  MATERIAL   COMPOSITION   OF   MAN. 

2.  Filamentous  and  vascular : — Mucous  membranes  ;  True  skin. 

8.  Membrane  and  cells: — Glands. 

4.  Membrane  and  bloodvessels,  &c. : — Lungs. 

In  combining  to  form  the  different  structures,  tlie  solids  are  arranged 
in  various  ways.  Of  these,  the  chief  are  in  filaments  or  elementary- 
fibres,  tissues,  organs  apparatuses,  and  systems.  A  filament  is  the 
elementary  solid.  A  fibre  consists  of  a  number  of  filaments  united 
together.  Occasionally  this  is  called  a  tissue: — the  term  tissue  usually, 
however,  means  a  particular  arrangement  of  fibres.  An  organ  is  a 
compound  of  several  tissues.  An  apparatus  is  an  assemblage  of  organs, 
concurring  to  the  same  end : — the  digestive  ajparatus  consists  of  the 
organs  of  mastication,  insalivation,  and  deglutition,  the  stomach,  duo- 
denum, pancreas,  liver,  &c.  These  may  be,  and  are,  of  very  dissimilar 
character,  both  as  regards  their  structure  and  functions ;  but,  if  they 
concur  in  the  same  object,  they  form  an  apparatus.  A  system^  on  the 
other  hand,  is  an  assemblage  of  organs,  all  of  which  possess  the  same 
or  an  analogous  structure.  Thus,  all  the  muscles  of  the  body  have  a 
common  structure  and  function ;  and  form,  in  the  aggregate,  the 
muscular  system.  All  the  vessels  of  the  body,  and  all  the  nerves,  for 
like  reasons,  constitute,  respectively,  the  vascular  and  nervous  sys- 
tems. 

d.  Of  the  Fluids  of  the  Human  Body. 

The  positive  quantity  or  proportion  of  the  fluids  in  the  human  body 
does  not  admit  of  appreciation,  as  it  must  vary  at  different  periods, 
and  under  different  circumstances.  The  younger  the  animal,  the 
greater  is  its  preponderance.  When  we  first  see  the  embryo,  it  ap- 
pears to  be  almost  wholly  fluid.  As  it  becomes  gradually  developed, 
the  proportion  of  solid  parts  increases,  until  the  adult  age;  after  which 
it  becomes  less  and  less  in  the  progress  of  life.  During  the  whole  of 
existence,  too,  the  quantity  of  fluids  in  the  body  fluctuates.  At  times, 
there  is  plethora  or  unusual  fulness  of  bloodvessels;  at  others,  the 
blood  is  less  in  quantity. 

Experiments  have  been  made  for  the  purpose  of  ascertaining  the 
relative  proportion  of  fluids  to  solids.  M.  Kicherand  says,  that  they 
are  in  the  ratio  of  six  to  one;  M.  Chaussier,  of  nine  to  one.  The  latter 
professor  put  a  dead  body,  weighing  one  hundred  and  twenty  pounds, 
into  a  heated  oven,  and  dried  it.  After  desiccation,  it  was  found  to 
be  reduced  to  twelve  pounds.  It  is  probable,  however,  that  some  of 
the  more  solid  portions  were  driven  oft'  by  the  heat  employed ;  and 
hence  that  the  estimated  proportion  of  fluids  was  too  high.  On  this 
account,  M.  Berard'  thinks,  that  instead  of  estimating  the  proportion 
of  liquids  at  nine-tenths,  it  would  be  better  to  take  the  mean  result  of 
experiments  by  M.  Chevreul,  who  performed  the  desiccation  in  vacuo 
and  with  a  very  moderate  heat.  This  would  give  the  proportion  of 
water  in  the  human  body  about  6.667  parts  in  the  10.000. 

In  the  Egyptian  mummies,  which  are  completely  deprived  of  fluid, 
the  solids  are  extremely  light,  not  weighing  more  than  seven  pounds ; 
but  as  we  are  ignorant  of  the  original  weight  of  the  body,  we  cannot 

'  Cours  de  Physiologic,  p.  200,  Paris,  1848. 


FLUIDS.  63 

arrive  at  any  approximation.  The  dead  bodies  found  in  the  arid  sands 
of  Arabia,  as  well  as  the  dried  preparations  of  the  anatomical  theatre, 
afford  additional  instances  of  reduction  by  desiccation.  To  a  less  ex- 
tent, we  have  the  same  thing  exhibited  in  the  excessive  diminution  in 
weight  that  occurs  in  disease,  and  occasionally  in  those  who  are  ap- 
parently in  health.  Not  many  years  ago,  an  Anatomie  vivante  was  ex- 
hibited in  London  to  the  gaze  of  the  curious  and  scientific,  whose 
weight  was  not  more  than  eighty  pounds.  Yet  the  ordinary  functions 
were  carried  on,  apparently  unmodified.  In  the  year  1830,  a  still 
more  wonderful  phenomenon  was  shown.  A  man  named  Calvin 
Edson,  forty-two  years  old,  five  feet  two  inches  high,  weighed  but  sixty 
pounds.  His  weight  had  formerly  been  one  hundred  and  thirty-five 
pounds.  For  sixteen  years  previously,  he  had  been  gradually  losing 
flesh,  without  any  apparent  disease,  having  enjoyed  perfect  health  and 
appetite,  and  eating,  drinking,  and  sleeping  as  well  as  any  one.  He 
■\vas  properly  called  the  "  living  skeleton^  It  was  stated  in  the  public 
journals'  that  Dr.  Edson,  a  brother  of  Calvin,  was  to  all  appearance 
entirely  destitute  of  flesh.  He  was,  in  18-17,  forty -two  years  old ;  of 
ordinary  height — five  feet  six  inches,  and  yet  weighed  only  forty-nine 
pounds.  He  retained  all  his  faculties  apparently  in  full  vigour.  We 
have  it  also,  on  the  authority  of  Captain  Eiley,^  that  after  protracted 
sufferings  in  Africa,  he  was  reduced  from  two  hundred  and  forty  pounds 
to  below  ninety  [?]. 

The  fluids  are  variously  contained;  sometimes  in  vessels — as  the 
blood  and  lymph ;  at  others,  in  cavities — as  the  fluids  secreted  by  the 
pleura,  peritoneum,  arachnoid  coat  of  the  brain,  &c. :  others  are  in 
minute  areolae — as  the  fluid  of  the  areolar  membrane  ;  whilst  others, 
again,  are  intimately  combined  with  the  solids.  They  differ  likewise 
in  density, — some  existing  in  the  state  of  halitus  or  vapour ;  others 
being  very  thin  and  aqueous — as  the  fluid  of  the  serous  membranes ; 
and  others  of  more  consistence — as  the  secretion  of  the  mucous  mem- 
branes, animal  oils,  &c. 

The  physical  and  chemical  properties  of  the  fluids  will  engage  atten- 
tion when  they  fall  individually  under  consideration ;  and  we  shall 
find  that  one  of  them  at  least — the  blood — exhibits  certain  phenomena 
analogous  to  those  of  the  livino^  solid. 

The  fluids  have  been  differently  classed,  according  to  the  particular 
views  that  have,  from  time  to  time,  prevailed  in  the  schools.  The  an- 
cients referred  them  all  to  four — blood,  bile,  phlegm  or  pituita,  and 
atrabilis ;  each  of  which  was  conceived  to  abound  in  one  of  the  four 
ages,  seasons,  climates,  or  temperaments.  Blood  predominated  in 
youth,  in  the  spring,  in  cold,  mountainous  regions,  and  in  the  sanguine 
or  inflammatory  temperament.  Pituita,  or  phlegm,  had  the  mastery  in 
old  age,  in  winter,  in  low  and  moist  countries,  and  in  the  lymphatic 
temperament.  Bile  predominated  in  mature  age,  in  summer,  in  hot 
climates,  and  in  the  bilious  temperament ;  and  atrabilis  was  the  cha- 
racteristic of  middle  age,  of  autumn,  of  equatorial  climes,  and  of  the 
melancholic   temperament.     This  was  their  grand  humoral  system, 

'  PhiladelpMa  Public  Leclger,  Feb.  2,  1847. 

^  Narrative  of  the  loss  of  the  American  Brig  Commerce,  &c.,  p.  302.  New  York,  1817. 


6-i  MATERIAL   COMPOSITION   OF   MAN. 

wliicli  lias  vanished  before  a  better  observation  of  facts,  and  more  im- 
proved methods  of  pbj^sical  and  metaphysical  investigation.  The 
atrabilis  was  a  creature  of  the  imagination ;  the  pituitous  condition  is 
unintelligible  to  us;  and  the  doctrine  of  the  influence  of  the  humours 
on  the  ages,  temperaments,  &c.,  irrational. 

Subsequent!}^,  the  humours  were  classed  according  to  their  physical 
and  chemical  properties  :  they  were  divided,  for  instance,  into  liquids, 
vapours,  and  gasek ;  into  acid,  alkaline,  and  neutral ;  into  thick  and 
thin ;  into  aqueous,  mucilaginous,  gelatinous,  and  oily;  into  saline,  oily, 
saponaceous,  mucous,  albuminous,  and  fibrinous,  &c.  In  more  modern 
times,  endeavours  have  been  made  to  arrange  them  according  to  their 
uses  in  the  economy  into — 1,  rccrementilial  fluids,  or  those  intended 
to  be  again  absorbed  ;  2,  excrementitial,  those  that  have  to  be  expelled 
from  the  body ;  and  3,  those  which  participate  in  both  purposes,  and 
are  hence  termed  excremento-recremetititial.  Blumenbach'  divided  them 
into  crude  humours,  blood,  and  secreted  humours,  a  division  which  has 
been  partly  adopted  by  M.  Adelon  :^  and  Chaussier,  whose  anatomical 
arrangements  and  nomenclature  have  rendered  him  justly  celebrated, 
reckoned  five  classes : — 1,  those  produced  by  the  act  of  digestion — 
chyme  and  chyle  ;  2,  the  circulating  fluids — lymph  and  blood ;  3,  the 
perspired  fluids;  4,  the  follicular  ;  and  5,  the  glandular.  This  arrange- 
ment has  been  adopted  by  M.  Magendie,^  and,  with  slight  modification, 
is  perhaps  as  satisfactory  as  any  that  has  been  proposed.  All  these 
will  have  to  engage  attention  under  Secretion. 

e.  Physical  Properties  of  the  Tissues. 

The  tissues  of  the  body  possess  the  physical  properties  of  matter  in 
general.  They  are  found  to  vary  in  consistence — some  being  hard, 
and  others  soft ;  as  well  as  in  colour,  transparency,  &c.  They  have, 
also,  physical  properties,  analogous,  indeed,  to  what  are  met  with  in 
certain  inorganic  substances,  but  generally  superior  in  degree.  These 
axe  flexibility,  extensibility,  and  elasticity,  which  are  variously  combined 
and  modified  in  the  different  forms  of  animal  matter,  but  exist  to 
a  greater  or  less  extent  in  every  tissue.  Elasticity  is  only  exerted 
under  particular  circumstances :  when  the  part,  for  example,  is  put 
upon  the  stretch  or  compressed,  the  force  of  elasticity  restores  it  to  its 
primitive  state,  as  soon  as  the  distending  or  compressing  cause  is  with- 
drawn. The  tissues,  in  which  elasticity  is  inherent,  are  so  disposed 
through  the  body,  as  to  be  kept  in  a  state  of  distension  by  the  mechani- 
cal circumstances  of  situation  ;  but  as  soon  as  these  circumstances  are 
modified,  elasticity  comes  into  play,  and  produces  shrinking  of  the  sub- 
stance. It  is  easy  to  see,  that  these  circumstances,  owing  to  the  con- 
stant alteration  in  the  relative  situation  of  parts,  must  be  ever  varying. 
Elasticity  is,  therefore,  constantly  called  into  operation,  and  in  many 
cases  acts  upon  the  tissues  as  a  new  power.  The  cartilages  of  the  ribs, 
joints,  &c,,  are  in  this  manner  valuable  agents  in  particular  functions. 

"We  have  other  examples  of,  the  mode  in  which  elasticity  exhibits 

•  Institutiones  Physiologicse,  Sect,  ii.,  §  4.     Getting.,  1798. 

^  Physiologie  de  PHomme,  2de  edit.,  i.  124.     Paris,  1829. 

3  Precis  Elementaire  de  Physiol.,  2de  edit.,  i.  20.     Paris,  1825. 


PHYSICAL   PROPERTIES   OF   TISSUES.  65 

itself,  when  the  contents  of  hollow  parts  are  withdrawn,  and  whenever 
muscles  are  divided  transversely.  The  gaping  wound,  produced  by  a 
cut  across  a  shoulder  of  mutton,  is  familiar  to  all  Previous  to  the 
division,  the  force  of  elasticity  is  kept  neutralized  by  the  mechanical 
circumstances  of  situation — or  by  the  continuity  of  the  parts ;  but  as 
soon  as  this  continuity  is  disturbed, — in  other  words,  as  soon  as  the  me- 
chanical circumstances  are  altered,  the  force  of  elasticity  is  exerted, 
and  produces  recession  of  the  edges.  This  property  has  been  described 
under  various  names,  tone  or  tonicity^  contractilite  de  tissii,  contractiUte  par 
defaut  d^ extension,  &c. 

The  other  properties,  flexibility  and  extensihility,  vary  greatly  ac- 
cording to  the  structure  of  parts.  The  tendons,  which  are  composed 
of  areolar  tissue,  exhibit  very  little  extensibility  ;  and  this  for  wise 
purposes.  They  are  the  conductors  of  force  developed  by  muscle,  and 
were  they  to  yield,  it  would  be  at  the  expense  of  the  muscular  efforts ; 
but  they  possess  great  flexibility.  The  articular  ligaments  are  very 
flexible,  and  somewhat  more  extensible.  On  the  other  hand,  the  fibrous 
or  ligamentous  structures,  which  are  employed  to  support  weights,  or 
are  antagonists  to  muscular  action — as  the  lifjamentuni  nuchm,  which 
passes  from  the  spine  to  the  head  of  the  quadruped — are  very  exten- 
sible and  elastic. 

Another  physical  property,  possessed  by  animal  substances,  is  a  kind 
of  contractility,  accompanied  with  sudden  corrugation  and  curling. 
This  effect,  which  Bichat  terms  racornissement,  is  produced  by  heat, 
and  by  chemical  agents,  especially  the  strong  mineral  acids.  The 
property  is  exhibited  by  leather  when  thrown  into  the  fire. 

An  effect,  in  some  measure  resembling  this,  is  caused  by  the  evapo- 
ration of  the  water  that  is  united  to  animal  substances.  This  consti- 
tutes what  has  been  called  the  hygrometric  2^'>'0perty  of  animal  mem- 
branes.^ It  is  characteristic  of  dry,  membranous  structures ;  all  of 
which  are  found  to  contract,  more  or  less,  by  the  evaporation  of  moist- 
ure, and  to  expand  again  by  its  reabsorption  ;  hence  the  employment  of 
such  substances  as  hygrometers.  According  to  M,  Chevreul,^  many  of 
the  tissues  are  indebted  for  their  physical  properties  to  the  water  they 
contain,  or  with  which  the}'"  are  imbibed.  When  deprived  of  this  fluid, 
they  become  unfit  for  the  purposes  for  which  they  are  destined  in  life, 
and  resume  them  as  soon  as  they  have  recovered  it. 

A  most  important  property  possessed  by  the  tissues  of  organized 
bodies  is  imbibition;  a  property  to  which  attention  has  been  chiefly 
directed  of  late  years.  If  a  liquid  be  put  in  contact  with  any  organ 
or  tissue,  in  process  of  time  the  liquid  will  be  found  to  have  passed 
into  the  areohe  of  the  organ  or  tissue,  as  it  would  enter  the  cells  of  a 
sponge.  The  length  of  time  occupied  in  this  imbibition  will  depend 
upon  the  nature  of  the  liquid  and  the  kind  of  tissue.  Some  parts  of 
the  body,  as  the  serous  membranes  and  small  vessels,  act  as  true 
sponges,  absorbing  with  great  promptitude;  others  resist  imbibition 
fur  a  considerable  time, — as  the  epidermis. 

'  Roget,  art.  Physiology,  in  Supplement  to  Encyclopsedia  Britannica  ;  and  Outlines 
of  Physiology,  with  an  Appendix  on  Phrenology.  First  American  edition,  with  notes 
by  the  author  of  this  work,  p.  73,  Philad.,  1839. 

^  Magendie,  Precis  Elementaire  de  Physiologie,  2de  edit.,  1825,  i.  13. 
VOL.  I. — 5 


G6  MATERIAL   COMPOSITION   OF   MAN. 

Liquids  penetrate  equally  from  within  to  without ;  the  process  is 
then  called  transudation. 

Some  singular  facts  have  been  observed  regarding  the  imbibition  of 
fluids  and  gases.  On  filling  membranous  expansions,  as  the  intestine 
of  a  chicken,  with  milk  or  some  dense  fluid,  and  immersing  it  in  water, 
M.  Dutrochet'  observed,  that  the  milk  left  the  intestine,  and  the  water 
entered  it;  hence  he  concluded,  that  whenever  an  organized  cavity, 
containino-  a  fluid,  is  immersed  in  another  fluid  less  dense  than  that 
which  is  in  the  cavity,  there  is  a  tendency  in  the  cavity  to  expel  the 
denser  and  absorb  the  rarer  fluid.  This  M.  Dutrochet  termed  endos- 
mose  or  "inward  impulsion;"  and  he  conceived  it  to  be  a  new  power, 
a  "  physico-organic  or  vital  action."  Subsequent  experiments  showed, 
that  a  reverse  operation  could  take  place.  If  the  internal  fluid  was 
rarer  than  the  external,  the  transmission  occurred  in  the  opposite 
direction.  To  this  reverse  process,  he  gave  the  name  exosmose,  or 
''outward  impulsion."  At  times,  the  term  endosmose  is  applied  to  the 
mutual  action  of  two  liquids  when  separated  by  a  membrane;^  at  others, 
to  the  passage  of  the  liquid,  that  permeates  the  membrane  in  greatest 
quantity,^ 

Soon  after  the  appearance  of  M.  Dutrochet's  essay,  the  experiments 
were  repeated,  with  some  modifications,  by  Dr.  Faust, "•  and  by  Dr. 
Togno,*  of  Philadelphia ;  and  with  like  results.  The  fact  of  this  im- 
bibition and  transudation  was  singular  and  impressive ;  and,  with  so 
enthusiastic  an  individual  as  M.  Dutrochet,  could  not  fail  to  give  birth 
to  numerous  and  novel  conceptions.  The  energy  of  the  action  of  both 
endosmose  and  exosmose  is  in  proportion,  he  asserted,  to  the  dift'erence 
between  the  specific  gravities  of  the  two  fluids ;  and,  independently  of 
their  gravity,  their  chemical  nature  affects  their  power  of  transmission. 
These  effects — he  at  once  decided — must  be  owing  to  electricity.  The 
cavities,  in  which  the  changes  take  place,  he  conceived  to  be  like  Ley- 
den  jars  having  their  two  surfaces  charged  with  opposite  electricities, 
the  ultimate  effect  or  direction  of  the  current  being  determined  by  the 
excess  of  the  one  over  the  other. 

In  an  interesting  and  valuable  communication  by  Prof.  J.  K.  Mit- 
chell,^ of  Philadelphia,  "on  the  penetrativeness  of  fluids,"  many  of  the 
visionary  speculations  of  M.  Dutrochet  are  sensibly  animadverted  upon. 
It  is  there  shown,  that  he  had  asserted,  in  the  teeth  of  some  of  his 
most  striking  facts,  that  the  current  was  always  from  a  less  dense  to  a 
more  dense  fluid;  and  that  it  was  from  positive  to  negative,  dependent 
not  on  an  inherent  power  of  filtration, — a  power  always  the  same  when 
the  same  membrane  is  concerned, — but  modified  at  pleasure  by  sup- 

'  M6m.  pour  servir  &,  I'Histoire  Anatom.  et  Physiol,  des  Animaux  et  des  Vegetaux, 
Paris,  1837 ;  art.  Endosmosis,  iu  Cyclopsedia  of  Anatomy  and  Physiology,  part  x.  p. 
98,  June,  1837.  See,  also,  Vierordt,  art.  Transudation  und  Endosmose,  in  Wagner's 
Handworterbuch  der  Physiologie,  s.  631,  Braunschweig,  1848.  Ludwig,  Lehrbuch  der 
Physiologie  des  Menschen,  1.  63,  Heidelb.  1852.  J.  Beclard,  Traite  6lementaire  de 
Physiologie,  p.  149,  Paris,  1855. 

^  Matteucci,  Lectures  on  the  Physical  Phenomena  of  Living  Beings ;  translated  by 
Pereira,  p.  45,  Amer.  edit.,  Pbilad.,  1848. 

»  Poiseuille,  Comptes  Rendus,  xix.  944,  Paris,  1844. 

*  Amer.  Journal  of  the  Med.  Sciences,  vii.  23,  Philad.,  1830. 

»  Ibid.,  iv.  73,  Philad.,  1829.  «  Ibid.,  vii.  23,  Philad.,  1830. 


PHYSICAL   PROPERTIES   OF   TISSUES. 


67 


posed  electrical  agencies.  This  view  was  subsequently  abandoned  by 
M.  Dutrochet,  in  favour  of  the  following  principle.  It  is  well  known 
that  porous  bodies,  as  sugar,  wood,  or  sponge,  are  capable  of  imbibing 
liquids,  with  which  they  are  in  contact.  In  such  case,  the  liquid  is  not 
merely  introduced  into  the  pores  of  the  solid,  as  it  would  be  into  an 
empty  space;  but  it  is  forcibly  absorbed,  so  that  it  will  rise  to  a  height 
considerably  above  its  former  level.  This  "osmotic  force"  is  molecular, 
and  is  the  same  that  we  witness  in  the  phenomena  presented  by  the 
capillary  tube,  which  affords  us  the  simplest  case  of  the  insinuation  of 
a  liquid  into  a  porous  body.  It  cannot  alone,  however,  cause  the  liquid 
to  pass  entirely  through  the  body.  If  a  capillary  tube,  capable  of 
raising  water  to  the  height  of  six  inches,  be  depressed,  so  that  one  inch 
only  be  above  the  surface,  the  water  will  rise  to  the  top  of  the  tube ; 
but  no  part  of  it  will  escape.  Even  if  the  tube  be  inserted  horizon- 
tally into  the  side  of  the  vessel  containing  water,  the  water  will  only 
pass  to  the  end  of  the  tube.  The  same  thing  occurs  when  a  liquid  is 
placed  in  contact  with  one  side  of  a  porous  membrane :  it  enters  the 
pores ;  passes  to  the  opposite  side,  and  is  there  arrested.  But  if  this 
membrane  communicates  with  a  second  vessel  containing  a  different 
liquid — as  a  saline  solution,  capable  of  mixing  with  the  first,  and 
affected  to  a  different  degree  by  capillary  attraction — a  new  phenome- 
non will  be  presented.  It  will  be  found,  that  both  liquids  enter  the 
pores,  and  pass  through  to  the  opposite  side.  They  will  not,  however, 
be  carried  through  with  the  same  force :  that  which  has  the  greatest 
power  of  capillary  ascension,  has  the  greatest  affinity  for 
the  membrane,  or  will  wet  it  more  readily, — in  other  words, 
that  which  will  rise  the  highest  in  a  capillary  tube, — will 
pass  through  in  greater  quantity,  and  cause  an  accumula- 
tion of  liquid  on  the  opposite  side.  The  action  is  well 
shown  by  the  simple  instrument  figured  in  the  margin. 
It  consists  of  a  glass  tube,  the  lower  extremity  of  which, 
covered  by  bladder,  is  funnel-shaped.  This  M.  Dutrochet 
termed  an  endosmometer.  If  an  aqueous  solution  of  either 
gum  or  sugar  be  poured  into  it,  and  the  closed  extremity 
be  immersed  in  pure  water,  the  water  is  found  to  pass  con- 
tinually into  the  tube  by  filtration  through  the  membrane, 
so  that  the  liquid  will  rise  in  the  tube,  and  may  even  flow 
out  at  the  upper  aperture.  At  the  same  time,  a  portion 
of  the  mucilaginous  or  saccharine  solution  will  escape  from 
the  tube  through  the  bladder,  and  become  mixed  with  the 
water,  but  the  quantity  will  be  much  less  than  that  of  the 
water  which  entered. 

The  facts  and  arguments  adduced  by  Dr.  Mitchell  clearly 
exhibit,  that  imbibition  and  transudation  are  dependent 
upon  the  penetrativeness  of  the  liquid,  and  the  penetra- 
bility of  the  membrane ;  that  if  two  liquids,  of  different       "^LTa-n"' 
rates  of  penetrativeness,  be  placed  on  opposite  sides  of  an 
animal  membrane,  "they  will  in  time  present  the  greater  accumulation 
on  the  side  of  the  less  penetrant  liquid,  whether  more  or  less  dense ; 
but  will,  finally,  thoroughly,  and  uniformly  mix  on  both  sides;  and  at 
length,  if  any  pressure  exist  on  either  side,  yield  to  that,  and  pass  to 


Fig.  1. 


68  MATERIAL    COMPOSITION   OF   MAN.  . 

I 

the  other  side."*  In  all  such  cases,  there  are  both  endosmose  and  exos- 
mose — or  double  imbibition ;  in  other  words,  a  certain  quantity  of  one 
fluid  passes  in,  and  a  certain  quantity  of  the  other  passes  out.^  As  a 
general  rule,  imbibition  takes  place  from  the  rarer  to  the  denser  me- 
dium; from  pure  water  or  dilute  solutions  towards  those  that  are  more 
concentrated.  It  would  appear,  again,  that  the  stronger  current  is 
always  from  the  medium  which  has  the  strongest  affinity  for  the  sub- 
stance of  the  septum.  It  is  well  known,  that  in  the  case  of  a  mixture 
of  dilute  alcohol  covered  over  by  a  piece  of  bladder,  the  alcohol 
becomes  concentrated,  owing  to  the  water — a  denser  fluid — passing 
more  rapidly  through  the  septum  or  bladder  than  the  alcohol ;  but  if 
the  same  mixture  be  tied  over  with  elastic  gum,  the  contrary  effect  will 
be  produced — the  alcohol  escaping  in  greater  quantity.^  The  general 
conditions  of  the  phenomena  of  endosmose  are: — first^  that  the  two 
liquids  shall  have  an  aflBnity  for  the  septum  or  interposed  membrane; 
and,  secondly^  that  they  shall  have  an  affinity  for,  and  be  miscible  with 
each  other. 

A  portion  of  the  communication  of  Dr.  Mitchell  relates  to  an  ana- 
logous subject,  to  which,  as  M.  Magendie"*  has  observed,  little  or  no 
attention  had  been  paid  by  physiologists — the  permeability  of  mem- 
hranes  by  gases.  "  The  lamince,"  M.  Magendie  remarks,  "  of  which 
membranes  are  constituted,  are  so  arranged  that  gases  can  penetrate 
them,  as  it  were,  without  obstacle.  If  we  take  a  bladder,  and  fill  it 
with  pure  hydrogen,  and  afterwards  leave  it  in  contact  with  atmo- 
spheric air,  in  a  very  short  time  the  hydrogen  will  have  lost  its  purity, 
and  be  mixed  with  the  atmospheric  air,  which  has  penetrated  the 
bladder.  This  phenomenon  is  more  rapid  in  proportion  as  the  mem- 
brane is  thinner  and  less  dense.  It  presides  over  one  of  the  most 
important  acts  of  life — respiration  ;  and  continues  after  death." 

Dr.  Mitchell  is  the  first  individual,  who  directed  his  observation  to 
the  relative  penetrativeness  of  different  gases.  This  he  was  enabled 
to  discriminate  by  the  following  satisfactory  experiment,  which  we 
give  in  his  own  words :  "  Having  constructed  a  syphon  of  glass,  with 
one  limb  three  inches  long,  and  the  other  ten  or  twelve  inches,  the 
open  end  of  the  short  leg  was  enlarged  and  formed  into  the  shape  of 
a  funnel,  over  which,  finally,  was  firmly  tied  a  piece  of  thin  gum 
elastic.  By  inverting  this  syphon,  and  pouring  into  its  longer  limb 
some  clear  mercury,  a  portion  of  common  air  was  shut  up  in  the  short 
leg,  and  was  in  communication  with  the  membrane.  Over  this  end,  in 
the  mercurial  trough,  was  placed  the  vessel  containing  the  gas  to  be 
tried,  and  its  velocity  of  penetration  measured  by  the  time  occupied  in 
elevating  to  a  given  degree  the  mercurial  column  in  the  other  limb. 
Having  thus  compared  the  gases  with  conmion  air,  and  subsequently 
by  the  same  instrument,  and  in  bottles  with  each  other,  I  was  able 
to  arrange  the  following  gases  according  to  their  relative  facility  of 

'  Amer.  .Toumal  of  the  Medical  Sciences  for  November,  1833,  p.  100. 

*  Magendie,  Lemons  sur  les  Phenomenes  Physiques  de  la  Vie,  torn.  i.  p.  99,  Paris, 
1836-38. 

3  Henle,  Allgem.  Anat.,  or  Jourdan's  French  translat.,  p.  210,  Paris,  1843;  and  Wag- 
ner, Elements  of  Physiology,  by  Willis,  p.  438,  Lond.,  1S42. 

''  Precis  Elemeutaire  de  Physiologic,  2de  edit.,  1825,  i.  13;  and  Lemons,  &c.,  torn.  i. 
p.  132. 


FUNCTIONS   OF   MAN.  69 

transmission,  beginning  with  the  most  powerful : — ammonia,  sulphu- 
retted hydrogen,  cyanogen,  carbonic  acid,  nitrous  oxide,  arseniuretted 
hydrogen,  olefiant  gas,  hydrogen,  oxygen,  carbonic  oxide,  and  nitro- 
gen." 

He  found  that  ammonia  transmitted  in  one  minute  as  much  in 
volume  as  sulpJiuretted  hydrogen  did  in  two  minutes  and  a  half;  cyan- 
ogen^ in  three  minutes  and  a  quarter;  carbonic  acid,  in  five  minutes  and 
a  half;  nitrous  oxide,  in  six  minutes  and  a  half;  arseniuretted  hydrogen, 
in  twenty-seven  minutes  and  a  half;  olefiant  gas,  in  twenty-eight 
minutes ;  hydrogen,  in  thirty-seven  minutes  and  a  half;  oxygen,  in  one 
hour  and  fifty-three  minutes  ;  and  carbonic  oxide,  in  two  hours  and 
forty  minutes.  It  was  found,  too,  that  up  to  a  pressure  of  sixty-three 
inches  of  mercury,  equal  to  more  than  the  weight  of  two  atmospheres, 
the  penetrative  action  was  capable  of  conveying  the  gases — the  sub- 
jects of  the  experiment — into  the  short  leg  through  the  gum  elastic 
membrane.  Hence,  the  degree  of  force  exerted  in  the  penetration  is 
considerable. 

The  experiments  were  all  repeated  with  animal  membranes,  such  as 
dried  bladder  and  gold-beater's  skin,  moistened  so  as  to  resemble  the 
natural  state.  The  same  results,  and  in  the  same  order,  followed  as 
with  the  gum  elastic.  The  more  fresh  the  membrane,  the  more  sjoeedy 
and  extensive  was  the  eflect;  and  in  living  animals  the  transmission 
was  very  rapid. 

To  these  experiments  there  will  be  frequent  occasion  to  refer  in  the 
course  of  this  work.^ 

All  these  different  properties  of  animal  solids  are  independent  of  the 
vital  properties.  They  continue  for  some  time  after  the  total  extinc- 
tion of  life  in  all  its  phenomena,  and  appear  to  be  connected  either 
with  the  physical  arrangement  of  the  molecules,  the  chemical  compo- 
sition of  the  substance  in  which  they  reside,  or  with  peculiar  proper- 
ties in  the  body  that  is  made  to  act  on  the  tissue.  They  do  not,  indeed, 
seem  to  be  aft'ected,  until  the  progress  of  decomposition  has  become 
sensible.  Hence,  many  of  them  have  been  termed  collectively,  by 
Haller,  vis  mortua. 

2.   FUNCTIONS  OF  MAN. 

Having  described  the  intimate  structure  of  the  tissues,  we  pass  to 
the  consideration  of  the  functions;  the  character  of  each  of  which  is, 
— that  it  fulfils  a  special  and  distinct  office  in  the  economy,  for  which  it 
has  in  general  an  organ  or  instrument,  or  evident  apparatus  of  organs. 
Physiologists  have  not,  however,  agreed  on  the  number  of  distinct 
offices ;  and  hence  the  difference,  in  regard  to  the  number  and  classifi- 
cation of  the  functions,  that  prevails  amongst  them.     The  oldest  divi- 

'  See,  connected  with  this  subject,  the  ingenious  papers  hy  Dr.  Robert  E.  Rogers, 
and  Dr.  Draper — the  former  in  tlie  American  Journal  of  the  Medical  Sciences,  May, 
1836,  p.  13  ;  and  the  latter  in  the  same  .Journal  for  August,  183(j,  p.  276  ;  Nov.  1837, 
p.  122;  and  Aug.  1838,  p.  302:  and  Abstract  of  Experiments  iipon  the  physical  influ- 
ences exerted  by  living,  organic  and  inorganic  membranes,  upon  chemical  substances 
in  solution  passing  through  them  by  endosmose,  by  Joseph  Jones,  A.  B.,  in  the  same 
Journal,  for  April,  1855,  p.  555  ;  and  Experimental  Investigations  to  ascertain  the 
action  of  saline  solutions  of  diflerent  densities  upon  living  animals,  and  the  recii)rocal 
action,  through  dead  animal  membranes,  of  serum,  water,  and  saline  solutions  ;  by  the 
same.  Ibid.,  .Jan.,  1856,  p.  61. 


70  FUNCTIONS   OF   MAN. 

sion  is  into  the  vital^  natural.,  and  animal;  the  vital  functions  including 
those  of  such  importance  as  not  to  admit  of  interruption, — circulation, 
respiration,  and  innervation;  the  natural  functions  those  that  effect 
nutrition,  digestion,  absorption,  and  secretion;  and  the  animal  those 
possessed  exclusively  by  animals, — sensation,  locomotion,  and  voice. 
This  classification,  with  more  or  less  modification,  prevails  at  the  pre- 
sent day. 

The  character  of  this  work  will  not  admit  of  a  detail  of  every  classi- 
fication which  has  been  proposed ;  that  of  Bichat,  however,  has  occu- 
pied so  large  a  space  in  the  public  eye,  that  it  cannot  well  be  passed 
over.  It  is  followed  by  A[.  Hicherancl,^  and  many  modern  writers. 
Bichat  includes  all  the  functions  under  two  heads,— /w?2dw??5  of  mdri- 
tio7i,  which  concern  the  life  of  the  individual^  and  functions  of  rei'trodvc- 
tion,  which  concern  the  hfe  of  the  species.  Nutrition  requires,  that  the 
being  shall  establish  relations  around  him  to  obtain  the  materials  of 
which  he  may  stand  in  need;  and,  in  animals,  the  functions  that  esta- 
blish such  relations,  are  under  the  volition  and  perception  of  the  being. 
Hence  they  are  divided  into  two  sets ;  those  that  commence  or  precede 
nutrition;  have  external  relations;  are  dependent  upon  the  will,  and 
executed  with  consciousness;  and  those  that  are  carried  on  within  the 
body  spontaneously,  and  without  consciousness.  Bichat  adopted  this 
basis;  and,  to  the  first  aggregate  of  functions,  he  applied  the  term 
animal  life,  because  it  comprised  those  that  characterize  animality: 
the  latter  he  termed  organic  life^  because  the  functions  comprised  under 
it  are  common  to  every  organized  body.  Animal  life  included  sensa- 
tion, motion,  and  expression;  organic  life,  digestion,  absorption,  respi- 
ration, circulation,  nutrition,  secretion,  &c.  In  animal  life,  Bichat  re- 
cognized two  series  of  actions,  antagonistic  to  each  other;  the  one  pro- 
ceeding from  without  and  terminating  in  the  brain,  or  passing  from 
circumference  to  centre,  and  comprising  the  external  senses;  the  other, 
commencing  iu  the  brain,  and  acting  on  external  bodies,  or  proceeding 
from  centre  to  circumference,  and  including  the  internal  senses,  loco- 
motion, and  voice.  The  brain,  in  which  one  series  of  actions  terminates 
and  the  other  begins,  he  considered  the  centre  of  animal  life.  In 
organic  life,  he  lilcewise  recognized  two  series  of  actions:  the  one,  pro- 
ceeding from  without  to  within,  and  effecting  composition;  the  other 
passing  from  within  to  without,  and  effecting  decomposition.  In  the 
former,  he  included  digestion;  absorption;  respiration,  by  which  the 
blood  is  formed;  circulation,  by  which  the  blood  is  conveyed  to  differ- 
ent parts;  and  the  functions  of  nutrition,  and  calorification.  In  the 
latter,  that  absorption  by  which  parts  are  taken  up  from  the  body ;  the 
circulation,  which  conducts  those  parts  or  materials  to  the  secretory  or 
depuratory  organs;  and  the  secretions,  which  separate  them  from  the 
economy.  In  this  kind  of  life,  the  circulation  is  common  to  the  two 
movements  of  composition  and  decomposition ;  and,  as  the  heart  is  the 
great  organ  of  the  circulation,  he  considered  it  the  centre  of  organic 
life.  Lastly,  as  the  lungs  are  united  with  animal  life  in  the  reception 
of  air,  and  with  organic  life  as  the  organs  of  sanguification,  Bichat 

•  Nouveaux  EL'mens  de  Physiologic,  13eme  edit.,  par  M.  B'rard,  ainp,  ^dit.  Beige, 
p.  42,  Bnixelles,  1837 ;  or  Amer.  reprint  of  Copland's  edit,  of  De  Lys's  translation,  New- 
York,  1836. 


FUNCTIONS   OF   MAN. 


71 


regarded  tliem  as  tlie  bond  of  union  between  the  two  lives.     Genera- 
tion constituted  the  life  of  the  species. 

M.  Brachet,'  who  gives  to  the  sympathetic  or  great  ganglionic 
nervous  system  a  pervading  influence  which,  it  will  be  seen,  does  not 
properly  belong  to  it,  adopts  the  following  classification : — 

METHODICAL  CLASSIFICATION  OF  THE  FUNCTIONS. 


First  Class.  —  Functions  of 
ganglionic  life,  common  to  all 
organized  bodies,  and  exercised 
under  tlie  influence  of  the  gan- 
glionic nervous  system  alone. 

Second  Class.  —  Functions  of 
cerebral  life  jieculiar  to  animals, 
and  exercised  under  the  influ- 
ence of  the  cerebral  nervous 
system  alone. 

Thikd  Class. — Mixed  func- 
tions, requiring  the  influence  of 
the  two  nervous  systems  for 
their  complete  exercise. 


Appendix. 


1.  Innervation  of  the  ganglionic  nervous  system. 

2.  Absorption. 

3.  Course  of  tlie  lympb. 

4.  Circulation. 

5.  Nutrition. 

6.  Secretions. 

1.  Innervation  of  the  cerebral  nervous  system. 

2.  Sensations. 

3.  Intellectual  functions. 

4.  Locomotion. 

5.  Voice  and  speech. 

1.  Digestion. 

2.  Respiration. 

3.  Generation. 

4.  Urinary  excretion. 

1.  Relations  and  connections  of  the  functions 
with,  each  other. 

2.  Sympathies. 

3.  Modifications  of  the  functions  by,  1,  age  ;  2, 
sex;  3,  temperament;  4,  habit;  5,  climate,  diseases, 
and  a  multitude  of  agents. 

4.  Comparative  physiology. 

The  classification,  adopted  in  this  work,  is  essentially  that  embraced 
by  M,  Magendie;^  and,  after  him,  by  M.  Adelon,^  who  has  written  one 
of  the  best  systems  of  liuman  physiology  that  we  possess.  The  first 
CLASS,  or  functions  of  relation  or  animal  functio7%s,  includes  those  that 
establish  our  counexion  with  the  bodies  that  surround  us;  the  sensa- 
tions^ voluntary  motions,  and  expressions.  The  SECOND  CLASS,  or  functions 
of  nutrition,  comprises  digestion,  absorption,  respiration,  circulation,  nutri- 
tion, calorification,  and  secretion;  and  the  THIRD  CLASS,  the  functions  of 
reproduction; — generation. 

TABLE  OF  FUNCTIONS. 


I.  Functions  that  relate 
to  the  pi-eservation  of  the 
individual. 


II.  Functions  that  relate 
to  the  preservation  of  the 
species. 


I.  Nutritive. 


II.  Animal  or  of  Relation. 


III.  Reproductive. 


1.  Digestion. 

2.  Absorption. 

3.  Resjairation. 

4.  Circulation. 

5.  Nutrition. 

6.  Calorification. 

7.  Secretion. 

1.  Sensation. 

2.  Mental      and     Moral 
Manifestations. 

3.  Muscular  Motion. 

4.  Expression    or    Lan- 
guage. 

Generation. 


In  Studying  each  of  these  functions,  we  shall  first  of  all  describe  the 
organ  or  apparatus  concerned  in  its  production, — but  so  far  only  as  is 

'  Physiologic  Elementaire  de  I'Homnie,  2de  edit.,  i.  61.     Paris  et  Lyon,  1855. 

^  Precis,  &c.,  i.  32.  *  Physiologic  de  I'Homme,  2de  edit.,  i.  llti.     Paris,  1829. 


72  FUNCTIONS   OF   MAN. 

necessary  in  a  physiological  point  of  view ;  and  shall  next  detail  what 
has  been  called  the  mechanism  of  the  function,  or  the  mode  in  which 
it  is  effected.  In  many  cases,  it  will  happen,  that  some  external  agent 
is  concerned, — as  light  in  vision ;  sound  in  audition ;  oclours  in  olfac- 
tion; tastes  in  gustation.  The  properties  of  these  agents  will,  in  all 
instances,  be  detailed  in  a  brief  manner. 

The  difficulty  of  observing  actions,  that  are  carried  on  by  the  very 
molecules  of  which  the  organs  are  composed,  has  given  rise  to  many 
hypothetical  speculations,  some  of  which  are  sufiiciently  ingenious ; 
others  too  fanciful  to  be  indulged  for  a  moment ;  and,  as  might  be 
expected,  the  number  of  these  fantasies  generally  bears  a  direct  pro- 
portion to  the  difficulty  and  obscurity  of  the  subject.  It  will  not  be 
proper  to  pass  over  the  most  prominent  of  these,  but  they  will  not  be 
dwelt  upon ;  whilst  the  results  of  direct  observation  and  experiment 
will  be  fully  detailed  ;  and  where  differences  exist  amongst  observers, 
such  differences  will  be  reconciled,  where  practicable. 

The  functions,  executed  by  different  organs  of  the  body,  can  be  de- 
duced by  direct  observation;  although  the  minute  and  molecular  action, 
by  which  they  are  accomplished  in  the  very  tissue  of  the  organ,  may 
not  admit  of  detection.  We  see  blood  proceeding  to  the  liver,  and  the 
vessels  that  convey  it  ramifying  in  the  texture  of  that  viscus,  and 
becoming  so  minute  as  to  escape  detection  even  when  the  eye  is  aided 
by  a  powerful  microscope.  We  find,  again,  other  canals  in  the  organ 
becoming  perceptible,  gradually  augmenting  in  size,  and  ultimately 
terminating  in  a  larger  duct,  which  opens  into  the  small  intestine.  If 
we  examine  each  of  these  orders  of  vessels  in  its  most  minute  appre- 
ciable ramifications,  we  discover,  in  the  one,  always  blood ;  and,  in  the 
other,  always  a  very  different  fluid — bile.  We  are  hence  led  to  the 
conclusion,  that  in  the  intimate  tissue  of  the  liver,  and  in  some  part 
communicating  directly  or  indirectly  with  both  these  Orders  of  vessels, 
bile  is  separated  from  the  blood ;  or  that  the  liver  is  the  organ  of  the 
biliary  secretion.  On  the  other  hand,  functions  exist,  which  cannot 
be  so  demonstratively  referred  to  a  special  organ.  We  have  every 
reason  for  believing  that  the  brain  is  the  exclusive  organ  of  the  mental 
and  moral  manifestations ;  but,  as  few  opportunities  occur  for  seeing 
it  in  action ;  and  as  the  operation  is  too  molecular  to  admit  of  direct 
observation  when  we  do  see  it,  we  are  compelled  to  connect  the  organ 
and  function  by  a  process  of  reasoning  only ;  yet,  we  shall  find,  that 
the  results  at  which  we  arrive  in  this  manner  are  often  by  no  means 
the  least  satisfactory. 

The  forces  which  preside  over  the  various  functions  are  either  gene- 
ral— that  is,  physical  or  chemical ;  or  sjjecial— that  is,  organic  or  vital. 
Some  of  the  organs  afford  us  examples  of  purely  physical  instruments. 
We  have  in  the  eye,  an  eye-glass  of  admirable  construction ;  in  the 
organ  of  voice,  an  instrument  of  music;  in  the  ear,  one  of  acoustics: 
the  circulation  is  carried  on  through  an  ingenious  hydraulic  apparatus  : 
and  station  and  progression  involve  various  laws  of  mechanics.  In 
many  of  the  functions,  again,  we  have  examples  of  chemical  agency, 
whilst  all  in  which  innervation  is  concerned  are  incapable  of  being  ex- 
plained on  any  physical  or  chemical  principle;  and  we  are  constrained 
to  esteem  them  vital. 


DIGESTIVE   ORGANS.  73 


BOOK   I. 

NUTRITIYE  FUNCTIONS. 

The  human  body,  from  the  moment  of  its  formation  to  the  cessation 
of  existence,  is  undergoing  constant  decay  and  renovation — decompo- 
sition and  composition: — so  that  at  no  two  periods  can  it  be  said  to 
have  exactly  the  same  constituents.  The  class  of  functions  about  to 
engage  attention  embraces  those  that  are  concerned  in  effecting  such 
changes.  They  are  seven  in  number; — digestion^  by  which  the  food, 
received  into  the  stomach,  undergoes,  in  that  organ  a,nd  in  the  intes- 
tines, such  conversion  as  fits  it  for  the  separation  of  its  nutritious  and 
excrementitious  portions ;  absorjjtion,  by  which  this  nutritious  portion, 
as  well  as  other  matters,  is  conveyed  into  the  mass  of  blood  ;^  resjxij-atmi, 
]>y  which  the  products  of  absorption  and  venous  blood  are  converted 
into  arterial  blood;  circulation^  by  which  the  vital  fluid  is  distributed 
to  every  part  of  the  system ;  nutrition,  by  which  the  intimate  changes 
of  composition  and  decomposition  are  accomplished;  calorification,  by 
which  the  system  is  enabled  to  resist  the  effects  of  greatly  elevated  or 
depressed  atmospheric  temperature,  and  to  exist  in  the  burning  regions 
within  the  tropics,  or  amidst  the  arctic  snows;  and  secretion,  by  which 
various  fluids  and  solids  are  separated  from  the  blood ; — some  to  serve 
useful  purposes  in  the  animal  economy ;  others  to  be  rejected  from  the 
body. 

CHAPTEE  I. 

OF  DIGESTION. 

The  food,  necessary  for  animal  nutrition,  is  rarely  found  in  such  a 
condition  as  to  be  adapted  for  absorption.  It  has,  therefore,  to  be 
subjected  to  various  actions  in  the  digestive  organs;  the  object  of 
which  is  to  enable  the  nutritive  matter  to  be  separated  from  it.  These 
actions  constitute  the  function  of  digestion;  in  the  investigation  of 
which  we  shall  commence  with  a  brief  description  of  the  organs  con- 
cerned in  it.  These  are  numerous,  and  of  a  somewhat  complicated 
nature. 

1.    ANATOMY  OF  THE  DIGESTIVE  ORGANS. 

The  human  digestive  organs  consist  of  a  long  canal,  varying  con- 
siderably in  its  dimensions  in  diSerent  parts,  and  communicating  ex- 

'  M.  Robin,  under  Digestion,  appears  to  include  both  these  acts.  "  La  digestion  est 
cette  fonction  qui  introduit  par  endosmose  les  materiaiix,  et  satisfait  h  I'acte  chimique 
de  composition  ou  assimilutioti  nutritive."  Beraud,  Manuel  de  Physiologie,  p.  54,  Paris, 
1853. 


74 


DIGESTION. 


ternally  bj  two  outlets, — the  mouth  and  amis.  It  is  usually  divided 
into  four  chief  portions — the  mouth,  jj/iar?/?Kr,  oesojjhagus,  stomach,  and 
intestines.     These  we  shall  describe  in  succession, 

1.  The  mouth  is  the  first  cavity  of  the  digestive  tube,  and  that  into 
which  the  food  is  immediately  received,  and  subjected  to  the  action 

of  the  organs  of  mastication  and 
Fig.  2.  insalivation.     Above  and  below, 

it  is  circumscribed  by  the  jaws, 
and  laterally  by  the  cheeks; — 
anteriorly  by  the  lips  and  their 
aperture,  constituting  the  mouth 
proper ;  and,  posteriorly,  it  com- 
municates with  the  next  portion 
of  the  tube, — the  pharynx.  It  is 
invested  by  a  mucous  exhalant 
membrane,  which  is  largely  sup- 
plied with  follicles;  and  into  it  the 
ducts  from  the  different  salivary 
glands  pour  their  secretion. 

In  all  animals  furnished  with 
distinct  diofestive  oro;ans,  means 
exist  for  comminuting  the  food, 
and  enabling  the  stomach  to  act 
with  greater  facility  upon  it. 
These  consist,  for  the  most  part, 
as  in  man,  of  the  jaws,  the  teeth 
fixed  into  the  jaws,  and  muscles 
by  which  the  jaws  are  moved. 

Thejaus  chiefly  determine  the 
shape  and  dimensions  of  the 
mouth;  the  vpper  forming  an  es- 
sential part  of  the  face,  and  mov- 
ing only  with  the  head ;  the  lower, 
on  the  contrary,  possessing  great 
mobility.  Each  of  the  jaws  has  a 
prominent  edge,  forming  a  semi- 
circle, in  which  the  teeth  are  im- 
planted. This  edge  is  called  the 
alveolar  arch. 

The  teeth  are  small  organs,  of  a 
density  superior  to  bone ;  and 
covered  externally  by  a  hard  sub- 
stance called  enamel.  By  many, 
they  have  been  regarded  as  bone ; 
but  they  differ  from  it  in  many 
essential  respects,  although  they  resemble  it  in  hardness  and  chemical 
composition.  At  another  opportunity  we  shall  inquire  into  their 
origin,  structure,  and  developement.  We  may  merely  remark,  at  pre- 
sent, that  by  many  they  are  looked  upon  as  analogous  to  the  corneous 
substances,  which  develope  themselves  in  the  tissue  of  the  skin.  De 
Bluinville  assimilates  them  to  the  hair;  and  believes,  that  they  are 


Diagram  of  the  Stomach  and  Intestines  to  show 
their  course. 

1.  Stomach.  2.  (E5iopliagus.  3.  Left,  and  4.  Right 
end  of  stomach,  fl,  6.  Ducdenum.  7.  Convolutions 
of  jejunum.  8.  Those  of  ileum.  9.  Cjecum.  10.  Ver- 
miform appendix.  11.  A.-conding;  12.  Transverse; 
and  1.3.  descending  colon.  14.  Commencement  of 
sigmoid  flexure.     15.  Rectum. 


DIGESTIVE   ORGANS. 


75 


primarily  developed  in  the  substance  of  the  membrane  lining  the 
mouth;  and  that  their  enclosure  in  the  substance  of  the  alveolar  arches 
of  the  jaws  occurs  subsequently. 

The  number  of  the  teeth  is  sixteen  in  each  jaw.  These  are  divided 
into  cla?ses,  according  to  their  shape  and  use.  There  are,  in  each  jaw, 
fonr  u I ciso res ;  two  ciispidati  or  canine  teeth;  fonr  bicuspidati ;  and  six 
molares  or  grinders.  Each  tooth  has  three  parts : — the  crmvji,  neck, 
and  faiig  or  roof.; — the  first  being  the  part  above  the  gum  ;  the  second 
that  embraced  by  the  gum;  and  the  third,  that  contained  in  the 
alveolus  or  socket;  The  crown  varies  in  the  different  classes.  In  the 
incisors,  it  is  wedge-shaped;  in  the  canine,  conical;  and  in  the  molar, 
cubical.  In  all,  it  is  of  extreme  hardness,  but  in  timiC  wears  away  by 
the  constant  friction  to  which  it  is  exposed.  The  incisor  and  canine 
teeth  have  only  one  root ;  the  molares  of  the  lower  jaw,  two ;  and  the 
upper,  three.  In  all  cases,  they  are  of  a  conical  shape,  the  base  of  the 
cone  corresponding  to  the  corona,  and  the  apex  to  the  bottom  of  the 
alveolus.  The  alveolar  margin  of  the  jaws  is  covered  by  a  thick, 
fibrous,  resisting  substance,  called  g7im.  It  surrounds  accurately  the 
inferior  part  of  the  crown  of  the  tooth,  adheres  to  it  strongly,  and  thus 
adds  to  the  solidity  of  the  junction  of  the  teeth  with  the  jaws.  It  is 
capable  of  sustaining  considerable  pressure  without  inconvenience. — 
But  we  shall  have  to  return  to  the  subject  of  the  teeth  hereafter. 

The  articulation  of  the  lower  jaw  is  of  such  a  nature  as  to  admit  of 
depression  and  elevation ;  of  horizontal  motion  forwards,  backwards, 
and  laterally ;  and  of  a  semi-rotation  upon  one  of  its  condyles.  The 
muscles  that  move  it  may  be  thrown  into  two  classes : — elevators  and 
depressors.  These,  by  a  combination  of  their  contraction,  can  produce 
every  intermediate  movement  between  elevation  and  depression.  The 
raisers  or  levator  muscles  of  the  jaw  extend  from  the  cranium  and 
upper  jaw  to  the  lower.  They  are  four  in  number  on  each  side, — the 
temporal  and  masseter, 
which  are  entirely 
concerned  in  the  func- 
tion; t\xe external  ptery- 
goid^ which,  whilst  it 
raises  the  jaw,  carries 
it  at  the  same  time 
forward,  and  to  one 
side;  and  the  internal 
pterygoid^  which,  ac- 
cording as  it  unites  its 
action  with  the  tem- 
poral or  with  the  ex- 
ternal pterygoid,  is  an 
elevator  of  the  jaw  or  a  lateral  motor.  The  depressors  may  be  divided 
into  immediate  and  mediate,  according  as  they  are,  or  are  not,  attached 
to  the  lower  jaw  itself.  There  are  only  three  of  the  former  class : 
1,  the  digastricus^  the  anterior  fasciculus  of  which,  or  that  which  passes 
from  the  os  hyoides  to  the  lower  jaw,  depresses  the  latter ;  2,  the  genio- 
hyoidens;  and  8,  the  mylo-hyoidens^  all  of  which  concur  in  the  formation 
of  the  floor  of  the  mouth.     The  indirect  or  mediate  depressors  are  all 


Skull  of  the  Polar  Bear. 


76 


DIGESTION-. 


those,  that  are  situate  between  the  trunk  and  the  lower  jaw,  without 
being  directly  attached  to  the  latter ; — as  the  thyro-liyoideus^  the  sterno- 
thyroideus,  and  the  omo-hyoideus ;  the  names  of  which  indicate  their 
origin  and  insertion.  These,  in  the  aggregate,  form  a  muscular  chain, 
which,  when  it  makes  the  trunk  its  fixed  point,  depresses  the  lower 
jaw.  The  arrangement  of  the  elevators  and  depressors  is  such,  that 
the  former  predominate  over  the  latter ;  and  hence  during  sleep  the 
jaws  continue  applied  to  each  other,  and  the  mouth  is  consequently 
closed. 

The  human  organs  of  mastication  hold  an  intermediate  place  between 
those  of  the  carnivorous  and  herbivorous  animal.  In  the  carnivorous 
animal,  which  has  to  seize  hold  of,  and  retain  its  prey  between  its 
teeth,  the  jaws  have  considerable  strength;  and  the  movement  of  ele- 
vation is  all  that  is  practicable;  or,  at  least,  that  can  be  effected  to  any 
extent.  This  is  dependent  upon  organization.  The  condyle  is  broader 
from  side  to  side,  which  prevents  motion  in  that  direction :  the  glenoid 

cavity  is  very  deep,  so  that  the  head 
of  the  jaw-bone  cannot  pass  out  of  it; 
and  it  is,  moreover,  fixed  in  its  place 
by  two  eminences  before  and  behind. 
The  muscular  apparatus  is  also  so  ar- 
ranged as  to  admit  of  energetic  action 
on  the  part  of  the  muscles  that  raise 
the  jaw ;  but  of  scarcely  any  in  a  hori- 
zontal direction.  The  deep  impres- 
sions in  the  regions  of  the  temporal 
and  masseter  muscles  indicate  the 
large  size  of  these  muscles  in  the 
purely  carnivorous  animal;  whilst  the 
pterygoid  muscles  are  extremely 
small.  The  teeth,  too,  are  charac- 
teristic ;  the  molares  being  compara- 
tively small,  at  the  same  time  that 
they  are  much  more  pointed.  On  the 
other  hand,  the  cuspidati  are  remark- 
able^ large,  and  the  incisors,  in  general, 
acuminated. 

The  herbivorous  animal  has  an  ar- 
rangement the  reverse  of  this.  The 
condyle  or  head  of  the  lower  jaw  is 
rounded ;  and  can,  therefore,  be  moved  in  all  directions ;  and  as  easily 
horizontally  as  up  and  down.  The  glenoid  cavity  is  shallow,  and 
yields  the  same  facilities.  The  articulation,  which  is  very  close  in  the 
carnivorous  animal,  is  here  quite  loose.  The  levator  muscles  are 
much  more  feeble ;  the  temporal  fossa  is  less  deep ;  the  zygomatic  arch 
less  convex;  and  the  zygomatic  fossa  less  extensive.  On  the  other 
hand,  the  pterygoid  fossa  is  ample  and  the  muscles  of  the  same  name 
are  largely  developed.  The  molares  are  large  and  broad ;  and  their 
magnitude  is  so  great  as  to  require,  that  the  jaw  should  be  much 
elongated  in  order  to  make  room  for  them. 

The  joint  of  the  lower  jaw  has,  in  man,  solidity  enough  for  the  jaws 


Skull  of  the  Cow. 


DIGESTIVE   ORGANS — SALIVARY   GLANDS.  77 

to  exert  considerable  pressure  with  impunity,  and  laxity  enough  that 
the  lower  jaw  may  execute  horizontal  movements.  The  action  of  the 
levator  muscles  is  the  most  extensive;  but  the  lateral  or  ginnding 
motion  is  practicable  to  the  necessary  extent ;  and  the  muscles  of  both 
kinds  have  a  medium  degree  of  developement.  The  teeth,  likewise, 
partake  of  the  characteristics  of  those  of  the  carnivorous  and  herbi- 
vorous animals ; —  twelve — the  canine  teeth  and  lesser  molares — cor- 
responding to  those  of  the  carnivorous;  and  twenty — the  incisors  and 
larger  molares — to  those  of  the  herbivorous. 

The  tongue  must  be  regarded  as  an  organ  of  mastication.  It  rests 
horizontally  on  the  floor  of  the  mouth ;  is  free  above,  anteriorly ;  and, 
to  a  certain  extent,  beneath  and  at  the  sides.  Behind,  it  is  united  to 
the  epiglottis  by  three  folds  of  the  mucous  membrane  of  the  mouth; 
and  is  supported  at  its  base  by  the  os  hyoides,  with  which  it  partici- 
pates in  its  movements.  The  tongue,  as  the  organ  of  taste  and  articu- 
lation, is  described  elsewhere.  We  have  only,  therefore,  to  describe 
the  OS  hyoides  and  its  attachment  to  that  bone.  The  hyoid  bone  has, 
as  its  name  imports,  the  shape  of  the  Greek  letter  v,  the  convex  part 
being  before.  It  is  situate  between  the  tongue  and  larynx :  and  is 
divided  into  bod?/  or  central  jmH  ;  and  into  branches,  one  extremity  of 
which  is  united  to  the  body  by  an  intermediate  cartilage,  that  admits 
of  slight  motion ;  whilst  the  other  is  free,  and  is  called  greater  cornu. 
Above  the  point,  at  which  the  branch  is  articulated  with  the  body,  is 
an  apophysis  or  process,  called  lesser  cornu.  The  os  hyoides  is  united 
to  the  neighbouring  parts  by  fibrous  organs,  and  muscles.  The  former 
are; — above,  the  stylo-hyoid  ligament,  which  extends  from  the  lesser 
cornu  of  the  bone  to  the  styloid  process  of  the  temporal  bone;  below, 
a  fibrous  membrane,  called  thyro-hyoid,  passing  between  the  body  of 
the  bone  and  the  thyroid  cartilage ;  and  two  ligaments,  extending 
from  the  greater  cornu  of  the  hyoid  bone  to  the  thyroid  cartilage, 
called  thyro-hyoid.  Of  the  muscles ;  some  are  above  the  hyoid  bone, 
and  raise  it; — viz.,  ^ul\Qgenio-  and  mylo-hyoideus,  already  referred  to;  the 
stylo-hyoid,  and  some  fibres  of  the  viiddle  constrictor  of  the  -pharynx. 
Others  are  below,  and  depress  it.  They  are  the  sterno-thyro-hyoideus, 
omo-hyoideus  and  sterno-thyroideus.  The  base  of  the  tongue  is  attached 
to  the  body  of  the  bone  by  a  ligamentous  tissue,  and  by  the  fibres  of 
the  hyoylossus  muscle. 

Among  the  collateral  organs  of  mastication  are  those  which  secrete 
the  saliva,  and  the  various  fluids  which  are  poured  out  into  the  mouth, 
— constituting  together  what  has  been  termed  the  apparatus  of  insali- 
vation.  These  fluids  proceed  from  different  sources.  Ihe  mucous 
membrane  of  the  mouth,  like  other  mucous  membranes,  exhales  a 
serous  or  albuminous  fluid,  besides  a  mucous  fluid  secreted  by  the 
numerous  follicles  contained  in  its  substance.  Four  glands  likewise 
exist  on  each  side,  destined  to  secrete  the  saliva,  which  is  poured  into 
the  mouth  by  distinct  excretory  ducts.  They  are  \he  parotid,  submax- 
illary, sublingual,  and  intra-liitgual  or  lingual.  The  first  is  situate 
between  the  ear  and  the  jaw;  and  its  excretory  duct  opens  into  the 
mouth  opposite  the  second  small  molaris  of  the  upper  jaw.  By  press- 
ing upon  this  part  of  the  cheek,  the  saliva  can  be  made  to  issue  into 
the  mouth,  in   perceptibly   increased   quantity.      The   submaxillary 


DIGESTION". 


glaud  is  situate  beneatli  the  base  of  the  jaw;  and  its  excretory  duct 

opens  into  the  mouth, 
at  the  side  of  the  frae- 
nuni  linguas.  The 
sublingual  gland  is 
situate  under  the 
tongue,  and  its  ex- 
cretory ducts  open  at 
the  sides  of  that  or- 
gan, and  the  intra- 
lingual  or  lingual  is 
seated  at  the  inferior 
surface  of  the  tono;ue, 
where  the  mucous 
membrane  forms  a 
fringed  fold.  The 
saliva,  as  met  with, 
is  a  compound  of  eve- 
ry secretion  poured 
into  the  mouth;  and 
it  is  this  fluid  which 
has  been  chiefly  sub- 
and  its  various  pro- 


Salivary  Glands  in  situ. 
1.  Parotid  gland  in  situ,  extending  from  tlie  zygoma  above,  to  the 
angle  of  tlie  jaw  lielow.     2.  Duct  of"  Steno.     3.  Submaxillary  gland. 
4.  Its  duct.     5.  Sublingual  glaud. 


jected  to  analysis.     The  secretion  of  the  saliva, 
perties,  will  be  considered,  however,  hereafter. 

The  two  apertures  of  the  mouth  are  the  labial  and  'pharyngeal.  The- 
former,  as  its  name  imports,  is  formed  by  the  lips,  which  consist  ex- 
ternally of  a  layer  of  skin;  are  lined  internally  by  a  mucous  mem- 
brane; and,  in  their  substance,  contain  numerous  muscles,  elsewhere 
described  under  the  head  of  Gestures.  These  muscles  may  be  ^0,-^2,- 
rated  into  constrictors  and  dilators ;  the  orbicularis  oris  being  the  only 
one  of  the  first  class,  and  the  antagonist  to  the  others,  which  are  eight 
in  number,  on  each  side — levator  labii  superior  is  alceque  nasi,  levator 
lahii  snperioris  proprius,  levator  anguli  oris,  zygomaticus  major,  zygoma- 
iicifs  minor,  huccinator,  triangularis,  and  quadratus  inenti.  To  the  last 
two  muscles  are  added  some  fibres  of  the  j)latysma  myoides. 

The  pharyngeal  opening  is  smaller  than  the  labial,  and  of  a  quadri- 
lateral shape.  It  is  bounded  above  by  the  velum  palati  or  jjcnduJous 
veil  of  the  palate ;^  below,  by  the  base  of  the  tongue;  and  laterall}',  by 
two  muscles,  which  form  iho,  jyiUars  of  the  fauces.  The  pendulous  veil 
is  a  musculo-membranous  extension,  constituting  a  kind  of  valve,  at- 
tached to  the  posterior  margin  of  the  bony  palate,  by  which  all  com- 
munication between  the  mouth  and  pharynx,  or  between  the  pharynx 
and  nose  can  be  prevented.  To  produce  the  first  of  these  eftects,  it 
becomes  vertical;  to  produce  the  latter,  horizontal.  At  its  inferior 
and  free  margin,  it  has  a  nipple-like  shape,  and  bears  the  name  of 
uvula.  It  is  composed  of  two  mucous  membranes,  and  of  muscles. 
One  of  the  membranes, — that  forming  its  anterior  surface, — is  a  pro- 
longation of  the  membrane  lining  the  mouth,  and  contains  numerous 
follicles;  the  otlier,  forming  its  posterior  surface,  is  an  extension  of 
the  mucous  membrane  lining  the  nose,  and  is  redder,  and  less  pro- 
vided with  follicles  than  the  other.     The  muscles  that  constitute  the 


DIGESTIVE   ORGANS — CESOPHAGUS. 


79 


body  of  the  velum  palati  are 
— the  circumjiexus  jxilati  or 
spheno-salpingo-staj)hylinus  of 
Chaussier;  the  levator  pah ti  or 
petro-salpingo-staphylinus ;  and 
the  azygos  uvulce  or  palato-sta- 
jihylinus.  The  velum  is  moved 
by  eight  muscles.  The  two 
internal  pterygoids  raise  it;  the 
two  external  pjtery golds  stretch 
it  transversely;  the  Wo  p)alaio- 
P'haryngei  or  pharyyigo-stajihy- 
Imi,  and  the  two  co7istrictores 
isthnii  faiicium  or  glosso-staphy- 
Uni  carry  it  downwards.  The 
last  four  muscles  form  the  pil- 
lars of  the  fauces ; — the  first 
two  the  posterior  pillars ;  and 
the  last  two  the  anterior ;  be- 
tween which  are  situate  the  ton- 
sil glands  or  amygdalce^  which 
are  composed  of  a  congeries  of 


Fig.  6. 


Cavity  of  the    Mouth,    as   shown    by  dividing  the 
Angles  and  turning  off  the  Lips. 

1.  Upper  lip,  turned  \\p.  2.  Its  frasnum.  3.  Lower 
lip,  turned  down.  4.  Its  frteuum.  5.  Internal  surface 
of  cheeks.  6.  Opening  of  duct  of  Steno.  7.  Eoof  of 
mouth.  S.  Anterior  portion  of  lateral  half  arches.  9. 
Posterior  portion  of  lateral  half  arches.  10.  Velum 
pendulum  palati.     11.  Tonsils.     12.  Tongue. 

mucous  follicles. 


Fig.  7. 


Pharynx  seen  from  behind. 

1.  A  section  carried  transversely  through  base 
of  skull.  2,  2.  Walls  of  pharynx  drawn  to  each 
side.  3,  3.  Posterior  nares,  separated  by  vomer. 
4.  Extremity  of  Eustachian  tube  of  one  side.  5. 
Soft  palate.  6.  Posterior  pillar  of  soft  palate.  7. 
Its  anterior  pillar ;  the  tonsil  seen  situate  in  the 
niche  between  the  two  pillars.  8.  Root  of  tongue, 
partly  concealed  by  uvula.  9.  Epiglottis  over- 
hanging (10)  opening  of  glottis.  11.  Posterior 
part  of  larynx.  12.  Opening  into  oesophagus. 
13.  External  surface  of  (Esophagus,     li.  Trachea. 


Longitudinal  Section  of  the 
Oesophagus,  near  the  Pha- 
rynx, seen  on  its  inside. 

1,  1.  Superior  part  near  pha- 
rynx. 2,  2.  Longitudinal  folds 
of  its  mucous  membrane.  3,  3. 
Prominences  formed  by  its  mu- 
ciparous glands.  4,4.  Capilla- 
ry bloodvessels.  5.  Shows  the 
muscular  coat  after  the  mucous 
coat  has  been  turned  ofl'. 


1^^ 


Section  of   the 
(Esophagus. 

n,  h.  Internal 
circular  fibres. 
c.  External  lon- 
gitudinal fibres. 


80 


DIGESTION. 


2.  The  pharynx  and  oesophagus  constitute  a  muscular  canal,  which 
forms  the  medium  of  communication  between  the  mouth  and  stomach, 
and  convcj^s  the  food  from  the  former  of  these  cavities  to  the  latter. 

The  pharynx  has  the  shape  of  an  irregular  funnel, — the  larger  open- 
ing of  the  funnel  looking  towards  the  mouth  and  nose;  the  under  and 
smaller  end  terminating  in  the  oesophagus.  Into  its  upper  part,  the 
nasal  fosste.  Eustachian  tubes,  mouth,  and  larynx  open.  It  is  inservient 
to  useful  purposes  in  the  production  of  voice,  respiration,  audition,  and 
digestion;  and  extends  from  the  basilary  process  of  the  occipital  bone, 
to  which  it  is  attached,  as  far  as  the  middle  part  of  the  neck.  Its  trans- 
verse dimensions  are  determined  by  the  os  hj^oides,  larynx,  and  ptery go- 
maxillary  apparatus,  to  which 
Fig- 10.  it  is  attached.     It  is  lined  by 

a  mucous  membrane,  less  red 
than  that  which  lines  the 
mouth,  but  more  so  than  that 
of  the  ossophagus,  and  the  rest 
of  the  digestive  tube;  and  it 
is  remarkable  for  the  deve- 
lopement  of  its  veins,  which 
form  a  very  distinct  network. 
Around  this  is  the  muscular 
la^^er,  the  circular  fibres  of 
which  are  often  divided  into 
three  muscles — superior,  mid- 
dle, and  inferior  constrictors. 
The  longitudinal  fibres  form 
part  of  the  stylopharyngei  and 
pxdato-pjharyngei  muscles.  The 
pharynx  is  raised  by  the  action 
of  the  last  two  muscles,  as  well 
as  by  all  those  that  are  situate 
between  the  lower  jaw  and  os 
hyoides,  which  cannot  raise 
the  latter  without,  at  the  same 
time,  raising  the  larynx  and 
pharynx.  These  muscles  are: 
— mylo-hyoideus,  genio-hyoidcvs, 
and  the  anterior  belly  of  the 
digastricus. 

The  oesophagus  is  a  continua- 
tion of  the  pharynx ;  and  ex- 
tends to  the  stomach,  where  it 
terminates.  Its  shape  is  cylin- 
drical, and  it  is  connected  with 
the  surrounding  parts  by  loose 
and  extensible  areolar  tissue, 
which  yields  readily  to  its 
movements.  On  entering  the 
abdomen,  it  passes  between 
the  pillars  of  the  diaphragm,  with  which  it  is  intimately  united.     The 


} 


A  view  of  the  Muscles  of  the  Tongue,  Palate,  Larynx 
and  Pharynx — as  well  as  the  position  of  the  upper 
portion  of  the  (Esophagus,  as  shown  by  a  vertical 
section  of  the  head. 

1,  1.  The  vertical  section  of  the  head.  2.  Points  to  the 
spinal  canal.  3.  Serticm  of  the  hard  palate.  4.  Inferior 
spnngy  bone.  !>.  Middle  sponey  hone.  6.  Orifice  of  the 
right  nostril.  7.  Section  of  theinferior  maxilla.  S.  Sec- 
ti.>n  of  the  os  hyoides.  ft.  Section  of  the  epiglottis.  10. 
Section  of  the  cricciid  cartilage.  11.  The  trachea,  covered 
by  its  lining  memhi-ane.  12.  Section  of  sternum.  13.  In- 
side of  the  npper  portion  of  the  thorax.  14.  Genio-hyo- 
glossus  mu.-;cle.  l.i.  Its  origin.  16,  17.  The  fan-like  ex- 
pansion of  the  fibres  of  this  mnscle.  IS.  Superfioialis 
linguse  muscle.  19.  Verticalis lingua;  muscle.  20.  Genio- 
liyoidons  muscle.  21.  Jlylo-hyoideus  muscle.  22.  An- 
terior belly  of  digastricus.  23.  Section  of  platysma  myoi- 
des.  24.  Levator  meuti.  2o.  Orbicularis  oris.  26.  Orifice 
of  Eustachian  tube.  27.  Levator  palati.  28.  Internal 
pterygoid.  2.0.  Section  of  velum  pendulum  palati,  and 
a/.ygos  uvulaj  muscle.  .30.  Stylo-pharyngeus.  31.  Con- 
strictor pharyngis  superior.  32.  Constrictor  pharyngis 
medins.  .33.  Insertion  of  stylo-pharyngeus.  34.  Con- 
strictor pharyngis  inferior.  .35,  .36,  37.  Muscular  coat  of 
wsophagus.  3S.  Thyreo-arytenoid  muscle  and  ligaments, 
and  above  is  the  ventricle  of  Galen.  .39.  Section  of  aryte- 
noid cartilage.     40.  Border  of  sterno-hyoideus. 


DIGESTIVE   ORGANS — STOMACH. 


81 


mucous  membrane  lining  it  is  pale,  tliin,  and  smooth  ;  forming  longi- 
tudinal folds,  well  adapted  for  favouring  tlie  dilatation  of  the  canal. 
Above,  it  is  confounded  with  that  of  the  pharynx ;  but  below,  it  forms 
several  digitations,  terminated  by  a  fringed  extremity,  which  is  free  in 
the  cavity  of  the  stomach.  It  is  well  supplied  with  mucous  follicles. 
The  muscular  coat  is  thick  ;  its  texture  is  denser  than  that  of  the 
pharynx, — and  cannot,  like  it,  be  separated  into  distinct  muscles,  but 
consists  of  circular  and  longitudinal  fibres,  the  former  of  which  are 
more  internal,  and  very  numerous,  the  latter  external  and  less  nume- 
rous. 

3.  The  stomach  is  situate  in  the  cavity  of  the  abdomen,  and  is  the 
most  dilated  portion  of  the  digestive  tube.  It  occupies  the  epigastric 
region,  and  a  part  of  the  left  hypochondre.  Its  shape  has  been  com- 
pared, not  inappropriately,  to  that  of  the  bag  of  a  bag-pipe.  It  is 
capable  of  holding,  in  the  adult  male,  when  moderately  distended, 
about  three  pints.    The  left  half  of  the  organ  has  always  much  greater 

Fig.  11. 


Stomach  yeen  Externiilly. 

A,  A.  Anterior  surface.     B.  Enlargement  at  lower  part.     D.  Cardiac  orifice.     E.  Commencement  of 
duodenum.    F  and  C.  Coronary  vessels.     II.  Omentum. 

dimensions  than  the  right.  The  former  has  been  called  the  spJmic 
portion,  because  it  rests  upon  the  spleen ;  the  latter  the  }yylonc  portion^ 
because  it  corresponds  to  the  pylorus.  The  inferior  border  of  the 
stomach,  which  is  convex,  is  termed  the  (jn^at  cunature  or  arch;  the 
VOL.  I. — 6 


82 


DIGESTION. 


superior  border,  tlie  lesser  curvat^rre  or  arch.  The  two  orifices  are  the 
cesophageal^  cardiac  or  vj)per  orifice^  formed  bj  the  termination  of  the 
oesophagus;  and  the  intestinal.^  pyloric  or  inferior  orifice.^  which  com- 
municates with  the  small  intestine. 

The  three  coats  that  constitute  the  parietes  of  the  stomach,  are  ar- 
ranged in  a  manner  the  most  favourable  for  permitting  variation  in  the 
size  of  the  organ.  The  outermost  or  jjeritoneal  coat  consists  of  two 
laminse,  which  adhere  but  slightly  to  the  organ,  and  extend  beyond  it, 
where  they  form  the  epiplooiis  or  omenta.^  the  extent  of  v/hich  is  in  an 
inverse  ratio  to  the  degree  of  distension  of  the  stomach.  The  omentum 
majus  or  gastro-colic  epiploon  is  the  part  that  hangs  down  from  the 
stomach  in  Fig.  11. 

The  mucous  or  lining  membrane  is  of  a  whitish,  marbled,  red  appear- 
ance, having  a  number  of  irregular  folds,  situate  especially  along  the 
inferior  and  superior  margins  of  the  organ.  These  folds  are  evident, 
also,  at  the  splenic  extremity ;  and  are  more  numerous  and  marked, 
the  more  the  stomach  is  contracted.  They  are  radiated  towards  the 
cardiac, — longitudinal  towards  the  pyloric,  orifice.  This  membrane, 
like  every  other  of  the  kind,  exhales  an  albuminous  fluid.    It  contains. 


Fig.  12. 


Fig.  13. 


Vertical  and  Longitudinal  Section  of  Stomach  and 
Duodenum. 

1.  CEsophagiis ;  upon  its  internal  surface,  the  plicated 
arrangement  of  cuticular  epithelium  shown.  2.  Cardiac 
orifice  of  stomach,  around  which  the  fringed  border  of 
cnticolar  epithelium  is  seen.  3.  Great  end  of  stomach. 
4.  Its  lesser  or  pyloric  end.  5.  Lesser  curve.  6.  Greater 
curve.  7.  Dilatation  at  lesser  end  of  stomach  which  re- 
ceived from  Willis  the  name  of  antrum  of  2?ylorus.  This 
may  be  regarded  as  the  rudiment  of  a  second  stomach. 
8.  Rugie  of  the  stomach  formed  by  mucous  membrane : 
their  longitudinal  direction  is  shown.  9.  Pylorus.  10. 
Oblique  portion  of  duodenum.  11.  Descending  portion. 
12.  Pancreatic  duct,  and  ductus  communis  choledochus, 
close  to  their  termination.  1.3.  Papilla  upon  which  ducts 
open.  14.  Transverse  portion  of  duodenum.  1.5.  Cora- 
niencement  of  jejunum.  In  interior  of  duodenum  and 
jejuntim,  the  valvula  conniventes  are  seen. 


Section  of  a  piece  of  Stomach  not  far 
from  Pylorus. 

1.  Magnified  about  three  diameters.  2. 
A  few  of  the  glands  with  their  racemiform 
ends  distended  with  fluid,  magnified  about 
20  diameters. 


likewise,  many  follicles,  which  are  especially  abundant  in  the  pyloric 
portion.  Several,  also,  exist  in  the  vicinity  of  the  cardiac  orifice,  but 
ia  the  rest  of  the  membrane  they  are  few  in  number.   When  examined 


DIGESTIVE   ORGANS  —  STOMACH. 


83 


witli  a  magnifying  glass,  the  internal  or  free  surface  presents  a  peculiar 
honeycomb  or  reticulated  appearance,  produced  by  shallow  polygonal 


Fig.  14. 


Fig.  15. 


Ml 


^-fjiMii^ 


A  portion  of  the  Mucous  Mombrane  of 
the  Stomach  magnified  seventy-live 
times. 

The  alveoli  measured  l-200th  of  an  inch 
in  length,  by  l-2.50th  in  breadth ;  the 
width  of  the  septa  being  1-lOOOth  of  an 
inch.  The  smaller  alveoli  measured 
l-2.)0th  of  an  inch  in  length,  and  l-300th 
in  breadth.  The  trifid  or  quadrifid  di- 
vision of  a  small  artery  is  seen  at  the 
bottom  of  each  alveolus,  and  in  the 
depressions  between  the  divisions  of 
the  artery,  the  apertures  of  the  gastric 
follicles  ;  two,  three,  or  four  in  each  de- 
pression. 


Tubular  Follicle  of  Pi 
Stomach. 


depressions  or  cells  as  represented  in  the  marginal  figures.  The  di- 
ameter of  these  cells  varies  from  g^^th  to  3I  o^^  of  ^^  inch  ;  but,  near 
the  pylorus,  it  is  as  much  as  jljjth.  of  an  inch.  In  the  bottom  of  the 
cells,  minute  openings  are  visible,  which  are  the  orifices  of  perpen- 
dicular glands  embedded,  side  by  side,  in  bundles  in  the  substance  of 
the  mucous  membrane,  and  composing  nearly  the  whole  structure.^ 
These  tubular  follicles  vary  in  length  from  one-fourth  of  a  line  to 
nearly  a  line.  They  are  longer  and  more  closely  set  towards  the  py- 
lorus than  elsewhere,  their  length  being  equal  to  the  thickness  of  the 
mucous  membrane  of  the  stomach,  which  varies. 

The  office  of  the  tubular  follicles,  it  has  been  thought,  is  to  secrete 
the  gastric  fluid,  during  digestion ;  for  in  the  intervals  they  are  at 
rest.  They  are  formed  by  inflections  of  basement  membrane,  with 
cylindrical  epithelium  resting  upon  it.  One  of  them  is  represented  in 
tlie  marginal  figure,  which  exhibits  the  nucleated  cells  at  the  bottom 
of  the  follicle  becoming  more  and  more  developed  as  they  approach 
the  free  surface.  These  cells  prepare  the  gastric  fluid,  and  ultimately 
burst  and  discharge  it  to  become  mixed  with  the  aliment  in  the  stomach, 
the  elaboration  of  the  fluid  in  these  cells  seeming  to  be  perfected  only 
as  they  reach  the  surface,  inasmuch  as,  according  to  M.  Bernard,^  the 
mucous  membrane  is  not  acid  a  little  below  the  surface.  Professors 
Donders  and  Kcilliker  are  of  opinion,  that  there  are  two  great  varieties 
of  glands  in  the  human  stomach, — the  ])eptic  gastric  glands^  with  j)eptic 
stomach  ov  rennet  cells,  of  the  latter  observer;  and  the  simple  mucous 
glands  with  cylinder  epithelium,  as  represented  in  the  subjoined  figures 
from  Kolliker.     Thus  far,  however,  they  have  only  been  seen  in  ani- 

'  Dr.  Sprott  Boyd,  Edinb.'Med.  and  Surg.  Journal,  vol.  slvi. ;  aud  E.  Wilson,  Lond. 
Med.  Times  and  Gazette,  Feb.  3,  1855. 
2  Gaz.  Med.  de  Paris,  xix.,  Mars,  1844. 


84 


DIGESTION. 


mals.*   Between  the  different  tubular  follicles  blood-vessels  pass  up  and 
form  a  vascular  network,  in  the  interspaces  of  which  the  orifices  of  the 


Fig.  16. 


Fig.  17. 


Fig.  18. 


Peptic  Gastric  Gland. 
a.  Common  trunk.  b,h.  Its  chief 
branches,  c.c.  Terminal  cseca  with 
spheroidal  gland-cells. 


Portions  of  one  of  the  caeca 
more  highly  magnitied, 
as  seen  lungitudinnliy 
(a),  and  in  transverse 
section  (b). 

a.  Basement  membrane.  6. 
Large  glandular  celLs.  c. 
Small  epithelium-cells  sur- 
ruunding  the  cavity. 

Fig.  19. 


Mucous    Gastric   Gland,  with 
Cylinder-Epithelium. 

a.  Wide  trunk.    6,  b.  Its  caecal 
appendages. 


Capillary  Network  of  the  Lining  Membrane  of  the  Stomach,  with  the  Orifices  of  the  Gastric 

Follicles. 

'  KiJlliker,  Mikroskopische  Anatomie,  2ter  Band.  S.  141,  Leipz.,  1852.  Manual  of 
Human  Histology,  translated  by  Busk  and  Huxley,  Sydenham  Society's  edit.,  ii.  87, 
Lond.,  1854;  and  American  edit.,  by  Dr.  Da  Costa,  p.  507,  Philad.,  1854. 


DIGESTIVE   ORGANS — STOMACH. 


85 


follicles  are  seen ;  and  Kcilliker^  observed  in  the  villi  numerous  mus- 
cular fibre  cells.  Briicke^  had  already  pointed  out  a  thin  layer  of 
smooth  or  organic  muscular  fibres,  separated  from  the  rest  of  the  mus- 
cular membrane  by  connective  tissue. 

Besides  these  glands  or  follicles,  small  opaque,  white  sacculi,  re- 
sembling Peyer's  glands,  are  met  with,  which  are  filled  with  minute 
cells  and  granules.  They  are  situate  chiefly  along  the  lesser  curvature 
of  the  stomach  beneath  the  lining  membrane ;  are  probably  concerned 


Fig.  20. 


Vertical  Section  of  a  Gastric  Follicle,  with  its 
Tubes. 

A.  In  the  middle  region,  b.  In  the  pyloric  region. 
a,  a.  Orifices  of  the  celLs  on  the  inner  surface  of  the 
stomach,  b,  b.  Different  depths  at  which  the  colum- 
nar epithelium  is  exchanged  for  glandular,  c.  Pylo- 
ric tube,  or  prolonged  stomach  cell.  d.  Pyloric 
tubes,  terminating  variously,  and  lined  to  their  ex- 
tremities with  sub-columnar  epithelium. 

From  the  dog,  after  twelve  hours'  fasting.  Magni- 
fied 200  diameters. 


Mucous  Membrane  of  the  Stomach. 

A.  Inner  surface  of  the  stomach,  showing  the 
cells  after  the  mucus  has  been  washed  out. — 
Magnified  2.5  diameters. 

B.  Columnar  epithelium  of  the  inner  surface 
and  cells  of  the  stomach,  a.  Free  ends  of  the 
epithelial  particles,  seen  on  looking  down  upon 
the  membrane,  b.  Nuclei  visible  at  a  deeper 
level,  e.  The  free  ends  seen  obliquely,  d.  Deep 
or  attached  ends  of  the  same.  The  oval  nuclei 
are  seen  near  the  deeper  ends. 

From  the  dog. — Magnified  300  diameters. 


in  the  separation  of  some  secretion  from  the  blood,  and,  when  filled, 
burst,  like  other  secreting  cells,  and  discharge  their  contents  into  the 
stomach.^ 

Dr.  Neill,"*  from  his  histological  examinations  of  the  stomach,  has 


'  Op.  cit. 

2  Sitzungsbericht.  der  Wiener  Akad.,  vi.  214,  and  Canstatt's  Jaliresbericht,  1851,  S. 
119,  WiirzWrg,  1851. 

3  Kirkes  and  Paget,  Manual  of  Physiology,  2d  Amer.  edit.,  p.  167,  Pliilad.,  1853. 
*  Amer.  Journ.  of  the  Med.  Sciences,  Jan.,  1851. 


86 


DIGESTION. 


described  the  arrangement  of  tlie  mucous  membrane  as  differing  essen- 
tially in  the  cardiac^ middle  and  pyloric  portions.  In  the  first  portion 
it  is  reticulated ;  in  the  last,  villous ;  whilst  the  second  is,  so  to  speak, 


Fig.  22. 


Appearance  of  the  Lining  Membrane  of  the  Stomach,  in  an  injected  preparation. 

A.  From  the  convex  surface  of  the  rugje.     b.  From  the  neighbourhood  of  the  pylorus,  where  the  ori- 
fices of  the  gastric  follicles  occupy  the  interspaces  of  the  deepest  portions  of  the  vascular  network. 

.    .  * 

in  a  transition  state.  In  the  cardiac  portion  the  blood-vessels  appear 
to  surround  the  orifices  of  the  tubes  ;  whilst  in  the  pyloric  portion  villi 
are  distinct,  but  not  as  much  so  as  in  the  small  intestines.  This  arrange- 
ment would  favour  the  idea,  that  secretion  takes  place  more  especially  in 
the  former  situation,  whilst  absorption  occurs  more  largely  in  the  latter. 
The  view  is  not,  however,  supported  by  Mr.  Erasmus  Wilson,^  who 
describes  the  reticular  arrangement  as  existing  over  the  whole  of  the 

linino;  membrane,  and  it 
Fig-  23.  does  not  accord  with  the 

observations  of  those  who 
consider  the  follicles  to 
be  especially  abundant 
in  the  pyloric  portion. 

The  'pyhrus^  or  the 
part  at  which  the  sto- 
mach terminates  in  the 
small  intestine, ismarked, 
externally,  by  a  manifest 
narroAvuess.  Internally, 
the  mucous  membrane 
forms  a  circular  fold, 
which  has  been  called 
valve  of  the  pyhriis^  be- 
tween the  two  laminae  of 

Front  View  of  Stomach,  distended  hy  flatus,  with  Peritoneal     wllich,    a    denSC,    fibroUS 

tissue  exists.     This  has 

1.  Antoriorface  of  oesophagus 

xtremifv-     4     Dii ^ „,  „. 

L  portion  of  the    tliors,  pvloric  muscU. 

ar  fibres  of  the  ^m  7 

i  he     muscular    coat, 
which  is  exterior  to  the 
mucous  coat, — as  in  the 
parts  of  the  digestive  tube   already  described, — consists  of  several 


Coat  turned  off. 

_      _  Cul-de-sac,  or  greater  ex-     'Upp.-i   ooPprl    Kv  qnmp  nil 

tremity.     3.    Lesser  or  pyloric  extremity.     4.    Duodenum.     5,5.      uecu  V..<Uieu,   uy    feUllltJ  d,U 

A  portion  of  the  peritoneal  coat  turned  back.     6. 

longitudinal  fibres  of  the  muscular  coat.     7.  Circnl 

muscular  coat.     8.  Oblique  muscular  fibres,  or  muscle  of  Gavard 

9.  A  portion  of  the  muscular  coat  of  the  duodenum,  where  its  peri 

toneal  coat  has  been  removed. 


'  Op.  cit. 


DIGESTIVE   ORGANS — STOMACH. 


87 


laminoB  of  fibres,  less  distinct  than  those  of  the  oesophagus;  or  rather 
more  irregularly  distributed.  The  most  common  opinion  is,  that  there 
are  three  laminee :  —  an 
external  longitudinal  se- 
ries; a  middle  transverse 
or  circular  stratum;  and 
an  inner  stratum  with 
fibres  running  obliquely. 
Both  circular  and  longi- 
tudinal fibres  are  sepa- 
rated from  each  other, 
especially  in  the  splenic 
portion,  —  the  separation 
ausfmentinor  or  diminish- 
ing  with  the  varying  size 
of  the  stomach. 

The  blood-vessels  and 
nerves  of  the  stomach  are 
more  numerous  than  those 
of  any  other  organ  of  the 
body.  The  arteries  are 
disposed  along  the  curva- 
tures. On  the  lesser  cur- 
vature are,  —  coronaria 
ventriculi,  and  the  pyloric 
branch  of  the  hepatic  ar- 
tery ;  on  the  great  curva- 
ture, the  right  gastro-epi- 
ploic,  which  is  a  branch 
of  the  hepatic;  and  the 
left  gastro-epiploic,  —  a 
branch  of  the  splenic.  The 
splenic  artery,  too,  fur- 
nishes numerous  branches 
to  the  left  cul-de-sac  be- 
hind. These  are  called 
vasa  brevia  or  gastro-sple- 
nic.  The  nerves  of  the 
stomach  are  of  two  kinds. 


Distribution  of  the  GloE!=o-Pharyn>;eaI.  Pneiunogastric  and 
Spinal  Accessorj'  Nerves,  or  the  Eighth  Pair. 


1.  The  inferior  maxillary  nerve.  2.  The  gustatory  nerve.  3. 
The  chorda  tympani.  4.  The  auricular  nerve.  5.  Its  coniniuni- 
Ciition  with  the  portio  dura.  6.  The  facial  nerve  coming  out  of 
tlie  stylo-mastoid  foramen.  7.  The  glosso-pharyngeal  nerve.  8. 
Brauehe.s  to  tlie  stylo-pharyngeus  muscle.  9.  Tlie  pharyngeal 
f-,  1      />  1  branch  of  the  pnoumogastric  nerve  de.scending  to  form  the  piuiryn- 

bOme  proceed  irom  tne  gealplexu.s.  lO.  Brauche-ioftheglo.sso-pliaryngealtothepliaryn- 
.l  ,•  p  geal  plexus.  11.  The  pneumogastric  nerve.  12.  The  pharyngeal 
great  SympatnetlC,  irOm  piexus.  13.  The  superior  laryngeal  branch.  14.  Branchob' to  the 
flip  or^y^r\n  T^lpvna  nnrl  pharyngeal  plexus.  15,  15.  Communication  of  the  superior  and 
tuc     uu^iicio      pn..Ji.u&,     aiiu.     inferior  laryngeal  nerves.     16.   Cardiac  branches.     17.   Cardiac 

branches  from  tlie  right  pneumogastric  nerve.  IS.  Tlie  left  car- 
diac ganglion  and  plexus.  19.  The  recurrent  or  inferior  laryngeal 
nerve.  20.  Branches  sent  from  the  curve  of  the  recurrent  nerve 
to  the  pulmonary  plexus.  21.  The  anterior  pulmonary  plexus. 
22,  22.  The  ojsophageal  plexus. 

nished  by  the  pneumo- 
gastric or  eighth  pair,  the  two  nerves  of  which  surround  the  cardiac 
orifice  like  a  ring.  The  number  of  the  nerves,  and  the  variety  of 
sources  whence  they  are  derived,  explain  the  great  sympathetic  influ- 
ence exerted  upon  the  stomach  by  aft'ections  of  other  parts  of  the 
system.     It  sympathizes,  indeed,  with  every  protracted  morbid  change 


coeliac   plexus, 
accompany   the    arteries 
through  all  their  ramifi- 
cations.    Others  are  fur- 


88 


DIGESTION. 


in  the  individual  organs ;    and   hence  was  termed,  by  Mr,  Hunter, 
the  centre  of  sympatliks. 

Like  the  teeth,  the  human  stomach  holds  a  medium  place  between 
that  of  the  carnivorous  and  herbivorous  animal.  As  the  former  makea 
use  of  aliment,  which  is  more  readily  assimilated  to  its  own  nature, 
and  more  nutritious,  it  is  not  necessary  that  it  should  take  food  in  such 
laro-e  quantities  as  the  lattei',  or  that  this  should  remain  so  long  in  the 
stomach.  On  this  account,  the  organ  is  generally  of  much  smaller 
size.  On  the  other  hand,  as  the  herbivora  subsist  solely  upon  grass, 
which  contains  but  a  small  quantity  of  nutritious  matter,  and  that  not 
easy  of  assimilation,  it  is  important  that  the  quantity  taken  in  should 
be  ample;  that  it  should  remain  for  some  time  in  the  organ  subjected 
to  the  action  of  its  secretions ;  and,  in  the  ruminant  class,  be  returned 
into  the  mouth,  to  undergo  fresh  mastication. 

In  this  class,  the  stomach  is  of  prodigious  extent.  In  the  ox,  which 
we  may  take  as  an  example  of  the  general  structure  of  the  organ,  it 
consists  of  four  separate  compartments.  The  first  stomach,  A  A, 
Fig.  25,  ventriculus  or  paunchy  is  much  the  largest.  Externally,  it  has 
two  sacs  or  appendices ;  and,  internally,  is  slightly  divided  into  four 
compartments.  The  second  stomach  is  tlie  reticulum^  lonnet  or  honey- 
comb hag,  B,  which  appears  to  be  a  globular  appendix  to  the  paunch. 
It  is  situate  to  the  right  of  the  oesophagus,  Gr,  and  has  usually  a 
thicker  muscular  coat  than  the  paunch.  Its  inner  surftice  is  arranged 
in  irregular  pentagonal  cells,  and  is  covered  with  fine  papillaB.     The 

third  stomach,  C,  is  the  smallest, 
and  is  called  omasum  or  manyplies. 
It  is  of  a  globular  shape,  and  has 
a  thinner  muscular  coat  than  the 
former.  It  consists  of  numerous 
broad  laminte,  sent  off  from  the  in- 
ternal coat,  running  in  a  longitudinal 
direction,  alternately  varying  in 
breadth,  and  covered  with  small  o-ra- 
nular  papilke.  The  fourth  stomach, 
D,  is  the  abomasum,  ventriculus  intes- 
tmalis,  reed,  or  caillette.  It  has  a  pyri- 
form  shape,  and  is  next  in  size  to  the 
paunch.  It  has  large  longitudinal 
rugi^,  covered  with  villi.  The  mus- 
cular coat  is  still  thinner  than  that 
of  the  former.  This  stomach  is  the 
only  one  that  resembles  the  human 
organ;  and,  in  the  young  of  the 
ruminant  animal,  with  the  milk  cur- 
dled in  it,  forms  the  runnet  or  rennet.  The  property  of  curdling  milk 
is,  however,  possessed  by  all  digestive  stomachs.  The  inner  surftice  of 
the  three  first  stomachs  is  covered  with  cuticle ;  whilst  that  of  the  fourth 
is  lined  by  a  true  mucous  or  secreting  membrane.  There  is  in  the 
interior  arrangement  of  the  stomachs  of  the  ruminant  animal  a  sin- 
gular provision  by  which  the  food  can  be  either  received  into  the  first 


Fi?.  25. 


Stoinanh  of  the  Ox. 


A,  A.  Paunch 
T>.  Abomasuiu. 
G.  CEsophagus. 


B.  Ri'ticulum. 
E     Pylorus.      F. 


^.  Omasnm. 
Buodeuuin. 


DIGESTIVE   ORGANS   OF   THE   RUMINANT  ANIMAL. 


8^ 


and  second  stomachs,  or  be  carried  on  into  the  third,  if  its  character 
be  such  as  to  be  fitted  at  first  for  the  action  of  the  omasum. 

From  the  oesophagus,  in  Fig.  26,  a  gutter  or  demi-canal  passes  into 
the  second  and  third  stomachs.  The  third  leads  into  the  fourth  by  a 
narrow  opening,  and  the  fourth  terminates  in  the  duodenum,  which 
has  a  pylorus  at  its  origin.  AVhen  the  animal  eats  solid  food,  it  is, 
after  slight  mastication,  passed  into  the  paunch,  and  thence,  by  small 
poitions,  into  the  second  stomach.     When  this  has  become  mixed  with 


Fig.  26. 


Fig.  27. 


Section  of  part  of  the  Stomach  of  the  Sheep,  to    m 
show  the  demi-canal  of  the  oesophngiis;  the 
mucous  membrane  is  for  the  most  part  re-     " 
moved,  to  show  the  arrangement  of  the  mus 
cular  fibres. 


At  a  is  seen  the  termination  of  the  oesophageal 
tube,  the  cut  edge  of  whose  mucous  membrane  is 
shown  at  b.  The  lining  of  the  first  stomach  is 
shown  at  e,  c ;  and  the  mucous  membrane  of  the 
second  stomach  is  seen  to  be  raised  from  the  sub- 


n 

P 


Digestive  Apparatus  of  Common  Fowl. 

a.  OSsophagus.  b.  Ingluvies  or  crop.  c.  Proven- 
jacent  fibres  at  (7.  At  e,e,  tlie  lips  of  the  demi-canal  triculus.  rf.  Gizzard,  e.  Liver.  /.Gall-bladder,  g. 
are  seen  bounding  the  groove,  at  the  lower  end  of  Pancreas,  h.  Duodenum,  i.  Small  intestine,  k. 
which  is  the  entrance  to  the  third  stomach  or  many-  C-eca.  I.  Large  intestine,  m,  m.  Ureters,  n.  Ovi- 
pUes.  duct.    o.  Cloaca. 

fluid,  and  kept  for  some  time  at  a  moderately  high  temperature,  a  morsel 
is  thrown  back  with  velocity  from  the  stomach  into  the  mouth,  where 
it  is  "ruminated,"  and  then  swallowed  and  passed  on  into  the  third 
stomach, — the  groove  or  gutter  being  now  so  contracted  as  to  form  a 
channel  for  its  passage  through  the  fii'st  two.  In  the  third  and  fourth 
stomachs,  more  especially  the  latter,  true  digestion  takes  place.  When 
the  food  is  of  such  a  character  as  not  to  require  rumination,  it  can  be  sent 
on  directly  into  the  third  stomach,  by  the  arrangement  just  described. 


90 


DIGESTION. 


In  bird  tribes,  we  see  an  admirable  adaptation  of  structure  to  the 
functions  which  the  digestive  organs  have  to  execute.  Animals  of 
this  class  may  be  divided  into  the  granivorous  and  the  carnivorous. 
It  is  in  the  former,  that  we  are  so  much  impressed  with  the  organiza- 
tion of  this  part  of  their  economy.  The  grain  on  which  they  feed, 
although  more  nutritious  than  grass,  which  constitutes  the  aliment  of 
the  herbivorous  quadruped,  requires  equal  difficulty  in  being  assimi- 
lated to  the  nature  of  the  being  it  has  to  nourish.  Added  to  this,  it  is 
in  such  a  condition,  that  the  juices  of  the  digestive  organs  cannot 
readily  act  upon  it.  The  bird  having  no  masticatory  apparatus  within 
the  mouth,  the  grain  must  of  necessity  be  swallowed  whole.     But  we 

find     that     lower 
Fig-  28.  down   in   the    ali- 

mentary tube,  a 
powerful  mastica- 
tory apparatus  ex- 
ists, which  has  fre- 
quently been  con- 
sidered as  a  part 
of  the  digestive  sto- 
mach ;  but  really 
seems  destined  for 
mastication  only. 
The  following  is 
the  arrangement  of 
their  gastric  appa- 
ratus. 

The  oesophagus 
terminates  at  the 
bottom  of  the  neck 
in  a  large  sac — in- 
gluvies,  crop  or  craw 
— which  is  of  the 
same  structure  with 
the  oesophagus,  but 
thinner.  On  the 
inner  side  of  the 
crop  are  numerous 
glands,  with  very 
distinct  orifices  in 
large  birds,  which 
secrete  a  fluid  to  as- 
sist in  the  solution 
of  the  food.  To  the 
crop  succeeds  an- 
other cavity,  in  the 
shape  of  a  funnel,  called  proventriculus,  irtpmdiljnlurii  or  second  stomach. 
This  is  seated  in  the  abdomen,  and  is  generally  smaller  than  the  former. 
It  is  usually  thicker  than  the  cesophagus,  partly  owing  to  its  numerous 
glands,  which  are  very  large  and  distinct  in  many  birds.  In  the 
ostrich,  they  are  as  large  as  the  garden-pea,  and  have  very  manifest 


Gastric  Apparatus  of  the  Turkey. 


DIGESTIVE   OEGAXS   OF   THE   GALLHSTACEA. 


91 


orifices.  The  infundibulum  terminates  in  the  ventriculus  callosus,  giz- 
zard or  third  stomach — the  most  curious  of  all  the  parts  of  the  apparatus. 
Figs.  28  and  29  afford  an  external  and  internal  view  of  the  gastric 
apparatus  of  the  turkey ;  «,  representing  the  oesophagus  immediately 
below  the  crop,  covered  with  cuticle ;  h,  the  openings  of  the  gastric 
glands  in  the  second  stomach,  placed  on  a  surface,  that  has  no  cuticular 
covering ;     c,    horny 

ridges,    between    the  Fig-  29. 

gastric  glands  and  the 
lining  of  the  gizzard ; 
cZ,  a  minutely  granu- 
lated surface  between 
the  cavity  of  the  giz- 
zard and  duodenum; 
and  e,  the  inner  sur- 
face of  the  duodenum. 
Fig.  28  accurately  re- 
presents the  mode  in 
which  the  second  sto- 
mach terminates  in  the 
gizzard,  and  the  latter 
in  the  duodeuum  ;  the 
gizzard  formingakind 
of  pouch  depending 
from  the  alimentary 
canal.  The  gizzard  is 
usually  of  a  globular 
figure,  flattened  at  the 
sides,  and  is  consider- 
ed to  consist  of  four 
muscles,  remarkable 
for  their  great  thick- 
ness and  streno;th  ; — a 
large  hemispherical 
pair  at  the  sides,  and  a 
small  pair  situate  at 
the  extremities  of  the 
stomach.  The  gizzard  is  covered  externally  by  a  beautiful  tendinous  ex- 
pansion; and  is  lined  by  a  thick,  strong,  callous  coat,  which  appears  to 
be  epidermous  in  its  character.  On  this  are  irregularities,  adapted  to 
each  other  on  the  opposite  surfaces.  The  cavity  of  the  organ  is  remark- 
ably small,  when  compared  with  its  outward  magnitude,  and  its  two  ori- 
fices, represented  in  ¥ig.  28,  are  very  near  each  other.  In  the  pouch 
formed  by  the  small  muscles  at  the  lower  part  of  the  gizzard,  numerous 
pebbles  are  contained,  which  seem  to  be  indispensable  to  the  digestion  of 
certain  tribes,  by  acting  as  substitutes  for  teeth.  In  the  gizzard  of  the  tur- 
key, two  hundred  have  been  found ;  in  that  of  the  goose,  one  thousand.^ 

'  J.  Hunter,  Observations  on  certain  parts  of  the  Animal  Economy,  with  Notes  by 
Prof.  Owen,  Amer.  edit.,  p.  119,  Philad.,  1840  ;  and  Roget,  Animal  and  Vegetable  Phy- 
siology, Amer.  edit.,  ii.  126.    Philad.,  183(J. 


Interior  of  the  Gastric  Apparatus  of  the  Turkey. 


92  DIGESTION. 

The  prodigious  power  with  which  the  digastric  muscle — as  it  has  been 
termed — acts,  and  the  callous  nature  of  the  cuticle,  are  strikingly  mani- 
fested by  certain  experiments,  instituted  by  the  Acaclemia  del  Cimento^^ 
and  by  Eedi,  Reaumur,^  and  Spallanzani.^  They  compelled  geese  and 
other  birds  to  swallow  needles  and  lancets,  and  in  a  few  hours  after- 
wards killed  and  examined  them.  The  needles  and  lancets  were  uni- 
formly  found  broken  off  and  blunted,  without  the  slightest  injury 
having  been  sustained  by  the  stomach. 

In  the  carnivorous  bird,  the  food  being  readily  assimilated,  in  con- 
sequence of  its  analogy  to  the  substance  of  the  animal,  the  gastric 
apparatus  is  as  simple  as  in  the  carnivorous  mammalia.  The  oesopha- 
gus is  of  great  size  for  receiving  the  large  substances  swallowed  by 
these  animals,  and  for  enabling  the  feathers  and  other  matters,  that 
cannot  easily  be  digested,  to  be  rejected  by  the  mouth.  The  stomach 
is  a  mere  musculo-membranous  sac ;  but  the  secretion  from  it  is  of  a 
potent  character,  so  as  to  enable  the  animal  to  dispense  with  mastica- 
tion, and  yet  to  admit  of  the  stomach  and  intestines  being  disposed 
within  a  small  compass,  so  as  to  give  them  the  necessary  lightness  to 
fit  them  for  flight. 

We  can  thus,  from  organization,  generally  form  an  idea  of  the  kind 
of  food  for  which  an  animal  is  naturally  destined ;  whether,  for  exam- 
ple, it  is  naturally  granivorous  or  carnivorous.  There  are  some  strik- 
ing facts,  however,  that  exhibit  the  signal  changes  exerted,  even  on 
organization,  by  restricting  an  animal  to  diet  of  a  different  character 
from  that  to  which  it  has  been  accustomed ;  or  to  one  which  is  foreign 
to  its  nature.  In  birds  of  prey,  the  digastric  muscle  has  the  bellies, 
which  compose  it,  so  weak,  that,  according  to  Sir  Everard  Home,-* 
nothing  but  an  accurate  examination  can  determine  its  existence. 
But  if  a  bird  of  this  kind,  from  want  of  animal  food,  be  compelled  to 
live  upon  grain,  the  bellies  of  the  muscle  become  so  large,  that  they 
would  not  be  recognized  as  belonging  to  the  stomach  of  a  bird  of  prey. 
Mr.  Hunter  kept  a  sea-gull  for  a  year  upon  grain,  when  he  found  the 
strength  of  the  muscle  much  augmented.  This  wondrous  adaptation 
of  structure  to  the  kind  of  food  which  the  animal  is  capable  of  obtain- 
ing, is  elucidated  by  the  South  American  and  African  ostriches.  The 
former  is  the  native  of  a  more  productive  soil  than  the  latter ;  and, 
accordingly,  the  gastric  glands  are  less  complex  and  numerous;  and 
the  triturating  organ  is  less  developed.* 

■i.  The  intestines  are  the  lowest  portion  of  tlie  digestive  apparatus; 
constituting  a  musculo-membranous  canal,  which  extends  from  the 
pyloric  orifice  of  the  stomach  to  the  anus.  The  human  intestines  are 
six  or  eight  times  longer  than  the  body;  and  hence  the  number  of  con- 
volutions in  the  abdominal  cavity.  They  are  attached  to  the  vertebral 
column  by  folds  of  peritoneum  called  mesentery ;  and  according  to  the 
length  of  these  folds  or  duplicatures  the  intestine  is  bound  down,  or 

'  Exper,  fatte  nell'  Acad,  del  Cimento,  2da  ediz.,  Firenz.,  1691. 

2  Memoir  de  I'Acad,  pour  1752,  p.  2(36  and  p.  46i, 

3  Dissertations  relative  to  the  Natural  History  of  Animals  and  Vegetables,  English 
translation,  i.  16,  London,  1789. 

•*  Lectures  on  Comparative  Anatomy,  i.  271,  Lond.,  1814, 

5  Ibid.,  i.  293.     See,  on  all  this  subject,  Carpenter's  Principles  of  Comparative  Phy- 
siology, Amer,  edit,,  pp,  190  and  200,  Philad.,  1854. 


I 


DIGESTIVE   ORGANS  —  INTESTINES. 


93 


Fig.  30, 


floats  in  the  abdominal  cavity.  Their  structure  is  nearly  alike  through- 
out: a  mucous  membrane  lines  them:  immediately  without  this  is  a 
muscular  coat;  and,  externally,  a  serous  coat,  formed  by  a  prolonga- 
tion of  the  peritoneum.  The  mucous  membrane  is  soft  and  velvety, 
and  is  the  seat  of  a  similar  secretion  to  that  of  other  membranes  of  the 
same  class.  The  muscular  coat  is  composed  of  two  planes  of  fibres,  so 
united  that  they  cannot  be  separated, — the  innermost  consisting  of 
circular,  and  the  outermost  of  longitudinal  fibres,  the  arrangement  of 
which  differs  in  the  small  and  large  intestines.  The  serous  or  peri- 
toneal coat  receives  the  intestine  between  two  of  its  lamince,  which,  in 
their  passage  to  it,  form  the  mesentery.  The  serous  coat  only  comes  in 
direct  contact  with  the  intestine  at  the 
sides  and  forepart.  Behind,  or  on  the 
mesenteric  side,  is  a  vacant  space,  by 
which  the  vessels  and  nerves  reach  and 
leave  the  intestine.  These  form  their 
first  network  between  the  serous  and 
muscular  coats ;  their  second,  between 
the  muscular  and  mucous. 

Between  the  upper  four  fifths  of  the 
intestinal  canal,  and  the  lower  fifth, 
there  is  a  well-marked  distinction  ;  not 
only  as  regards  structure  and  magni- 
tude, but  function.  This  has  given  oc- 
casion to  a  division  of  the  canal  into 
small  and  large  intestine;  and  these, 
again,  have  been  subdivided  in  the  va- 
rious modes  that  will  fall  under  con- 
sideration.   As  the  small  intestine  forms 

so  large  a  portion  of  the  intestinal  canal,  its  convolutions  occupy  con- 
siderable space  in  the  abdominal  cavity, — in  the  middle,  umbilical, 
and  hypogastric  regions, — and  terminate 
— in  the  right  iliac  region — in  the  large 
intestine.  Its  calibre  differs  in  different 
parts ;  but  it  may  be  regarded  on  the 
average  as  about  one  inch.  It  is  usually 
divided,  arbitrarily,  into  three  parts; — 
duodenum^  jejunum^  and  ileum.  The  duo- 
denum, is  so  called,  in  consequence  of  its 
length  having  been  estimated  at  about 
twelve  fingers'  breadth.  It  is  larger  than 
the  rest  of  the  small  intestine ;  and  has 
received,  also,  the  name  o^  second  stomach, 
and  of  ventriculus  siicceniuriatus.  It  is 
more  firmly  fixed  to  the  body  than  the 
other  intestines;  and  does  not,  like  them, 
float  loosely  in  the  abdomen.  In  its  course 
to  its  termination  in  the  jejunum,  it  de- 
scribes a  kind  of  Italic  c,  the  concavity  of 

which  looks  to  the  left.     From  this  shape  it  has  been  separated  into 
three  portions; — the  first  situate  horizontally  beneath  the  liver:  the 


Portion  of  tlie  Stomach  and  Duodenum 
laid  open  to  show  their  interior. 

1,1.  Right  or  pyloric  extremity  of  stomach. 
2,  2.  Folds  and  mucous  follicles  of  mucous 
coat  of  stomach.  3.  Points  into  the  pylorus. 
4.  Thickness  of  the  pylorus.  5,  5.  Rugie  of 
the  internal  coatof  the  duodenum.  6.  Open- 
ing of  the  ductus  communis  choledochus  into 
the  duodenum. 


Longitudinal  Section  of  the  Upper 
Part  of  the  Jejuuum  extended 
under  water. 


94 


DIGESTION. 


second  descending  vertically  in  front  of  the  right  kidney ;  and  the  third 
in  the  transverse  mesocolon.  Its  mucous  membrane  presents  a  number 
of  circular  folds  or  rugee,  very  near  each  other,  which  have  been  called 
valvules  conniventes.  (Figs.  30  and  31.)     By  some  anatomists,  however, 


Fig.  32. 


Fie.  33. 


Muscular  Coat  of  the  Ileum. 

1,  1.  Peritoneal  coat.  2.  A  portion  of  this  coat 
turned  off  and  showing  a  portion  of  the  longitudinal 
fibres  of  the  muscular  coat  adherent  to  it.  3,  -t,  5.  Cir- 
cular muscular  fibres  indifferent  parts  of  the  intestine. 


Distribution  of  Ciqullaries  in  the  Villi  of 
the  Intestine. 


i 


this  name  is  not  given  to  the  irregular  rugae  of  its  mucous  coat;  but 
to  those  of  the  lining  membrane  of  the  jejunum.  The  valvules  are  not 
simple  rugas,  passively  formed  by  the  contraction  of  the  muscular  coat. 
They  are  dependent  upon  the  original  formation  of  the  mucous  mem- 


Fig.  34. 


Fie.  35. 


Arrangement  of  the  capillaries  on  the 
mucous  membrane  of  the  lari^e  intestine 
in  the  human  subject. — Magnified  50 
diameters. 


Distribution  of  Capillaries   around  Follicles    of 
JIucous  Membrane. 


brane;  and  are  not  effaced,  whatever  may  be  the  distension  of  the 
intestine.  On  and  between  these  duplicatures,  the  difi'erent  exhalant 
and  absorbent  vessels  are  situate,  forming,  in  part,  the  villi  of  the  intes- 
tine, which  are  from  a  quarter  of  a  line  to  a  line  and  two-thirds  in 
length.^  These  villi  give  to  the  membrane  a  veh^ety  appearance,  and 
are  not  simply  composed  of  exhalants  and  absorbents,  but  of  nerves ; 
all  of  which  are  distributed  on  an  areolar  and  perhaps  erectile  tissue. 
In  its  healthy  state,  when  successfully  injected,  the  membrane  appears 
to  consist  almost  entirely  of  a  cribriform  intertexture  of  veins.  It  was 
formerly  believed,  that  the  villi  are  not  supplied  with  bloodvessels. 
In  each  villus,  however,  there  is  a  minute  vascular  plexus,  the  larger 
branches  of  which,  when  distended  with  blood,  may  be  seen  even  by 
the  naked  eje.  Marginal  illustration,  Fig.  36,  exhibits  the  vessels  of 
one  of  the  intestinal  villi  of  the  hare,  from  Wagner,  after  an  extremely 


J.  Miiller,  Elements  of  Pliy.siology,  by  Baly,  2d  edit.,  p.  285,  Lond.,  1S40. 


DIGESTIVE   OEGAlSrS — SMALL   INTESTINE. 


95 


beautiful  dry  preparation  by  Dollinger,  magnified  about  45  diameters. 
The  most  obvious  use  of  these  villi  is  to  increase 
the  surface  from  which  the  secretion  is  prepared, 
and  from  which  absorption  is  effected.  Within 
the  membrane  are  numerous  follicles,  which, 
with  the  exhalants,  secrete  a  mucous  fluid, 
called  by  Haller  succus  iritestmalis.  Their  entire 
number  in  the  whole  alimentary  canal  is  esti- 
mated by  Dr.  Horner  to  be  4(5,900,000.^  At 
about  four  or  five  fingers'  breadth  from  the  py- 
lorus, the  duodenum  is  perforated  by  the  ter- 
mination of  the  biliary  and  pancreatic  ducts, 
which  pour  bile  and  pancreatic  fluids  into  it. 
Generally,  these  ducts  enter  the  intestine  by  one 
opening;  at  times,  they  are  distinct,  and  lie 
alongside  each  other.  The  structure  of  the 
duodenum  is  the  same  as  that  of  the  whole  of 
the  intestinal  canal.  The  muscular  coat  is, 
however,  thicker,  and  the  peritoneal  coat  only 
covers  its  first  portion,  passes  before  the  second, 
and  is  totally  wanting  in  the  third,  which  we 
have  described  as  included  in  the  transverse 
mesocolon. 

The  other  two  portions  of  the  small  intestine 
are  of  considerable  length;  the  jejunum  com- 
mencing at  the  duodenum,  and  the  ileum  termi- 
nating, in  the  right  iliac  fossa,  in  the  first  of  the 
great  intestines — the  cascum.  They  occupy  the 
middle  and  almost  the  whole  of  the  abdomen,  being  surrounded  by  the 
great  intestine  (1^'ig.  2).  The  jejunum  is  so  called  from  being  generally 
found  empty ;  and  the  ileum  from  its  numerous  windings.  The  line  of 
demarcation,  however,  between  the  duodenum  and  jejunum,  as  well  as 
between  the  latter  and  the  ileum,  is  not  fixed :  it  is  an  arbitrary  division. 


Bloodvessels  of  Villi  of  the 
Hare. 

1,  1.  Veins  filled  with  white 
injection.  2,  2.  Arteries  filled 
with  red.  A  heautifnl  rete  of 
capillaries  between  the  two. 


Fig.  37. 


Fig.  38. 


One  of  the  Glanrlulfe  Majores  Sim- 
plices  of  the  Large  Intestine,  as 
seen  from  above,  and  also  in  a 
Section. 


Vertical    Section  of  the    Mucous   Membrane   of  the 
Duodenum  in  the  Horse,  slightly  magnified. 
"D.  Villi,      h,  c.   Mucons   membrane  and   submacous  tis- 
sue,  ff.  Brunner's  glands  cut  vertically,  and  a  little  spread 
out,  showing  their  lobulated  structure. 


The  jejunum  has,  internally,  the  greatest  number  of  valvulse  conniventes 
and  villi.    The  ileum  is  the  lowest  portion.    It  is  of  a  paler  colour,  and 


'  Special  Anatomy  and  Histology,  8th  edit.,  ii.  51,  Philad.,  1851. 


96  DIGESTIOISr.  I 

has  fewer  valvulre  conniventes.  The  jejunum  is  situate  at  the  upper 
part  of  the  umbilical  region ;  the  ileum  at  the  lower  part,  extending  as 
far  as  the  hypogastric  and  iliac  regions.  The  mucous  membrane  of 
the  jejunum  and  ileum  resembles,  in  all  essential  respects,  that  of  the 
duodenum;  the  valvula?.  conniventes  are,  however,  more  numerous  in 
the  jejunum  than  in  the  duodenum;  and,  in  the  course  of  the  ileum, 
they  gradually  disappear,  and  are  replaced  by  simple  longitudinal 
rugcie.  The  villi,  too,  which  are  chiefly  destined  for  chylous  absorp- 
tion, abound  in  the  jejunum,  but  gradually  disappear  in  the  ileum. 
The  mucous  membrane  of  both  is  largely  supplied  with  follicles, 
commonly  called  glands  of  Brunner  and  Lieberkiihn,  which  are  con- 
cerned in  secreting  the  succus  entericus,  sneezes  intestinalis — a  mucous 
fluid  to  which,  in  digestion,  Haller  attached  great  importance.  M. 
Lelut*  estimates  the  number  of  these  glands  in  the  small  intestine  at 
40,000.  Dr.  Horner  considers  the  follicles  to  be  formed,  in  every  in- 
stance, of  meshes  of  veins;  the  arteries  entering  inconsiderably  into 
their  composition, — or  in  about  the  same  proportion  as  they  do  in 
other  erectile  tissues.^ 

The  tubular  glands  of  the  small  intestine  have  long  been  known 
under  the  name  o^  follicles  of  LieberkUlm..  These  become  especially 
evident  if  the  mucous  membrane  is  inflamed,  when  they  are  filled 
with  an  opaque  whitish  secretion,  whieh  is  absent  in  the  healthy 
state.' 

The  true  glands  of  Brunn  or  Brunner  are  chiefly  in  the  duodenum. 
They  are  situate  in  the  submucous  tissue,  where  they  form  a  continu- 


Fig.  39. 


Yis.  40. 


Portion  of  one  of  Bruntier's  Glands,  from  the 
iluniua  Duodenum. 


)a 


Section  of  the  Mucous  Menihrane  of  the  Small 
Intestine  in  the  Dog,  showing  Lieberkiihn's 
follicles  and  villi. 


a.  Villi.      &,  Lieberki'.hn's  follicles. 
coals  of  the  intestine. 


c.  Other 


ous  layer  of  white  bodies  surrounding  the  intestine.     They  are  not 
larger  than  a  hemp-seed;  each  consisting  of  numerous  minute  lobules, 


'  Gazette  Medicale,  Juin,  1832.  «  Op.  cit.,  ii.  54. 

»  Boehm,  cited  in  Brit,  and  For.  Med,  Rev.,  i.  621,  Loud.,  183ij. 


DIGESTIVE   ORGANS  —  SMALL   INTESTINE. 


97 


the  ducts  of  which  open  into  a  common  excretory  duct.  They  a,re  com- 
plex structures,  differing  from  the  other  glands  and  follicles  of  the  intes- 
tines.    Nothing  is  positively  known  of  the  nature  of  their  secretion. 

The  glands  of  Peyer  form  large  patches  on  the  mucous  membrane, 
when  they  are  called  glandulce  agminaice  and  Peyer^s  patches.  Exa- 
mined in  a  healthy  mucous  membrane,  they  have  the  appearance  of 


Fiff.  42. 


a, 

A.  Transverse  section  of  Lieber- 
kiihn's  Tubes  or  F(41icles.  show- 
iTig  t)ie  basement-membrane  and 
subcolumnar  epithelium  of  their 
walls,  with  the  Areolar  Tissue 
which  connects  the  tubes. 

a.  Basement-membrane  and  epithe- 
linm,  constituting  the  wall  of  the  tube. 
h.  Cavity  or  lumen  of  the  tube.  Mag- 
nified 200  diameters. 

B.  A   single    Lieberkiihn's 

highly  magnifiefl. 
A  happy  accidental  section  in  the 
oblique  direction  has  served  to  display 
very  distinctly  the  form  and  mode  i>f 
packing  of  the  epithelial  particles,  the 
cavity  of  the  tube,  and  the  mosaic 
pavement  of  its  exterior,  a.  Base- 
ment-membrane, e.  Internal  surface 
of  the  wall  of  the  tube.  Magnified 
200  diameters. 


Horizontal  Section  through  the  middle  plane  of  three 
Peyerinn  Glands  in  the  Rabbit,  showing  the  distributiou 
of  the  Bloodvessels  in  the  interior. 


circular  white,  slightly  raised  spots,  about  a  line  in  diameter,  over 
which  the  mucous  membrane  is  least  studded  with  villi,  and  often 
wholly  without  them.  On  rupturing  one  of  the  white  bodies  a  cavity 
is  found,  but  it  has  no  excretory  duct.  It  contains  a  grayish-white 
mucous  matter.  There  are  likewise  closed  solitary  glands  in  both 
the  small  and  large  intestines.^  At  times,  however,  the  aggregatas 
exhibit  openings  so  distinct,  as  to  have  warranted  the  belief  that  such 
openings  are  the  normal  condition;^  yet  Kcilliker  considers  it  as  quite 
certain,  that  the  follicles  of  Peyer's  patches  are  shut  sacs  [gdnzlich 
geschlossen?f 


'  Baly,  Lond.  Med.  Gazette,  Mar.,  1847. 

'^  Allen  Tliomson,  in  Goodsir's  Annals  of  Anatomy  and  Physiology,  No.  1,  p.  34,  Feb. 
1850;  and  Carpenter's  Principles  of  Human  Physiology,  Amer.  edit.,  p.  153,  note,  Phi- 
lad.,  1855. 

3  Mikroskopische  Anatomie  2ter  Band.  s.  187  and  528,  Leipz.,  1852;  or  Amer.  edit, 
of  Sydenham  Society's  edition  of  his  Human  Histology,  by  Dr.  Da  Costa,  p.  523,  Phi- 
lad.,  1854.  i 

VOL.  I. — 7 


98 


DIGESTION. 


\ 


Fig.  43. 

*55'  ft*  -/•..:  -!R 


The  precise  use  of  the  glands  of  Peyer  is  generally  considered 
to  be  unknown.  Wagner'  has  well  observed,  that  the  intimate 
structure  of  the  whole  of  these  glandular  bodies  requires  farther 
study,  and  is  almost  as  little  known   as   their  individual  functions. 

It  has  been  conceived,  that  they  secrete 
a  putrescent  matter  from  the  blood, 
which  may  be  concerned  in  giving 
to  the  excrement  its  peculiar  odour; 
this  matter,  as  in  other  cases,  being 
formed  by  cells,  which  burst  on  the  free 
surface  of  the  mucous  membrane,  and 
discharge  their  contents  to  be  mixed 
with  the  fteces.  Such  has  been  the  view, 
until  recently,  embraced  by  Dr.  Car- 
penter. Professor  Brlicke,^  of  Vienna, 
adopts  a  different  opinion — maintain- 
ing, that  they  are  always  closed  in  their 
natural  condition.  He  regards  them  as 
appendages  to  the  lymphatic  system  ;  as 
the  lymphatics  can  be  filled  by  injections 
directed  from  them.  The  contents  of 
their  areolae  or  cells  resemble  also,  in  appearance  and  character,  those 
of  the  mesenteric  ganglia.     This  view  is  embraced  by  Professors  Frei, 


Vertical  Section  of  two  of  the  Peyerian 
Glandulse  from  the  Ileum  of  the  Pig, 
one  of  them  closed  and  full,  the  other 
open  and  empty,  with  their  neigh- 
bouring villi;  magnified  15  diameters. 

a.  Cellular  contents  of  the  vesicle;  mag- 
nified 250  diameters. 


Fig.  44. 


Fig.  45. 


I 


A  patch  of  Pcyer'.s  Glands  of  the  adult  hu- 
man subject,  from  the  lowest  part  of  the 
Ileum. — After  Boehm. 


Section  of  Small  Intestine,  containing  gome 
of  the  Glands  of  Peyer,  as  shown  under 
the  microscope. 

These  glands  appear  to  be  small  lenticular  ex- 
cavations, containing,  according  to  Boehra,  a 
white,  milky,  and  rather  thick  fluid,  with  nu- 
merous round  corpuscles  of  various  sizes,  but 
mostly  smaller  than  blood  globules.  The  meshes 
seen  in  the  cut  are  the  ordinary  tripe-like  folds 
of  the  mucous  coat. 


'  Elements  of  Physiology,  translated  by  R.  Willis,  §  137,  Lond.,  1842. 
2  Denkrichriften  der  K.  Akademie  der  Wissenachaft.     Wien,  1850. 


1 


DIGESTIVE   ORGANS — LARGE   INTESTINE. 


99 


Kolliker/  Donders,  and  Gerlach,^  as  well  as  the  opinion  of  Professor 
Briicke,  that  they  are  ganglia  for  the  elaboration  of  the  chyle,  which 
passes  through  them  by  the  delicate  chyliferous  vessels,  which  origin- 
ate in  the  villi,  on  their  way  to  the  mesenteric  ganglia;  and  Dr.  Car- 
penter^ admits,  that  the  results  appear  to  prove  quite  conclusively, 
that  the  Peyerian  glandulfe  are  really  ap- 
pendages to  the  absorbent  system,  cor- 
responding in  every  respect,  save  their 
situation,  to  the  mesenteric  and  lymphatic 
glands. 

The  muscular  coat  of  the  small  intes- 
tine is  composed  of  circular  and  longitu- 
dinal fibres ;  and  the  outer  coat  is  formed 
by  the  prolongation  of  the  peritoneum, 
which,  after  having  surrounded  the  intes- 
tines, completes  the  mesentery,  by  which 
the  gut  floats,  as  it  were,  in  the  abdominal 
cavity. 

The  large  intestine  terminates  the  intes- 
tinal canal.  It  is  much  shorter  than  the 
small,  and  considerably  more  capacious, 
being  manifestly  intended,  in  part,  as  a  re- 
servoir. It  is  less  loose  in  the  abdominal 
cavity  than  the  portion  of  the  tube  which 
we  have  described.     It  commences  at  the  right  iliac  fossa  (Fig.  2) ; 

Fig.  47. 


o  h 

Side  View  of  Intestinal  Mucous 
Membrane  of  a  Cat. 

a.  A  Peyer's  gland,  imbedded  in  sub- 
mucous tissue,/,  h.  A  tubular  follicle. 
c.  Fossa  in  mucous  membrane,  d.  Villi. 
e.  Follicles  of  Lieberkiihn. 


Vertical  Section  through  a  patch  of  Peyer's  Glands  in  the  Dog. 

a.  Villi,  h.  Tubes  of  Lieberkiihn  with  the  apices  of  Peyer's  glands,  c.  Submucous  tissue  with  the 
glands  of  Peyer  imbedded  in  it.  d.  Muscular  and  peritoneal  coats,  e.  Apex  of  one  of  Peyer's  glauda 
projecting  among  the  tubes  of  Lieberkiihn.  The  glands  are  seen  laid  open  by  the  section.  MaguificU 
about  20  diameters. 


'  Manual  of  Human  Microscopical  Anat.,  Amer.  edit,  by  Da  Costa,  p.  51G,  note,  and 
page  523,  Philad.,  1854. 

^  Brit,  and  For.  Med.-CMr.  Rev.,  Oct.,  1855,  p.  527.  *  Op.  cit. 


100  DIGESTION. 

ascends  along  the  riglit  flank,  as  far  as  the  under  surface  of  the  liver; 
crosses  over  the  abdomen  to  gain  the  left  flank,  along  which  it  de- 
scends into  the  left  iliac  region,  and  thence  through  the  pelvis,  along 
the  hollow  of  the  sacrum,  to  terminate  at  the  a7ius.  Like  the  small 
intestine  it  is  divided  into  three  portions;  the  ccecwn,  colon,  and  redv.m. 

The  ccecuni  or  blind  gut  is  the  part  of  the  great  intestine  into  which 
the  ileum  opens.  It  is  about  four  fingers'  breadth  in  length,  and 
nearly  double  the  diameter  of  the  small  intestine.  It  occupies  the 
right  iliac  fossa,  in  which  it  is  bound  down,  so  as  not  to  be  able  to 
change  its  position.  The  extremity  of  the  ileum  joins  the  caecum, 
at  an  angle ;  and  if  we  examine  the  interior  of  the  caecum,  at  the 
point  of  junction,  we  find  a  valvular  arrangement,  which  has  been 
called  valve  of  Tulpius,  valve  of  Bauhm,  ileo-ccecal  valve,  &;c.  Fig,  4"J 
exhibits  the  nature  of  this  arrangement.  At  the  point  of  unioa 
of  the  two  intestines,  a  soft  eminence  exists,  flattened  from  above  to 
below,  and  elliptical  transversely,  which  is  divided  into  two  li])S. 
One  of  these  seems  to  belong  to  the  ileum  and  colon — hence  called 
ileo-colic;  the  other  to  the  ileum  and  crecum,  and  termed  ileo-ccecal. 
From  the  disposition  of  these  lips  a  valve  results,  so  constituted,  that 
the  lips,  which  form  it,  separate  when  the  feecal  matters  pass  from  the 
small  to  the  large  intestine;  whilst  they  approximate,  cross,  and  com- 
pletely prevent  all  retrogression,  when  the  fieces  tend  to  pass  from  the 
great  intestine  to  the  small.  At  the  extremities  of  the  valve  are  small 
tendons,  which  give  it  strength,  and  have  been  termed  frcena  or  reli- 
nacula  of  the  valve  of  Bauhin. 

Although  this  valvular  arrangement  prevents  the  ready  return  of 
the  excrementitious  matter  into  the  small  intestine,  we  have  many 
pathological  opportunities  for  discovering  that  it  is  not  effectual  in  all 
cases.  In  stricture  of  the  large  intestine,  stercoraceous  vomiting  is  a 
frequent  phenomenon,  and  there  have  been  cases  of  substances,  thrown 
into  the  rectum,  having  been  evacuated  by  the  mouth. 

At  the  posterior  and  left  side  of  the  cascum,  a  small  process  detaches 
itself,  called,  from  its  resemblance  to  a  worm,  ap'pendix  vermifornvis  ; 
and,  from  its  connexion  with  the  ccecum,  appendix  cceci.  It  is  convo- 
luted, variable  in  length,  and  attached,  by  its  sides,  to  the  caecum. 
Its  free  extremity  is  impervious ;  the  other  opens  into  the  back  part  of 
the  caecum.  This  appendage  has  all  the  characters  of  an  intestine. 
Various  hypotheses  have  been  indulged  regarding  its  uses.  Some  have 
conceived  it  to  be  a  reservoir  for  the  faeces;  but  its  diminutive  size,  in 
the  human  subject,  precludes  this  idea :  others  have  thought,  that  it 
secretes  a  ferment,  necessary  for  fascal  formation ;  and  others,  again,  a 
mucus  for  preventing  the  induration,  that  might  result  from  the  deten- 
tion of  the  fieces  in  the  caecum.  The  opinion — that  it  is  a  mere  vestige 
of  the  useful  and  double  casca,  which  exist  in  certain  animals — is  as 
philosophical  as  any.  M,  de  Blainville,'  indeed,  regards  it  as  the  true 
CEecum;  and  what  is  named  the  ctecum  as  the  commencement  of  the 
colon.  It  is  manifestly  of  little  importance,  as  it  has  been  found 
wanting  or  obliterated  in  many  subjects,  and  has  been  extirpated  re- 
peatedly with  impunity.     The  cascum  is  said  to  be  wanting  in  all  ani- 

'  De  rOrganisation  des  Animaux,  &c.,  Paris,  1S25. 


DIGESTIVE   ORGANS  —  LARGE   INTESTINE. 


101 


Muscular  Coat  of  the  Colon,  as  seen  after  the  removal 
of  the  Peritoneum. 


1,  1. 

fill  res. 


One  of  its  three  bands  of  longitudinal  muscular 
2,  2.  Circular  fibres  of  the  muscular  coat. 


mals  that  hybernate.  It  is  small  in  the  Carnivora;  very  large  and 
long  in  the  Solidungula,  Euminantia  and  Kodentia ;  in  which, — as  will 
be  seen  hereafter, — there  is  reason  to  believe,  that  digestion  of  the  ali- 
ment, which  has  escaped  change  higher  up,  occurs. 

The  colon  is  by  much  the  longest  of  the  large  intestines,  (Fig.  2.) 
It  is  a  continuation  of  the  cascum,  from  which  it  cannot  be  distin- 
guished ;  but  is  considered  to 
commence  at  the  termination 
of  the  ileum.  From  the  right 
iliac  fossa  it  ascends  along  the 
right  lumbar  region,  over  the 
kidney,  to  which  it  is  con- 
nected. It  is,  in  this  part, 
called  colon  dextrum^  ascending 
or  right  lumbar  colon.  From 
the  kidney  it  passes  forwards 
and  crosses  the  abdomen  in 
the  epigastric  and  hypochon- 
driac reo-ions,  beinoj  connected 
to  the  duodenum.  This  por- 
tion is  called  great  arch  of  the  colon,  colon  transversum.  The  right  por- 
tion of  the  great  arch  is  situate  under  the  liver  and  gall-bladder ;  and 
hence  is  found  tinged  yellow  after  death,  owing  to  the  transudation  of 
bile.  The  left  portion  of  the  arch  is  situate  under  the  stomach  ;  and, 
immediately  below  it,  are  the  convolutions  of  the  jejunum.  In  the  left 
hypochondre,  the  colon  turns  backward  under  the  spleen,  and  de- 
scends along  the  left  lumbar  region, 
anterior  to  the  kidney,  to  which  it  is 
closely  connected.  This  portion  is 
termed  colon  sinistrum,  descending  or 
left  lumbar  colon.  In  the  left  iliac 
region,  it  forms  two  convolutions, 
which  have  been  compared  to  the 
Greek  j,  or  to  the  Roman  S;  and 
hence  this  part  of  the  intestine  has 
been  designated  sigmoid  flexure,  Ro- 
man S,  or  iliac  turn  of  the  colon.  This 
flexure  varies  greatly  in  length  in  dif 
ferent  persons,  extending  frequently 
into  the  hypogastric  region,  and,  in 
some  instances,  as  far  as  the  caecum. 
The  colon,  through  its  whole  extent, 
is  fixed  to  the  body  by  the  mesocolon. 

The  coats  of  the  great  intestine  are 
the  same  in  number  and  structure  as 
those  of  the  small ;  but  are  thinner, 
and  not  as  easily  separable  by  dissec- 
tion. The  mucous  membrane  is  less 
villous  and  velvety.  The  most  cha- 
racteristic difference,  however,  in  their 
general  appearance,  is  the  pouched  or 


Fig.  49. 


Longituilinal  Section  of  the  End  of  the 
Ileum,  and  of  the  Beginning  of  the  Large 
Intestine. 


1,  1.  Portion  of  the  ascending  colon.  2,  2. 
C;ecuin.  3,  3.  Lower  portion  of  ileum.  4,  4. 
Muscular  coat,  covered  by  peritoneum.  5,  5. 
Areolar  and  mucous  coats.  6,  6.  Folds  of  mu- 
cous coat  at  this  end  of  the  colon.  7,  7.  Pro- 
longations of  areolar  coat  into  these  folds.  8,  S. 
Ileo-colic  valve.  9,  9.  Union  of  the  coats  of 
t)ie  ileum  and  colon. 


102  DIGESTION. 

cellular  aspect  of  tlie  former.  These  pouches  are  reservoirs  for  excre- 
ment, and  in  tliem  it  becomes  more  indurated,  by  the  absorption  of  the 
fluid  portions.  In  torpor  of  this  part  of  the  intestinal  canal,  the  f^ces 
are  retained,  at  times,  so  long,  that  they  form  hard  balls  or  scybala;  and 
not  unfrequently  occasion  the  inflammation  of  the  lining  membrane  of 
the  large  intestine,  which  constitutes  dysentery.  The  longitudinal 
muscular  fibres  are  concentrated  into  three  ligamentous  bands  or  fasci- 
culi, which  run  the  whole  length  of  the  intestine.  These  being  shorter 
than  the  intestine,  pucker  it,  and  are  the  occasion  of  the  pouched  or 
saccated  arrangement.  The  inner  or  circular  muscular  fibres  are,  like 
those  of  the  small  intestine,  uniformly  spread  over  the  surface,  but  are 
stronger.  Lastly,  on  the  great  intestine,  especially  the  colon,  are  nume- 
rous processes  of  the  peritoneum  containing  fat,  and  hence  called 
appendiculcB  epi2:)loicce  and  appendiculce  piinguedinosce.  These  are  seen 
in  greatest  abundance  on  the  right  and  left  lumbar  portions  of  the 
colon. 

The  rectum  terminates  the  intestinal  canal,  and  extends  from  the  end 
of  the  colon  to  the  anus.  It  commences  about  the  fifth  lumbar  ver- 
tebra, and  descends  vertically  into  the  pelvis,  following  the  concavities 
of  the  sacrum  and  coccyx ;  and,  consequently,  is  not  straight,  as  its 
name  would  import.  At  its  upper  part,  there  are  a  few  appendiculas 
epiploicas;  and  a  small  duplicature  of  the  mesentery,  called  mesorectimi, 
attaches  it  to  the  sacrum.  It  differs  from  the  other  intestines  in  be- 
coming wider  in  its  progress  downwards,  and  in  its  parietes  being 
thicker.  The  lower  part  of  the  mucous  membrane  exhibits  several 
longitudinal  folds  or  rugae,  called  "  columns,"  which  have  been  con- 
sidered as  the  effect  of  the  contraction  of  the  circular  fibres  of  the 
muscular  coat.  At  the  lower  ends  of  the  wrinkles  between  the  columns 
are  small  pouches,  from  two  to  four  lines  in  depth,  the  orifices  of  which 
point  upwards.  They  are  occasionally  the  seat  of  disease,  and,  when 
enlarged,  give  rise  to  painful  itching.  The  nature  of  this  affection  was 
first  pointed  out  by  Dr.  Physick,  and  the  remedy  consists  in  slitting 
them  open.  The  longitudinal  fibres  of  the  muscular  coat  have  a  dif- 
ferent^ arrangement  from  that  which  exists  in  the  other  portions  of  the 
large  intestine.  They  are  distributed  over  the  whole  surface,  as  in  the 
small  intestine, — or  rather,  as  in  the  oesophagus.  At  the  anus,  an 
arrangement  of  the  muscular  coat  prevails,  which  has  been  pointed  out 
by  Professor  Horner.^  The  longitudinal  fibres,  having  reached  the 
lower  margin  of  the  internal  sphincter,  turn  under  this  margin  between 
it  and  the  external  sphincter,  and  then  ascend  upwards  for  an  inch  or 
two  in  contact  with  the  mucous  coat,  into  which  they  are  finally 
inserted  by  fasciculi,  which  form  the  base  of  the  columns  of  the  rectum : 
many  of  the  fibres,  however,  terminate  also  between  the  fasciculi  of  the 
circular  fibres.  The  circular  fibres  are  more  and  more  marked,  as  they 
approach  the  outlet,  and,  by  circumscribing  the  margin  of  the  anus, 
they  form  the  sphincter  ani  muscle.  Immediately  within  the  anus  is 
the  widest  portion  of  the  rectum ;  and,  in  this,  accumulations  of  indu- 
rated fieces  sometimes  take  place  in  old  people  to  a  surprising  extent, 
owing  to  the  torpor  of  the  muscular  powers  concerned  in  the  expul- 

'  General  Anatomy  and  Histology,  Sth  edit.,  it.  46,  Philada.,  1S51. 


DIGESTIVE   ORGANS. 


103 


sion  of  the  feeces.     The  mucous  coat  of  the  rectum  is  thick  and  red, 
and  abounds  in  follicles. 

Lastly  ;  there  are  a  few  muscles,  which  are  concerned  in  the  act  of 
expelling  the  fceces.  These  require  a  short  notice.  1.  The  siiihincter 
ani,  coccygeo-anal  muscle,  which  keeps  the  anus  constantly  closed,  ex- 
cept during  defecation.  2.  The  levator  am",  snhptibio-coccygeus,  which, 
with  the  next  muscle,  constitutes  the  floor  of  the  pelvic  and  abdominal 
cavities.  It  restores  the  anus  to  its  place,  when  pushed  outwards  during 
defecation.  3.  The  coccygeus^  ischio-coccygeus^  which  assists  the  levator 
ani  in   supporting  or  raising 


the  lower  extremity  of  the  rec- 
tum; and  4.  The  transversus 
pennei,  iscMo-jperineal  muscle, 
some  fibres  of  which  unite  both 
with  the  bulbo-cavernosi  and 
with  the  sphincter  ani  muscles; 
and,  consequently,  it  is  asso- 
ciated slightly  with  the  action 
of  both  one  and  the  other. 

In  regard  to  the  intestinal 
canal,  we  find,  that  man  holds 
a  medium  place  between  the 
carnivorous  and  herbivorous 
animal,  although  approximat- 
ing more  to  the  latter.  In 
the  carnivorous — for  reasons 
hereafter  mentioned — it  is  un- 
necessary that  the  food  should 
remain  long ;  accordingly,  the 
canal  is  very  short.  In  the 
herbivora,  on  the  other  hand, 
and  for  opposite  reasons,  the 
canal  is  long,  and  there  is 
generally  a  large  caecum  and 
a  pouched  colon.  Cuvier'  has 
given  tables  of  the  length  of 
the  digestive  tube,  compared 
with  that   of  the  body;    but 


Fig.  50. 


View  of  External  Parietes  of  Abdomen,  with  the  po- 
sition of  the  Lines  drawn  to  mark  off  its  Regions. 

1,  1.  Line  drawn  from  the  highest  point  of  one  ilium  to 

^   ,  the  same  point  of  the  opposite  one.     2,  2.  Line  drawn  from 

wl-)p-pp  tVip  pnmnn-rn<5nn  1ti«  Vipph  '''®  anterior  superior  spinous  process  to  the  cartilages  of 

Wiiei  e  tne  comparison  naS  Oeen  the  ribs.     3,  3.  a  similar  one  for  the  oppo.site  side.     4,  4. 

applied    to  man,  the    length  of  ^'"®   drawn  perpendicularly  to  these,  and  touching  the 

,r:      1       1       1          •       1      1     1     ,r     ,       n  ii>ost  prominent  part  of  the  costal  cartilages,  thus  forminir 

tne   body  naS  inCiudea    that  01  nine  regions.     5,  5.  Right  and  left  hypochondriac  regions. 

th.  ipc.«   Tn«fp«^  fL...w  lJtsri^^^:^.L''i^,:!&^^^^ 

Eight  and  left  iliac  regions.     11.  The  lower  part  of  the 
hypogastric,  sometimes  called  pubic. 


the  legs.  Instead,  therefore, 
of  the  canal,  in  him,  being  con- 
sidered to  bear  the  proportion 
of  six  to  pne,  it  ought  to  be  doubled,  or  be  regarded  as  twelve  to  one; 
a  proportion  somewhat  greater  than  prevails  in  the  simias  or  ape  tribe'. 
It  is  not,  however,  always  in  length,  that  the  canal  of  the  herbivorous 
exceeds  that  of  the  omnivorous  animal ;  but  as  a  general  rule,  it  may 
be  aifirmed,  that  its  capacity  is  much  more  considerable. 


Lejons  d'Anatomie  Comparee,  Paris,  1799. 


104  DIGESTIO:^. 

5.  The  aldomen,  in  wliicL  the  principal  digestive  organs  are  situate, 
and  whose  parietes  exert  considerable  influence  on  the  digestive  func- 
tion, requires  a  brief  description.  It  is  the  division  of  the  body,  which 
is  betwixt  the  thorax  and  pelvis ;  is  bounded,  above,  by  the  arch  of 
the  diaphragm ;  behind,  by  the  vertebral  column ;  laterally,  and  ante- 
riorly, by  the  abdominal  muscles;  and,  below,  by  the  ossa  ilii,  os  pubis, 
and  the  cavity  of  the  pelvis. 

To  connect  the  knowledge  of  the  internal  parts  of  the  abdomen  with 
the  external,  it  is  customary  to  mark  certain  arbitrary  divisions  on  the 
surface,  called  regio-iis.  (Fig.  50.)  The  epirjasiric  region  is  at  the  upper 
portion  of  the  abdomen,  under  the  point  of  the  sternum,  and  in  the 
angle  formed  by  the  cartilages  of  the  ribs.  The  hypochondria/^  regions 
are  covered  by  the  cartilages  of  the  ribs.  These  three  regions — the 
epigastric,  and  right  and  left  hypochondre — constitute  the  upper  divi- 
sion of  the  abdomen,  in  which  are  seated  the  stomach,  liver,  spleen, 
pancreas,  duodenum,  and  part  of  the  arch  of  the  colon.  The  space  sur- 
rounding the  umbilicus,  between  the  epigastric  region  and  a  line  drawn 
from  the  crest  of  one  os  ilii  to  the  other,  is  the  umbilical  region.  Here 
the  small  intestines  are  chiefly  situate.  This  region  is  bounded  by  lines, 
raised  perpendicularly  to  the  spine  of  the  ilium;  and  the  lateral  por- 
tions on  the  outside  of  these  lines,  form  the  iliax^  regions^  behind  which, 
again,  are  the  lumbar  regions  or  loins.  In  these,  the  colon  and  kidneys 
are  chiefly  situate.  The  hypogastric  is,  likewise,  divided  into  three 
regions, — the  puhic  in  the  middle,  in  which  is  the  bladder ;  and  an 
inguinal  on  each  side. 

The  muscles  that  constitute  the  abdominal  parietes,  are, — first  of  all, 
aZ/ore,  the  diaphragm,  which  is  the  boundary  between  the  thorax  and 
abdomen,  convex  towards  the  chest,  and  considerably  concave  towards 
the  abdominal  cavity.  Below,  if  we  add  the  pelvic  cavity, — which,  as 
it  contains  the  rectum,  and  muscles  concerned  in  the  evacuation  of  the 
faeces,  it  may  be  proper  to  do, — the  cavity  is  bounded  by  the  perineum, 
formed  chiefly  of  the  levatores  ani  and  coccygei  muscles.  Behind,  la- 
terally, and  anteriorly,  from  the  lumbar  vertebrge  round  to  the  umbilicus, 
the  parietes  consist  of  planes  of  muscles,  and  aponeuroses  in  super- 
position, united  at  the  median  line,  by  a  solid,  aponeurotic  band,  extend- 
ing from  the  cartilago  ensiformis  of  the  sternum  to  the  pubes,  called 
linea  alba.  The  abdominal  muscles,  properly  so  called,  are, — reckoning 
tlie  planes  from  within  to  without, — the  greater  ob'lvpie  nmscle,  lesstr 
oblique,  and  trausversalis,  which  are  situate  chiefly  at  the  sides  of  the 
abdomen ;  and  the  rectus  and  ^-^yramidalis,  which  occupy  the  anterior 
part.  The  greater  oblique,  obliquus  externum,  costo-abdominalis ;  leaser 
oblique,  obliquus  internum,  ilio-abdominalis ;  and  trausversalis,  transversus 
abdominis,  lumho-abdominalis,  support  and  compress  the  abdominal 
viscera :  assist  in  the  evacuation  of  the  fasces  and  urine,  and  in  the 
expulsion  of  the  fcetus;  besides  other  uses,  connected  with  respiration 
and  the  attitudes.  The  rectus,  puhio-sternalis  or  sterno-puhialis ;  and 
the  pyramidalis  or  piuhio  subumbilicalis,  are  more  limited  in  their  ac- 
tion, and  compress  the  forepart  of  the  abdomen;  besides  having  other 
functions. 

Lastly,  a  serous  membrane — the  peri/oneum — lines  the  alxlomen,  and 
gives  a  coat  to  most  of  the  viscera.     The  mode,  in  which  its  vaiious 


DIGESTIVE   ORGANS  —  PERITONEUM. 


105 


reflections  are  made,  is  singular,  but  easil)^  intelligible  from  the  accom- 
panying figure  (Fig.  51).     It  has  neither  beginning  nor  end,  constitut- 


Fiff.  51. 


1.  Section  of  tlip  spinal  column  and  canal.  2. 
Section  of  the  sacrum.  3.  Section  of  the  ster- 
num, &c.  4.  Umbilicus.  5.  A  section  of  the 
llnea  alba  and  abdominal  muscles.  6.  Mons 
veneris.  7.  Section  of  the  pubis.  8.  Peni.s 
divided  at  the  corpora  cavernosa.  9.  Section  of 
the  scrotum.  10.  Superior  right  half  of  the  dia- 
phragm. 11.  Section  of  the  liver.  12.  Section 
of  the  stomach,  showing  its  cavity.  13.  Section 
of  the  transverse  colon.  1-t.  Section  of  the  pan- 
creas. 15.  Section  of  the  bladder,  deprived  of 
the  peritoneum.  16.  Rectum  cut  olf,  tied  and 
turned  back  on  the  promontory  of  the  sacrum. 
17.  Peritoneum  covering  the  anterior  parietes  of 
the  abdomen.  IS.  Peritoneum  on  the  inferior 
under  side  of  the  diaphragm.  19.  Peritoneum 
on  the  convex  side  of  the  diaphragm.  20.  Ee- 
flection  of  peritoneum  from  diaphragm  to  liver. 
21.  Peritoneum  on  front  of  liver.  22.  The  same, 
on  its  under  surface.  23.  Hepato-gastric  omen- 
tum. 21.  A  largo  pin  passed  through  the  fora- 
men of  Winslow  into  the  cavity  behind  the 
omentum.  25.  Anterior  face  of  the  hepato-gas- 
tric omentum,  passing  in  front  of  the  stomach. 
26.  The  same  membrane  leaving  the  stomach  to 
make  the  anterior  of  the  four  layers  of  the  great 
omentum.  27,  28.  Junction  of  the  peritoneum 
from  the  front  and  back  part  of  the  stomach,  as 
they  turn  to  go  up  to  the  colon.  29.  Gastro-colic, 
or  greater  omentum.  30.  Separation  of  its  layers, 
80  as  to  cover  the  colon.  31.  Posterior  layer 
passing  over  the  jejunum.  32.  Peritoneum  in 
front  of  the  riglit  kidney.  33.  Jejunum  cut  olf 
and  tied.  34,  31.  Me.seutery  cut  otf  from  tlie 
email  intestines.  35.  Peritoneum  reflected  from 
the  posterior  paries  of  the  bladder  to  the  anterior 
of  the  rectum.  36.  Cul-de-sac  between  the  blad- 
der and  the  rectum. 


Reflections  of  the  Peritoneum,  a?  shown  in  a  Ver- 
tical Section  of  the  Body. 

ing,  like  all  serous  membranes,  a  shut  sac ;  and,  in  reality,  having  no 
viscus  within  it.  If  we  assume  the  diaphragm  as  the  part  at  which  it 
commences,  we  find  it  continued  from  the  surface  of  that  muscle  over 
the  abdominal  muscles,  5 ;  then  reflected,  as  exhibited  by  the  curved 
line,  over  the  bladder,  15;  and,  in  the  female,  over  the  uterus;  thence 
over  the  rectum,  16;  the  kidney,  enveloping  the  intestine,  13,  and 
constituting,  by  its  two  laminas,  the  mesentery,  34;  giving  a  coat  to 
the  liver,  11 ;  and  receiving  the  stomach,  12,  between  its  duplicatures. 
The  use  of  this  membrane  is  to  fix  and  support  the  different  viscera; 
to  constitute,  for  each,  a  pedicle,  along  which  the  vessels  and  nerves 
may  reach  the  intestine ;  and  to  secrete  a  fluid,  which  enables  them  to 
move  readily  upon  each  other.  When  we  speak  of  the  cavity  of  the 
peritoneum,  we  mean  the  inside  of  the  sac;  and  when  it  is  distended 
with  fluid,  as  in  ascites,  the  fluid  is  contained  between  the  peritoneum 
lining  the  abdominal  muscles,  and  that  which  forms  the  outer  coat  of 
the  intestines.  The  omenta  or  epipha  are  fatty  membranes,  which  hang 
over  the  face  of  the  bowels;  and  are  reflections,  formed  by  the  perito- 
neum after  it  has  covered  the  stomach  and  intestines.  Their  names 
sufficiently  indicate  their  position: — the  lesser  epiploon  or  omentum^ — 
the  omeidum  hepato-gastricum ;  the  greater  or  gastro-colic;  and  the  appen- 


106  DIGESTION". 

dices  or  appendladce  epiploicce;  wliicli  last  have  already  been  referred  to, 
and  may  be  regarded  as  so  many  small  epiploons. 

Tbe  abdomen  is  entirely  filled  by  tbe  contained  viscera.  There  are 
several  apertures  in  it;  three,  above,  in  the  diaphragm,  for  the  passage 
of  the  oesophagus,  vena  cava  inferior,  and  aorta ;  one  anteriorly  in  the 
course  of  the  Tinea  alba,  which  is  closed  after  birth, — the  umbilicus; 
and  two  anteriorly  and  inferiorly;  the  one — the  abdominal^  inguinal; 
or  sup-a-imhian  ring — which  gives  passage  to  the  vessels,  nerves,  &c., 
of  the  testicle ;  and  the  other — the  crural  arch — through  which  the  ves- 
sels and  nerves  pass  to  the  lower  extremity.  Lastly,  two  others  exist 
in  the  inferior  paries,  for  the  passage  of  the  obturator  vessels  and  nerves, 
and  sciatic  vessels  and  nerves,  respectively. 

Such  is  a  brief  view  of  the  various  organs  concerned  in  digestion. 
To  this  might  have  been  added  the  general  anatomy  of  the  liver  and 
pancreas, — each  of  which  furnishes  a  fluid,  that  is  a  material  agent  in 
the  digestive  process, — and  of  the  spleen,  which  has  been  looked  upon 
by  many  as  inservient,  in  some  manner,  to  the  same  function.  As, 
however,  the  physiology  of  tliese  organs  will  be  considered  in  another 
place,  we  defer  their  anatomy  for  the  present. 

2.    FOOD  OF  MAN. 

The  articles,  inservient  to  the  nourishment  of  man,  have  usually 
been  considered  to  belong  entirely  to  the  animal  and  vegetable  king- 
doms; but  there  seems  to  be  no  suf&cient  reason  for  excluding  those 
articles  of  the  mineral  kingdom  that  are  necessary  for  the  due  consti- 
tution of  the  different  parts  of  the  body.  Generally,  the  term  food  or 
aliment  is  applied  to  substances,  which,  when  received  into  the  digestive 
organs,  are  capable  of  being  converted  into  chjde;  but,  from  this  class 
again,  the  products  of  the  mineral  kingdom — as  chloride  of  sodium,  phos- 
phorus, sulphur,  and  lime,  either  in  combination  or  separately — cannot, 
with  entire  propriety,  be  excluded.  There  are  numerous  tribes  who  feed 
at  particular  seasons  more  especially  on  mineral  substances.  Kessler 
affirms,  that  the  quarriers  on  the  Kyffhauser,  in  northern  Thuringia, 
spread  a  Steinbutter — "rock  butter,"  on  bread,  which  they  eat  with 
appetite;  and  Von  Humboldt  relates,  among  many  other  instances,  that 
of  the  Ottomacs,  who,  during  the  periodical  rise  of  the  Orinoco  and 
Meta,  when  the  taking  of  fish  ceases — a  period  of  two  or  three  mouths' 
duration — swallow  great  quantities  of  earth.  They  found  piles  of  clay- 
balls  in  pyramidal  heaps  in  the  huts,  and  Humboldt  was  informed,  that 
an  Ottomac  would  eat  from  three-quarters  of  a  pound  to  a  pound  and 
a  quarter  in  a  day.  Some  of  this  earth  was  analyzed  by  M.  Vauquelin, 
and  found  to  contain  no  organic  matter.  It  would  appear,  that  the 
practice  of  eating  earth  exists  in  many  parts  of  the  torrid  zone,  among 
indolent  nations,  who  inhabit  the  finest  and  most  fertile  regions  of  the 
globe.  But  it  is  not  confined  to  them ;  for  the  same  writer  affirms,  that 
in  the  north,  by  information  communicated  by  Berzelius  and  Retzius, 
hundreds  of  cartloads  of  earth  containing  infusoria  are  annually  con- 
sumed by  the  country  people  in  the  most  remote  parts  of  Sweden  as 
bread  meal,  and  even  more  as  a  luxury — like  tobacco — than  as  a  neces- 
sary. In  Finland,  the  earth  is  occasionally  mixed  with  the  bread.  It 
consists  of  empty  shells  of  animalcules,  so  small  and  soft  as  not  to 


FOOD   OF   MAN.  107 

crancli  perceptibly  between  the  teeth,  filling  the  stomach,  but  affording 
no  real  nutriment.     Many  similar  cases  are  recorded  by  Humboldt.^ 

Animals  are  often  characterized  by  the  kind  of  food  on  which  they 
subsist.  The  carnivoroiLs  feed  on  flesh ;  the  piscivorous  on  fish ;  the 
insectivorous  on  insects;  the  phytivorous  on  vegetables;  the  granivorous 
on  seeds;  the  fnigivorous  on  fruits;  the  graminivorous  and  herbivorous 
on  grasses;  and  the  omnivorous  on  the  products  of  both  the  animal  and 
the  vegetable  kingdom.  In  antiquity,  we  find  whole  tribes  designated 
according  to  the  aliment  they  chiefly  used.  Thus,  there  were  the 
>ZEthiopian  and  Asiatic  ichthyoplicuji  or  fish-eaters;  the  hylopjJiagi^  who 
fed  on  the  young  shoots  of  trees;  the  elephantophagi^  and  struthiophagi, 
elephant  and  ostrich-eaters,  &c.  &c. 

We  have  already  shown,  that  the  digestive  apparatus  of  man  is  inter- 
mediate between  that  of  the  carnivorous  and  the  herbivorous  animal; 
that  it  partakes  of  both,  and  that  man  may,  consequently,  be  regarded 
omnivorous ;  that  is,  capable  of  subsisting  on  both  the  products  of  the 
animal  and  the  vegetable  kingdom ; — an  important  capability,  seeing, 
that  he  is  destined  to  live  in  arctic  regions,  in  which  vegetable  food  is 
not  to  be  met  with,  as  well  as  in  the  torrid  zone,  which  is  more  favour- 
able for  vegetable  than  animal  life. 

The  nature  of  the  country  must,  to  a  great  extent,  regulate  the  food 
of  its  inhabitants;  for  although  commerce  can  furnish  articles  of  luxury, 
and  many  which  are  looked  upon  as  necessaries,  no  nation  is  entirely 
indebted  to  it  for  its  supplies.  Besides,  numerous  extensive  tribes  of 
the  human  family  are  denied  the  advantages  of  commerce,  and  com- 
pelled to  subsist  on  their  own  resources.  This  is  the  main  cause  why 
the  Esquimaux,  Samoiedes,  &c.,  live  wholly  on  animal  food;  and  why 
the  cocoa-nut,  plantain,  banana,  sago,  yam,  cassava,  maize  and  millet, 
form  chief  articles  of  diet  with  the  natives  of  torrid  regions. 

In  certam  countries,  the  scanty  supply  of  the  useful  and  edible  ani- 
mals has  given  occasion  to  certain  prohibitory  dietetic  rules  and  regu- 
lations, which  have  been  made  to  form  part  of  the  religious  creed,  and, 
of  course,  are  most  scrupulously  observed.  Thus,  in  Ilindostan,  animal 
food  is  not  permitted  to  be  eaten ;  but  the  milk  of  the  cow  is  excepted. 
Accordingly,  to  insure  the  necessary  supply  of  this  fluid,  the  cow  is 
made  sacred ;  and  its  destruction  a  crime  against  religion.  Amongst 
the  laws  of  the  Egyptians  are  similar  edicts,  but  they  seem  to  have 
been  chiefly  enacted  for  political  purposes,  and  not  in  consequence  of 
the  unwholesome  character  of  the  interdicted  articles.  The  same 
remark  applies  to  many  of  the  dietetic  rules  of  Moses,  for  the  regula- 
tion of  the  tables  of  the  Hebrews.  Blood  was  forbidden,  in  conse- 
quence, probably,  of  the  fear  entertained,  that  it  might  render  the 
people  too  familiar  with  that  fluid,  and  diminish  the  horror  inculcated 
against  shedding  it;  the  parts  of  generation  were  excluded  from  the 
table,  because  the  taste,  if  indulged,  might  interfere  with  the  repro- 
duction of  the  species,  &c.  &c. 

We  have  said,  that,  in  his  arrangement  of  the  digestive  organs,  man 
is  intermediate  between  the  carnivorous  and  the  herbivorous  animal. 

'  Ansicliten  der  Natur;  translated  under  the  title  of  Aspects  of  Nature,  by  Mrs. 
Sabine,  Amer,  edit.,  p.  159,  Philadelphia,  1849. 


108  DIGESTION". 

Not  tlie  sli.ojlitest  ground  is  afforded  by  anatomy  for  the  opinion  of 
Rousseau,  tiiat  man  was  originally  herbivorous;  or  for  that  of  Hel- 
vetius,'  that  he  was  exclasively  carnivorous.  Broussonet  affirms,  that 
lie  is  more  herbivorous  than  carnivorous,  since,  of  his  thirty-two  teeth, 
twenty  resemble  those  of  the  herbivorous,  whilst  twelve  only  resemble 
those  of  the  carnivorous  animal.  Accordingly,  he  infers,  that,  in  the 
origin  of  society,  the  diet  of  man  must  have  been  exclusively  vege- 
table. Mr.  Lawrence,^  too,  concludes,  that,  whether  we  consider  the 
teeth  and  jaws,  or  the  immediate  instruments  of  digestion,  the  human 
structure  closely  resembles  that  of  the  simiae — the  great  archetypes, 
according  to  Lord  Monboddo-'  and  Rousseau,  of  the  human  race, — all 
of  which  are,  in  their  natural  state,  herbivorous. 

Again: — a  wide  discrepancy  between  man  and  animals  is  observed 
in  the  variety  of  their  aliments.  Whilst  the  latter  are  generally  re- 
stricted to  either  the  animal  or  vegetable  kingdom,  and  to  but  a  small 
part  of  either,  man  embraces  an  extensive  range,  and  by  means  of  his 
culinary  inventions  can  convert  a  variety  of  articles  from  both  king- 
doms into  materials  of  sustenance.  But  it  has  been  argued  by  those, 
who  are  sticklers  for  the  natural^  that  man  probably  confined  himself, 
primitively,  like  animals,  to  one  kind  of  food;  that  he  adhered  to  this 
whilst  he  remained  in  his  natural  state,  and  that  his  omnivorous  prac- 
tices are  a  proof  of  his  degeneracy.  Independently,  however,  of  all 
arguments  deduced  from  organization,  experience  sufficiently  shows 
the  inaccuracy  of  such  assertions.  If  we  trace  back  nations  to  their 
state  of  infancy,  we  find,  that  then,  as  in  their  more  advanced  condition, 
their  diet  was  animal,  or  vegetable,  or  both,  according  to  circumstances. 
Of  this  fact  we  have  some  signal  examples  in  a  part  of  the  globe  where 
the  lights  of  civilization  have  penetrated  to  a  less  extent  than  in  most 
others;  and  where  the  influence  of  circumstances  that  prevailed  in 
ancient  periods  has  continued,  almost  unmodified,  until  the  present 
time.  Agatharchides''  describes  the  rude  tribes,  who  lived  on  the  coast 
of  the  Red  Sea,  and  subsisted  on  fish,  under  the  name  ichthyophagi. 
Along  both  banks  of  the  Astaboras,  which  flows  on  one  side  of  Meroe, 
dwelt  another  nation,  who  lived  on  roots  of  reeds  growing  in  the  neigh- 
bouring swamps.  These  roots  they  cut  to  pieces  with  stones,  formed 
them  into  a  tenacious  mass,  and  dried  them  in  the  sun.  Close  to  them 
were  the  hylophagi,  who  lived  on  the  fruits  of  trees,  vegetables  growing 
in  the  valleys,  &c.  To  the  west  of  these  were  hunting  nations,  who 
fed  on  wild  animals,  which  they  killed  with  the  arrow.  There  were, 
also,  other  tribes,  who  lived  on  the  flesh  of  the  elephant  and  ostrich, — 
elephaatophagi  and  struthiophagi.  Besides  these,  he  mentions  another 
and  less  populous  tribe,  who  fed  on  locusts,  which  came  in  swarms 
from  the  southern  and  unknown  districts.  The  mode  of  life,  with  the 
tribes  described  by  Agatharchides,  does  not  seem  to  have  varied  for 
the  last  two  thousand  years.  Although  cultivated  nations  are  situated 
around  them,  they  have  made  no  progress  themselves.  Hylophagi  are 
still  to  be  met  with.     The  Dobenahs,  the  most  powerful  tribe  amongst 

■  De  rHomme,  ii.  23,  Londres,  1775. 

*  Lectures  on  Physiology,  Zoology,  &c.,  p.  221,  London,  1819. 

*  On  tlie  Origin  and  Progress  of  Language,  Pt.  i.  Book  2,  Chap.  2,  Edinburgh,  1773. 

*  De  Rubro  Mare,  in  Hudson's  Geograph.  Minor.,  i.  37. 


FOOD   OF   MAN.  109 

the  Sliangallas,  still  live  on  the  elephant ;  and,  farther  to  the  west, 
dwells  a  tribe,  which  subsists  in  the  summer  on  the  locust;  and,  at 
other  seasons,  on  the  crocodile,  hippopotamus,  and  fish.' 

In  the  infancy  of  society,  as  in  his  own  infancy,  man  was  perhaps 
almost  wholly  carnivorous;  as  the  tribes  least  advanced  in  civilization 
are  at  the  present  day.  For  a  time,  he  may,  in  most  situations,  have 
confined  himself  to  the  vegetable  banquet  prepared  for  him  by  his 
bounteous  Maker ;  but,  as  population  increased,  the  means  of  subsist- 
ence would  become  too  scattered  for  him,  and  it  would  be  necessary  to 
crowd  together  a  number  of  nutritious  vegetables  into  a  small  space, 
and  to  cultivate  the  earth,  so  as  to  multiply  its  produce;  but  this 
would  imply  the  existence  of  settled  habits  and  institutions  which 
could  only  arise  after  society  had  made  progress.  Probably,  much 
before  this  period,  it  would  have  been  discovered,  that  certain  of  the 
beasts  of  the  forest,  and  of  the  birds  of  the  air,  and  some  of  the  insect 
tribes,  could  minister  to  his  wants,  and  form  agreeable  and  nutritious 
articles  of  diet;  and  thus  would  arise  their  adoption  as  food.  On  the 
coasts  of  the  ocean,  animal  food  was  perhaps  employed  from  the  period 
of  their  first  settlement;  as  well  as  on  the  banks  of  the  large  streams 
which  are  so  common  in  Asia, — the  cradle  of  mankind.  The  fish,  left 
upon  the  land  after  the  periodical  inundations  of  the  rivers,  or  thrown 
on  the  sea-coast,  would  minister  to  their  necessities,  without  the  slightest 
eftbrt  on  their  part ;  and,  hence,  they  would  have  but  little  incentive 
to  mental  or  corporeal  exertion.  This  is  the  cause  of  the  abject  con- 
dition of  the  ichthyophagous  tribes  of  old;  and  of  their  comparatively 
low  state  of  civilization  at  the  present  day.^  Again: — savages,  in 
various  parts  of  the  globe,  live  by  the  chase  or  the  fishery ;  and  must, 
consequently,  be  regarded  as  essentially  carnivorous.  It  would  not, 
however,  be  justifiable,  to  regard  barbarism  as  the  natural  state  of 
man;  nor  is  it  clear  what  the  difi'erent  writers  on  this  point  of  anthro- 
pology have  meant  by  the  term.  The  Author  of  nature  has  invested 
him  with  certain  prerogatives,  one  of  which  is  the  capability  of  ren- 
derinfj:  the  organized  kino-dom  subservient  to  his  wishes  and  necessi- 
ties;  and,  by  the  invention  of  the  culinary  art,  of  converting  various 
organized  bodies  into  wholesome  and  agreeable  articles  of  diet,  which 
thus  become  as  natural  to  him  as  the  restriction  to  one  species  of 
aliment  is  to  the  animal. 

It  has  been  remarked,  that  the  exclusive  or  predominant  use  of  ani- 
mal or  of  vegetable  food  has  a  manifest  effect  upon  the  physical  and 
moral  powers.  Bufibn  affirms,  that  if  man  were  obliged  to  abstain 
from  flesh  in  our  climates,  he  could  not  exist,  nor  propagate  his  kind. 
Others,  again,  have  depicted  a  state  of  ideal  innocence,  in  the  infancy 
of  society,  when  he  lived,  as  they  conceive,  entirely  on  vegetables; 

"  His  food  the  fruits ;  liis  drink  the  crystal  well ;" 

unsolicitous  for  the  future  in  consequence  of  the  abundant  subsistence 
spread  before  him;  independent;  and  always  at  peace  with  his  fellows, 
and  with  animals;  but  he  gradually  sacrificed  his  liberty  to  the  bonds 

'  Bruce,  Travels,  3d  edit.,  v.  83. 

2  The  Author,  in  Amer.  Med.  Intelligencer,  i.  99,  Philad.,  1838. 


110  DIGESTION. 

of  society;  and  cruelty,  TN'ith  an  insatiable  appetite  for  flesli  and  blood, 
were  the  first  fruits  of  a  depraved  nature.  Either  immediately  or 
remotely,  all  the  physical  and  moral  evil,  by  which  mankind  are 
afflicted,  arose  from  these  carnivorous  practices.  "The  principal 
patrons  of  this  twaddle,  in  modern  times" — says  Dr.  Fletcher — "  to 
say  nothing  of  Pvthagoras  and  the  ancients — have  been  Gassendi, 
Kousseau,  AYallis,  Lamb,  and  jSTewton ;  the  last  of  whom,  in  the  pleni- 
tude of  his  infatuation,  asserts  that  real  men  have  never  yet  been  seen, 
nor  ever  will  be,  till  they  shall  be  content  to  subsist  entirely  on  herbs 
and  fruits  and  distilled  water."^  In  point  of  fact,  we  find,  that  the 
inhabitants  of  countries,  in  which  mankind  are  accustomed  to  be  om- 
nivorous, or  to  unite  animal  witli  vegetable  diet,  are  those  most  dis- 
tinguished for  both  mental  and  corporeal  endowments.  The  tribes, 
which  feed  altogether  on  animal  food, — as  the  Laplanders,  Samoiedes, 
Esquimaux,  &c., — are  far  inferior,  in  both  these  respects,  to  the  Euro- 
pean, or  Europeo- American ;  and  the  same  may  be  said,  although  not 
to  the  like  extent,  of  the  various  tribes  in  whose  diet  animal  food  pre- 
dominates,— as  the  Indian  inhabitants  of  our  own  continent.  A  similar 
remark  is  applicable  to  those,  who  live  almost  exclusively  on  vegeta- 
bles, as  the  Hindoos,  millions  of  whom  are  kept  in  subjection  by  a  few 
Europeans.^ 

Attempts  have  frequently  been  made  to  refer  the  nutrient  properties 
of  all  articles  of  diet  to  a  particular  principle  of  a  constant  character, 
which,  alone,  of  all  the  elements,  is  entirely  capable  of  assimilation. 
Haller^  conceived  this  to  be  jelly; — Dr.  Cullen''  thought  it  to  be  oily, 
or  saccharine,  or  what  seemed  to  be  a  combination  of  the  two; — Becker, 
Stah],  Fordyce,*  &c.,  to  be  mucilage;  M.  Dumas,^  mucus;  and  M. 
Halle,  a  hydro-carbonous  oxide  very  analogous  to  gummi-saccharine 
matter  V  It  is  probable,  that  there  is  no  such  special  principle  as  the 
one  contended  for ;  and  that,  in  all  cases,  in  the  formation  of  the  chyle 
or  reparative  fluid,  which  is  separated  from  it,  the  food  is  resolved 
into  its  elements.  To  this  conclusion  w*s  are  necessarily  impelled, 
when  we  reflect,  that  chyle  can  be  formed  from  both  animal  and  vege- 
table substances.  In  an  early  part  of  this  work,  occasion  was  taken  to 
mention,  that  all  organized  tissues,  animal  and  vegetable,  are  reducible 
into  nearl}'-  the  same  ultimate  elements, — oxygen,  hydrogen,  carbon, 
and  nitrogen.  Great  light  has  been  thrown  on  this  subject,  in  recent 
periods,  by  the  labours  of  the  organic  chemist.  These  have  shown, 
that  the  chief  proximate  principles  of  animal  tissues,  and  those  that 
have  been  regarded  as  highly  nutritious  amongst  vegetables,  have 
almost  identically  the  same  composition;  and  are  modifications  of 
protein.^      The   following  tables  from   Liebig'*  exhibit   the   striking 

'  Riirliments  of  Physiology,  Part  ii.,  a.  p.  121,  Edinb.,  1S36. 
2  Lawrence's  Lectures,  edit,  cit.,  p.  216. 
'^  Elementa  Phyrfiologise,  Lib.  xix.,  Sect.  3,  Bernje,  1764. 
*  Institutions  of  Medicine,  Part  i.,  Physiology,  §  211,  Edinb.,  1785. 
^  Treatise  on  the  Digestion  of  Food,  p.  84,  2d  edit.,  Lond.,  1791. 
^  Principes  de  Physiologic,  i.  187,  Paris,  1806. 
'  Tiedemann,  Pliysiologie  des  Menschen,  iii.  95,  Darmstadt,  1836. 
^  See  page  39. 

9  Animal  Chemistry,  Gregory's  and  Webster's  edit.,  pp.  100,  283,  and  301,  Cambridge, 
Mass.,  1842. 


FOOD   OF   MAN. 


Ill 


similarity  in  constitution,  and  in  the  proportion  of  constituents,  of 
different  animal  and  vegetable  compounds  of  organization. 

Animal  proximate  principles,  according  to  Mulder, 


Albumen. 

Fibrin. 

Casein. 

Carbon, 

54-84 

54-56 

54-96 

Hj^drogen,    . 

7-09 

6-90 

7-15 

Nitrogen, 

15-&3 

15-72 

15-80 

Oxygen, 

21-23 

22-13 

21-73 

Sulphur, 

0-OS 

0-33 

0-36 

Phosphorus, 

0-33 

0-36 

100-00 


100-00 


100-00 


Carbon, 

Hydrogen, 

Nitrogen, 

Oxygen, 

Sulphur, 

Phosphorus 


Vegetable  proximate  principles,  according  to  ScJierer  and  Jones. 

Albumeu,  from  wheat.  Fibrin.  Casein  or  Legumin. 

55-01         !         .       54-603         .         .      54-138 
7-23         .         .         7-302         .         .        7-156 
15-92         .         .       15-809         .         .      15-672 


21-84 


100-00 


22-286 


100-000 


23-034 


100-000 


As  tlie  different  parts  of  organized  bodies  contain  a  considerable 
portion  of  nitrogen,  a  question  has  arisen  regarding  its  source ;  some 
believing,  that  it  is  obtained  from  the  food,  others  by  respiration. 

]\L  Magendie'  instituted  experiments  with  the  view  of  determining 
the  nutritive  qualities  of  non-nitrogenized  substances.  They  consisted 
in  feeding  animals,  for  the  necessary  time,  on  a  diet  whose  chemical 
composition  was  rigidly  determined.  He  fed  a  dog,  three  years  old 
and  in  good  condition,  on  pure  white  sugar  and  distilled  water.  For 
seven  or  eight  days,  the  animal  appeared  to  thrive  well,  was  lively,  and 
ate  and  drank  with  avidity.  In  the  second  week,  it  began  to  fall  off, 
although  its  appetite  continued  good,  and  it  ate  six  or  eight  ounces  of 
sugar  in  the  twenty -four  hours.  In  the  third  week,  it  became  ema- 
ciated, its  strength  diminished,  its  gaiety  was  gone,  and  its  appetite 
impaired.  An  ulcer  formed  on  each  eye,  at  the  centre  of  the  cornea, 
which  subsequently  perforated  it,  and  allowed  the  humours  to  escape. 
The  emaciation,  as  well  as  loss  of  strength,  went  on  progressively 
increasing;  and,  although  the  animal  ate  daily  three  or  four  ounces  of 
sugar,  the  debility  became  so  great,  that  it  could  neither  chew,  swal- 
low, nor  execute  the  slightest  movement.  It  died  on  the  thirty-second 
day  of  the  experiment.  On  dissection,  the  fat  was  found  to  have 
entirely  disappeared ;  the  muscles  were  reduced  to  less  than  five-sixths 
of  their  ordinary  size;  the  stomach  and  intestines  were  much  dimi- 
nished, and  powerfully  contracted ;  and  the  gall  and  urinary  bladders 
filled  with  fluids  not  proper  to  them.  These  were  examined  by  M. 
Chevreul,  who  found  them  to  possess  almost  all  the  characters  of  the 
bile  and  urine  of  herbivorous  animals.  The  urine,  in  place  of  being 
acid,  as  it  is  in  the  caruivora,  was  sensibly  alkaline,  and  presented  no 
trace  of  uric  acid  or  phosphates.  The  bile  contained  a  considerable 
proportion  of  picromel,  like  that  of  the  ox  and  herbivora  in  general. 

'  Precis  i-lementaire,  2de  edit.,  ii.  4SS,  Paris,  1825. 


112  DIGESTION. 

The  excrements  contained  very  little  nitrogen,  wliicli  tliej  usually  do 
in  abundance, 

A  second  dog  was  subjected  to  the  like  regimen,  and  with  similar 
results.  He  died  on  the  thirty -fourth  day  of  the  experiment.  A  third 
experiment,  having  eventuated  in  the  same  manner,  j\[.  Magendie  con- 
cluded that  sugar  alone  is  incapable  of  nourishing  the  dog.  In  all 
these  cases,  ulceration  of  the  cornea  occurred,  but  not  exactly  at  the 
same  period  of  the  experiment.  He  next  endeavoured  to  discover, 
whether  these  effects  might  not  be  peculiar  to  sugar ;  or  whether  non- 
nitrogenized  substances,  generally  considered  nutritions,  might  not  act 
in  the  same  manner.  He  took  two  young  and  vigorous  dogs,  and  fed 
them  on  olive  oil  and  distilled  water.  For  fifteen  days  they  were  appa* 
rently  well ;  but,  after  this,  the  same  train  of  phenomena  supervened 
as  in  the  other  cases,  except  that  there  was  no  ulceration  of  the  cornea. 
They  died  about  the  thirty-sixth  day  of  the  experiment.  Similar 
experiments  were  made  with  gum  Arabic,  and  with  butter — one  of 
the  animal  substances  that  do  not  contain  nitrogen.  The  results  were 
identical. 

Although  the  character  of  the  excrements  passed  by  the  difl'erent 
animals  indicated  that  the  substances  were  well  digested,  M.  Magendie 
was  desirous  of  establishing  this  in  a  positive  manner.  Accordingly, 
after  having  fed  animals  for  several  days  on  oil,  gum,  or  sugar,  he 
opened  them,  and  found  that  each  of  these  substances  was  reduced  to 
a  particular  kind  of  chyme  in  the  stomach ;  and  that  all  aflbrded  an 
abundant  supply  of  chyle ;  that  from  oil  being  of  a  manifest  milky 
appearance,  and  that  from  gum  or  sugar,  transparent,  opaline,  and  more 
aqueous  than  the  chyle  from  oil ;  facts  which  prove,  that  if  the  various 
substances  did  not  nourish  the  animals,  the  circumstance  could  not  be 
attributed  to  their  not  having  been  digested.  These  results,  M.  Ma- 
gendie thought,  render  it  likely,  that  the  nitrogen,  found  in  different 
parts  of  the  animal  economy,  is  originally  obtained  from  the  food. 
This,  however,  is  doubtful.  We  have  no  proof,  that  the  animals  died 
simply  from  privation  of  nitrogen.  It  is,  indeed,  probable,  that  it  had 
little  or  no  agency  in  the  matter,  for  there  seems  to  be  no  sufficient 
reason  why  it  should  not  have  been  procured  from  the  air  in  respira- 
tion, as  well  as  from  that  contained  between  the  particles  of  the  sugar, 
where  this  substance  was  administered.  It  must  be  recollected,  more- 
over, that  the  subjects  of  these  experiments  were  dogs; — animals 
which,  in  their  natural  state,  are  carnivorous,  and,  in  a  domestic  state, 
omnivorous ;  and  that  they  were  restricted  to  a  diet  foreign  to  their 
nature,  and  one  to  which  they  had  not  been  accustomed.  Ought  we, 
under  such  circumstances,  to  be  surprised,  that  they  should  sicken,  and 
fall  oft"? 

In  the  period  that  elapsed  between  the  publication  of  the  first  and 
second  editions  of  his  Precis  Eltmentaire  de  Fhi/siologie,  M.  Magendie 
found  that  his  deductions  were  not,  perhaps,  as  absolute  or  demonstra- 
tive as  he  had  at  first  imagined;  and  additional  experiments  induced 
him  to  conclude,—  as  Dr.  Bostock^  afterwards  did,  without  being  aware, 
apparently,   of  his   observation,— "that  variety  and   multiplicity  of 

'  riiysiology,  3d  edit.,  p.  561,  Lond.,  1S36. 


FOOD   OF   MAN.  113 

articles  of  food  constitute  an  important  hygienic  rule."  "  This,"  M, 
Magendie'  adds,  "  is  indicated  to  us  by  our  instinct,  as  well  as  by  the 
changes  that  wait  upon  the  seasons,  as  regards  the  nature  and  kind  of 
alimentary  substances."  The  additional  facts,  detailed  by  M.  Magendie, 
are  the  following : — A  dog,  fed  at  discretion  on  pure  wheaten  bread, 
and  drinking  common  water,  does  not  live  beyond  fifty  days ;  whilst 
another,  fed  exclusively  on  military  bread — pain  de  munition — seems 
to  suffer  in  no  respect.  Eabbits  or  Guinea-pigs,  fed  on  a  single  sub- 
stance, as  wheat,  oats,  barley,  cabbage,  carrots,  &c.,  commonly  die,  with 
every  mark  of  inanition,  in  a  fortnight;  and,  at  times,  much  earlier. 
"When  the  same  substances  are  given  together,  or  in  succession,  at  short 
intervals,  the  animals  continue  in  good  keeping.  An  ass,  fed  on  rice, 
lived  only  fifteen  days,  refusing  his  food  for  the  last  few  days ;  whilst 
a  cock  was  fed  upon  boiled  rice  for  several  months  without  his  health 
suffering.  Dogs,  fed  exclusively  on  cheese,  and  others  on  hard  eggs, 
lived  for  a  long  time ;  but  they  were  feeble  and  lean,  losing  their  hair, 
and  their  whole  appearance  indicated  imperfect  nutrition.  The  sub- 
stance, which,  when  given  alone,  appeared  to  support  the  rodentia^  for 
the  greatest  length  of  time,  was  muscular  flesh. 

Lastly,  M.  Magendie  found,  that  if  an  animal  had  subsisted  for  a 
certain  time  on  a  substance,  which,  taken  alone,  is  incapable  of  nour- 
ishing it, — on  white  bread,  for  instance,  for  forty  days, — it  is  useless, 
at  the  end  of  that  time,  to  vary  his  nourishment,  and  restore  him  to 
his  accustomed  regimen.  He  will  feed  greedily  on  the  new  food  pre- 
sented to  him;  but  continues  to  fall  off";  and  dies  at  the  same  period  as 
he  would  probably  have  done,  if  maintained  on  his  exclusive  regimen. 
That  these  effects  are  not  owing  to  privation  of  nitrogen,  the  same  ob- 
server' has  since  been  amply  satisfied.  As  chairman  of  a  committee 
appointed  to  inquire  into  the  nutritive  properties  of  gelatin,  he  re- 
ported that  gelatin,  albumen,  and  fibrin — all  of  which  are  highly 
nitrogenized — when  taken  separately,  nourish  animals  for  a  limited 
period  only,  and  imperfectly.  They  generallj^  soon  excite  so  insur- 
mountable a  disgust  that  the  animals  would  rather  die  than  partake  of 
them.  These  experiments  led  to  the  too  hasty  conclusion,  that  the 
gelatinous  tissues  are  incapable  of  conversion  into  blood.  "  The  gela- 
tinous substance,"  says  Liebig,"*  "  is  not  a  compound  of  protein ;  it  has 
no  sulphur,  no  phosphorus,  and  contains  more  nitrogen  or  less  carbon 
than  protein.  The  compounds  of  protein,  under  the  influence  of  the 
vital  energy  of  the  organs  that  form  the  blood,  assume  a  new  form, 
but  are  not  altered  in  composition ;  whilst  these  organs,  as  far  as  our 
experience  reaches,  do  not  possess  the  power  of  producing  compounds 
of  protein,  by  virtue  of  any  influence,  from  substances  that  contain  no 
protein.     Animals,  which  were  fed  exclusively  on  gelatin,  the  most 

'  Op.  citat.,  ii.  494. 

^  The  rodentia  are  gnawing  animals,  having  large  incisors  in  each  jaw,  with  which 
they  divide  hard  substances.  They  are  the  rongeurs  of  the  French  naturalists.  The 
squirrel,  mouse,  rat,  Guinea-pig,  hare,  rabbit,  beaver,  kangaroo,  porcupine,  &c.,  belong 
to  this  division, 

'  Comptes  Rendus,  Aout,  1841.  Similar  results  were  obtained  by  the  Amsterdam 
Commission,  Het  Instituut,  No.  ii.  1843,  pp.  97-114,  cited  by  Mr.  Paget,  Brit,  and  For. 
Med.  Rev.,  April,  1845,  p.  563. 

■*  Animal  Chemistry,  Amer.  edit.,  by  Webster,  p.  124,  Cambridge,  Mass.,  1842. 
VOL.  I. — b 


114  DIGESTION". 

highly  nitrogenized  element  of  the  food  of  carnivora,  died  with  symp- 
toms of  starvation."  "  In  short,"  he  adds,  "  gelatinous  tissues  are  in- 
capable of  conversion  into  blood."  Such  too,  seems  to  be  the  opinion 
of  Professor  Berard.^  Yet  it  has  been  shown  above,  that  fibrin  and 
albumen — both  compounds  of  protein — when  exhibited  singly  to  ani-' 
mals,  nourished  them  as  imperfectly  as  gelatin ;  and  there  is  some 
reason  to  believe,  that  it  is  mainly  on  chemical  considerations  that  the 
value  of  gelatin  as  a  nutriment  has  been  much  underrated.  "  Such 
persons  only,"  says  Professor  Mulder,^  "as  are  under  the  influence  of 
prejudice  (making  their  experiments  with  dogs — animals  which,  ac- 
cording to  the  account  of  the  gelatin  committee,  prefer  to  starve  in 
the  midst  of  gelatin,  rather  than  touch  it),  such  persons  only  as  deny 
the  results  of  innumerable  observations,  will  refuse  to  gelatin  its  place 
among  useful  nutritive  substances."  And  he  adds :  "  I  have  thought 
it  necessary,  before  closing  this  short  account  of  gelatin,  to  express  my 
opinion  of  the  experiments  by  which  pure  gelatin  is  rejected  as  food: — 
namely,  that  these  experiments  have  taught  ine  nothing  but  how  ex- 
periments ought  not  to  be  made."  It  is  somewhat  singular,  too,  that 
most  of  those  who  deny  much  nutrient  property  to  gelatin  are  of 
opinion,  that  the  nutritious  properties  of  different  articles  of  vegetable 
food  may  be  generally  estimated  by  the  proportion  of  nitrogen  they 
contain,  and  on  this  principle  tables  have  been  formed  by  several  ex- 
perienced chemists, — by  Boussingault,  Schlossberger,  Kemp,^  and 
Professor  Horsford,''  of  Cambridge,  Massachusetts.  The  latter  gentle- 
man, especially,  has  published  the  results  of  elaborate  investigations 
into  the  nature  of  different  kinds  of  vegetable  food,  based  upon  the 
amount  of  nitrogen.  The  tables  of  Boussingault  and  Horsford  are 
considered  by  Professor  Frerichs,^  of  value ;  whilst  those  of  Schloss- 
berger and  Kemp  are  declared  to  be  practically  useless,  because  no 
regard  was  paid  to  the  quantity  of  water  in  the  fresh  condition ;  and 
for  the  strange  reason,  "that  the  nitrogen  found  in  most  of  the  sub- 
stances analyzed  that  contain  gelatin  is  no  measure  of  the  quantity  of 
the  htematogenetics  or  blood-forming  constituents !" 

Independently  of  showing  the  necessity  of  variety  of  food  for  animal 
sustenance,  the  experiments  of  M.  Magendie  exhibit  some  singular 
anomalies ;  and  sufficiently  demonstrate,  that  we  have  j%i  much  to  learn 
on  the  subject.  A  great  deal,  doubtless,  depends  on  the  habits  of  the 
particular  animal  or  individual ;  and  on  the  morbid  effects  excited  by 
completely  changing  the  function  of  assimilation.  It  has  been  long 
known,  that  if  a  man,  previously  habituated  to  both  animal  and  vege- 
table diet,  be  restricted  exclusively  to  one  or  the  other,  he  will  fall  off, 
and  become  scorbutic ;  and  yet,  that  he  is  capable  of  subsisting  on 
either  one  or  the  other  exclusively,  provided  the  restriction  has  been 
enforced  from  early  infancy,  has  been  sufficiently  shown  by  the  refer- 

'  Archives  Genemles  de  Medecine,  Fevrier,  1850,  p.  247. 

2  The  Chemistry  of  Vegetable  and  Animal  Physiology,  by  G.  J.  Mulder,  &c.,  p.  328, 
Edinb.  and  Lend.,  1849.  J  bj ,    j  ,        ,i  > 

3  Annal.  der  Chemie  und  Pharmacie,  B.  Ivi.  s.  78-94 ;  see  also,  Philosophical  Maga- 
zine for  Nov.,  1845. 

*  Philosophical  Magazine,  for  Nov.,  1846,  p.  365. 

5  Art.  Verdauung,  in  Wagner's  Handwurterbuch  der  Physiologic,  19te  Liefening,  s. 
732,  Braunschweig,  1848. 


FOOD   OF   MAN.  115 

ence  made  to  carnivorous  and  herbivorous  tribes  existing  in  different 
regions  of  our  globe.  Tlie  importance  of  variety  of  diet  is  illustrated 
by  the  experiments  made  by  Dr.  Stark/  upon  his  own  digestive  powei^s, 
and  to  which  he  ultimately  became  a  martyr.  His  object  was  to  dis- 
cover the  relative  effect  of  various  simple  substances,  when  used  exclu- 
sively for  a  long  space  of  time  as  articles  of  food.  The  system,  he 
found,  was  in  all  cases  reduced  to  a  state  of  extreme  debility,  and  there 
was  not  a  single  aliment,  that  was  capable,  of  itself,  of  sustaining  the 
vigour  of  the  body  for  any  considei'able  period.  By  this  kind  of  regi- 
men Dr.  Stark  is  said  to  have  so  completely  ruined  his  own  health,  as 
to  bring  on  premature  death. 

It  would  seem,  too,  that  for  continued  sustenance,  a  due  supply  of 
vegetable  food,  which  is  not  deprived  of  its  organic  acids  and  salts, 
must  be  permitted ;  hence  the  production  of  scurvy  by  the  want  of 
fresh  vegetables,  and  its  removal  by  a  proper  admixture  of  the  same, 
which  must  either  be  eaten  raAV,  or  so  cooked  that  they  may  not  be  de- 
prived of  their  saline  constituents.^  Occasionally,  too,  where  scurvy  has 
arisen  under  the  exclusive  use  of  animal  diet,  it  has  disappeared  Avhen 
a  fresh  article  of  nitrogenized  diet  has  been  obtained.  Thus,  his  friend 
Dr.  Kane,  of  the  United  States  Navy,  informed  the  author  that  during 
the  first  expedition  to  the  Arctic  regions  in  search  of  Sir  John  Frank- 
lin, when  the  sailors  were  suffering  with  scorbutus,  and  the  lesser  awlz 
visited  the  region  in  its  periodical  migration,  the  fresh,  uncooked  flesh 
of  the  bird  soon  dispelled  every  symptom  of  the  malady. 

In  accordance  with  his  views,  that  nitrogenized  food  is  alone  capable 
of  formiog  organized  tissue;  and  that  the  non -nitrogenized  food  is 
inservient  to  respiration  only,  Liebig  thus  classifies  aliments: — 

Nitror/enized  Food  or  Plastic  Elements  of  Non-nitrogenized  Food  or  Elements  of 

Nutrition.  Respiration. 

Vegetable  Fibrin, 
"         Albumen, 
"         Ccaseiu, 

Flesh, 

Blood. 

These  views,  however,  are  more  chemical  than  physiological,  and  cer- 
tainly have  always  been  considered  by  the  author  to  demand  proof 
which  has  not  been  sufficiently  afforded.  They  are  not  confirmed  by 
what  is  observed  in  chylification.  In  the  small  chyliferous  vessels, 
more  fat,  which  is  a  non-nitrogenized  substance,  is  found  than  can  be 
accounted  for  by  the  adipose  matter  in  the  food ;  and  of  the  conver- 
sion of  the  amylaceous  and  saccharine  matters  in  the  food  to  oil  during 
the  digestive  function  a  striking  example  has  been  published  by  M. 
Ivciss.^  A  workman  was  killed  on  a  railroad  after  having  eaten  a  full 
meal  of  bread  and  grapes  only.  On  examining  his  body,  the  process 
of  chymification  was  found  to  have  been  in  full  activity;  and  in  those 
portions  of  the  small  intestine,  which  the  chyme  had  reached,  the 
mucous  membrane  was  dotted  with  white  points,  which,  on  closer 

'  The  Works  of  the  late  Wm.  Stark,  M.  D.,  &c.,  by  Dr.  J.  C.  Smyth,  Lond.,  1787. 
^  Britisli  and  Foreign  Medico-Chirurg.  Rev.,  Oct.  1848,  p.  473. 
_  ^  Cited  in  London  Med.  Gazette,  Oct.,  1846.     See,  on  this  sul)ject,  Moleschott,  Pliy- 
siologie  des  Stoffwechsels  im  Pflanzen  und  Thieren,  S.  203,  Erlangen,  1851. 


Fat, 

Pectin, 

Starch, 

Bassorin, 

Gum, 

Wine, 

Cane  Sugar, 

Beer, 

Grape  Sugar, 

Spirits. 

Sugar  of  Milk, 

116  DIGESTION". 

examination,  were  found  to  be  owing  to  drops  of  oil  in  the  epithelial 
cells  surrounding  the  extremities  of  the  villi.  As  the  chyle  proceeds 
along  the  lacteals,  the  proportion  of  fat  becomes  less  and  less,  whilst 
that  of  the  nitrogenized  matters  increases;  hence  nitrogen  must  have 
been  obtained,  and  a  conversion  have  taken  place  of  non-nitrogenized 
into  nitrogenized  matters.  (See  Physiology  of  Chylosis.) 

The  implicit  believers  in  the  views  of  Liebig,  have  affirmed,  as  a 
matter  of  course,  that  fat  can  only  be  an  "  element  of  respiration ;"  yet 
it  appears  to  be  necessary  in  all  cell  formation ;  and,  in  the  yolk,  to  be 
an  aliment  destined  for  the  formation  of  every  tissue  in  the  animal; 
as  starch — an  equally  non-nitrogenized  article — is  in  the  case  of  the 
seed  of  the  vegetable.  Moreover,  it  enters  largely  into  the  composi- 
tion of  neurine.  These,  and  analogous  considerations,  have  caused 
some  of  those  who  hastily  embraced  the  doctrine  of  the  distinguished 
chemist  on  this  subject  to  pause,  and  even  to  retrace  their  steps;'  and 
evidence  enough  seems  to  exist  to  cause  it  to  be  abandoned.^ 

The  alimentary  substances,  employed  by  man,  have  generally  been 
classed  either  according  to  the  ultimate  chemical  elements  entering 
into  their  composition;  or  to  the  chief  proximate  principle  or  com- 
pound of  organization.  In  the  former  case,  they  have  been  grouped 
into : — 1,  those  that  contain  nitrogen,  carbon,  hydrogen,  and  oxygen; — 
2,  those  that  contain  carbon,  hydrogen,  and  oxygen ;  and  3,  those  tha^ 
contain  neither  nitrogen  nor  carbon.  The  first  class  will  comprise 
most  animal  and  many  vegetable  substances;  the  second,  vegetable 
substances  chiefly ;  whilst  water  is  perhaps  the  only  alimentary  matter 
that  belongs  to  the  third. 

The  division  proposed  by  M.  Magendie,^  and  adopted  by  Dr.  Paris,* 
is  according  to  the  proximate  principles,  which  predominate  in  the 
aliment. 

1.  Amylaceous  aliments;  wheat,  barley,  oats,  rice,  rye,   Indian   corn,  potato,  sago^ 
salep,  peas,  haricots,  lentils,  &c. 

2.  Mucilaginous  aliments ;  carrot,  salsify,  beet,  turnip,  asparagus,  cabbage,  lettuce 
artichoke,  melon,  &c. 

3.  Saccharine  aliments ;  the  different  kinds  of  sugar,  figs,  dates,  raisins,  &c. 

4.  Acidulous   aliments;   the    orange,  currant,    cherry,  peach,  raspberry,  strawberr 
mulberry,  grapes,  prunes,  pears,  apples,  tomatos,  &c. 

5.  Oili/  and  fatty;  cocoa,  olives,  sweet  almonds,  hazelnuts,  walnuts,  animal  fats,  oil^ 
butter,  &c. 

6.  Caseous  aliments  ;  the  different  species  of  milk,  cheese,  &c.  _ 

7.  Gelatinous  aliments;  the  tendons,  aponeuroses,  skin,  areolar  tissue,  the  flesh  of 
very  young  animals,  &c. 

8.  Albuminous  aliments ;  the  brain,  nerves,  eggs,  &c. 

9.  Fibrinous  aliments  ;  comprehending  the  flesh  and  blood  of  different  animals. 

To  these  proximate  principles  gluten  may  be  added,  which  has  been 
termed  the  most  animalized  of  vegetable""  principles.  According  to 
Dr.  Prout,*  it  is  separable  into  two  portions,  analogous  to  gelatin  and 
albumen.     It  is  very  generally  met  with,  although  only  in  small  pro- 

'  Carpenter,  Principles  of  Human  Physiology,  p.  69,  Amer.  edit.,  Philad.,  1855. 

2  Rudolph  Wagner's  Lehrbuch  der  Specielleu  Physiologie,  u.  s.  w.  von  D.  Otto  Funke. 
Iste  Lieferung,  S.  181,  Leipz.,  1854. 

^  Precis,  &c.,  ii.  34. 

<  A  Treatise  on  Diet,  3d  edit.,  p.  182,  Lond.,  1837 ;  and  art.  Dietetics,  in  Cyclopjedia 
of  Practical  Medicine,  Amer.  edit.,  Philad.,  1845. 

*  Chemistry,  INIeteorology,  and  the  Function  of  Digestion,  (Bridgewater  Treatise,) 
Amor,  edit.,  p.  558,  Philad.,  1834. 


FOOD   OF   MAN. 


117 


portion,  in  the  vegetable  kingdom; — in  all  the  farinaceous  seeds,  in 
the  leaves  of  cabbage,  cress,  &c.;  in  certain  fruits,  flowers,  and  roots, 
and  in  the  green  fecula  of  vegetables  in  general;  but  it  is  especially 
abundant  in  wheat,  and  imparts  to  wheaten  flour  the  property  of  fer- 
menting and  making  bread.  Of  the  nutritious  properties  of  gluten, 
distinct  from  other  principles,  we  know  nothing  precise :  the  superior 
nutritious  powers  of  wheaten  flour  over  those  of  all  other  farinaceous 
substances  sufficiently  attest,  that,  in  combination  with  starch,  it  is 
highly  nutritive. 

Dr.  Prout'  arranges  alimentary  principles  in  four  great  divisions — 
the  aqueous^  saccharine^  oleaginous,  and  albuminous.  This  has  been  taken 
as  the  basis  for  a  classification  by  Dr.  Pereira,^  who  admits  twelve 
divisions : — the  aqueous,  mucilaginous  or  gummy,  saccharine,  amylaceous, 
ligneous,  pectinaceous,  acidulous,  alcoholic,  oily  ov  fatty,  proteinaceous,  gela- 
tinous, and  saline.  By  the  combination  of  these  alimentary  principles 
and  simjjle  aliments,  our  ordinary  articles  of  food  or  compound  aliments 
are  formed.  In  this  classification,  the  proteinaceous  and  gelatinous 
aliments  are  separated.  The  following  simple  arrangement  is,  per- 
haps, as  little  liable  to  objection  as  any : — 


Nitrogenized  aliments, 
(Albuminous  of  Prout.) 


II.  Non-nitro(jenized  aliments, 


Fibrinous  (Glutinous.) 

Albuminous. 

Caseinous. 

Gelatinous. 

Amylaceous. 

Saccharine. 

Oleasrinous. 


The  second  division  might  be  still  farther  simplified;  for  amylaceous 
aliments  are  convertible  into  sugar  during  the  digestive  process  ;  and 
of  both — as  has  been  seen, — oleaginous  matter  may  be  formed. 

Milk,  furnished  by  the  parent  for  the  use  of  its  offspring,  contains  an 
admixture  of  nitrogenized  and  non-nitrogenized  aliments,  which,  as 
remarked  by  Dr.  Prout,^  is  the  true  type  of  all  food ;  and  the  same 
may  be  said  of  flour.  It  is  interesting,  indeed,  to  compare  the  ingre- 
dients which  enter  into  the  composition  of  milk,  wheaten  flour,  and 
blood,  as  given  by  Dr.  Robert  Dundas  Thomson'' : — 


Milk. 

Flouk. 

Blood. 

'  Fibrin, 

'  Fibrin, 

Curd  or  Casein, 

Albumen, 
Casein, 

Albumen, 
Casein, 

Butter, 

^  Gluten, 
Oil, 

Colouring  matter. 
Fat. 

Sugar, 

Sugar,  starch, 

Sugar. 

Chloride  of  potassium, 
Chloride  of  sodium, 

r 

Phosphate  of  soda. 
Phosphate  of  lime. 
Phosphate  of  magnesia, 
Phosphate  of  iron. 

Ditto, 

Ditto. 

'  On  the  Nature  and  Treatment  of  Stomach  and  Renal  Diseases,  Amer.  edit.,  from 
the  4th  revised  London  edit.,  ii.  354,  Philad.,  1843. 

^  A  Treatise  on  Food  and  Diet,  Amer.  edit,  by  Dr.  C.  A.  Lee,  p.  38,  New  York,  1843. 

^  Op.  cit.,  p.  3(32;  and  Chemistry,  Meteorology,  and  the  Function  of  Digestion,  &c., 
Amer.  edit.,  p.  259,  Philad.,  1834. 

^  Experimental  Researches  on  the  Food  of  Animals,  &c.,  Amer.  edit., p.  43,  New  York, 
1846. 


118  DIGESTIOISr. 

Water  forms  tlie  basis  of  all  drinks ;  but  it  frequently  contains  in 
addition  other  substances.  These  have  been  classed  as  follows : — 1. 
Water,  of  different  kinds,  2.  Vegetable  and  animal  juices  and  infusions, 
as  lemon-juice,  orange-juice,  whey,  tea,  coffee,  &c.  3.  Fermented  liq^iors, 
as  wines,  beer,  cider,  perry,  &c.;  and  4.  Alcoholic  liquors,  as  brandy, 
alcohol,  kirsch-wasser,  rum,  gin,  whisky,  arrack,  &c.  &c.  Dr.  Pereira* 
has  proposed  the  following  more  complete  classification : — 1.  Mucila- 
ginous, farinaceous  or  saccharine  drinks.  2.  Aromatic  or  astringent  drinks. 
3.  Acidulous  drinks.  4.  Animal  broths,  or  drinks  containing  gelatin 
•and  osmazome.  5.  Emulsive  or  milky  drinks;  and  6.  Alcoholic  and 
other  intoxicating  drinks.  Water — as  has  been  seen — is  considered  by 
him  amongst  the  alimentary  principles. 

An  inquiry  into  the  different  properties  of  these  various  liquids  does 
not  belong  to  the  physiologist.  It  may  be  remarked,  however,  that  the 
arguments  regarding  the  natural  have  been  extended  to  this  variety  of 
aliments;  and  it  has  been  contended,  that  water  is  "the  most  natural 
drink ;"  and  that  all  others,  which  are  the  products  of  art,  ought  to  be 
avoided.  The  remarks,  already  made  on  this  subject,  are  sufficient. 
Water  was,  doubtless,  at  one  period,  the  only  beverage  of  man,  as 
nakedness,  the  use  of  raw  aliment,  and  the  most  profound  ignorance  of 
the  universe,  were  his  original  condition ;  but  no  one  will  be  presump- 
tuous enough  to  declare,  that  he  ought  to  continue  naked,  abjure  cook- 
ery, and  be  plunged  into  his  primitive  darkness,  on  the  plea  that  all 
these  changes  are  so  many  artificial  sophistications.^  Water  is,  un- 
questionably, sufficient  for  all  his  wants;  but  the  moderate  use  of 
fermented  liquors,  even  if  habitual,  except  in  particular  constitutions, 
is  devoid,  we  think,  of  every  noxious  result.  They  are  grateful ;  and 
many  of  them  are  even  directly  nutritious  from  the  undecomposed 
sugar  and  mucilage  which  they  contain.  For  this  reason  beer  has  been 
termed,  not  inaptly,  "  liquid  bread."*  With  regard  to  distilled  spirits, 
no  evil  would  result  from  their  total  rejection  from  the  table.  Although 
they  may,  by  their  action  on  the  digestive  organs,  be  indirect  means  of 
nutrition,  they  contain  no  alimentary  principle.  They  are  received  into 
the  vessels  of  the  stomach  by  imbibition ;  and  always  produce  undue 
stimulation,  when  taken  to  any  amount.  This  may  be  productive  of 
little  or  no  mischief,  provided  they  be  only  used  occasionally ;  but,  if 
taken  habitually  and  freely,  serious  visceral  disorder  may  sooner  or 
later  ensue. 

^  Lastly, — There  are  certain  substances  called  condiments  employed  in 
diet,  not  simply  because  they  are  nutritive, — for  many  of  them  possess 
no  such  properties, — but  because,  when  taken  with  food  capable  of 
nourishing,  they  promote  its  digestion,  correct  some  injurious  property, 
or  add  to  its  sapidity.  Dr.  Paris  has  divided  these  into  saline,  spicy  or 
aromatic,  and  oily.  It  may  be  remarked,  however,  that  certain  articles 
are  called,  at  times,  aliments ;  at  others,  condiments,  according  as  they 
constitute  the  basis  or  the  accessory  to  any  dish ; — such  are  cream, 
butter,  mushrooms,  olives,  ka.   The  advantage  of  condiments  in  animal 

•  Op.  cit.,  p.  189.  \i^ 

2  Sue  an  article  by  the  author  in  the  American  Quarterly  Review,  ii.  422,  Thilad., 
1827;  and  Fletcher,  op.  citat.,  p.  121. 

3  Kitchener,  Invalid's  Oracle,  Amer.  edit.,  p.  136,  New  York,  1831. 


FOOD   OF   MAN.  119 

digestion  is  exemplified  by  many  cases.  The  bitter  principle,  wliicli 
exists  in  grasses  and  other  plants,  appears  to  be  essential  to  the  diges- 
tion of  the  herbivora, — acting  as  a  natural  stimulant ;  and  it  has  been 
found  that  cattle  do  not  thrive  upon  grasses  which  are  destitute  of  it. 
Of  the  value  of  salt  to  the  digestive  function  of  his  cattle,  the  agricul- 
turist has  ample  experience ;  and  the  salt  licks  of  our  country  show 
how  grateful  this  natural  stimulant  is  to  the  beasts  of  the  forests. 
Charcoal,  administered  with  fat, — as  is  done,  in  rural  economy  for  fat- 
tening poultry,  in  many  parts  of  England, — exhibits  the  advantage  of 
administering  a  condiment ;  the  charcoal  of  itself  contains  no  nourish- 
ment, bat  it  puts  the  digestive  function  in  a  condition  for  separating 
more  nutritious  matter  from  the  food  taken  in,  than  it  could  otherwise 
do.  A  similar  effect  is  produced  by  the  plan, — adopted  for  the  same 
purpose  in  certain  parts  of  Great  Britain, — of  cramming  the  animal 
with  walnuts,  coarsely  bruised,  with  the  shell.  This  is  asserted,  by 
many  rural  economists,  to  be  the  most  effectual  plan  for  fattening  poul- 
try speedily  ;  the  coarse  shell,  in  passing  along  the  mucous  membrane 
of  the  intestines,  seems  to  stimulate  it  to  augmented  action,  and  a  more 
bountiful  separation  of  nutritious  matter  is  the  consequence.  The 
aromatic  condiments  act  in  a  similar  manner. 

In  regard  to  the  quantity  of  food  required  for  human  sustenance, 
nothing  definite  can  be  laid  down.  It  must  differ  according  to  habit, 
constitution,  way  of  life,  age,  sex,  &c.  The  diet  scale  of  the  British, 
navy  affords  a  good  average  for  the  adult  male  in  busy  life,  who 
requires  more  aliment  than  those  in  less  active  employment.  It  con- 
sists of  from  31  to  35|  ounces  of  dry  nutritious  matter  daily;  of  which 
26  ounces  are  vegetable  and  the  rest  animal, — 9^  ounces  of  salt 
meat,  or  4|-  ounces  of  fresh,  being  the  proportion  of  the  latter.  This 
is  found  to  be  an  ample  allowance.  That  of  the  navy  of  the  United 
States  consists,  four  days  in  the  week,  of  about  45  ounces ;  of  which 
about  29  ounces  are  vegetable,  and  the  rest  a}iimal, — the  other  three 
days,  of  about  40  ounces,  of  which  about  24  ounces  are  vegetable,' — 
the  vegetable  matters  consisting  of  beans  or  peas,  biscuit,  pickles, 
cranberries,  sugar,  tea,  flour,  dried  fruit,  and  rice,  an  admixture  of 
nitrogenized  and  non-nitrogenized  articles,  which,  under  ordinary  cir- 
cumstances, is  amply  suflicient  for  full  nutrition;  for,  true  scurvy 
appears  to  be  caused  by  a  deficient  supply  not  only  of  nitrogenized 
food,  but  of  the  organic  acids  or  salts  of  fresh  vegetables ;  and  one  of 
the  best  of  these,  although  not  the  most  palatable,  is  the  raw  potato.^ 

In  prisons  a  reduction  must  be  made.  In  a  convict  ship,  which  took 
out  433  prisoners  to  New  Holland,  in  1802,  the  mortality  was  trifling, 
and  the  general  health  good,  although  the  prisoners  were  allowed  only 
16  ounces  of  vegetable  food,  and  7|  ounces  of  animal  food  per  day. 
Whenever  the  allowance  is  more  restricted,  or  a  due  admixture  of  ani- 
mal and  vegetable  food  is  not  permitted,  the  health  suffers,  and  signs 
of  scorbutus  appear; — a  result  occasionally  witnessed  in  our  public 
eleemosynary  institutions,  when  under  the  care  of  ignorant  and  too 

'  The  author's  Diet,  of  Med.  Science,  art.  Diet,  12th  edit.,  p.  293,  Philad.,  1855. 
^  See  a  good  article  on  the  causation  of  scurvy  iu  tlie  Briti,^h  and  Foreign  Medico- 
Cliirurgical  Review,  IV.,  439,  Loud.,  1S4S. 


120  DIGESTION. 

economical  superintendents.  It  would  seem,  from  the  experiments  of 
M.  Chossat,  tliat  under  such  circumstances  an  incapabilit}^  is  induced 
of  digesting  even  the  inadequate  amount  supplied. 

The  smallest  quantity  of  food  upon  which  life  is  known  to  have 
been  actively  supported  was  in  the  case  of  Cornaro,  who  affirms  that 
he  took  no  more  than  12  ounces  a  day,  and  that  chiefly  vegetable,  for 
a  period  of  sixty-eight  years.  Of  the  amount  that  can  be  eaten  by  the 
glutton,  we  have  surprising  instances  on  record, — the  stomach  acquir- 
ing, at  times,  an  enormous  capacity.  Captain  Parry  relates  the  case 
of  a  young  Esquimaux,  who  was  permitted  to  devour  as  much  as  he 
chose.  It  amounted,  in  the  twenty -four  hours,,  to  thirty-five  pounds 
of  various  kinds  of  aliment,  including  tallow  candles;  and  a  case  has 
been  published  of  a  Hindoo,  who  could  eat  a  whole  sheep  at  a  time. 

These  few  remarks  on  the  food  of  man  will  serve  as  an  introduction 
to  the  mode  in  which  the  various  digestive  processes  are  accomplished. 
The  more  intimate  consideration  of  alimentary  substances,  with  their 
comparative  digestibility,  &c.,  will  be  found  in  another  work  of  the 
author,  to  which  the  reader  is  referred.^ 

3.    PHYSIOLOGY  OF  DIGESTION. 

The  detail  entered  into  re2:arding  the  various  organs  concerned  in 
digestion  will  have  led  to  the  anticipation,  that  the  history  of  the  func- 
tion must  be  multiple  and  complex.  The  food  is  not,  in  the  case  of  the 
animal — as  it  is  in  that  of  the  vegetable — placed  in  immediate  contact 
wdth  the  being  to  be  nourished;  an  act  of  volition  is,  consequently, 
necessary  to  procure  and  to  convey  it  to  the  upper  orifice  of  the  di- 
gestive tube.  This  act  of  volition  is  excited  .by  an  internal  sensation 
— that  of  hunger — which  indicates  the  necessity  for  taking  fresh  nour- 
ishment into  the  system.  The  appetite  and  hunger,  with  the  prehension 
or  reception  of  food,  must  therefore  be  regarded  as  part  of  the  digestive 
ojDerations.  These  may  be  enumerated  and  investigated  in  the  follow- 
ing order: — 1st.  Hunger^  or  the  sensation  that  excites  us  to  take  food. 
2dly.  Prehension  of  food,  the  voluntary  muscular  action,  that  introduces 
it  into  the  mouth.  3rdly.  Oral  or  buccal  digestion,  comprising  the  changes 
w^rought  on  the  food  in  the  mouth.  4:thly.  Deglutition,  or  the  part  taken 
by  the  pharynx  and  oesophagus  in  digestion.  5thly.  Chymi/icatio7i,  or 
the  action  of  the  stomach  on  the  food.  6thly.  The  action  of  the  small 
intestine.  7thly.  The  action  of  the  large  intestine.  And,  Sthly.  Defeca- 
tion or  the  exjmlsion  of  the  fceces.  All  these  processes  are  not  equally 
concerned  in  the  formation  of  chyle.  It  is  separated  in  the  small  in- 
testine: the  first  six,  therefore, belong  to  it; — the  remainder  relate  only 
to  the  excrementitious  part  of  the  food.  The  digestion  of  solid  food 
requires  all  the  eight  processes:  that  of  liquids  is  more  simple;  com- 
prising only  thirst,  prehension,  deglutition,  the  action  of  the  stomach, 
and  that  of  the  small  intestine.    Fluid  rarely  reaches  the  large  intestine. 

In  inquiring  into  this  important  and  interesting  function,  we  shall 
first  attend  to  the  digestion  of  solids,  and  afterwards  to  that  of  liquids. 

'  Human  Health,  p.  179,  Philad.,  1844.  For  different  dietaries,  &c.,  see  Pereira, 
Treatise  on  Food  and  Diet,  Amer.  edit.,  by  Dr.  C.  A.  Lee,  p.  222,  New  York,  1843;  and 
Art.  Diet  Scale,  in  tlie  author's  Med.  Dictionary,  7th  edit.,  Philad.,  1S4S. 


HUNGER.  121 

4.    DIGESTION  OF  SOLID  FOOD. 

a.  Hunger. 

Hunger  is  an  internal  sensation,  the  seat  of  whicli  is  invariably  re- 
ferred to  the  stomach.  Like  every  internal  sensation,  it  proceeds  from 
changes  in  the  very  texture  of  the  organ.  It  is  not  produced  by  any 
external  cause;  and  to  it  are  applicable  all  those  observations,  that  are 
elsewhere  made  on  internal  sensations  in  o-eneral.  In  its  slio-htest  con- 
dition,  it  is  merely  an  appetite  (optlij;  Germ.  Esslust);  but  if  this  be 
not  heeded,  the  painful  sensation  of  hunger  {Fames^  ?Ltjuo$),  supervenes, 
which  becomes  more  and  more  acute  and  lacerating  unless  food  is  taken. 
If  this  be  the  case,  however,  the  uneasiness  gradually  abates;  and  if 
sufficient  be  eaten,  a  feeling  of  satiety  is  produced.  The  sensation 
usually  occurs,  in  the  healthy  state,  after  the  stomach  has  been  for 
some  time  empty,  having  finished  the  digestion  of  substances  taken  in 
at  the  previous  meal.  Habit  has  a  great  effect  in  regulating  this  recur- 
rence ;  the  appetite  always  appearing  about  the  time  at  which  the  sto- 
mach has  been  accustomed  to  receive  food.  This  artificial  desire  may 
be  checked  by  various  causes; — by  the  exciting  or  depressing  passions, 
the  sight  of  a  disgusting  object,  or  any  thing  that  occasions  intense 
mental  emotion ;  or  it  may  be  appeased  by  filling  the  stomach  with 
substances  that  contain  no  nutritious  properties.  As,  however,  the 
feeling  of  true  hunger  arises  from  the  wants  of  the  system,  the  natural 
and  instinctive  sensation  soon  appears,  and  cannot  be  long  postponed 
by  any  of  these  means.  Hence,  it  has  been  proposed  to  make  a  dis- 
tinction between  appetite  and  liunger;  applying  the  former  term  to  the 
artificial,  the  latter  to  the  natural,  desire.  In  these  respects,  there  is 
certainly  a  wide  distinction  between  them,  as  well  as  in  the  capricious- 
ness,  which  occasionally  characterizes  the  former,  and  gives  rise  to 
singular  and  fantastic  preferences. 

The  sensation  of  hunger  varies  in  intensity  according  to  different 
circumstances.  It  is  more  powerful  in  the  child  and  youth  than  in  one 
who  has  attained  his  full  height.  In  the  period  of  second  childhood, 
it  is  urgent, — probably  owing  to  the  diminished  power  of  assimilation 
requiring  that  more  aliment  should  be  received  into  the  stomach.  In 
disease,  the  sensation  is  generally  suppressed,  and  its  place  often  sup- 
plied by  loathing  or  disgust  for  food :  at  times,  again,  its  intensity 
makes  it  a  phenomenon  of  disease,  as  in  bulimia,  and  pica;  in  the 
latter  of  which,  the  appetite  is,  at  times,  irresistibly  directed  to  sub- 
stances, which  the  person  never  before  relished,  or  are  not  edible, — as 
chalk,  earth,  slate-pencil,  &c.,  a  prominent  symptom  of  chlorotic  and 
African  cachexia.  The  appetite  is  also  modified  by  exercise  or  in- 
activity, and  other  circumstances,  extrinsic  and  intrinsic, — regular  exer- 
cise, and  the  exhilarating  passions ;  a  cold  and  dry  atmosphere,  &c., 
augmenting  it,  whilst  it  is  blunted  by  opposite  circumstances.  Long 
continued  exertion,  with  a  scanty  supply  of  nourishment,  if  not  con- 
tinued so  long  as  to  injure  the  tone  of  the  stomach,  produces,  occasion- 
ally, in  adults,  a  voracious  appetite  and  rapid  digestion.  Mr.  Hunter 
has  quoted,  in  illustration  of  this  point,  the  following  extract  from 
Admiral  Byron's  narrative.  After  describing  the  privations  he  had 
suffered  when  shipwrecked  on  the  coast  of  South  America,  the  Admiral 


122  DIGESTIO:^. 

incidentally  refers  to  tlieir  effect  upon  his  appetite.  "The  governor 
ordered  a  table  to  be  spread  for  us  with  cold  bam  and  fowls,  which 
only  we  three  sat  down  to,  and  in  a  short  time  despatched  more  than 
ten  men  mth  common  appetites  would  have  done.  It  is  amazing,  that 
our  eating  to  that  excess  we  had  done  from  the  time  we  first  came 
among  these  kind  Indians  had  not  killed  us,  as  we  were  never  satisfied, 
and  used  to  take  all  opportunities  for  some  months  after,  of  filling  our 
pockets,  when  we  were  not  seen,  that  we  might  get  up  two  or  three 
times  in  the  night  to  cram  ourselves."^ 

Authors  have  distinguished  the  local  from  the  general  phenomena 
of  hunger;  but  many  of  their  assertions  on  these  points  appear  ima- 
ginative. We  are  told  by  M.  Adelon^  and  others,^  that  the  stomach 
becomes  contracted,  and  that  this  change  is  effected  by  the  action  of 
its  muscular  coat  alone; — the  mucous  or  lining  membrane  beconjing 
wrinkled,  and  the  peritoneal  coat,  externally,  permitting  the  organ  to 
retire  between  its  laminae.  Such,  MM.  Tiedemann  and  Gmelin^  assert, 
is  the  result  of  their  observations.  M.  Magendie,^  however,  afiGirms, 
that  after  twenty-four,  forty-eight,  and  even  sixty  hours  complete 
abstinence,  he  has  never  witnessed  this  contraction  of  the  organ.  It 
had  always  considerable  dimension,  especially  in  its  splenic  portion; 
and  not  until  after  the  fourth  or  fifth  day  did  it  appear  to  him  to  close 
upon  itself,  diminish  greatly  in  capacity,  and  slightly  change  its  posi- 
tion; and  these  effects  were  not  observed  unless  the  fasting  was  rigor- 
ouslj''  maintained. 

At  the  time  that  the  stomach  changes  its  shape  and  situation,  the 
duodenum  is  said  to  be  drawn  slightly  towards  it;  its  parietes  appear 
thicker, — and  the  mucous  follicles  and  nervous  papillae  project  more 
into  the  interior.  Its  cavity  is  void  of  food,  and  contains  only  a  little 
saliva,  mixed  with  bubbles  of  air;  a  small  quantity  of  mucus;  and, 
according  to  some,  a  little  bile  and  pancreatic  juice,  which  the  traction 
of  the  duodenum  has  caused  to  flow  into  it. 

Much  dispute  has  arisen  as  to  whether  the  circulation  of  the  blood 
in  the  stomach  experiences  any  mutation.  M.  Dumas^  was  of  opinion, 
that  when  the  organ  is  empty,  it  receives  less  blood  than  when  full ; 
either  on  account  of  the  great  flexion  of  the  vessels  in  the  former  case, 
or  on  account  of  the  compression  experienced  by  the  nerves  in  conse- 
quence of  the  contracted  state  of  the  organ.  He  thinks  that,  under 
such  circumstances,  a  part  of  the  blood  sent  to  it  reflows  into  the  liver, 
spleen,  and  omentum;  and  he  regards  these  organs  as  diverticula  for 
the  blood  of  the  stomach,  especially  as  the  liver  and  spleen  are  then 
less  compressed,  and  the  omentum  is  more  extensive,  owing  to  the 
retraction  of  the  stomach.  Bichat,  however,  denies  both  the  fact  and 
its  explanation.  He  affirms,  that  on  opening  animals  suffering  under 
hunger,  he  never  observed  the  vessels  of  the  stomach  less  full  of  blood, 
the  mucous  membrane  less  florid,  or  the  vessels  of  the  omentum  more 

■  Bvron's  Voyage,  p.  181 ;  and  Hunter  on  the  Animal  Economy,  p.  196. 
^  riiysiologie  de  rtlomme,  ii.  39i3. 

8  Riillier,  Art.  Paim,  in  Diet,  de  Midecine,  torn,  viii.,  Paris,  1823. 
■»  Die  Verdauung  nach.  Versuclieu,  u.  s.  w. ;  or  French  translation,  by  A.  J.  L.  Jour- 
dan,  Paris,  1827. 

*  Op.  citat.,  ii.  25.  6  Principes  de  Pliysiologie,  Paris,  1806. 


HUNGEK.  123 

turgid.  Is  it  not  true,  he  adds,  that  the  vessels  of  the  stomach  are 
more  flexuous  when  the  organ  is  empty ;  being,  as  well  as  the  nerves, 
connected  with  the  serous  coat,  they  are  unaffected  by  changes  of  size 
in  the  organ;  and  besides,  the  retraction  of  the  stomach  could  never 
be  great  enough  to  compress  the  nerves.  He  denies,  moreover,  that 
the  liver  and  spleen  are  more  free,  and  the  omentum  larger,  whilst  the 
stomach  is  empty,  as  the  abdominal  parietes  contract  in  the  same  pro- 
portion as  the  stomach.  Magendie,^  however,  contests  this  last  asser- 
tion of  Bichat ;  and  affirms,  on  the. faith  of  positive  experiments,  that 
the  pressure  sustained  by  the  abdominal  viscera  is  in  a  ratio  with  the 
distension  of  the  stomach.  If  the  stomach  be  full,  the  linger,  intro- 
duced into  the  cavity  of  the  abdomen  through  an  incision  in  its  parie- 
tes, will  be  strongly  pressed  upon,  and  the  viscera  forced  towards  the 
opening;  whilst,  if  it  be  empty,  the  pressure  as  well  as  the  tendency 
of  the  viscera  to  escape  through  the  opening  is  considerable.  During 
the  state  of  vacuity  of  the  organ,  he  remarked  that  the  different  reser- 
voirs in  the  cavity  of  the  abdomen, — the  bladder  and  gall  bladder, — 
were  more  easily  filled  by  their  proper  fluids.  With  regard  to  the 
quantity  of  blood  circulating  through  the  stomach  in  the  empty  and 
full  state, — he  is  disposed  to  believe,  that  the  organ  receives  less  in 
the  former  condition;  but  that  in  this  respect  it  does  not  differ  from 
other  abdominal  viscera. 

The  general  effects,  said  to  be  produced  by  hunger,  in  contradistinc- 
tion to  the  local,  are; — debility  and  diminished  action  of  every  organ; 
the  circulation  and  respiration  are  less  frequent ;  the  heat  of  the  body 
sinks;  the  secretions  diminish,  and  all  the  functions  are  exerted  with 
more  difficulty,  if  we  except  absorption,  which  it  is  affirmed,  and  with 
much  probability,  is  augmented.  If  the  abstinence  be  so  long  pro- 
tracted as  to  cause  death,  the  debility  of  the  functions  becomes  real, 
and  not  sympathetic.  Eespiration  and  circulation  languish;  all  the 
animal  functions  totter;  whilst  absorption  continues,  and  the  blood  is 
supplied  by  the  decomposition  of  the  different  organs, — the  fat,  the 
various  liquid  matters  and  the  tissues  of  the  organs  being  successively 
subjected  to  its  action.  It  is  obvious,  however,  that,  with  the  drain 
perpetually  taking  place,  this  state  of  affairs  cannot  exist  long;  the 
blood  becomes  diminished  in  quantity,  and  insufficient  in  every  respect 
to  vivify  the  organs;  the  functions  of  the  brain  are  perverted,  and,  in 
many  instances,  furious  delirium  has  closed  the  scene ;  whilst,  at 
others,  the  miserable  sufferer  has  sunk  passivel}''  into  the  sleep  of 
death.  Occasionally,  again,  so  dreadfully  painful  are  the  sensations 
caused  by  protracted  privation  of  food,  that  the  most  violent  antipa- 
thies and  dearest  affections  have  been  overcome;  and  numerous  in- 
stances have  occurred  in  which  the  sufferer  has  attacked  his  own 
species,  friends,  children,  and  even  his  own  person.  The  horrible 
picture  of  the  shipwreck,  by  B3aT>n,^  is  not  a  mere  romance.  It  is  a 
narrative  of  facts  that  have  actually  occurred,  expanded  somewhat  by 
the  imagination  of  the  poet. 

Dr.  James  Currie^  has  related  the  case  of  a  person,  who  died  of 

'  Precis,  &c.,  edit,  cit.,  ii.  26.  ^  Don  Juan,  canto  ii.  58. 

^  Medical  Reports,  &c.,  Amer.  edit.,  Pliilad.,  1808. 


124  DIGESTIOX. 

inanition  from  stricture  of  the  oesophagus,  the  particulars  of  which 
may  exemplif}^  the  phenomena  presented  by  some  of  those  who  perish 
from  abstinence.  The  records  of  such  cases  are  rare.  From  the  17th 
of  October  to  the  6tli  of  December,  the  patient  was  supported,  without 
the  aid  of  the  stomach,  by  means  of  broth  clysters;  and  was  immersed 
in  a  bath  of  milk  and  water.  At  one  period  he  had  a  parched  mouth : 
a  blister  discharged  only  a  thin,  coagulable  h'mph ;  and  the  urine  was 
scanty,  extremely  high-colored,  and  intolerably  pungent.  The  heat 
of  the  body  was  natural  and  nearly  uniform  from  first  to  last ;  and  the 
pulse  was  perfectly  natural  until  the  last  days.  His  sleep  was  sound 
and  refreshing;  spirits  even;  and  intellect  unimpaired,  until  the  last 
four  days  of  existence,  when  clysters  were  no  longer  retained.  Vision 
was  deranged  on  the  first  of  December,  and  delirium  followed  on  the 
succeeding  day ;  yet  the  eye  was  unusually  sensible,  and  the  sense  of 
touch  remarkably  acute.  The  surface  and  extremities  were  at  times 
of  a  burning  heat;  at  others,  clammy  and  cold.  On  the  fourth,  the  pulse 
became  feeble  and  irregular,  and  respiration  laborious;  and,  in  ninety- 
six  hours  after  all  means  of  nutrition  as  well  as  medicine  had  been 
abandoned,  he  ceased  to  breathe.  He  was  never  much  troubled  by 
hunger.  Thirst  was,  at  first,  troublesome,  but  it  was  relieved  by  the 
tepid  bath.  This  was  a  case  in  which  the  patient  sank  tranquill}^  to 
death.  In  others,  the  distressing  accompaniments  above  described 
are  met  with ;  and  the  death  is  that  of  a  furious  maniac. 

The  period  at  which  the  fatal  event  may  occur  from  protracted  absti- 
nence is  dependent  on  many  circumstances.  As  a  general  rule  the 
young  and  robust  will  expire  sooner  than  the  older ;  and  this  will  have 
to  be  our  guidance  in  questions  of  survivorship,  where  several  indi- 
viduals have  perished  together  from  this  cause.  Tlie  picture,  drawn 
by  Dante  of  the  sufferings  and  death  of  Count  Ugolino  della  Gherar- 
descha,  who  saw  his  sons  successively  expire  before  him  from  hunger, 
is  in  this  respect  true  to  nature. 

"  Now  when  our  fourth,  sad  morning  was  renew'd, 
Gaddo  fell  at  my  feet,  outstretch'd  and  cold, 
Crying : — '  Wilt  thou  not,  father !  give  me  food  ?' 

There  did  he  die ;  and  as  thine  eyes  behold 
Me  now.  so  saw  I  three  fall,  one  by  one, 
On  the  fifth  day  and  sixth ;  whence  in  that  hold, 

I,  now  grown  blind,  over  each  lifeless  son 

Stretch'd  forth  mine  arms.     Three  days  I  called  their  names. 
Then  Fast  achieved  what  Grief  not  yet  had  done." 

"IxFERXO,"  canto  xxxiii. 

_  In  some  experiments  on  inanition  undertaken  by  M.  Chossat,^  on 
pigeons  and  turtle  doves,  the  following  general  phenomena  were  ob- 
served. Commonly,  the  animal  remained  calm  during  the  first  lialf  or 
two-thirds  of  the  period.  It  then  became  more  or  less  agitated,  and 
this  state  continued  as  long  as  the  temperature  remained  elevated. 
On  the  last  day  of  life,  however,  the  restlessness  ceased,  and  gave  place 
to  stupor.  When  set  at  liberty,  it  sometimes  looked  round  with 
astonishment,  without  attempting  to  fly,  and  at  times  closed  its  eyes, 
as  if  in  a  state  of  sleep.     Gradually,  the  extremities  became  cold,  and 

'  Recherches  Experimentales  sur  I'lnanition,  Paris,  1343 ;  noticed  in  Brit,  and  For. 
Med.  Ilev.,  April,  1844,  p.  347. 


HUNGER. 


125 


the  limbs  so  weak  as  to  be  no  longer  able  to  sustain  it  in  the  standing 
posture.  It  fell  over  on  one  side,  and  remained  in  any  position  in 
■\vhicli  it  might  be  placed,  without  attempting  to  move.  Kespiration 
became  slower  and  slower;  the  general  weakness  increased,  and  the 
insensibility  became  more  profound ;  the  pupils  dilated ;  and  life  be- 
came extinct. — at  times  in  a  calm  and  tranquil  manner ;  at  others,  after 
convulsive  actions,  producing  opisthotonic  rigidity  of  the  body. 

He  tried  to  discover  the  effect  of  age  in  modifying  the  continu- 
ance of  life  during  inanition,  but  was  unable  to  ascertain  the  re- 
lative ages  of  the  turtle  doves,  the  subjects  of  his  experiments ;  he 
endeavoured,  however,  to  form  some  estimate — although,  obviously,  a 
fallacious  one — from  their  relative  weights,  classing  them  as  "young," 
"  middle-aged,"  or  "  adult,"  according  as  their  weights  were  beneath 
120  grammes,  from  120  to  160,  or  above  160.  The  following  table  is 
interesting,  'however,  by  showing  the  duration  of  life,  and  the  loss  of 
substance  during  inanition,  in  animals  of  different  weights. 


WEIGHT  OF  THE  BODT. 

LOSS  OF  THE  BODT. 

Duration 
of  life. 

Weight  at 

commeuce- 

ment. 

Weight  at 
death. 

Entire  ah.so- 
lute  loss. 

Proportional 

less  in  1000 

part.s. 

Daily  propor- 
tional loss. 

a.  Young  .  .  . 
h.  Middle-aged 
c.  Old    .... 

Gram. 

110-42 
143-62 
189-36 

Gram. 

82-84 

91-60 

101-61 

Gram. 

27-58 
52-02 

87-75 

0-250 
0-362 
0-463 

0-081 
0-059 
0-035 

3-07 

6-12 

13-36 

The  entire  absolute  loss,  and  the  proportionate  loss,  were  much 
greater  in  the  heavier  animals;  the  daily  loss  was  by  much  the  most 
rapid  in  the  lightest ;  and  it  is  probable,  that  this  was  owing  to  the 
more  rapid  waste  which  takes  place  in  the  young. 

The  sensation  of  hunger  resembles  every  other  sensation  in  the  mode 
in  which  it  is  accomplished.  There  must  be  impression,  conduction, 
and  perception.  That  the  encephalon  is  the  organ  of  the  last  part  of 
the  process  is  proved  by  all  the  arguments  used  in  the  case  of  the 
internal  sensations  in  general.  Without  its  intervention  in  this,  as  in 
every  other  case,  no  sensation  can  be  accomplished.  The  stomach  is 
the  organ  in  which  the  impression  is  effected;  and  by  means  of  the 
nerves  this  impression  is  conveyed  to  the  spinal  marrow  and  encepha- 
lon. The  eighth  pair  or  pneumogastric  nerves  have  generally  been 
regarded  as  the  agents  of  this  transmission ;  and  it  has  been  affirmed 
by  Baglivi,  Valsalva,  Haller,  Dumas,  Legallois,  Chaussier,  and  others, 
that  if  they  be  divided  in  the  neck,  although  the  stomach  may  be 
favourably  circumstanced,  in  other  respects,  for  the  developement  of 
the  impression  of  hunger,  and  the  encephalon  for  its  reception,  there 
is  no  sensation;  but  MM.  Leuret  and  Lassaigne,'  Dr.  John  Eeid,^ 
Nasse,^  and  Longet,*  tleny,  that  such  effect  follows  the  division  of  these 

'  Recherclies  Pliysiologiques  et  Cliiiniques  pour  servir  a  I'Histoire  de  la  Digestion 
Paris,  1825. 

^  Edinb.  Med.  and  Surg.  Journal,  April,  1839,  and  art.  Par  Vacum,  in  Cj-clop.  of 
Anat.  and  Physiol.,  Pt.  xxviii.  p.  899,  Lond.,  April,  1847. 

"  Untersuchungen  zur  Physiologie  und  Pathologie,  Bonn,  1835-6. 

"  Traite  de  Physiologic,  ii.  342,  Paris,  1850. 


126  DIGESTION. 

nerves ;  and  the  first  gentlemen  affirm,  that  horses  have  eaten  as  usual,! 
and  apparently  with  the  same  appetite,  after  they  had  removed  severalj 
inches  of  the  pneuraogastric  nerves;  and  even  continued  to  eat  afterj 
the  stomach  was  filleft  To  these  experiments  we  shall  have  occasion 
to  refer  hereafter.  They  by  no  means,  however,  exhibit  that  this  in-| 
ternal  sensation  differs  in  its  essence  from  others. 

A  difficulty,  which  the  physiologist  has  always  felt,  concerns  thei 
precise  nature  of  the  action  of  impression.  Its  seat  is  clearly  in  thej 
stomach.  This  was  shown  incontestably  by  a  case  of  fistulous  open- 
ing into  the  organ,  which  fell  under  the  care  of  Dr.  Beaumont,  and  to 
which  there  will  be  frequent  occasion  to  refer.  When  the  subject  of 
this  case  was  made  to  fast  until  his  appetite  was  urgent,  it  was  imme- 
diately assuaged  by  feeding  him  through  the  aperture.  To  the  sto- 
mach, indeed,  all  our  feelings  refer  the  sensation.  It  is  dependent 
upon  some  modification  occurring  in  the  very  tissue  of  the  viscus; 
and  in  the  nerves,  which,  as  has  been  shown,  are  the  sole  agents  in  all 
phenomena  of  sensibility.  These  nerves  are  spread  over  the  stomach, 
so  that  the  precise  seat  of  the  impression  cannot  be  as  accurately  de- 
fined as  in  the  case  of  the  organs  of  external  sense.  Moreover,  the 
nerves  of  the  stomach  proceed  from  two  essentially  different  sources, — ■ 
the  eighth  pair,  and  great  sympathetic.  The  question  consequently 
arises: — on  which  of  these  is  the  impression  made?  The  results  of 
the  experiment  of  cutting  the  eighth  pair  in  the  neck  would  appear 
to  decide  in  favour  of  the  former. 

As  to  the  proximate  or  efficient  cause  of  hunger,  we  cannot  expect 
to  arrive  at  any  satisfactor}^  conclusion.  It  is  a  sensation;  and,  like 
all  sensations,  inscrutable.'  Theories,  however,  as  on  all  obscure 
topics,  have  been  numerous,  and  these  have  generally  been  of  a  me- 
chanical or  a  chemical  nature.  Some  have  attributed  it  to  the  mecha- 
nical friction  of  the  parietes  of  the  stomach  against  each  other,  in 
consequence  of  its  contraction;  in  which  state,  they  affirm,  the  mucous 
coat  is  rugous,  and  its  papillae  and  follicles  prominent.  It  is  manifest, 
however,  from  the  structure  of  the  organ,  that  no  such  friction  can 
take  place.  Yet  this  view  was  embraced  by  Haller.^  Dr.  Fletcher^ 
ascribes  it  to  a  kind  of  permanent  though  partial  contraction  of  the 
muscular  fibres  of  the  stomach ; — "  not  that  alternate  general  contrac- 
tion and  relaxation,  which  produces  a  sensible  motion  of  this  organ, 
nor  that  permanent  general  contraction,  which  would  serve  to  dimi- 
nish its  cavit}'',  but  that  kind  of  permanent  contraction,  which  takes 
place  in  certain  fibres  alone,  and  perhaps  through  a  part  of  their  length 
only,  and  by  which  these|^bres  are,  as  it  were,  drawn  away  from  the 
others,  or,  in  other  words,  a  minor  degree  of  cramp."  Others,  again, 
have  accounted  for  the  sensation  by  the  action  of  the  gastric  juice, 
which  is  supposed  to  have  a  tendency  to  irritate  the  internal  mem- 
brane. In  proof  of  this,  they  refer  to  a  case,  mentioned  by  ]\Ir.  Hun- 
ter, in  which  the  mucous  membrane,  in  a  man  who  died  of  fasting, 
was  found  corroded.    The  gastric  j  nice  is,  however,  incapable  of  eroding 

'  J.  Beclard,  Traite  elementaire  de  Physiologie,  p.  26,  Paris,  1855. 

2  Element.  Physiol.,  lib.  xix.,  sect.  2,  §  12,  Bern.,  1764. 

3  Rudiments  of  Physiology,  Part  iii.,  by  Dr.  Lewins,  p.  73,  Edinb.,  1837.- 


PEEHENSIOX   OF   FOOD.  127 

living  animal  matter;  and  the  numerous  cases,  wliicli  have  occurred 
since  that  of  Hunter,  have  shown,  that  the  corrosion  and  perforation, 
which  we  meet  with  on  dissection,  may  be  referred  to  an  action  after 
death,  and  be  totally  unconnected  with  the  sensation  felt  during  life. 
We  have,  indeed,  no  reason  for  believing,  that  the  gastric  juice  can 
ever  attain  a  state  of  acridity,  and  affect  physically  the  surface  by 
which  it  is  secreted.  It  has  been  remarked,  that  it  is  a  law  of  the 
animal  economy,  that  no  secretion  acts  upon  the  part  over  which  it  is 
destined  to  pass,  provided  such  part  be  in  a  healthy  condition.  Yet 
Stimmering^  ascribes  the  pain  from  long-continued  fasting  to  the  action 
of  the  gastric  juice;  and  Dr.  Wilson  Philip^  is  manifestly  induced  to 
believe  that  its  influence  on  the  stomach  is,  in  some  mode  or  other, 
productive  of  the  sensation :  his  remarks,  however,  tend  simply  to 
show, — what  we  have  so  many  opportunities  for  observing,  that  the 
sensation  can  be  postponed  by  exciting  vomiting,  or  inducing,  for  the 
time,  a  morbid  condition  of  the  stomach. 

The  unanswerable  objection  to  all  these  views  is  the  fact — repeatedly 
proved  by  Dr.  Beaumont,^  and  which  the  author  had  an  opportunity 
of  observing — that,  in  the  fasting  state  there  is  little  or  no  gastric 
juice  in  the  cavity  of  the  stomach.  Dr.  Beaumont  thinks,  that  the 
sensation  of  hunger  is  produced  by  distension  of  the  vessels,  that 
secrete  the  solvent ;  but  such  distension,  if  it  exist — which  is  by  no 
means  proved — must  itself  be  consecutive  on  the  nervous  condition 
that  engenders  the  sensation:  the  efficient  cause  of  such  condition  has 
still  to  be  explained. 

Bichat,  again,  attributed  it  to  the  lassitude  or  fatigue  of  the  stomach, 
occasioned  by  the  contraction  of  its  muscular  coat  when  continued 
beyond  a  certain  time.  In  answer  to  this,  it  may  be  remarked,  that 
if  any  thing  impedes  the  nutrition  of  the  body,  hunger  continues, 
although  the  stomach  may  be  distended.  This  happens  in  cases  of 
scirrhous  pylorus,  where  the  nutritive  mass  cannot  pass  into  the  small 
intestine,  to  be  subjected  to  the  action  of  the  chyliferous  vessels,  and 
the  losses  of  the  body  cannot,  therefore,  be  repaired ; — facts  which 
would  seem  to  show,  that  hunger  is  a  sensation  excited  in  the  stomach 
by  sympathy  with  the  wants  of  the  constitution ;  and  that  it  is  imme- 
diately produced  by  some  inappreciable  alteration  in  the  condition  of 
the  nerves  of  the  organ.  It  appears,  from  the  experiments  of  M.  Ma- 
gendie,^  that  when  the  cerebrum  and  a  great  part  of  the  cerebellum 
were  removed  in  ducks,  the  instinct  of  seeking  food  was  lost  in  every 
instance,  and  the  instinct  of  deglutition  in  many :  food,  however,  in- 
troduced into  the  stomach,  was  found  to  be  digested. 

b.  Prehension  of  Food. 

The  arms  and  mouth  have  been  described  as  organs  of  prehension. 
It  is  scarcely  necessary  to  say,  that  the  hands  seize  the  food  and  convey 
it  to  the  mouth  under  ordinary  circumstances ;  but  there  are  cases  in 

'  De  Corp.  Hiimcan.  Fabric,  torn,  vi.,  Traject.  ad  Moenum,  1794-1801. 

*  Experimental  Inquiry  into  tlie  Laws  of  the  Vital  Functions,  2d  edit.,  Lond.,  1818. 
^  Experiments  and  Observations  on  the  Gastric  Juice,  and  the  Physiology  of  Diges- 
tion, p.  57,  Plattsburg,  1833. 

*  Precis,  &c.,  ii.  1G8. 


128  DIGESTION. 

wliicli  the  mouth  is  the  sole  or  chief  organ  of  prehension.  !Mopt  ani- 
mals are  compelled  to  use  the  mouth  only,  "When  the  food  is  conveyed 
to  it  by  the  hands,  it  must  open  to  receive  it.  The  mode  in  which  this 
is  effected  has  given  rise  to  controversy ;  and,  strange  to  say,  is  not  yet 
considered  determined.  Whilst  some  physiologists  have  asserted,  that 
the  lower  jaw  alone  acts  in  opening  the  mouth  moderately;  others  have 
affirmed,  that  both  the  jaws  separate  a  little; — the  lower,  however, 
moving  five  or  six  times  as  much  as  the  upper.  That  the  latter  is  the 
correct  view  can  be  proved  by  positive  experiment.  If,  when  the 
mouth  is  closed,  we  place  the  flat  side  of  the  blade  of  a  knife  against 
the  teeth  of  both  jaws;  and,  holding  the  knife  immovably,  separate  the 
jaws;  we  find,  that  both  jaws  move  on  the  blade;  but  the  lower  to  a 
much  greater  extent  than  the  upper.  Now,  as  the  upper  jaw  is  fixed 
immovably  to  the  head,  the  whole  head  must,  of  necessity,  participate 
in  this  movement;  and  the  question  arises,  what  are  the  agents  that 
produce  it?  Some  attribute  it  to  a  slight  action  of  the  extensor  muscles 
of  the  head;  and  affirm,  that  whilst  the  depressors  of  the  lower  jaw 
carry  it  downwards,  the  extensors  of  the  head  draw  the  head  slightly 
backwards,  and  thus  raise  the  upper  jaw. 

MM.  Magendie^  and  Adelon^  assert,  that  when  the  mouth  is  opened 
moderately,  the  upper  jaw  does  not  participate;  but,  that  if  the  motion 
be  "forced"  or  extensive,  it  participates  slightly.  The  experiment, 
however,  with  the  knife,  which  is  adduced  by  M.  Adelon  himself,  com- 
pletely overthrows  this  notion  ;  and  shows,  that  both  jaws  act,  whenever 
the  mouth  is  slightly  opened.  M.  Magendie  agrees  with  those  who 
consider,  that,  whenever  the  upper  jaw  is  raised,  it  must  be  by  the  head 
being  thrown  back  on  the  vertebral  column;  and  he  properly  remarks, 
that  where  there  is  a  physical  impediment  to  the  depression  of  the  lower 
jaw,  the  mouth  must  be  opened  solely  by  the  retroversion  of  the  head 
on  the  spine.  M.  Ferrein^  conceived,  that  the  motion  of  the  upper  jaw 
is  occasioned  by  the  action  of  the  stjdo-hyoideus  muscle,  and  the  pos- 
terior belly  of  the  digastricus;  and  he  affirms,  that  whilst  the  anterior 
fasciculus  or  belly  of  the  digastricus  depresses  the  lower  jaw;  the  pos- 
terior belly  with  the  stylo-hyoideus  carries  the  head  backwards,  and, 
with  it,  the  upper  jaw.  The  attachments,  however,  of  these  muscles 
sufficiently  show,  that  they  cannot  be  the  agents:  the  mastoid  process, 
to  which  the  posterior  belly  of  the  digastric  muscle  is  attached,  is  near 
the  articulation  of  the  head  with  the  atlas;  whilst  the  styloid  process, 
to  which  the  stylo-hyoideus  is  attached,  is  anterior  to  the  articulation ; 
and  its  effect  ought  to  be  to  depress  the  upper  jaw.  The  view  of  Pro- 
fessor Chaussier  is  the  most  probable.  He  ascribes  the  slight  elevation 
of  the  upper  jaw  to  the  mechanical  arrangement  of  the  joint  of  the 
lower.  The  temporo-maxillary  articulation  is  not  formed  by  a  single 
condyle,  but  by  two,  which  are  so  disposed,  that  the  lower  cannot  roll 
downwards  during  the  depression  of  the  lower  jaw  without  causing  the 
upper  condyle  to  roll  upwards,  and,  consequently,  to  elevate  slightly, 
the  upper  jaw.  Under  ordinary  circumstances,  then,  the  jaws  cannot  be 
at  all  separated  without  both  participating;  but  if  we  determine  to  fix 
the  upper  jaw,  we  can  make  the  lower  the  sole  agent  in  the  movement. 

•  Op.  citat.,  ii.  43.  2  Qp.  citat.,  ii.  408. 

^  Memoir,  de  TAcad.  des  Sciences  pour  1744. 


PREHENSION   OF   FOOD. 


129 


As  soon  as  the  food  is  introduced  into  tlie  mouth,  the  jaws  are  closed 
to  retain  it,  and  subject  it  to  mastication.  Frequently,  however,  they 
assist  in  the  act  of  prehension,  as  when  we  bite  a  fruit,  to  separate  a 
portion  from  it ;  the  incisor  teeth  acting,  in  such  case,  like  scissors. 
This  is  chiefly  produced  by  the  contraction  of  the  muscles  that  raise 
the  lower  jaw  ;  and  it  is  probable,  that  the  action  of  the  stylo-hyoideus 

Fiff.  52. 


Action  of  the  Lower  Jaw  in  Prehension. 

A.  Frontal  bone.  B.  Temporal.  C.  Parietal.  D.  Occipital.  E.  Coronoid  process  of  the  lower  jaw, 
to  which  the  temporal  muscle  i.s  attached.  F.  Condyloid  process  or  head  of  the  lower  jaw.  G.  Lower 
jaw.  H.  Mastoid  process.  I.  Upper  jaw.  J.  Cheeli  bone.  K.  Orbit.  L.  Meatus  auditorius  externus. 
L*.  Coronal  suture.     M.  Squamous  suture.     N.  Lambdoidal  suture,    g.  Lower  jaw  depressed. 

is  concerned  in  the  movement ;  drawing  the  head  and  upper  jaw  with 
it  downwards  and  forwards.  The  levator  muscles  of  the  jaw  act  here 
with  great  disadvantage ; — the  lower  jaw  representing  a  lever  of  the 
third  kind;  the  fulcrum  being  in  the  joint;  the  ])Ower  at  the  insertion 
of  the  levator  muscles ;  and  the  resistance  in  the  substance  between 
the  teeth.  The  arm  of  the  resistance  is,  consequently,  the  whole  length 
of  the  lever;  and  we  can  understand  why  we  are  capable  of  developing 
so  much  more  force,  when  the  resistance  is  placed  between  the  molares ; 
and  why  old  people, — who  have  become  toothless,  and  are,  consequently, 
constrained  to  bite  with  the  anterior  part  of  the  jaws, — the  only  por- 
tion that  admits  of  contact, — cannot  bite  with  any  degree  of  strength. 
The  size  of  the  body,  put  between  the  incisor  teeth,  influences  the 
degree  of  force  that  can  be  brought  to  bear  upon  it.  AVhen  small  the 
force  can  be  much  greater,  as  the  levator  muscles  are  inserted  perpen- 
VOL.  I. — 9 


130  DIGESTIO^^. 

dicularly  to  the  lever  to  be  moved,  and  the  whole  of  their  power  is 
advantageously  exerted ;  but  if  the  body  be  so  large,  that  it  can  scarcely 
be  received  into  the  mouth,  and  be  resisting  withal,  the  incisors  can 
scarcely  penetrate  it; — the  insertion  of  the  levator  muscles  into  the 
jaw  being  rendered  very  oblique;  and  the  greater  part  of  the  force  they 
develope  consequently  lost.  This  will  be  readily  seen  by  Figure  52. 
When  the  mouth  is  closed,  or  nearly  so,  the  masseter,  and  temporal 
muscles  represented  respectively  by  the  lines  B  E  and  jy,  are  inserted 
nearer  the  perpendicular;  but  when  the  lower  jaw  is  depressed,  so  that 
the  situation  of  these  muscles  is  represented  by  the  dotted  lines  B  e  and 
J  A",  the  direction  in  which  the  muscles  act  will  be  more  oblique,  and, 
therefore,  more  disadvantageous.  When  the  muscles  of  the  jaws  are 
incapable,  of  themselves,  of  separating  the  substance,  as  in  the  case  of 
the  apple,  the  assistance  of  the  muscles  of  the  hand  is  invoked;  whilst 
the  muscles  on  the  posterior  part  of  the  neck,  which  are  inserted  into 
the  head,  draw  it  backwards;  and,  by  these  combined  efforts,  the  sub- 
stance is  forcibly  divided. 

c.  Oral  or  Buccal  Digestion. 

The  changes,  effected  upon  the  food  in  the  mouth,  are  important 
preliminaries  to  the  function  that  has  to  be  executed  in  the  stomach 
and  duodenum.  As  soon  as  it  enters  the  cavity,  it  is  subjected  to  the 
action  of  the  organ  of  taste,  and  its  sapid  qualities  are  appreciated. 
By  its  stay  there,  it  also  acquires  nearly  the  temperature  of  the  cavity. 
This  is,  however,  a  change  of  little  moment,  unless  the  food  is  so  hot, 
that  it  would  injure  the  stomach,  if  passed  rapidly  into  it.  Undei 
such  circumstances,  it  is  tossed  about  in  the  mouth,  until  it  has  partec 
with  its  caloric  to  various  portions  of  the  parietes  of  the  cavity;  an^ 
then,  if  in  a  fit  state  for  the  action  of  deglutition,  it  is  transmitted  aloni 
the  oesophagus ;  but  the  most  important  parts  of  oral  digestion  are  th^ 
movements  of  mastication  and  insalivation  by  which  solid  food  is  coraJ 
minuted,  and  imbued  with  the  secretions  poured  into  the  interior  of  th^ 
mouth,  and  which  we  have  shown  to  be  of  a  very  compound  character; 

Under  the  sense  of  taste,  the  influence  of  the  agreeable  or  disagree- 
able character  of  the  food  upon  the  digestive  function  is  expatiated 
upon.  It  is  unnecessary,  therefore,  to  do  more  than  allude  to  the  sub- 
ject here.  We  find  that  whilst  a  luscious  aliment  excites  to  prolonged 
mastication,  and  the  salivary  glands  to  augmented  secretion,  the  mas- 
ticatory and  salivary  organs,  by  dividing  and  moistening  the  food, 
permit  the  organs  of  gustation  to  enjoy  the  savour  by  successive  ap- 
plications. 

When  the  food  is  received  into  the  mouth,  if  it  be  sufficiently  soft, 
it  is  commonly  swallowed  immediately  ;  unless  the  flavour  is  delicious, 
when  it  is  detained.  If  solid,  and,  especially,  if  of  any  size  or  density, 
it  is  divided  into  separate  portions,  or  chewed, — the  action  constituting 
mastication.  If  the  consistence  of  the  substance  be  moderate,  the 
tongue,  by  being  pressed  strongly  against  the  bony  palate,  is  sufilcient 
to  effect  this  division;  bruising  it,  and  at  the  same  time,  expressing  its 
fluid  portions.  If  the  consistence  be  greater,  the  action  of  the  jaws 
and  teeth  is  required.  For  this  purpose,  the  lower  jaw  is  successively 
depressed  and  elevated  by  the  action  of  its  depressors  and  levators ; 


ORAL   DIGESTIOX.  131 

and  the  horizontal  or  grinding  motion  is  produced  at  pleasure  by  the 
action  of  the  pterygoids.  Whilst  these  muscles  are  acting,  the  tongue 
and  cheeks  are  incessantl}^  moving,  so  as  to  convey  the  food  between 
the  teeth,  and  insure  its  comminution.  Mastication  is  chiefly  effected 
by  the  molares.  There  is  advantage  in  using  them,  independently  of 
their  form,  in  consequence  of  the  arm  of  the  resistance  being  much 
shortened,  as  has  already  been  shown. 

The  teeth  are  well  adapted  for  the  service  they  have  to  perform. 
The  incisors,  as  their  name  imports,  are  used  for  cutting;  hence  their 
coronte  come  to  an  edge;  the  canine  teeth  penetrate  and  lacerate,  and 
their  coronas  are  acuminated ;  whilst  the  molares  bruise  and  grind,  and 
their  touching  surfaces  are  tuberous.  The  first,  having  usually  no  great 
eftbrt  to  sustain,  are  placed  at  the  extremity  of  the  lever  ;  the  latter,  for 
opposite  reasons,  are  nearest  the  fulcrum.  To  preclude  displacement 
by  the  eftbrts  they  have  occasionally  to  sustain,  they  are  firmly  fixed  in 
the  alveoli  or  sockets ;  and,  as  th'^  roots  are  conical,  and  the  alveoli 
accurately  embrace  them,  the  force,  as  in  the  case  of  the  wedge,  is 
transmitted  in  all  directions,  instead  of  bearing  perpendicularly  on  the 
jaw,  which  it  would  do,  were  the  fangs  cylindrical.  The  molar  teeth, 
having  the  greatest  efforts  to  sustain,  are  furnished  with  several  roots; 
or  with  one  that  is  extremely  large. 

The  gums  add  materially  to  the  solidity  of  the  junction  of  the  teeth 
with  the  jaws.  They  are  themselves  formed  of  highly  resisting  mate- 
rials, so  as  to  withstand  the  pressure  of  hard  and  irregular  substances. 
Whenever  they  become  spongy,  and  fall  away  from  the  teeth,  the  latter 
become  loose ;  and  are  frequently  obliged  to  be  extracted,  in  conse- 
quence of  the  loose  tooth  acting  as  an  extraneous  body,  and  inflaming 
the  lining  membrane  of  the  alveolus.  The  arrangement  of  the  jaw  is 
well  adapted  to  the  function ;  the  lower  jaw  passing  behind  the  upper 
at  its  anterior  part ;  but  coming  in  close  contact  at  the  sides,  where 
mastication  is  chiefly  effected. 

During  the  whole  time  that  mastication  is  going  on,  the  mouth  is 
closed ; — anteriorly,  by  the  lips  and  teeth,  which  prevent  the  food  from 
falling  out  of  the  cavity;  and  posteriorly  by  tiie  velum  palati,  the 
anterior  surface  of  which  is  applied  to  the  base  of  the  tongue.  At  the 
same  time,  the  food  is  undergoing  insalivation  or  admixture  with  the 
various  fluids  poured  into  the  mouth,  and  particularly  with  the  saliva, 
the  secretion  of  which  is  augmented,  not  only  by  the  presence  of  food, 
but  even  by  the  sight  of  it,  especially  if  the  food  be  desirable; — giving 
rise  to  what  is  called  "mouth-watering."  It  is  probable,  that,  inde- 
pendently of  mental  association,  the  action  of  the  secretory  organs  is 
increased  by  the  agitation  of  the  organs  themselves  during  the  masti- 
catory movements.  It  has,  indeed,  been  asserted,  that  the  parotid 
glands  are  so  situate,  as  regards  the  jaws,  that  the  movement  of  the 
lower  jaw  presses  upon  them,  and  forces  out  the  saliva;  but  MM. 
Bordeu  and  J.  Cloquet  have  demonstrated,  anatomically  and  by  expe- 
riment, that  this  is  not  the  case.' 

It  has  been  supposed  by  some,  that  admixture  with  saliva  commu- 
nicates to  the  food  its  first  degree  of  animalization ;  or  in  other  words, 

'  Adelon,  op.  cit.,  ii.  418. 


132  BTGESTION. 

its  first  approximation  to  the  substance  of  the  animal  it  lias  to  nourish. 
Such  are  the  opinions  of  Professor  Jackson'  and  M,  Voisin.^  The 
former  asserts,  that  he  has  ascertained  positively,  that  the  saliva  exerts 
a  very  energetic  operation  on  the  food,  separating,  by  its  solvent  pro- 
perties, some  of  its  constituent  principles,  and  performing  a  species  of 
digestion.  MM.  Tiederaann  and  Graelin.  too,  think  that  the  water,  and 
the  carbonates  and  acetates  of  potassa  and  soda,  and  the  chlorides  of 
potassium  and  sodium,  of  the  saliva,  contribute  to  soften  and  dissolve 
the  food;  whilst  the  nitrogenized  materials,  the  salivary  and  albumi- 
nous matters,  communicate  to  it  a  first  degree  of  animalization.  It  is 
.more  probable,  however,  that  the  main  use  of  mastication  and  insali- 
vation  is  to  give  the  food  the  necessary  consistence,  in  order  that  the 
stomach  and  small  intestine  may  exert  their  action  upon  it  in  the  most 
favourable  manner ;  and  that,  consequently,  the  changes  effected  upon 
it  in  the  mouth,  are  chiefly  of  a  mechanical  character.  In  the  case  of 
many  substances — as  sugar,  salt,  &p,. — a  true  solution  takes  place  in 
the  saliva ;  and  this  probably  happens  to  sapid  bodies  in  general ; — 
the  particles  being  separated  by  imbibing  the  fluid.  Krimer,^  of  Leip- 
zig, held  in  his  mouth  a  piece  of  ham,  weighing  a  drachm,  for  three 
hours.  At  the  expiration  of  this  time,  the  ham  was  white  on  its  sur- 
face, and  had  increased  in  weight  twelve  grains.  He  believes,  that  the 
tears  assist  in  digestion,  and  that  they  flow  constantly  by  the  posterior 
nares  into  the  stomach. 

It  would  seem  that  an  important  action  of  the  saliva  is  the  conver- 
sion of  starch — boiled  starch — into  dextrin  or  grape  sugar.  From  one 
drachm  of  starch,  Dr.  Wright"  obtained  in  twelve  hours,  at  a  tempera- 
ture of  98°,  by  admixture  with  saliva,  thirty-one  grains  of  sugar.  This 
probably  takes  place  by  the  action  of  some  nitrogenized  secretion,  like 
pepsin  in  stomachal  digestion.  It  has  been  affirmed,  indeed,  on  the 
strength  of  numerous  and  varied  experiments  detailed  before  the 
French  Academy  of  Sciences,*  by  MM.  Bernard  de  Villefranche  and 
Barreswil,  that  in  the  gastric  juice,  pancreatic  fluid,  and  saliva,  an 
organic  principle  or  ferment  exists,  which  is  common  to  them  all;  and 
that  it  is  the  nature  of  the  chemical  reaction  associated  with  it,  which 
alone  determines  their  power  of  digesting  the  different  alimentary 
principles.  In  an  alkaline  fluid,  all  three  have  the  power  of  trans- 
forming starch,  and  do  not  digest  meat;  whilst  in  an  acid  fluid  they 
dissolve  meat,  but  do  not  act  on  starch.  Hence,  they  think,  it  appears 
easy  to  transform  these  fluids  into  each  other,  and  to  make  for  example 
an  artificial  gastric  juice  from  pancreatic  fluid.  The  action  of  saliva, 
however,  is  said  to  be  less  energetic,  both  on  meat  and  starch,  than 
the  pancreatic  fluid.  For  the  organic  compound  in  the  saliva,  M. 
Mialhe'*  proposes  the  name  animal  diastase  or  diastase  salivaire.  It 
would  seem,  however,  from  the  experiments  of  MM.  Magendie^  and 

'  Principles  of  Medicine,  j).  354,  Philad.,  1832. 

2  Nouvel  Aper(;u  sur  la  Physiologie  du  Foie,  &:c.,  Paris,  1833. 

3  Versuch  einer  Physiologic  des  Blutes,  Leipz.,  1820. 

*  Lend.  Lancet,  1841-2.  s  Comptes  Rendus.  7  Juillet,  1845. 

6  Lancette  Franc-aise,  Avril,  1845  ;  and  Miallie,  Chimie  appliquee  a  la  Pliysiologie  et  i. 
la  Tlierapeutiqiae,  p.  39,  Paris,  185(i. 
'  Comptes  Reudus,  1847,  p.  117. 


OEAL   DIGESTIO^r.  133 

Bernard/  that  many  substances  besides  saliva, — as  pieces  of  the  mu- 
cous membrane  of  the  mouth,  bhidder,  rectum,  and  other  parts,  various 
animal  and  vegetable  tissues,  and  even  morbid  products  effect  the 
transformation  of  starch  into  sugar ;  but  that  the  gastric  fluid  does  not. 
The  part  of  the  saliva,  according  to  M.  Bernard,  which  appears  to  be 
most  active  in  this  transformation,  is  that  secreted  by  the  small  glands 
and  the  mucous  membrane  of  the  mouth  ;^  but  it  has  been  properly 
observed,  by  Messrs.  Kirkes  and  Paget,^  that  if  the  influence  of  saliva 
in  aiding  the  digestion  of  farinaceous  food  be  admitted,  we  have  yet 
to  seek  for  the  corresponding  purpose  served  by  the  saliva  of  the  car- 
nivora,  which  consume  no  such  food;  and  on  this  point  we  possess  at 
present  no  information. 

M.  Bernard'*  believes,  that  the  parotid,  labial  and  buccal  glands,  which 
secrete  a  more  watery  fluid,  are  aquiparous ;  and  more  especially 
auxiliaries  in  mastication;  whilst  the  maxillary,  sublingual  and  palatal 
are  muciparous,  and  furnish  the  thicker  mucous  matter  which  sur- 
rounds the  alimentary  bolus,  and  facilitates  its  onward  course  in  the 
act  of  deglutition.*  The  secretion  from  the  different  glands  certainly 
varies  greatly.  M.  Lassaigne^  examined  the  fluid  from  the  parotid  andv 
the  submaxillary  in  the  same  animal.  The  latter  was  much  more 
viscid,  and  resembled  mucus  in  consistence. 

It  is  probable  that  the  main  action  of  saliva  is  to  soften  the  food ;  for 
when  substances  are  well  mixed  with  water,  they  are  retained  in  the 
mouth  for  a  short  time  only;  and,  consequently,  in  an  amylaceous 
solution  there  is  no  opportunity  for  change  to  be  effected.  Experi- 
ments, instituted  by  M.  Lassaigne,''  by  a  committee  of  the  Institute, 
and  by  M.  Bernard^  show,  that  when  the  food  is  dry  a  considerable 
admixture  of  saliva  takes  place,  whilst  if  it  be  so  softened,  that  masti- 
cation is  not  needed,  it  absorbs  scarcely  any.  In  executing  these 
experiments,  the  aliment  was  weighed  before  giving  it  to  the  animal ; 
the  oesophagus  was  cut  across;  and  the  aliment,  after  having  been 
chewed  and  insalivated,  was  received  through  the  wound  in  the  neck. 
jThe  difference  in  weight  indicated  the  quantity  of  saliva  that  had  been 
added  to  it.  According  to  Professor  Berard,^  these  experiments  teach 
us:  First.  That  dry  forage  absorbs  about  four  or  five  times  its  v/eight 
'of  saliva  and  mucus.  Secondly.  That  dry  feculaceous  articles  (oats, 
starch  and  barley  meal)  absorb  a  little  more  than  their  weight.  Thirdly. 
That  green  forage  (green  leaves  and  stalks  of  barley)  absorb  a  little 
less  than  half  their  weight;  and  fourthly ;  that  moist  feculaceous  arti- 
cles (starch  and  bran)  to  which  sufficient  water  has  been  added  for  the 

'  Canstatt  und  Eisenmann,  Jahresbericlit  iiber  die  Fortscliritte  in  der  Biologie,  im 
lahre,  1847,  s.  117. 

^  See,  also,  Frerichs,  in  Canstatt's  Jahiesbericlit,  1850,  p.  134;  and  art.  Verdaunng, 
n  Wagner's  Handwort.  der  Physiologie,  Bd.  iii.  Abth.  1,  Braunscli.,  184(j ;  and  Bidder 
ind  Schmidt,  Die  Verdauungssiifte,  s.  1,  Mitau  und  Leipz.,  1852. 

'  Manual  of  Pliysiology,  2d  Amer,  edit.,  p.  163,  Pliilad.,  1853. 

*  Comptes  Rencius,  1852,  p.  236. 

*  Beraud,  Manuel  de  Physiologie,  p.  88,  Paris,  1853. 

^  Journ.  de  Chimie  Med.,  p.  393  ;  and  Scherer,  in  Canstatt's  Jahresbericlit,  1852,  s. 
06. 
'  Journal  de  Chimie  Medicale,  p.  472,  Paris,  1845. 

*  Archives  Generales  de  Medecine,  4e  s  rie,  torn.  xiii.  p.  1. 

*  Cours  de  Physiologie,  p.  721,  Paris,  1848. 


134:  DIGESTION. 

food  to  be  swallowed  witliout  previous  mastication,  do  not  sensibly 
absorb  any. 

Botli  mastication  and  insalivation  are  of  moment,  in  order  that 
digestion  shall  be  accomplished  in  perfection;  and,  accordingly,  they 
who  swallow  food  without  due  mastication,  or  waste  the  saliva  by  con- 
stant and  profuse  spitting,  are  more  liable  to  attacks  of  dyspepsia,  or 
imperfect  digestion.  It  is  proper,  however,  to  add,  that  Dr.  Trudge,* 
on  extirpating  the  salivary  glands  in  animals,  did  not  find  that  they 
sustained  the  smallest  apparent  injury;  whence  he  conjectures,  that 
certain  glands  can  act  as  succedanea  to  others,  and  that  on  the  removal 
of  the  salivary  glands  the  pancreas  supplies  perhaps  the  fluid  usually 
secreted  by  the  other. 

A  table  given  by  Dr.  Robert  Dundas  Thomson^  as  the  results  of  ex- 
periments on  two  cows,  signally  exhibits  the  beneficial  effects  of  a 
proper  grinding  of  the  food.  The  cows  were  fed  on  entire  barley  and 
malt  steeped  in  hot  water.  They  were  then  fed  on  crushed  barley  and 
malt  prepared  in  the  same  manner.  The  influence  of  the  finer  division 
of  the  grain  in  increasing  the  quantity  of  milk  is  strikingly  shown, 
f 


Browx  Cow. 

White  Cow. 

Milk  in  periods  of  five 

days. 

Milk 

in  periods  of  five  days 

Entire  barley  and  grass,    .     .      i 

lllilbs 

97l   " 

.       106  lbs. 
94     " 

Entire  malt  and  grass,       .     .      ] 

r 

96      " 
95      " 

98     " 
.       104    " 

1151    « 

.       109i  " 

Crushed  barley,  grass  and  hay,  < 

r 

105"    " 
110      " 

97     " 

.       109i  " 
.       110     " 
.       1061  " 

Crushed  malt  and  hay,     .     .      -l 

96     " 

98     " 

.       107i  " 

.     ml " 

The  table  exhibits,  that  with  the  entire  barley,  the  milk  diminished 
during  the  second  five  days  of  the  experiment,  whilst  with  the  crushed 
barley  it  had  a  tendency  to  increase  during  each  succeeding  period. 

The  degree  of  resistance,  and  sapidity  of  the  food,  apprise  us  when 
mastication  and  insalivation  have  been  sufficiently  exerted.  When  this 
is  the  case  it  is  subjected  to  the  next  of  the  digestive  processes.  Some 
physiologists  have  affirmed,  that  the  uvula  is  the  organ  which  judges 
when  the  food  is  adapted  for  deglutition.  M.  Adelon,  whose  views  are 
generally  worthy  of  great  favour  and  attention,  asserts,  "  that  it  judges 
by  its  mode  of  sensibility,  of  the  degree  in  which  the  aliment  has  been 
prepared  in  the  mouth ;  of  the  extent  to  which  it  has  been  chewed,  im- 
pregnated with  saliva,  and  reduced  to  paste;  and,  according  to  the 
impression  it  receives,  it  excites,  sympathetically,  the  action  of  all  those 
parts ;  directs  the  convulsive  contraction  of  the  muscles  that  raise  the 
pharynx:  even  keeps  the  stomach  on  the  alert,  and  disposes  it  to  receive 
favourably  or  to  reject  the  food  passing  to  it."  Such  a  function  would 
be  anomalous.  It  is,  indeed,  inconceivable  that  so  insignificant  an 
organ  could  be  possessed  of  those  elevated  attributes.  Observation, 
also,  proves,  that  the  notion  is  the  offspring  of  fancy.     M.  Magendie^ 

'  jredicinischo  Zeitung,  May  4,  1842;  cited  in   British  and  For.  Med.  Rev.,  July, 
1842,  p.  221. 
'  i:xperimental  Researches  on  the  Food  of  Animals,  Amer.  edit.,  New  York,  1846. 
3  Op.  cit.,  ii.  58. 


DEGLUTITION.  135 

asserts,  that  lie  has  known  several  persons  who  had  entirely  lost  the 
uvula,  either  by  venereal  ulceration  or  by  excision,  and  yet  he  never 
remarked  that  their  mastication  experienced  the  slightest  modification, 
or  that  they  swallowed  inopportunely.  Our  experience  corresponds 
with  that  of  M.  Magendie.  We  know  of  more  than  one  individual 
in  whom  there  is  not  the  slightest  vestige  of  uvula ;  yet  they  taste, 
chew,  and  swallow  like  other  persons. 

d.  Deglutition. 

The  act  of  swallowing,  although  executed  with  extreme  rapidity, 
and  apparently  simple,  is  the  most  complicated  of  the  digestive  opera- 
tions, and  requires  the  action  of  mouth,  pharynx  and  oesophagus.  It 
has  been  well  analyzed  by  M.  Magendie, — first  of  all  in  a  thesis,  main- 
tained at  the  Ecole  de  M&lecine  of  Paris,  in  1808,  and  subsequently,  in 
his  Precis  EUmentaire  de  Physiologie}  To  facilitate  its  study,  he  divides 
it  into  three  stages.  In  the  first^  the  food  passes  from  the  mouth  into 
the  pharynx ;  in  the  second^  it  clears  the  apertures  of  the  glottis  and 
nasal  fossas,  and  attains  the  oesophagus;  and,  in  the  third^  it  clears  the 
oesophagus  and  enters  the  stomach. 

1.  When  the  food  has  been  sufficiently  masticated  and  imbued  with 
saliva,  it  is  collected  by  the  action  of  the  cheeks  and  tongue  upon  the 
upper  surface  of  the  last  organ ; — the  mass  being  more  or  less  rounded, 
and  hence  usually  termed  alinierdary  bolus.  Mastication  now  stops; 
the  tongue  is  raised  and  applied  against  the  bony  palate  in  succession 
from  the  tip  to  the  root,  and  the  alimentary  bolus,  having  no  other  way 
of  escaping  from  the  force  pressing  it,  is  directed  towards  the  pharynx. 
Previous  to  this,  the  pendulous  veil  of  the  palate  had  been  applied  to 
the  base  of  the  tongue.  The  bolus  now  raises  it  to  the  horizontal  posi- 
tion :  the  circumflexus  palati  muscles  render  the  velum  tense,  so  that  the 
food  cannot  pass  into  the  nasal  fosste ;  and  the  muscles  that  constitute 
the  pillars  of  the  fauces— palato-pharyngei  and  glosso-staphylini — 
contribute  to  this  eflect.  By  this  combination  of  results,  the  food  is 
impelled  into  the  pharynx.  The  muscles,  which,  by  their  action,  apply 
the  tongue  to  the  roof  of  the  mouth  and  to  the  velum  palati,  are  the 
proper  muscles  of  the  organ,  aided  by  the  mylo-hyoidei.  In  this  first 
stage  of  deglutition,  the  motions  are  voluntary,  except  those  of  the 
velum  palati.  The  process  is  not  executed  with  rapidity,  and  is  easily 
intelligible.  Such  is  not  the  case  with  the  second  stage.  The  actions 
in  it  are  complicated,  and  executed  with  so  much  celerity,  that  they 
have  been  re2;arded  as  a  kind  of  convulsion. 

2.  The  distance  over  which  the  bolus  has  to  travel,  in  the  second 
stage,  is  trivial ;  the  rapidity  of  its  course  is  owing  to  the  larynx  or 
superior  aperture  of  the  windpipe,  which  opens  into  the  pharynx 
having  to  be  cleared  instantaneously,  otherwise  respiration  might  be 
arrested,  and  serious  effects  ensue.  The  mode,  in  which  the  second 
stage  is  accomplished,  is  as  follows.  As  soon  as  the  alimentary  bolus 
comes  in  contact  with  the  pharynx  all  is  activity ;  the  pharj^nx  con- 
tracts, embraces,  and  presses  the  bolus ;  and  the  velum  pendulum, 
drawn  down  by  the  palato-pharyngei  and  glosso-staphylini  muscles, 

»  Edit,  cit.,  ii.  G3. 


136  DIGESTIOX. 

fulfils  a  similar  office.  At  the  same  time,  the  genio-glossus,  by  apply- 
ing the  tongue  to  the  palate,  from  the  tip  to  the  roof,  raises  the  os 
hyoides,  the  larynx,  and,  with  it,  the  anterior  paries  of  the  pharynx. 
The  same  effect  is  directly  induced  by  the  contraction  of  the  mylo- 
hyoidei,  and  genio-hyoidei  muscles ;  which,  instead  of  acting  as  de- 
pressors of  the  lower  jaw,  as  they  do  during  mastication,  take  the  jaw 
as  their  fixed  point,  and  are  levators  of  the  os  hyoides.  The  larynx 
is  thus  elevated,  carried  forwards,  and  meets  the  b6lus  to  render  its 
passage  over  the  aperture  of  the  larynx  shorter,  and,  therefore,  more 
speedy.  To  aid  this  effect, — when  we  make  great  efforts  to  swallow, 
the  head  is  inclined  forwards  on  the  thorax.  Whilst  the  os  hyoides 
and  the  larynx  are  raised,  they  approach  each  other, — the  upper  mar- 
gin of  the  thyroid  cartilage  passing  behind  the  body  of  the  hyoid  bone: 
the  epiglottic  gland  is  pushed  backward,  and  the  epiglottis  is  depressed, 
and  inclined  backwards  and  downwards,  so  as  to  cover  the  entrance  to 
the  lar^mx.  The  cricoid  cartilage  executes  a  rotatory  motion  on  the 
inferior  cornua  of  the  thyroid  cartilage,  which  occasions  the  entrance 
of  the  larynx  to  become  oblique  from  above  to  below,  and,  of  course, 
from  before  to  behind.  The  bolus  thus  glides  over  its  surface ;  and, 
forced  on  by  the  veil  of  the  palate,  and  by  the  constrictors  of  the 
pharynx,  reaches  the  oesophagus. 

At  one  time,  it  was  universally  believed,  that  the  epiglottis  is  the 
sole  agent  in  preventing  substances  from  passing  into  the  larynx. 
The  experiments  of  M.  Magendie'  have,  however,  demonstrated,  that 
this  is  the  combined  effect  of  the  motions  of  the  larynx  just  described, 
and  of  the  muscles,  whose  office  it  is  to  close  the  glottis;  so  that,  if 
the  laryngeal  and  recurrent  nerves  be  divided  in  an  animal,  and  the 
epiglottis  be  left  in  a  state  of  integrity,  deglutition  is  rendered  ex- 
tremely difficult; — the  principal  cause,  that  prevented  the  introduction 
of  aliments  into  the  glottis,  having  been  removed  by  the  section.  M. 
Magendie,  and  MM.  Trousseau  and  Belloc^  refer  to  cases  of  individuals, 
who  were  totally  devoid  of  epiglottis,  and  yet  swallowed  without  any 
difficulty,^  and  Magendie  remarks,  that  if,  in  laryngeal  phthisis  with 
destruction  of  the  epiglottis,  deglutition  be  laboriously  and  imperfectly 
accomplished,  it  is  owing  to  the  carious  condition  of  the  arytenoid 
cartilages,  and  to  the  lips  of  the  glottis  being  so  much  ulcerated  as  not 
to  be  able  to  close  the  glottis  accurately.  Whilst  the  bolus,  then,  is 
passing  over  the  top  of  the  larynx,  respiration  must  be  momentarily 
suspended,  owing  to  closure  of  the  glottis;  and  if,  from  distraction  of 
any  kind,  we  attempt  to  speak,  laugh,  or  breathe,  at  the  moment  of 
deglutition,  the  glottis  opens,  the  food  enters,  and  cough  is  excited, 
which  is  not  appeased  until  the  cause  is  removed.  This  is  what  is 
called,  in  common  language,  "  the  food  going  the  wrong  way."  As 
soon  as  the  bolus  has  cleared  the  glottis,  the  larynx  descends,  the  epi- 
glottis rises,  and  the  glottis  opens  to  give  passage  to  the  air.     This  is 

'  Memoire  sur  I'Usage  de  I'Epiglotte  dans  la  Deglutition,  Paris,  1813;  and  Precis, 
&c.,  i.  (57. 

^  2  A  Practical  Treatise  on  Lar^-ngeal  Phthisis,  &c.  &c. ;  Dr.  Warder's  translation, 
p.  84,  in  Dunglison's  American  Medical  Library,  Philad.,  1839. 

*  A  similar  case  is  given  by  Targioni,  in  which  neither  deglutition  nor  speech  was 
impaired  ;  Morgagni,  xxviii,  13. 


DEGLUTITION",  137 

owing  to  the  relaxation  of  the  muscles  that  had  previously  raised  the 
larynx,  and  closed  the  glottis.  M.  Chaussier  thinks,  that  the  sterno- 
hyoidei  muscles  now  act,  and  aid  in  producing  the  descent  of  the 
parts.*  The  author  had  an  excellent  opportunity  for  noticing  the 
laryngeal  phenomena  of  deglutition  in  a  man,  who  had  cut  his  throat, 
and  in  whom  a  fistulous  opening  remained,  which  permitted  the  infe- 
rior ligaments  of  the  larynx  to  be  seen  distinctly.  The  glottis  was 
observed  to  be  firmly  closed.*  M.  Longet,^  who  has  made  experiments 
connected  with  this  subject  on  animals,  is  disposed  to  think,  that  the 
displacements  of  the  base  of  the  tongue  and  epiglottis  are  the  two  most 
important  conditions,  and  that  the  closed  glottis  is  only  the  last  obsta- 
cle set  up  against  the  passage  of  food  into  the  larynx ;  but  he  evi- 
dently assigns  too  much  importance  to  the  epiglottis. 

The  velum  pendulum,  then,  protects  the  posterior  nares  and  the 
orifices  of  the  Eustachian  tube  from  the  entrance  of  tlic  food ;  and  the 
epiglottis,  the  elevation  of  the  larynx,  with  the  contraction  of  the  mus- 
cles that  close  the  glottis,  are  the  great  agents  in  preventing  it  from 
passing  into  the  larynx.  The  whole  of  this  second  stage  consists  of 
rapid  movements,  of  an  entirely  involuntary  character,  which,  accord- 
ing to  Bellingeri,''  are  under  the  presidency  of  the  palatine  filaments 
of  the  fifth  pair;  but  these  filaments  are  sensory;  the  motor  filaments 
being  probably  derived  from  the  pneumogastric;  or,  according  to  M. 
Longet,  from  the  spinal.* 

o.  In  the  third  stage,  the  pharynx,  by  its  contraction,  forces  the  ali- 
mentary bolus  into  the  oesophagus,  so  as  to  somewhat  dilate  the  upper 
part  of  the  organ.  The  upper  circular  fibres  are  thus  excited  to  action, 
and  force  the  food  onward.  In  this  way,  by  the  successive  contraction 
of  the  circular  fibres,  it  reaches  the  stomach.  In  the  up]5er  part  of 
the  oesophagus,  the  relaxation  of  the  circular  fibres  speedily  follows 
their  contraction;  but  this  is  not  the  case  in  the  lowest  third,  the  cir- 
cular fibres  remainins;  contracted,  for  some  time  after  the  entrance  of 
the  bolus  into  the  stomach, — probably  to  prevent  its  return  into  the 
oesophagus.  The  passage  of  the  bolus  along  the  oesophagus  is  by  no 
means  rapid.  M.  Magendie^  affirms,  that  he  was  struck,  in  the  prose- 
cution of  his  experiments,  with  the  slowness  of  its  progression.  At 
times,  it  was  two  or  three  minutes  before  reaching  the  stomach ;  at 
others,  it  stopped  repeatedly,  and  for  some  time.  Occasionally,  it  even 
ascended  from  the  inferior  extremity  of  the  oesophagus  towards  the 
neck,  and  subsequently  descended  again.  When  any  obstacle  existed 
to  its  entrance  into  the  stomach,  this  movement  was  repeated  a  num- 
ber of  times,  before  the  food  was  rejected.  Every  one  must  have  felt 
the  slowness  of  the  progression  of  the  food  through  the  oesophagus 
when  a  rather  larger  morsel  than  usual  has  been  swallowed.  If  it 
stops,  we  are  in  the  habit  of  aiding  its  progress  by  drinking  some  fluid, 

'  Adelon,  op.  citat.,  ii.  424. 

^  Dunglison's  American  Medical  Intelligencer,  Oct.,  1841,  p.  73. 

'  L'Examinateur  Medical,  17  Oct.,  1841;  and  Brit,  and  For.  Med.  Rev.,  Jan.,  1842, 
p.  228. 

'  Dissert.  Inaugural.,  Turin,  1823  ;  noticed  in  Ediub.  Med.  and  Surg.  Journ.  for  July, 
1834. 

'  Traite  de  Physiologie,  ii.  337,  Paris,  1850.  ^  Op.  citat.,  ii.  69. 


138  DIGESTION. 

or  by  swallowing  a  piece  of  bread.  Occasionally,  however,  the  pro- 
bang  is  necessary  to  propel  it.  The  pain  produced  in  these  cases, 
according  to  M.  Magendie,  is  owing  to  the  distension  of  the  nervous 
filaments,  that  surround  the  pectoral  portion  of  the  canal.  In  the  case 
of  a  female,  labouring  under  a  disease  which  permitted  the  interior 
of  the  stomach  to  be  seen,  M.  Halle  noticed,  that  whenever  a  portion 
of  food  passed  into  the  stomach,  a  sort  of  ring  or  hourrelet  was  formed 
at  the  cardiac  orifice,  owing  to  the  mucous  membrane  of  the  oeso- 
phagus being  forced  into  the  stomach  by  the  contraction  of  its  circular 
fibres.'  The  mucous  fluid,  pressed  out  from  the  different  follicles  by 
the  passage  of  the  bolus,  materially  facilitates  its  progress. 

Notwithstanding  the  facility  with  which  deglutition  is  accomplished, 
almost  every  part  of  it  is  uninfluenced  by  volition,  being  dependent 
upon  organization,  and  exerted  instinctively.  If  the  alimentar}"  mat- 
ter contained  in  the  mouth  be  not  sufficiently  masticated  ;  or  if  it  has 
not  the  shape,  consistence,  and  dimensions,  it  ought  to  possess;  or 
if  the  ordinary  movements,  that  precede  mastication,  have  not  been 
executed, — whatever  effort  we  may  make,  deglutition  is  impractica- 
ble. We  constantly  meet  with  persons  who  are  unable  to  swallow 
the  smallest  pill;  and  yet  can  swallow  a  much  larger  mass,  if  certain 
preliminary  motions  be  executed,  which,  in  the  case  of  the  pill,  are 
inadmissible,  in  consequence  of  its  being  usually  of  a  nauseous 
character.  It  appears,  that  the  involuntary  parts  of  the  function  are 
excited  by  the  stimulation  of  the  aliment ;  for,  if  we  attempt  to  swal- 
low the  saliva  several  times  in  succession,  we  find  after  a  time,  that 
the  act  is  impracticable,  owing  to  the  deficiency  of  saliva.  Every 
one  must  have  experienced  the  difficulty  of  deglutition,  when  the 
mouth  and  fauces  were  not  duly  moistened  by  their  secretions.  The 
involuntary  part  of  deglutition  is  under  the  control  of  the  reflex  system 
of  nerves.  An  impression  is  made  by  the  alimentary  matters  upon  the 
excitor  or  aflerent  nerves,  which  impression  is  conveyed  to  the  gray 
matter  of  the  spinal  cord,  and  in  the  invertebrata  to  ganglia  corre- 
sponding to  it;  whence  it  is  reflected  to  the  muscular  fibres  tliat  have 
to  be  thrown  into  contraction.  The  portion  of  the  spinal  cord,  which 
serves  as  a  centre  for  the  reception  of  the  impression,  and  the  point  of 
departure  for  the  motor  influence,  is  the  medulla  oblongata;  and  the 
experiments  of  Dr.  John  Eeid*  lead  to  the  inference,  that  the  glosso- 
pharyngeal, which  is  chiefly  distributed  to  the  mucous  surface  of  the 
tongue  and  fauces,  is  the  excitor  nerve ;  the  pharyngeal  branches  of  the 
pneumogastric,  the  motors.  It  would  seem,  however,  that  these  nerves 
donot  alone  possess  the  function;  for  after  they  have  been  divided,  the 
animal  is  still  capable  of  imperfect  deglutition.  The  associate  excitor 
or  afferent  nerves.  Dr.  Reid  concludes  to  be— the  branches  of  the  fifth 
pair,  that  are  distributed  to  the  fauces,  and  probably  also  those  of  the 
superior  laryngeal  distributed  to  the  pharynx: — the  associate  motor  or 
efferent  nerves  being  branches  of  the  hypoglossal,  that  are  distributed 
to  the  muscles  of  the  tongue,  and  to  the  sterno-hyoid,  sterno-thyroid, 
and  thyro-hyoid  muscles ;  filaments  of  the  inferior  laryngeal  that  ramify 
on  the  larynx ;  some  of  the  branches  of  the  fifth  pair  that  supply  the 

'  Op.  cit.,  ii.  70.  2  Ediub.  Med.  and  Surg.  Journ.,  vol.  xlix. 


chymificatio:n'.  139 

levator  muscles  of  the  lower  jaw ;  the  branches  of  the  portio  dura  that 
ramify  upon  the  digastric  and  stylo-hyoid  muscles,  and  upon  the  mus- 
cles of  the  lower  part  of  the  face  ;  and  probably  some  of  the  branches 
of  the  cervical  plexus,  which  unite  themselves  to  the  descendens  noni. 
It  must  be  admitted,  however,  that  this  part  of  the  physiology  of  deglu- 
tition is  obscure.* 

Some  individuals  are  capable  of  swallowing  air;  and,  according  to 
M.  Magendie,^  it  is  an  art  that  can  be  attained  by  a  little  practice. 
He  affirms  it,  indeed,  to  be  a  more  common  power  than  is  usually  sup- 
posed. In  100  students  he  has  generally  found  eight  or  ten  who  pos- 
sessed it.  In  the  stomach,  the  air  acquires  the  temperature  of  the  vis- 
cus,  becomes  rarefied,  and  distends  the  organ ;  exciting,  in  some,  a  feel- 
ing of  burning  heat;  in  others,  an  inclination  to  vomit,  or  acute  pain. 
He  thinks  it  probable,  that  its  chemical  composition  undergoes  change ; 
bui;,  on  this  point,  nothing  certain  is  known.  The  time  of  its  stay  in 
the  stomach  is  variable.  Commonly,  it  ascends  into  the  oesophagus, 
and  makes  its  exit  through  the  mouth  or  nostrils.  At  other  times,  it 
passes  through  the  pylorus,  and  diffuses  itself  through  the  whole  of  the 
intestinal  canal,  as  far  as  the  anus, — distending  the  abdominal  cavity, 
and  simulating  tympanites.  M.  Magendie  refers  to  the  case  of  a  young 
conscript,  who  feigned  the  disease  in  this  manner. 

e.   Chymijication. 

When  the  food  has  experienced  changes  impressed  upon  it  by  the 
preceding  process,  it  reaches  the  cavity  of  the  stomach,  where  it  is  re- 
tained for  several  hours,  and  undergoes  another  portion  of  the  digestive 
action,  being  converted  into  a  pultaceous  mass,  to  which  the  term  chyme 
has  been  applied ;  whilst  the  process  has  been  called  chymification.  It 
does  not  seem,  that  all  physiologists  have  employed  these  term^in  this 
signification;  some  have  confounded  c/iy/e  with  chyme ;  and  chyufication 
with  chymification.  The  former  of  these  processes  is  distinctly  an  in- 
testinal act:  the  latter  is  exclusively  gastric. 

The  aliment,  as  it  is  sent  down  by  repeated  efforts  of  deglutition, 
descends  into  the  splenic  portion  of  the  stomach  without  difficulty,  as 
regards  the  first  mouthfuls.  The  stomach  is  but  little  compressed  by 
the  surrounding  viscera,  and  its  parietes  readily  separate  to  receive  the 
food;  but  when  it  is  taken  in  considerable  quantity,  the  distension  gradu- 
ally becomes  more  difficult,  owing  to  the  compression  of  the  viscera 
and  the  distension  of  the  abdominal  parietes.  The  accumulation  takes 
place  chiefly  in  the  splenic  and  middle  portions.  Dr.  Beaumont^  ob- 
served, that  when  a  piece  of  food  was  received  into  the  stomach,  the 
rug^B  of  the  latter  gently  closed  upon  it ;  and  if  it  were  sulffciently  fluid, 
gradually  diffused  it  through  the  cavity  of  the  organ,  but  entirely  ex- 
cluded more  whilst  the  action  continued.  The  contraction  ceasing, 
another  quantity  of  food  was  received  in  the  same  manner.  It  was 
found,  in  the  subject  of  his  experiments,  that  when  the  valvular  portion 
of  the  stomach,  situate  at  the  fistulous  aperture,  was  depressed,  and 

'  Longet,  Traite  de  Physiologie,  ii.  334,  837,  Paris,  1850. 

2  Op.  cit.,  ii.  14G. 

'  Expei'iiueuts,  &c.,  on  tUe  Gastric  Juice,  p.  110. 


140  DIGESTIOI!T. 

solid  food  introduced,  either  in  large  pieces  or  finely  divided,  the  same 
gentle  contraction  or  grasping  motion,  took  place,  and  continued  for 
fifty  or  eiglity  seconds,  and  it  would  not  allow  of  another  quantity,  until 
that  period  had  elapsed :  the  valve  could  then  be  depressed,  and  more 
food  put  in.  When  the  man  was  so  placed,  that  the  cardia  could  be 
seen,  and  was  permitted  to  swallow  a  mouthful  of  food,  the  same  ccm- 
traction  of  the  stomach  and  grasping  of  the  bolus  were  invariably 
observed  to  commence  at  the  oesophageal  ring.  Hence,  when  food  is 
swallowed  too  rapidly,  irregular  contractions  of  the  muscular  fibres  of 
the  oesophagus  and  stomach  are  produced ;  the  vermicular  motions  of 
the  rugsa  are  disturbed,  and  the  regular  process  of  digestion  is  inter- 
rupted. 

Whilst  the  stomach  is  undergoing  distension  by  food,  it  experiences 
changes  in  its  size,  situation,  and  connexion  with  the  neighbouring 
organs.  The  dilatation  does  not  afi'ect  its  three  coats  equally.  T^lie 
two  lamina3  of  the  peritoneal  coat  separate,  and  permit  the  stomach  to 
pass  farther  between  them.  The  muscular  coat  experiences  a  true  dis- 
tension ;  its  fibres  lengthen,  but  still  so  as  to  preserve  the  particular 
shape  of  the  organ  ;  whilst  the  mucous  coat  yields,  in  those  parts  espe- 
cially where  the  rugae  are  numerous;  that  is,  along  the  great  curvature 
and  splenic  portion.  In  place,  too,  of  being  flattened  at  its  anterior 
and  posterior  surfaces,  and  occup3dng  only  the  epigastrium,  and  a  part 
of  the  left  hj'pochondrium,  it  assumes  a  rounded  figure.  Its  great 
cul-de-sac  descends  into  the  left  hj-pochondre  and  almost  fills  it,  and 
the  greater  curvature  descends  towards  the  umbilicus,  especially  on 
the  left  side.  The  pylorus  preserves  its  position  and  connexion  with 
the  surrounding  parts ; — being  fixed  down  by  a  fold  of  the  peritoneum. 
It  is  chiefly  forwards,  upwards,  and  to  the  left  side,  that  the  dilatation 
occurs.  The  posterior  surface  cannot  dilate  on  account  of  the  resist- 
ance of  the  vertebral  column,  and  of  a  ligamentous  formation  which 
prevents  the  stomach  from  pressing  on  the  great  vessels  behind  it.  Its 
cardiac  and  pyloric  portions  are  also  fixed ;  so  that  when  it  is  under- 
going distension,  a  movement  of  rotation  takes  place,  by  which  the 
great  curvature  is  directed  slightly  forwards;  the  posterior  surface 
inclined  downwards,  and  the  superior  upwards.  A  wound  received  in 
the  epigastric  region,  will,  consequently,  penetrate  the  stomach  in  a 
very  difierent  part,  according  as  the  viscus  may  be,  at  the  time,  full  or 
empty. 

The  dilatation  of  the  organ  produces  changes  in  the  condition  of  the 
abdomen  and  its  viscera.  The  total  size  of  the  abdominal  cavity  is 
augmented ;  the  belly  becomes  prominent ;  and  the  abdominal  viscera 
are  compressed, — sometimes  so  much  as  to  excite  a  desire  to  evacuate 
the  contents  of  the  bladder  or  rectum.  The  diaphragm  is  crowded 
towards  the  thorax,  and  is  depressed  with  difficulty;  so  that,  not  only 
is  ordinary  respiration  cramped;  but  speaking  and  singing  become 
laborious.  When  the  distension  of  the  organ  is  pushed  to  an  enormous 
extent,  the  parietes  of  the  abdomen  may  be  painfully  distended,  and 
the  respiration  really  difficult.  It  is  in  these  cases  of  over-distension, 
that  an  energetic  contraction  of  the  oesophagus  is  necessary;  hence  the 
advantage  of  the  strong  muscular  arrangement  at  its  lower  ])art.  In 
proportion  as  the  food  accumulates  in  the  stomach,  the  sensation  of 


CHTMIFICATIOX.  141 

hunger  diminishes ;  and  if  we  go  on  swallowing  additional  portions, 
it  entirely  disappears,  or  is  succeeded  by  nausea  and  loathing.  The 
quantity,  necessary  to  produce  this  effect,  varies  according  to  the  indi- 
vidual, as  well  as  to  the  character  of  the  food ;  a  very  luscious  article 
sooner  cloying  than  one  that  is  less  so.  A  due  supply  of  liquid  with 
solid  aliment  also  enables  us  to  prolong  the  repast  with  satisfaction. 

As  the  stomach,  when  distended,  presses  upon  the  different  viscera 
and  upon  the  abdominal  parietes,  it  is  obvious,  that  it  must  experience  a 
proportionate  reaction.  An  interesting  question  consequently  arises; — 
to  determine  the  causes,  which  oppose  the  passage  of  the  food  back 
along  the  oesophagus,  as  well  as  through  the  pylorus,  M.  Magendie^ 
found,  in  his  vivisections,  that  the  lower  portion  of  the  oesophagus 
experiences,  continuously,  an  alternate  motion  of  contraction  and  re- 
laxation. The  contraction  begins  at  the  junction  of  the  two  upper 
thirds  with  the  lowest  third;  and  is  j^ropagated,  with  some  rapidity, 
to  the  termination  of  the  oesophagus  in  the  stomach.  Its  duration, 
when  once  excited,  is  variable ;  the  average  being,  at  least,  half  a 
minute.  When  thus  contracted,  it  is  hard  and  elastic,  like  a  cord 
strongly  stretched.  The  relaxation,  that  succeeds  the  contraction,  oc- 
curs suddenly  and  simultaneously  in  all  the  contracted  fibres;  at  times, 
however,  it  appears  to  take  place  from  the  upper  fibres  towards  the 
lower.  In  the  state  of  relaxation,  the  oesophagus  is  remarkably  flac- 
cid; — forming  a  singular  contrast  with  that  of  contraction.  This 
movement  of  the  oesophagus  is,  according  to  M.  Magendie,^  under  the 
dependence  of  the  eighth  pair  of  nerves.  AVhen  these  nerves  were 
divided  in  an  animal,  the  oesophagus  was  no  longer  contracted.  Still 
it  was  not  relaxed.  Its  fibres,  deprived  of  nervous  influence,  were 
shortened  with  a  certain  degree  of  force ;  and  the  canal  remained  in  a 
state  intermediate  between  contraction  and  relaxation. 

The  lower  part  of  the  oesophagus  of  the  horse,  for  an  extent  of  eight 
or  ten  inches,  is  not  contractile  in  the  manner  of  muscles.  M.  Magen- 
die^  found,  when  the  eighth  pair  of  nerves  was  irritated,  or  the  parts 
were  exposed  to  the  galvanic  stimulns,  that  no  contraction  was  pro- 
duced. The  oesophagus  of  that  animal  is,  however,  highly  elastic;  and 
its  lower  extremity  is  kept  so  strongly  closed,  that  for  a  long  time  after 
death,  it  is  difficult  to  introduce  the  finger;  and  considerable  pressure 
is  required  to  force  air  into  it.  M.  Magendie  considers  this  arrange- 
ment to  be  the  true  reason,  why  horses  vomit  with  such  difficulty  as  to 
occasionally  rupture  the  stomach  by  their  efforts.  The  alternate  mo- 
tions of  the  oesophagus,  which  we  have  described,  oppose  the  return 
of  the  food  from  the  stomach.  The  more  the  organ  is  distended,  the 
more  intense  and  prolonged  is  the  contraction,  and  the  shorter  the 
relaxation.  The  contraction  commonly  coincides  with  inspiration;  the 
time  at  which  the  stomach  is,  of  course,  most  strongly  compressed. 
The  relaxation  is  synchronous  with  expiration. 

The  pylorus  prevents  the  alimentary  mass  from  passing  into  the 
duodenum.  In  living  animals,  whether  the  stomach  be  filled  or  empty, 
this  aperture  is  constantly  closed  by  the  constriction  of  its  fibrous  ring, 
and  the  contraction  of  its  circular  fibres ;  and,  so  accurately  is  it  closed, 

'  Precis,  <S:c.,  ii.  82.  ^  i^i^.^  ii.  ig.  3  ibjd.,  ii.  19. 


l-i2  DIGESTION". 

that  if  air  be  forced  into  tlie  stomach  from  the  oesophagus,  the  organ 
must  be  distended,  and  considerable  exertion  made  to  overcome  the 
resistance  of  the  pylorus.  Yet,  if  air  be  forced  from  the  small  intes- 
tine in  the  direction  of  the  stomach,  the  pylorus  offers  no  resistance; — 
suffering  it  to  enter  the  organ  under  the  slightest  pressure; — a  circum- 
stance that  accounts  for  the  facility  ^vith  which  bile  enters  the  stomach; 
especially  .when  there  exists  inverted  action  of  the  duodenum.  To  the 
pylorus,  however,  a  more  active  part  has  been  assigned  in  the  passage 
of  the  clwme  from  the  stomach  into  the  intestine.  "Nothing  in  the 
animal  economy,"  says  Dr.  South  wood  Smith, ^  "is  more  curious  and 
wonderful  than  the  action  of  that  class  of  organs  of  which  the  pylorus 
fiffords  a  remarkable  example.  If  a  portion  of  undigested  food  present 
itself  at  this  door  of  the  stomach,  it  is  not  only  not  permitted  to  pass, 
but  the  door  is  closed  against  it  with  additional  firmness;  or,  in  other 
words,  the  muscular  fibres  of  the  pylorus,  instead  of  relaxing,  contract 
with  more  than  ordinary  force.  In  certain  cases,  where  the  digestion 
is  morbidly  slow,  or  where  very  indigestible  food  has  been  taken,  the 
mass  is  carried  to  the  pylorus  before  it  has  been  duh^  acted  upon  by 
the  gastric  juice:  then,  instead  of  inducing  the  pylorus  to  relax,  in 
order  to  allow  of  its  transmission  to  the  duodenum,  it  causes  it  to  con- 
tract with  so  much  violence  as  to  produce  pain,  while  the  food,  thus 
retained  in  the  stomach  longer  than  natural,  disorders  the  organ :  and 
if  digestion  cannot  ultimatel}^  be  performed,  that  disorder  goes  on 
increasing  until  vomiting  is  excited,  by  which  means  the  load  that 
oppressed  it  is  expelled. 

"The  pylorus  is  a  guardian  placed  between  the  first  and  the  second 
stomach,  in  order  to  prevent  any  substance  from  passing  from  the 
former  until  it  is  in  a  condition  to  be  acted  upon  by  the  latter;  and  so 
faithfully  does  this  guardian  perform  its  office,  that  it  often,  as  we  have 
seen,  forces  the  stomach  to  reject  the  offending  matter  by  vomiting, 
rather  than  allow  it  to  pass  in  an  unfit  state;  whereas,  when  chyme, 
duly  prepared,  presents  itself,  it  readily  opens  a  passage  for  it  into  the 
duodenum."  This  view  of  the  functions  of  the  pylorus  has  antiquity 
in  its  favour.  It  is,  indeed,  as  old  as  the  name,  which  was  given  to  it 
in  consequence  of  its  being  believed  to  be  a  faithful  porter  or  janitor 
{rtv-Kiopoi,  "a  porter");  but  it  is  doubtless  largely  hypothetical.  AVe  con- 
stantly see  substances  traverse  the  whole  extent  of  the  intestinal  canal, 
without  having  experienced  the  slightest  change  in  the  stomach.  But- 
tons, half-pence,  &c.,  have  made  their  way  through,  without  difiiculty; 
as  well  as  the  tubes  and  globes,  employed  in  the  experiments  of  Spal- 
lanzani,  Stevens,  and  others.  There  are  certain  parts  of  fruits,  which 
are  never  digested,  yet  the  "janitor"  is  always  accommodating.  Castor 
oil  is  capable  of  being  wholly  converted  into  chyle ;  and  would  be  so,  if 
it  could  be  retained  in  the  stomach  and  small  intestines;  yet  there  is 
no  agent,  which  arrests  its  onward  progress.  Still,  from  these,  and 
other  circumstances,  M.  Broussais^  has  inferred,  that  there  is  an  internal 
gastric  sense,  which  exerts  an  elective  agency ;  detaining,  as  a  general 
rule,  substances  that  are  nutritive ;  but  suffering  others  to  pass. 

'  Animal  Physiology,  Library  of  Useful  Knowledge,  p.  41. 

*  Traite  de  Physiol,  appliquee  a  la  Pathologie  ;  translated  bv  Drs.  Bell  and  La  Roche, 
p.  314,  Philad.,  1832. 


CHYMIFICATIOlSr.  143 

The  presence  of  food  in  the  stomach  after  a  meal  soon  excites  the 
organ  to  action,  although  no  change  in  the  food  is  perceptible  for  some 
time.  The  mucous  membrane  becomes  more  florid,  in  consequence  of 
the  larger  afflux  of  blood;  and  the  different  secretions  appear  to  take 
place  in  greater  abundance ;  become  mixed  with  the  food,  and  exert  an 
active  and  important  part  in  the  changes  it  experiences  in  the  stomach. 
Direct  experin>ent  has  proved  that  such  augmented  secretion  actually 
occurs.  If  an  animal  be  kept  fasting  for  some  time,  and  then  be  made 
to  swallow  dry  food,  or  even  stones,  and  be  deprived  of  liquid  aliment, 
the  substances  swallowed  will  be  found, — on  killing  it  some  time  after- 
wards,— surrounded  by  a  considerable  quantity  of  fluid.  Such  is  not 
the  case  with  animals  killed  after  fasting.  The  stomach  then  contains 
no  fluid  matter.  The  augmented  secretion  in  the  former  case  must, 
therefore,  be  owing  to  the  presence  of  dry  food  in  the  stomach.  That 
it  is  not  simply  the  fluid  passed  down  by  deglutition, — the  salivary  and 
mucous  secretions,  for  example, — is  proved  by  the  fact,  that  the  same 
thing  occurs  when  the  oesophagus  has  been  tied.  Besides,  if  the  sto- 
mach of  a  living  animal  be  opened,  and  any  stimulating  substance  be 
applied  to  its  inner  surface,  a  secretion  is  seen  to  issue  in  considerable 
quantity  at  the  points  of  contact;  and,  again,  if  an  animal  be  made  to 
swallow  small  pieces  of  sponge,  attached  to  a  thread  hanging  out  of  the 
mouth,  by  means  of  which  they  can  be  withdrawn,  they  become  filled 
with  the  fluids  secreted  by  the  stomach,  and,  on  withdrawing  them,  a 
sufficient  quantity  can  be  obtained  for  analysis.  Such  experiments 
have  been  repeatedly  performed  by  MM.  Reaumur,^  Spallanzani,^  and 
others.  In  Dr.  Beaumont's  case^  the  collection  of  gastric  secretion  was 
obtained  by  inserting  an  elastic  gum  tube  through  the  opening:  in  a 
short  time  fluid  enough  was  secreted  to  flow  through  the  tube.  This 
admixture  with  the  fluids  of  the  mucous  membrane  of  the  stomach,  and 
the  secretions  continually  sent  down  from  the  mouth  by  the  efforts  of 
deglutition,  is  the  only  apparent  change  witnessed  for  some  time  after 
the  reception  of  solid  food.  Sooner  or  later,  according  to  circumstances, 
the  pyloric  portion  of  the  organ  contracts,  sending  into  the  splenic  por- 
tion the  food  it  contains :  to  the  contraction  dilatation  succeeds ;  and 
this  alternation  of  movements  goes  on  during  the  whole  of  digestion. 
After  this  time  chyme  only  is  found  in  the  pyloric  portion  mixed  with 
a  small  quantity  of  unaltered  food.  This  motion  of  contraction  and 
relaxation  has  been  called  j^eristole;  and  it  appears,  at  first,  to  be  limited 
to  the  pyloric  portion,  but  gradually  extends  to  the  body  and  splenic 
portion,  so  that,  ultimately,  the  whole  stomach  participates  in  it.  It 
consists  in  an  alternate  contraction  and  relaxation  of  the  circular  fibres; 
and  the  gentle  oscillation,  thus  produced,  not  only  facilitates  the  admix- 
ture of  the  food  with  the  gastric  secretions,  but  continually  exposes 
fresh  portions  to  their  action.  The  experiments  of  Bichat  satisfied 
him,  that  the  peristole  is  more  marked,  the  greater  the  fulness  of  the 
stomach.  He  made  dogs  swallow  forced-meat  balls,  in  the  centre  of 
which  he  placed  cartilage,  and  found,  that  when  the  stomach  was  greatly 
charged,  the  cartilages  were  pressed  out  of  the  balls.  This  did  not  hap- 
pen, when  the  organ  contained  a  smaller  quantity  of  food. 

'  Memoir,  de  I'Acad.  pour  1752.  *  Exper.  sur  la  Digestion,  Geneve,  1783. 

'  Experiments,  &c.,  ou  the  Gastric  Juice,  p.  106. 


144  DIGESTION. 

The  ordinary  course  and  direction  of  the  revolutions  of  tlie  food, 
according  to  Dr.  Beaumont/  are  as  follows: — The  bolus,  as  it  enters 
the  cardia,  turns  to  the  left;  passes  the  aperture;  descends  into  the 
splenic  extremity,  and  follows  the  great  curvature  towards  the  pyloric 
end.  It  then  returns  in  the  course  of  the  lesser  curvature,  and  makes 
its  appearance  again  at  the  aperture  in  its  descent  into  the  great  curva- 
ture to  perform  similar  revolutions.  That  these  are  the  revolutions  of 
the  contents  of  the  stomach,  he  ascertained  by  identifying  particular 
portions  of  food;  and  by  the  fact,  that  when  the  bulb  of  the  thermo- 
meter was  introduced  during  chymification,  the  stem  invariably  indi- 
cated the  same  movements.  Each  revolution  is  completed  in  from  one 
to  three  minutes,  and  the  motions  are  slower  at  first  than  when  chymi- 
fication has  made  considerable  progress.  In  addition  to  these  move- 
ments, the  stomach  is  subjected  to  more  or  less  succussion  from  the 
neighbouring  organs.  At  each  inspiration  it  is  pressed  upon  by  the 
diaphragm;  and  the  large  arterial  trunks  in  its  vicinity,  as  well  as  the 
arteries  distributed  over  it,  subject  it  to  constant  agitation. 

It  has  been  already  remarked,  that  t\\e  peristaltic  or  vermicular  action 
— j)eristole — of  the  stomach, — and  the  action  extends  likewise  to  the 
intestines, — is  effected  by  the  muscular  coat  of  the  organ.  It  is,  how- 
ever, an  involuntary  contraction,  and  appears  to  be  little  influenced  by 
the  nervous  system ;  continuing,  for  instance,  after  the  division  of  the 
eighth  pair  of  nerves;  becoming  more  active,  according  to  ]\[.  Magen- 
die,^  as  animals  are  more  debilitated,  and  even  at  death ;  and  persisting 
after  the  alimentary  canal  has  been  removed  from  the  body.  MM, 
Tiedemann  and  Gmelin,^  however,  affirm,  that  by  irritating  the  plexus 
of  the  eighth  pair  of  nerves  situate  around  the  oesophagus  with  the 
point  of  a  scalpel,  or  touching  it  with  alcohol,  the  peristole  of  both 
stomach  and  intestines  can  be  constantly  excited;  and  Valentin  and 
Dr.  John  Reid  state,  that  distinct  movements  may  be  excited  in  the 
stomach  by  irritating  the  pneumogastric.  This  involuntary  function, 
as  well  as  that  exerted  by  the  heart  and  other  involuntary  organs,  affords 
us  a  striking  instance  of  the  little  nervous  influence,  which  seems  to  be 
requisite  for  carrying  on  many  of  those  functions  that  have  to  be  exe- 
cuted independently  of  volition  through  the  whole  course  of  existence; 
and  which  appear  to  be  excited  at  times,  in  a  reflex  manner,  by  the 
presence  of  appropriate  excitants; — of  food,  in  the  case  of  the  peri- 
staltic action  of  the  stomach ;  of  blood,  in  that  of  the  heart,  &c. ;  and 
yet  may  be  carried  on  in  the  absence  of  all  nervous  influence,  as  in  the 
cases  of  the  intestinal  canal,  and  the  heart,  which  may  contract  for  a 
long  time  after  they  have  been  removed  from  the  body.  In  the  intes- 
tinal canal,  the  movements  are  doubtless  influenced  by  the  spinal  cord, 
probably  through  the  sympathetic  by  means  of  the  fibres  which  the 
canal  derives  from  it;  but  although  influenced  by  the  spinal  cord,  they 
are  not  dependent  upon  it  for  contractility.  As  Dr.  Carpenter  has 
remarked,  the  canal  is  enabled  to  propel  its  contents  by  its  inherent 
powers ;  but — as  in  other  instances — the  nervous  centres  exert  a  gene- 
ral control  over  even  the  organic  functions,  "doubtless  for  the  purpose 

'  Op.  citat.,  p.  110.  2  Precis  Elementaire,  ii.  20. 

3  Die  Verdauung,  u.  s.w.,  or  Frencli  edit.,  Recherches  sur  la  Digestion,  Paris,  1S27. 


CHYMIFICATIO]^.  145 

of  liarraonizing  them  witli  eacli  otlier,  and  witli  the  conditions  of  tlie 
organs  of  animal  life."^ 

The  gentle,  oscillatory  or  vermicular  motion  of  the  stomach,  and  the 
admixture  with  the  fluids,  secreted  by  its  internal  membrane,  as  well 
as  by  the  different  follicles,  &c.,  in  the  supra-diaphragmatic  portion  of 
the  alimentary  canal,  are  probably  the  main  agents  in  the  digestion 
operated  in  the  stomach. 

Much  contrariety  of  sentiment  has  existed  regarding  the  precise 
organs  that  secrete  the  fluid  which  oozes  out  as  soon  as  food  is  placed 
in  contact  with  the  mucous  coat  of  the  stomach.  Whilst  some  believe 
it  to  be  exhaled  from  that  membrane;  others  conceive  it  to  be  secreted 
by  the  numerous  follicles,  seated  in  the  membrane  as  well  as  in  that 
of  the  lower  portion  of  the  oesophagus;  or  by  what  have  been  termed 
gastric  glands.  The  analogy  of  many  animals,  especially  of  birds,  would 
render  the  last  opinion  the  most  probable.  In  them  we  find,  in  the 
second  stomach,  the  cardiac  or  gastric  glands  largely  developed ;  and 
it  is  probable  that  they  are  the  great  agents  of  the  secretion  of  the 
digestive  fluid.  (See  Figs.  28  and  29.)  MM.  Tiedemann  and  Gmelin^ 
affirm,  that  the  more  liquid  portion  of  the  gastric  fluid  is  exhaled,  and 
that  the  thicker,  more  ropy  and  mucous  portion  is  secreted  by  the  fol- 
licles. Rudolphi^  assigns  it  a  double  origin; — from  exhalants,  and 
gastric  glands;  whilst  MM.  Leuret  and  Lassaigne^  ascribe  its  formation 
exclusively  to  the  villi.  The  views  of  Bernard  and  Kolliker  have  been 
given  before.* 

Dr.  Beaumont,^  who  had  an  excellent  opportunity  for  experimenting 
on  this  matter,  remarks,  that  on  applying  aliment,  or  any  irritant,  to 
the  internal  coat  of  the  stomach,  and  observing  the  effect  through  a 
magnifying-glass,  innumerable  minute,  lucid  points,  and  very  fine  pa- 
pilke,  could  be  seen  protruding,  from  which  a  pure,  limpid,  colourless, 
slightly  viscid  fluid  distilled,  which  was  invariably  and  distinctly  acid. 
On  applying  the  tongue  to  the  mucous  coat  in  its  empty,  unirritated 
state  of  the  stomach,  no  acid  taste  could  be  perceived.  Although  no 
apertures  were  perceptible  in  the  papillae,  even  with  the  assistance  of 
the  best  microscope  that  could  be  obtained,  the  points,  whence  the  fluid 
issued,  were  clearly  indicated  by  the  gradual  appearance  of  innumer- 
able very  fine,  lucid  specks,  rising  through  the  transparent  mucous 
coat,  and  seeming  to  burst,  and  discharge  themselves  upon  the  very 
points  of  the  papillas,  diffusing  a  limpid,  thin  fluid  over  the  whole 
interior  gastric  surface. 

A  like  difference  of  opinion  has  prevailed  regarding  the  chemical 
character  of  the  fluids;  and  this  has  partly  arisen  from  the  difficulty 
of  obtaining  them  identical.  The  true  fluid  secreted  by  the  gastric 
follicles  or  mucous  membrane  can  never,  of  course,  be  obtained  for 
examination  in  a  state  of  purity-  It  must  always  be  mixed  not  only 
with  the  other  secretions  of  the  stomach,  but  with  all  those  transmitted 
to  the  organ,  by  the  constant  efforts  of  deglutition.  It  is,  consequently, 
to  this  mixed  fluid  that  the  term  gastric  juice  has  really  been  applied; 

'  Human  Physiology,  p.  151,  Lond.,1842.  ^  Op.  citot. 

'  Grundriss  der  Physiologie,  2ter  Band,  2te  Abtlieilung,  s.  iii.,  Berlin,  1828. 
*  Reclierchos  surla  Digestion,  Paris,  1825.  *  Page  83.  ^  Op.  citat.,p.  103. 

VOL.  I.— 10 


1-16  DIGESTION. 

althougli  it  is  more  especially  appropriated  to  the  particular  fluid,  pre- 
sumed to  be  secreted  by  the  stomach,  and  to  be  the  great  agent  in  diges- 
tion. To  the  nature  of  the  gastric  juice  and  its  effects  in  the  process  of 
digestion,  we  shall  have  occasion  to  recur  presently. 

It  is  probably  owing  to  the  quantity  of  fluid  secreted  by  the  stomach, 
that  it  is  so  largely  supplied  with  bloodvessels;  and  that  the  mucous 
membrane  is  more  injected,  during  the  presence  of  food  in  the  organ. 
Experiments,  by  Sir  Benjamin  Brodie^  and  others,  would  seem  to  show, 
that  the  secretion  is  under  the  influence  of  the  eighth  pair  of  nerves. 
Having  administered  arsenic  to  difterent  animals — on  some  of  which 
he  had  divided  these  nerves, — he  found,  that,  whilst  the  stomachs  of 
those,  in  Avhich  the  nerves  were  entire,  contained  a  large  quantity  of  a 
thin,  mucous  fluid;  in  those,  whose  nerves  were  divided,  the  organ  was 
inflamed  and  dry.  Leuret  and  Lassaigne,'^  however,  affirm,  that  divi- 
sion of  the  nerves  had  no  influence  on  the  secretion.  But  more  of  this 
presently. 

Before  entering  into  the  views  of  different  physiologists  on  chymifi- 
cation, — in  other  words,  into  the  theories  of  digestion, — it  will  be  well 
to  refer  to  the  physical  and  chemical  properties  of  the  chyme.  Whether 
the  changes  in  the  food  be  simply  physical  or  chemical,  or  whether  the 
first  stage  of  animalization  be  eflected  within  the  stomach,  will  be  a 
topic  for  future  inquiry.  Chyme  is  a  soft,  homogeneous  substance,  of 
grayish  colour  and  acid  taste.  Such  are  its  most  common  characters: 
it  varies,  however,  according  to  the  food  taken,  as  may  be  observed,  by 
feeding  animals  on  difierent  simple  alimentary  substances,  and  killing 
them  during  digestion.  This  ditierence  in  its  properties  accounts  for 
the  discrepancy  observable  in  the  accounts  of  writers.  The  change 
wrought  on  aliments  is,  doubtless,  of  a  chemical  nature;  but  the  new 
play  of  aflinities  is  controlled  by  circumstances  inappreciable  to  us. 
In  the  case  of  a  female  patient  at  the  hospital  La  Gharite,  of  Paris, 
who  had  been  gored  by  a  bull,  and  had  a  fistulous  opening  in  the  sto- 
mach, the  fopd,  during  its  conversion  into  chyme,  appeared  to  have 
acquired  an  increase  of  its  gelatin  ;  a  greater  proportion  of  chloride  of 
sodium;  phosphate  of  soda  and  phosphate  of  lime ;  and  a  substance,  in 
appearance,  fibrinous.-'' 

It  has  been  said,  again,  that  the  food  becomes  decarbonized  and  more 
nitrogenized ;  that  the  carbon  which  disappears  is  removed  by  the  oxy- 
gen of  the  air  swallowed  with  the  food,  or  by  that  contained  in  the  food 
itself;  and  that  the  nitrogen  proceeds  from  the  secretions  of  the  sto- 
mach, or  predominates  simply  because  the  food  is  decarbonized.  M. 
Adelon-*  has  properly  remarked,  that  the  fact  and  the  explanation  are 
here  equally  hypothetical.  Generally,  the  chyme  possesses  acid  pro- 
perties. MM.  de  Montegre,^  Magendie,'^  and  Tiedemann  and  Gmelin,^ 
always  observed  it  to  be  so.  Haller*  and  Marcet  found  it  to  be  neither 
acid  nor  alkaline.  In  the  chyme  examined  by  the  latter  gentleman,  he 
detected  albumen,  an  animal  matter,  and  some  salts,  difi'ering,  however, 

'  Philos.  Trans,  for  1S14.,  2  Op.  citat. 

3  Richerand's  Nouveaux  Elemens  de  Physiologic,  edit.  13eme,  par  Berard,  aine,  p.  72, 
Bruxelles,  1837. 

*  Physiol,  de  rHomme,  &c.,  edit,  cit.,  torn.  ii. 

5  Experiences  sur  la  Digestion,  Paris,  1824.  6  Op.  citat.,  ii.  p.  87. 

7  Op.  cit.  8  Element.  Physiol.,  xix.  1. 


CHYMIFICATIOX.  147 

slightly,  according  as  it  proceeded  from  animal  or  vegetable  food.  In 
the  latter  case,  it  aflbrded  four  times  as  much  carbon  as  in  the  former, 
but  less  saline  matter;  and  this  consisted  of  lime  and  an  alkaline  chlo- 
ride. MM.  Leuret  and  Lassaigne^  analyzed  the  chyme  from  the  sto- 
mach of  an  epileptic,  who  died  suddenly  in  a  fit,  five  or  six  hours  after 
having  eaten.  It  was  of  a  white,  slightly-yellowish  colour;  and  strong, 
disagreeable  taste.  On  analysis,  it  afforded  a  free  acid, —  the  lactic ;  a 
white,  crystalline,  slightly  saccharine  matter,  analogous  to  the  sugar  of 
milk;  albumen,  soluble  in  water;  a  yellowish,  fatty,  acid  matter,  ana- 
logous to  rancid  butter;  an  animal  matter,  soluble  in  water,  having  all 
the  properties  of  casein ;  and  a  little  chloride  of  sodium,  phosphate  of 
soda,  and  much  phosphate  of  lime.  Dr.  Prout^  affirms,  that  a  quantity 
of  chlorohydric  acid  is  present  in  the  stomach  during  the  process  of 
digestion.  He  detected  it  in  that  of  the  rabbit,  hare,  horse,  calf,  and 
dog,  and  in  the  sour  matter  ejected  by  persons  labouring  under  indi- 
gestion : — a  fact  which  has  been  confirmed  by  Mr.  Children.  MM. 
Tiedemann  and  Gmelin,  and  Dr.  Beaumont,^  affirm,  that  the  secretion 
of  acid  commences,  as  soon  as  the  stomach  receives  the  stimulus  of  a 
foreign  body,  and  that  it  consists  of  chlorohydric  and  acetic  acids. 
The  experiments  of  these  gentlemen  were  not  confined  to  the  chymous 
mass  obtained  from  digestible  food.  They  examined  the  fluids,  secreted 
by  the  mucous  membrane  when  indigestible  substances  were  sent  into 
the  stomach,  and  the  acid  character  was  equally  manifested.  These  ex- 
periments, consequently,  remove  an  objection,  made  by  Dr.  Bostock,"* 
regarding  the  detection  of  the  chlorohydric  acid  by  Dr.  Prout; — that, 
as  there  did  not  appear  to  be  any  evidence  of  the  existence  of  this  acid 
before  the  introduction  of  food  into  the  stomach,  it  might  rather  be 
inferred,  that  it  is,  in  some  way  or  other,  developed  during  the  process 
of  digestion.  In  all  Dr.  Beaumont's  experiments,  the  chyme  was  in- 
variably and  distinct!}^  acid. 

The  principal  theories  on  chymification  have  been  the  following  :* — 
1.  Coction^  or  elixation. — This  originated  with  Hippocrates,  and  was 
vaguely  used  by  him  to  signify  the  maceration,  and  maturation  expe- 
rienced by  the  food  in  the  stomach.  The  doctrine  was  embraced  by 
Galen  and,  others,  Avho  ascribed  to  the  organ,  an  attracting,  retaining, 
concocting,  and  expelling  quality  effected  by  heat.*  In  proof  of  this, 
they  affirmed  that  the  heat  of  the  stomach  is  increased  during  chymi- 
fication ;  that  the  process  is  more  rapid  in  the  warm,  than  cold-blooded 
animal;  that  it  is  aided  by  artificial  heat,  and  continues  even  after  death, 
if  care  be  taken  to  keep  up  the  heat  of  the  body;  that  in  the  experi- 
ments on  artificial  digestion  made  by  Spallanzani,  heat  was  always 
necessary,  and  the  greater  the  degree  of  heat  the  more  easy  and  com- 
plete the  digestion. 

It  is  hardly  necessary  to  say  that  the  heat  of  the  stomach  is  totally 
insufficient  to  excite  any  coction  or  ebullition  in  the  physical  sense  of 

'  Eecherches,  &c.,  p.  114. 

*  Philos.  Trans,  for  1824;  and  Bridgewater  Treatise  on  Chemistry,  &c.,  Amer.  edit., 
*p.  268,  Philad.,  1834. 

^  On  the  (lastric  Juice,  &c.,  p.  105.  "  Physiology,  3d  edit.,  p.  569,  Lend.,  1836. 

*  For  different  theories,  ancient  and  modern,  on  chymification,  see  Berand,  Manuel  de 
Physiologie,  p.  130,  Paris,  1853. 

••  Boerhaav.,  Piselectiones  Academ.  Not.  Adv.,  §86,  torn,  i..  Gutting.,  1740-1743. 


148  DIGESTION". 

tlie  term,  and  this  applies  ])articularly  to  tlie  cold-blooded  animal,  wliicli 
must  digest,  if  not  witli  the  same,  with  due,  rapidity. 

2.  Putrefaction. — The  next  great  hypothesis  was  that  oi  putrefaction, 
which,  we  are  informed  by  Celsus,'  was  embraced  by  Plistonicus,  a  dis- 
ciple of  Praxagoras  of  Cos,  who  flourished  upwards  of  three  hundred 
years  before  the  birth  of  Christ.  Of  late,  it  has  had  no  advocates,  but 
appears  to  have  been  the  view  embraced  by  Cheselden,^  The  reasons, 
urged  in  favour  of  it,  have  been; — the  putrescible  character  of  the  ma- 
terials employed  as  food;  the  favourable  circumstances  of  a  heat  of 
98°  or  100°,  and  of  moisture;  and,  by  some,  the  foetor  of  the  excre- 
ments. The  objections  are,  1.  That  when  the  contents  of  the  stomach 
are  rejected,  during  chymification,  they  exhibit  no  evidence  of  putridity. 
2.  That  in  all  the  experiments,  which  have  been  made  on  the  compara- 
tive digestibility  of  different  substances,  Avhen  it  has  been  necessary  to 
kill  the  animals  at  different  stages  of  the  digestive  process,  there  has 
not  been  the  slightest  sign  of  putrefaction.  8.  That  opportunities  fre- 
quently occur  for  v/itnessing  ravenous  fishes  and  reptiles  with  an  ani- 
mal or  portion  of  an  animal, — too  large  to  be  entirely  swallowed, — 
partly  in  the  stomach,  and  the  remainder  in  the  gullet  and  mouth.  In 
these  cases,  where  the  food  has  remained  in  this  situation  some  days, 
the  part  contained  in  the  throat  has  been  found  putrid,  whilst  that  in 
the  stomach  has  been  entirely  sweet ;  and  lastly,  in  Spallanzani's  and 
other  experiments,  to  be  detailed  presently,  it  was  found,  when  food, 
in  a  state  of  putridity,  was  taken  into  the  stomach,  or  mixed  with  the 
gastric  juice  out  of  the  stomach,  that  it  recovered  its  sweetness.  It  has 
been  already  observed,  that  it  is  the  custom,  in  some  countries,  to  eat 
the  gilier  or  game  in  a  state  of  incipient  putrefaction;  jet  the  breath 
is  not  tainted  by  it. 

3.  Trituration. — The  mathematical  phj'siologists, — Borelli,^  Hecquet,^ 
Megallotti,^  Pitcairne,^  and  others, — after  the  example  of  Erisistratus,^ 
attempted  to  refer  the  whole  process  of  digestion  to  trituration,  imagin- 
ing, that  the  food  is  subjected  in  the  stomach  to  an  action  similar  to 
that  of  the  pestle  and  mortar  of  the  apothecary,  or  of  the  millstone; 
and  that  the  chyle  is  formed  like  an  emulsion.  The  most  plausible 
arguments,  in  favour  of  this  view  of  the  subject,  are  drawn  from  the 
presumed  analogy  of  the  granivorous  bird,  whose  stomach  is  capable 
of  exerting  an  astonishing  degree  of  pressure  on  substances  submitted 
to  it.  There  is  no  analogy,  however,  between  the  human  stomach,  and 
the  gizzard  of  birds.  The  latter  is  a  masticatory  organ,  and  therefore 
possessed  of  the  surprising  powers  which  we  have  elsewhere  described; 
whilst  mastication,  in  man,  is  accomplished  by  distinct  organs.  No 
comparison  can  be  instituted  between  the  gentle  oscillatory  motion  of 
the  stomach,  and  the  forcible  compression  exerted  by  the  digastric 
muscle  of  the  gizzard.  The  simple  introduction  of  the  finger  through 
a  wound  of  the  abdomen  has  shown,  that  the  compression  exerted  by 

'  De  Medicina,  cura  E.  Milligan,  edit.  2da,  p.  5,  Edinb.,  1831. 

2  Anatomy  of  the  Human  Body,  &c.,  8tli  edit.,  p.  155,  Lend.,  17C3. 

*  De  Motu  Animalium;  Addit.  J.  Bernouillii,  M.  D.,  Medit.  Math.em.  MusciiL,  Lusd. 
Bat.,  1710. 

*  Traite  de  la  Digestion,  Paris,  1710.  5  Haller,  Elem.  Physiol.,  six.  5. 
6  Works,  &c.,  Lond.,  1715.                                         '•  Cels.,  loc.  citat. 


CHYMIFICATIOX.  14:9 

it  on  its  contents  is  totally  insufficient  to  bruise  any  resisting  substance. 
Moreover,  we  constantly  see  fruits, — as  raisins  and  currants, — passing 
through  the  whole  intestinal  canal  unchanged ;  whilst  worms  remain 
in  the  stomach — reside  there — unhurt;  and,  we  shall  see  presently, 
that  the  experiments  of  Eeaumur  and  Spallanzani  proved  most  con- 
vincingly, that  digestion  is  effected  independently  of  all  pressure.  The 
futility,  indeed,  of  this  mode  of  viewing  the  sulDJect  is  signally  illus- 
trated by  the  fact,  that,  whilst  Pitcairne  estimated  the  power  of  the 
muscular  fibres  of  the  stomach  at  12,951  pounds.  Hales'  thought  that 
twenty  pounds  would  come _ nearer  the  truth;  and  Astruc^  valued  its 
compressive  force  at  five  ounces ! 

4.  Fermentation. — The  system  of  fermentation  had  many  partisans; 
amongst  whom  may  be  mentioned  Van  Helmont,^  Sylvius,'*  Willis,^ 
Boyle,^  Grew,^  Charleton,^  Lower,^  Easpail,^"  &c.  Digestion,  in  this 
view,  was  ascribed  to  the  chemical  reaction  of  the  elements  of  the  food 
during  their  stay  in  the  stomach; — the  action  being  excited  by  food 
that  had  already  undergone  digestion,  or  by  a  leaven  secreted  for  the 
purpose  by  the  stomach  itself.  In  favour  of  this  view,  it  was  attempted 
to  show,  that  air  is  constantly  generated  in  the  organ,  and  that  an  acid 
is  always  produced  as  the  result  of  fermentation, — the  formation  of 
chyme  being  referred  by  the  greater  number  of  physiologists  to  the 
food  undergoing  the  vinous  and  acetous  fermentations.  The  objections 
to  this  doctrine  of  fermentation  are; — that  digestion  ought  to  be  totally 
independent  of  the  stomach,  except  as  regards  temperature;  and  the 
food  ought  to  be  converted  into  chyme,  exactly  in  the  same  manner, — 
if  it  were  reduced  to  the  same  consistence,  and  placed  in  the  same  tem- 
perature,— out  of  the  body ;  which  is  not  found  to  be  the  case.  Bones 
are  speedily  reduced  to  chyme  in  the  stomach  of  the  dog,  although 
they  would  remain  unchanged  for  weeks,  in  the  same  temperature,  out 
of  the  body.  The  facts  of  the  voracious  fishes  before  mentioned  like- 
wise prove  the  insufiiciency  of  the  hypothesis;  according  to  which, 
digestion  ought  to  be  accomplished  as  effectually  in  the  oesophagus  as 
in  the  stomach.  Yet  it  is  found  that,  whilst  the  portion  in  the  stomach 
is  digested,  the  other  may  be  unaltered,  or  be  putrid.  The  truth  is; — 
in  healthy  digestion,  fermentation,  in  the  ordinary  acceptation  of  the 
term,  does  not  occur;  and,  Avhenever  the  elements  of  the  food  react 
upon  each  other,  it  is  an  evidence  of  imperfect  digestion ;  hence,  fer- 
mentation is  one  of  the  most  common  signs  of  dj^spepsia. 

5.  Chemical  solution. — The  theory  of  chemical  solution,  jDroposed  by 
Spallanzani,"  and  subjected  to  modifications,  has  met  with  more  favour 
from  physiologists  than  any  of  the  others  that  have  been  mentioned, 
and  may  be  regarded  as  established.      According  to  that  observer, 

•  statical  Essays,  ii.  174,  4th  edit,,  Lond.,  1769. 

^  Traite  de  la  Cause  de  la  Digestion,  &c.,  Toulouse,  1714;  and  Haller,  loc.  citat. 
'  Ortus  Medicinae,  &c.,  Amstel.,  1G48.  *  Opera,  Genev.,  1781. 

'  Diatribae  duse  Medico-Pliilosopliicte,  &c.,  Lond.,  1659. 
®  Works,  vol.  ii.,  Lond.,  1772. 

^  Comp.  Anat.  of  the  Stomach,  kc,  Lond.,  1681.  *  CEcou.  Anim.  Exerc.  2. 

^  Tractatus  de  Corde,  &c.,  Amstel.,  1G71. 
'°  Chimie  Organique,  p.  356,  Paris,  1833. 

"  Dissertations  relative  to  the  Natural  History  of  Animals  and  Vegetables:  sect,  i., 
Lond.,  1789. 


150  DIGESTION. 

chymKication  is  owing  to  the  solvent  action  of  a  fluid,  secreted  by  the 
stomach,  which  accumulates  in  that  viscus  between  meals  and  during 
hunger,^  and  acts  as  a  true  menstruum  on  the  substances  exposed  to  it. 
This  fluid, — to  which  he  gave  the  name  gastric  juice^ — he  affirmed  to 
be  peculiar  in  each  animal,  according  to  its  kind  of  alimentation, — 
corresponding,  as  regards  its  energy,  with  the  rest  of  the  digestive 
apparatus,  and  differing  in  its  source  in  the  series  of  animals;  in  some, 
proceeding  from  the  follicles  of  the  oesophagus;  in  others  from  those 
of  the  stomach;  but  always  identical  in  the  same  animal;  generally 
transparent,  yellowish ;  of  a  saline  taste;  bitter;  slightly  volatile;  and 
stronger  in  animals  with  a  membranous  than  in  those  with  a  muscular 
stomach,  and  than  in  ruminant  animals.  To  obtain  tbe  juice,  Spallan- 
zani  opened  animals,  after  they  had  been  made  to  fast  for  a  time;  and 
collected  the  juice  that  had  accumulated  in  their  stomachs;  or  he  made 
them  swallow  tubes  pierced  with  holes,  and  filled  with  small  sponges. 
By  withdrawing  these  tubes,  by  means  of  a  thread  attached  to  them 
and  suffered  to  hang  out  of  the  mouth,  and  expressing  the  sponges,  he 
obtained  the  fluid  in  quantity  sufficient  for  examination.  To  determine 
■whether  this  fluid,  obtained  from  fasting  animals,  was  destined  to  chy- 
mify  the  food,  he  tried  the  following  experiments.  He  caused  numerous 
animals  to  swallow  tubes  filled  Avith  food,  but  pierced  with  holes,  so 
that  the  juices  of  the  stomach  might  be  able  to  get  into  their  interior; 
and-fouud  that  chymification  was  effected,  when  he  had  taken  the  pre- 
caution to  chew  the  substances  before  they  were  pitt  into  the  tubes,  or 
to  triturate  them;  and  the  process  was  alwa3^s  more  readily  accom- 
plished, the  more  easy  the  access  of  the  fluids.  On  repeating  these 
experiments  on  animals  of  various  kinds,  with  a  muscular  or  mem- 
branous, and  musculo-membranous  stomach ;  on  pullets,  turkeys,  ducks, 
pigeons,  rooks,  frogs,  salamanders,  eels,  serpents,  sheep,  cats,  &c.,  he 
obtained  the  same  results;  and  hence  he  affirmed,  that  trituration  can- 
not be  the  essence  of  chymification.  Eeaumur,^ — originally  a  believer 
in  the  doctrine  of  trituration, — had  previously  arrived  at  the  same  con- 
clusion, by  experiments  of  a  similar  kind.  Spallanzani  next  repeated 
those  experiments  upon  himself.  Having  well  chewed  different  articles 
of  food,  he  enclosed  them  in  wooden  tubes  pierced  with  holes,  and 
swallowed  them ;  but,  as  the  tubes  caused  pain  in  the  bowels,  he  sub- 
stituted small  bags  of  linen.  The  substances  contained  in  bags  were 
digested  without  the  bags  being  torn;  a  fact,  which  proved,  that  diges- 
tion must  have  been  accomplished  by  means  of  a  fluid,  that  penetrated 
them.  In  1777,  Dr.  Stevens^  repeated  these  experiments.  He  made  a 
person  swallow  balls  of  metal,  filled  with  masticated  food,  and  pierced 
with  holes:  when  the  balls  were  voided, — thirty-six  or  fortj^-eight  hours 
afterwards, — they  were  entirely  empty.  Lastly. — Spallanzani  was  de- 
sirous of  seeing  whether  this  solvent  juice  could  effect  digestion  out  of 
the  body.  He  put  ^ome  Avell-raasticated  food  in  small  glass  tubes,  and 
mixed  gastric  juice  with  it.  These  tubes  he  placed  in  his  axilla,  in 
order  that  they  might  be  exposed  to  the  same  degree  of  heat  as  in  the 

'  It  has  been  already  stated,  that  the  experiments  of  Dr,  Beaumont  have  satisfac- 
torily proved  that  no  such  accumulation  takes  place  during  hunger. 

2  Memoir,  de  I'Acad.  pour  1752.  ^  De  Alimentorum  Concoctione,  §  24 


CHYMIFICATION".  151 

stomacli ;  and  in  the  space  of  fifteen  hours,  or  of  two  clays, — more  or 
less, — the  substances  appeared  to  be  converted  into  chyme.  In  these 
experiments  he  found  it  important  to  employ  gastric  juice,  that  had  not 
been  previously  used,  and  to  have  a  sufficient  quantity  of  it. 

From  all  these  experiments,  Spallanzani  conceived  it  to  be  demon- 
strated, that  chymification  is  a  true  chemical  solution;  and  he  endea- 
voured to  deduce  from  them  the  degree  of  digestibility  of  different 
alimentary  substances.  Similar  experiments  were  instituted  by  Dr. 
Beaumont.'  In  all  cases,  solution  occurred  as  perfectly  in  the  artificial 
as  in  the  real  digestions,  but  they  were  longer  in  being  accomplished, 
for  reasons  which  appear  sufficient  to  explain  the  difference.  In  the 
former,  the  gastric  secretion  is  not  continuous;  the  temperature  cannot 
be  as  accurately  maintained,  and  there  is  an  absence  of  those  gentle 
motions  of  the  stomach,  wliich  are  manifestly  so  useful  in  accomplish- 
ing real  digestion. 

With  regard  to  the  precise  nature  of  the  gastric  juice  of  Spallanzani, 
we  have  already  observed  that  great  contrariety  of  sentiment  has  pre- 
vailed; and  that,  in  ordinary  cases,  it  is  impracticable  to  procure  it 
unmixed  with  the  other  secretions  of  the  dia-estive  mucous  membrane. 
Spallanzani  affirmed,  that  the  only  properties  he  detected  in  it,  were, — 
a  slightly  salt,  bitterish  taste;  it  was  neither  acid  nor  alkaline.  Gosse^ 
found  it  vary  according  to  the  nature  of  the  animal, — whether  herbi- 
vorous or  carnivorous; — and  to  be  always  acid  in  the  former.  Dyimas^ 
held  the  same  sentiments,  and  maintained,  from  experiments  on  dogs, 
that  it  was  acid  or  alkaline,  according  as  the  animal'  had  fed  on  vege- 
table or  animal  diet.  He  declared  it,  moreover,  to  be  mawkish,  thick, 
and  viscid.  Viridet*  and  others  affirmed  that  it  was  always  acid.  Mr. 
Ilunter^  was  not  inclined  to  suppose,  that  there  is  any  acid  in  the  gas- 
tric juice  as  a  component  or  essential  part  of  it,  "although  an  acid  is 
very  commonly  discovered  even  when  no  vegetable  matter  has  been 
introduced  into  the  stomach."  Scopoli^  analyzed  the  gastric  juice  of 
the  rook,  and  found  it  to  consist  of  water,  gelatin,  a  saponaceous  matter, 
muriate  of  ammonia,  and  phosphate  of  lime.  Carminati^  describes  it 
as  salt,  bitter,  and  frequently  acid;  and  MM.  Macquart^  and  Yauquelin,' 
in  the  gastric  juice  of  the  ruminant  animal,  found  albumen  and  fi-ee 
phosphoric  acid.'°  All  these  analyses  were  made  on  the  mixed  fluid, 
to  which  the  term  gastric  juice  has  been  applied.  That  such  a  mixed 
fluid  does  exist  in  the  stomach  at  the  time  of  chymification,  and  is 
largely  concerned  in  the  process,  is  proved  by  the  facts  already  men- 
tioned, as  well  as  by  the  following.  M.  Magendie"  asserts,  that  one  of 
his  pupils — M.  Pinel — could  procure,  in  a  short  time  after  swallowing 
a  little  water  or  solid  food,  as  much  as  half  a  pint.     M.  Pinel  "pos- 

'  Op.  citat.,  p.  139.  *  Experiences  sur  la  Digestion,  §81,  Genev.,  17S3. 

*  Principes  de  Pliysiologie,  Paris,  1806. 

*  Tractatus  Novus  de  Prima  Coctione,  &c.,  Genev.,  1G91. 

*  Observations  on  Certain  Parts  of  the  Animal  Econoniv,  with  Notes  by  Prof.  Owen, 
Amer.  edit.,  p.  134,  Philad.,  1840.  ^  In  Spallanzani,  §  244. 

'  Ricerche  suUa  Natura,  &c.,  del  Succo  Gastrico,  Milano,  1785  ;   or  Journal  Phys., 
t.  xxiv.  ^ 

*  Mem.  de  la  Societe  de  Med.,  Paris,  1786.  ^  Fourcroy,  Elem.  de  Cliim.,  torn.  iv. 
'°  See  Burdach,  Die  Pliysiologie  als  Erfahrungswissenschaft,  v.  240  und  431,  Leipzitr, 

1835.  ^  "  Precis,  &c.,  ii.  11. 


152  DIGESTION. 

sessed  the  faculty  of  vomiting  at  pleasure."  In  tliis  wa}^,  he  obtained 
from  his  stomach,  in  the  morning,  about  three  ounces  of  fluid,  which 
was  analyzed  by  M.  Thdnard,  who  found  it  composed  of  a  considerable 
quantity  of  water,  a  little  mucus,  and  salts  with  a  base  of  soda  and 
lime ;  but  it  was  not  sensibly  acid,  either  to  the  tongue  or  to  reagents. 
On  another  occasion,  M.  Pinel  obtained  two  ounces  of  fluid  in  the  same 
manner.  This  was  analyzed  by  ]M.  Chevreul,  and  found  to  contain 
much  water,  a  considerable  quantity  of  mucus,  lactic  acid — united  to 
an  animal  matter,  soluble  in  water,  and  insoluble  in  alcohol, — a  little 
muriate  of  ammonia,  chloride  of  potassium,  and  some  chloride  of  sodium. 
Messrs.  Tiedemann  and  Gmelin^  procured  the  gastric  fluid  by  making 
animals,  that  had  fasted,  swallow  indigestible  substances,  as  flints.  It 
always  appeared  to  them  to  be  produced  in  greater  quantity,  and  to 
have  a  more  acid  character,  in  proportion  as  the  alimentary  matter  was 
less  digestible  and  less  soluble ;  and  they  assign  it,  as  constituents, — 
chlorohydric  acid ;  acetic  acid ;  mucus ;  no,  or  very  little,  albumen ; 
salivary  matter;  osmazome;  chloride  of  sodium,  and  sulphate  of  soda. 
In  the  ashes,  remaining  after  incineration,  were,  carbonate,  phosphate, 
and  sulphate  of  lime,  and  chloride  of  calcium.  MM.  Leuret  and  Las- 
saigne^  assign  its  composition,  in  one  hundred  parts,  to  be, — water, 
ninety-eight;  lactic  acid;  muriate  of  ammonia;  chloride  of  sodium; 
animal  matter  soluble  in  water ;  mucus ;  and  phosphate  of  lime,  two 
parts.  M.  Braconnot'  examined  the  gastric  juice  of  a  dog,  and  found 
it  to  contain — free  chlorohydric  acid  in  great  abundance ;  muriate  of 
ammonia;  chloride  of  sodium  in  very  great  quantity;  chloride  of  cal- 
cium; a  trace  of  chloride  of  potassium;  chloride  of  iron;  chloride  of 
magnesium;  colourless  oil  of  an  acid  taste;  animal  matter  soluble  in 
water  and  alcohol,  in  very  considerable  quantity;  animal  matter  solu- 
ble in  weak  acids ;  animal  matter  soluble  in  water,  and  insoluble  in 
dlcohoi  {salivary  matter  of  Gmelin);  mucus;  and  phosphate  of  lime. 
In  the  winter  of  1832-3,  the  author  was  favoured  by  Dr.  Beaumont,"* 
with  a  quantity  of  the  gastric  secretion  obtained  from  the  individual 
with  the  fistulous  opening  into  the  stomach,  which  was  examined  by 
himself,  and  his  friend,  the  late  Professor  Emmet,  of  the  University  of 
Virginia,  and  found  to  contain  free  chlorohydric  and  acetic  acids, 
phosphates,  and  chlorides,  with  bases  of  potassa,  soda,  magnesia,  and 
lime,  and  an  animal  matter — probably  pe/^sm — soluble  in  cold  water, 
but  insoluble  in  hot.  The  quantity  of  free  chlorohydric  acid  was  sur- 
j^rising :  on  distilling  the  fluid,  the  acids  passed  over,  the  salts  and 
animal  matter  remaining  in  the  retort:  the  amount  of  chloride  of  sil- 
ver thrown  down  on  the  addition  of  the  nitrate  of  silver  to  the  dis- 
tilled fluid,  was  astonishing.  The  author  had  many  opportunities  for 
examining  the  gastric  secretion  obtained  from  the  case  in  question.  At 
all  times,  when  pure  or  unmixed  except  with  a  portion  of  the  mucus 
of  the  lining  membrane  of  the  digestive  tube,  it  was  a  transparent 
fluid,  having  a  marked  smell  of  chlorohydric  acid;  and  of  a  slightly 

1  Op.  cit.  2  Recherc]ies,cS:c.,  Paris,  1825. 

s  Journal  de  Chimie  Medicale,  torn,  ii.,  ser.  2,  1S36,  and  Records  of  General  Science, 
Jan.,  1836. 

*  See  a  letter  from  the  author  to  Pr.  Beaumont,  in  Beaumont's  Experiments,  &c.,  on 
the  Gastric  Juice,  p.  77 ;  and  the  author's  Elements  of  Hygiene,  p.  21G,  Philad.,  1835. 


CHYMIFICATIO:^-.  153 

salt,  and  very  perceptibly  acid,  taste.  It  matters  not,  therefore,  that 
M.  Blondlot,^  in  his  experiments  on  the  gastric  secretions  of  dogs  and 
other  animals,  obtained  by  artificial  fistulous  openings  made  into  the 
stomach,  did  not  find,  when  distilled,  that  they  exhibited  any  acid 
reaction,  whilst  the  residue  in  the  retort  was  always  strongly  acid. 
The  results  referred  to  by  the  author  as  regards  the  gastric  juice  of 
man  were  positive  and  uniform ;  and  established,  that  it  always  con- 
tains a  large  quantity  of  chlorohydric  acid. 

Moreover,  free  chlorohydric  acid  was  found  in  the  gastric  juice  of 
animals  by  Enderlin,^  Hiibbenet,^  and  Bidder  and  Schmidt.'*  Funke' 
is  of  opinion  that  their  researches  leave  no  doubt  on  the  subject  of 
its  presence ;  and  Dr.  Brinton,"  after  an  inquiry  into  the  whole  matter, 
thinks  "  there  seems  little  doubt  that  we  ought  to  regard  the  balance 
of  evidence  as  inclining  decisively  towards  a  single  gastric  acid,"  and 
that  acid  the  chlorohydric.  Schmidt  is  of  opinion,  that  the  essential 
gastric  acid  is  the  chlorohj^dric,  and  believes  it  to  be  a  conjugated  acid 
in  union  with  pepsin — chloro-pepso-hydric  acid — chlorj^epsimcosserstoff'- 
sdure; — the  existence  of  which  is  hypothetical.''  More  recently, 
Griinewaldt^  has  had  an  opportunity  of  instituting  a  variet}^  of  expe- 
riments in  a  case  of  fistulous  opening  into  the  stomach  of  a  woman. 
Three  analyses  of  the  fluid  obtained  were  made  by  Schmidt,  who 
found  the  mean  to  be  as  follows : — 

Water 90.44 

Solid  residue    .         .         .         .         .         .         .         .         .         .         0.5(5 

Ferment,  &c 0.32 

Inorganic  constituents       .         .         .         •         .         .         .         .  0.24 

Chloroliydric  acid     ..........  0.02 

Chloride  of  potassium      .         .         .         .         .         .         .         .  0.06 

"         of  sodium  ........  0.15 

"         of  calcium 0.006 

Phosphate  of  lime,  magnesia,  and  iron     .         .         .         .         .  0.013 

From  this  analysis  it  is  manifest,  that  the  proportion  of  water  is 
very  great.  It  would  seem,  indeed,  that  an  enormous  amount  of  fluid 
is  secreted  from  the  stomach  in  the  twenty-four  hours.  It  has  been 
attempted  to  estimate  the  amount  by  that  of  the  albuminous  matter 
known  to  be  dissolved  by  it;  but  all  calculations  thus  made  must  be 
vague  and  uncertain.  Certain  aliments  are  known  to  occasion  a  more 
copious  secretion  of  the  gastric  solvent  than  others;  and  those  nitro- 
genized  substances  which  remain  longest  in  the  stomach  will  require 

'  Traite  Analytique  de  la  Digestion,  Paris,  1844.  An  abstract  of  his  views  is  given 
by  Mr.  Pa^et,  Brit,  and  For.  Med.  Rev.,  Jan.,  1845,  p.  270 ;  see,  also,  Gazette  Medicale 
de  Paris,  1851,  No.  33,  p.  526. 

2  Canstatt,  Jahresbericht,  1843,  i.  149. 

'  Disquisitiones  de  Succo  Gastrico,  Dorp.  Liv.  1850:  and  Canstatt,  op.  cit.,  1851,  s. 
97,  and  1852,  s.  109. 

*  Die  Verdauungsafte  und  der  Stoffwechsel,  s.  46,  Mitau  und  Leipzig,  1852. 

^  Rudolph  Wagner's  Lehrbuch  der  Speciellen  Physiologie,  von  D.  Otto  Funke,  s.  163, 
Leipz.,  1854. 

'  Art.  Stomach  and  Intestines  in  Cyclop,  of  Anat.  and  Physiol.,  Pt.  46,  p.  332,  June, 
1855. 

'  Moleschott,  Physiologie  des  StofFwechsels,  u.  s.w.,s.  428,  Erlangen,  1851  ;  and  Leh- 
mann,  Lehrbuch  der  Physiologisch.  Chemie,  iii.  330,  Leipz.,  1852. 

*  Succi  Gastrici  Huniani  Indoles,  &c.,  Dorpat,  1853 ;  Vierordt's  Archiv.  fiir  Physiol. 
Ileilkund.  xiii.  459 ;  and  Canstatt,  1854,  i.  145,  Wtirzburg,  1855.  Griiucwaldt  found 
free  chlorohydric  acid  in  smaller  proportion  in  man  than  in  animals. 


154  DIGESTION". 

a  greater  amount  of  fluid.  Lelimanu^  estimates  the  daily  quantity  in 
man  to  be  al)out  four  pounds;  whilst  Bidder  and  Schmidt,^  founding 
their  deductions  on  experiments  on  dogs  with  gastric  fistulce,  infer 
that  in  that  animal  as  much  as  one-tenth  of  its  weight  is  daily  secreted ; 
and  Griinewaldt,'  from  his  experiments  on  the  woman  with  the  gastric 
fistula,  was  led  to  infer  that  the  secretion  amounts  to  the  enormous 
quantity  of  from  one-fifth  to  one-quarter  of  the  weight  of  the  body 
daily  !  Of  course,  a  large  amount  of  this  fluid  passes  again  into  the 
circulation  along  with  the  products  of  digestion  that  are  dissolved  in 
it."*  Still,  the  amount  is  so  vast,  it  is  difficult  to  imagine  that  there  is 
not  some  error  in  the  observation,  or  fallacy  in  the  deductions. 

After  this  it  seems  unnecessary  to  examine  into  the  statement  of  M. 
Blondlot,  that  the  true  and  almost  only  source  of  the  acidit}^  of  healthy 
gastric  fluid  is  the  presence  of  acid  phosphate  salts.  If,  at  least,  we 
admit  this  to  be  the  case  in  animals,  it  is  assuredly  not  so  in  man. 
The  remark  applies  equally  to  the  experiments  of  i)r.  K.  D.  Thomp- 
son on  the  gastric  secretions  of  the  sheep  and  pig.^  By  these  ob- 
servers, the  results  obtained  from  the  examination  of  the  gastric  secre- 
tions in  man,  seem  to  have  been  passed  over,  and  they  have  deduced 
their  inferences  from  those  of  animals,  which  may,  in  part — but  in  part 
only — account  for  the  great  discrepancy  in  their  statements.*^ 

The  source  of  the  chlorine  or  chlorohydric  acid  in  the  gastric  juice, 
as  Dr.  Prout^  suggests,  must  be  the  common  salt  existing  in  the  blood, 
which,  he  conceives,  is  decomposed  by  galvanic  action :  the  soda,  set 
free,  remaining  in  the  blood,  a  portion  being  "  requisite  to  preserve 
the  weak  alkaline  condition  essential  to  the  fluidity  of  the  blood;"  but 
the  larger  part  being  directed  to  the  liver  to  unite  with  the  bile.  This 
is  plausible;  but,  it  need  scarcely  be  added,  not  the  less  hypothetical. 
Drs.  Purkinje  and  Pappenheim^  are  of  a  similar  opinion  in  regard  to 
the  source  of  the  chlorohydric  acid.  From  their  galvanic  experiments 
they  think  it  follows,  that  the  juices  mixed  with  the  food  in  the  natu- 
ral way,  saliva,  mucus,  the  portions  of  chloride  of  sodium  present 
therein,  and  still  more  the  gastric  raucous  membrane  itself,  develope 
as  much  as  is  required  :  and  that  if  the  nervous  action  in  the  stomach 
be  either  identical  w^ith,  or  analogous  to,  galvanism,  it  would  be  suffi- 
cient to  account  for  the  secretion  of  the  quantity  of  chlorohydric  acid 
requisite  for  digestion,  without  the  assumption  of  a  special  organ  of 
secretion.^ 

M,  Blondlot'"  denies — and  Liebig'^  formerly  did  likewise — that  in 

'  Lelirbaclx  der  Physiologischen  Chemie,  ii.  49,  and  iii.  330,  342,  Leipz.,  1852,  or 
Translation  by  Dr.  Day,  Anier.  edit,  by  Dr.  R.  E.  Rogers,  i.  448  and  ii.  520,  Pliilad., 
1855. 

'^  Op.  cit.,  s.  36.  3  Op.  cit. 

*  See  on  the  Gastric  Juice  and  its  office  in  Digestion,  Dalton,  Amer.  Journ.  of  the 
Med.  Sciences,  Oct.,  1854,  p.  317. 

°  Ranking's  Abstract,  vol.  i.,  Pt.  2,  Amer.  edit.,  p.  271,  New  York,  1846. 

^  Carpenter,  Principles  of  Physiology,  4th  Amer.  edit.,  p.  494.  Philad.,  1850 ;  and 
Kirkes  and  Paget,  Manual  of  Physiology,  2d  Amer.  edit.,  p.  170,  Philadelphia,  1853. 

'  Bridgewater  Treatise,  Amer.  edit.,"!).  268,  Philad.,  1834. 

^  Miiller's  Archiv.  fiir  Anatomic,  u.  s.  w.  Heft  1, 1838,  noticed  in  Brit,  and  For.  Med. 
Eev.,  Oct.,  1838,  p.  529. 

^  See  also  Dr.  Brinton,  loc.  cit.  'O  Op.  cit. 

"  Animal  Chemistry,  Gregory's  and  Webster's  edit.,  p.  107,  Cambridge,  1S42. 


CHYMIFICATIOISr.  155 

healtli  lactic  acid  exists  in  the  stomach.  In  certain  diseases,  accord- 
ing to  the  latter,  both  it  and  mucilage  are  formed  from  the  starch,  and 
sugar  of  the  food  ;  and  he  affirms,  that  the  property  possessed  by  these 
substances  of  passing,  by  contact  with  animal  substances,  in  a  state  of 
decomposition,  into  lactic  acid,  has  induced  physiologists  without  far- 
ther inquiry,  to  assume  that  lactic  acid  is  produced  during  digestion. 
lie  now,  however,  admits  its  existence  in  health,'  and  Avith  Dr.  R.  D. 
Thompson,  MM.  Bernard  and  Barreswil,  Frerichs,^  J.  Beclard,*  and 
others,  consider  it  to  be  an  important  agent  in  the  digestive  process. 
"With  some  other  chemists,  he  denies  the  existence  of  free  chloro- 
hydric  acid  in  the  stomach,  and  believes,  that  when  it  is  obtained  by 
the  simple  distillation  of  the  gastric  juice  it  is  formed  by  the  reaction 
of  the  lactic  and  phosphoric  acids,  which  are  present  in  the  fluid,  on 
the  chlorides;  and  Lehmann'*  found,  when  he  experimented  on  the 
stomachs  of  dogs  placed  in  vacuo  in  such  a  manner  as  to  cause  the 
vapours  from  the  gastric  juice  to  pass  through  a  tube  containing  a  so- 
.  lution  of  nitrate  of  silver,  that  there  was  no  indication  of  free  chloro- 
hydric  acid  until  the  fluid  had  become  so  concentrated  as  to  permit 
the  action  of  the  lactic  acid  on  the  earthy  chlorides.  His  results 
would  tend  to  confirm  the  later  conclusions  of  Liebig,  as  well  as  those 
of  MM.  Bernard  and  Barreswil,  and  others,  as  to  the  nature  of  the 
acid  of  the  gastric  juice  of  certain  animals  at  least.^  It  is  proper  to 
remark,  however,  that  neither  Prout  nor  Braconnot  could  detect  lactic 
acid  in  the  gastric  juice;  and,  moreover,  it  does  not  appear  to  be 
formed  in  artificial  digestion ." 

The  diversity  of  results  obtained  by  chemical  analysis;  the  difficulty 
of  comprehending  how  the  same  fluid  can  digest  substances  of  such 
opposite  character;  and  the  uncertainty  we  are  in,  regarding  the  organs 
concerned  in  its  production,  had  led  some  physiologists  to  doubt  the 
existence  of  any  such  gastric  juice  or  solvent  as  that  described  by  Spal- 
lanzani.  M.  Montegre,^  for  example,  in  the  year  1812,  presented  to 
the  French  Institute  a  series  of  experiments,  from  which  he  concluded, 
that  the  gastric  juice  of  Spallanzani  is  nothing  more  than  saliva,  either 
in  a  pure  state,  or  changed  by  the  chymifying  action  of  the  stomach 
and  become  acid.  As  M.  Monti^gre  was  able  to  vomit  at  pleasure,  he 
obtained  the  gastric  juice,  as  it  had  been  done  by  previous  experi- 
menters, in  this  manner,  whilst  fasting.  He  found  it  frothy,  slightly 
viscid,  and  turbid;  depositing,  when  at  rest,  some  mucous  flakes;  and 
commonly  acid  ;  so  much  so,  indeed,  as  to  irritate  the  throat,  and  render 
the  teeth  rough.  He  was  desirous  of  proving,  whether  this  fluid  was 
in  any  manner  inservient  to  chymification.    For  this  purpose,  he  began 

'  Chemistry  of  Food,  London,  1847. 

2  CanstaU,  Jahresbericht,  1850,  Bd.  i.  s.  134. 

'  Traite  Elementaire  de  Physiologie,  p.  8(j,  Paris,  1855. 

*  Lelirbuch  der  Physiologischen  Chemie,  ii.  42,  Leipz.,  1852,  or  Amer.  edit,  of  Dr. 
Day's  translation  by  Dr.  Robt.  E.  Rogers,  i.  441,  Philad.  1855. 

*  Archiv.  der  Pharmacie,  cited  in  the  British  and  Foreign  Medico-Chirurgical  Re- 
view, p.  261,  Jan.,  1849. 

^  A  full  account  of  the  various  views  in  regard  to  the  gastric  acid  is  given  by  Fre- 
richs,  Art.  Verdauung,  Wagner's  Handworterbuch  der  Physiologie,  21ste  Lieferung,  s. 
780,  Braunschweig,  1849 ;  a"nd  Berard,  Cours  de  Physiologie,  lie  Livraisou,  p.  97,  Paris, 
1849. 

■^  Exper.  sur  la  Digestion,  p.  20,  Paris,  1824. 


156  DIGESTION". 

by  ejecting  as  mneli  as  possible  by  vomiting;  and,  afterwards,  swallowed 
magnesia  to  neutralize  what  remained.  On  eating  afterwards,  tlie  food 
did  not  appear  less  cliymified,  nor  was  it  less  acid;  whence  he  con- 
cluded, that,  instead  of  the  fluid  being  the  agent  of  chymification,  it  was 
nothing  more  than  saliva  and  the  mucous  secretions  of  the  stomach, 
changed  by  the  chymifying  action  of  that  viscus.  To  confirm  himself 
in  this  view,  he  repeated  with  it,  Spallanzani's  experiments  on  artificial 
digestion;  making,  at  the  same  time,  similar  experiments  with  saliva: 
the  results  were  the  same  in  both  cases.  When  gastric  juice,  not  acid, 
was  put  into  a  tube,  and  placed  in  the  axilla, — as  in  Spallanzani's  ex- 
periments,— in  twelve  hours  it  was  in  a  complete  state  of  putrefaction. 
The  same  occurred  to  saliva  placed  in  the  axilla.  Gastric  juice,  in  an 
acid  state,  placed  there,  did  not  become  putrid,  but  this  seemed  to  be 
owing  to  its  acidit}^ ;  for  the  same  thing  happened  to  saliva,  when  ren- 
dered acid  by  the  addition  of  a  little  vinegar ;  and  even  to  the  gastric 
juice, — used  in  the  experiment  just  referred  to, — when  mixed  with  a 
little  vinegar.  Again: — he  attempted  artificial  digestion  with  the  gas- 
tric juice,  acid  and  not  acid  ;  fresh  and  old;  but  they  were  unsuccessful. 
The  food  alwaj^s  became  putrid ;  but  sooner  when  the  juice  em^^loyed 
was  not  acid ;  and,  if  it  sometimes  liquefied  before  becoming  putrid, 
this  was  attributed  to  the  acidity  of  the  juice,  as  the  same  efl'ect  took 
place,  when  saliva,  mixed  with  a  little  vinegar,  was  employed.  M. 
Montegre,  moreover,  observed,  that  the  food  rejected  from  the  stomach 
was  longer  in  becoming  putrid,  in  proportion  to  the  time  it  had  been 
subjected  to  the  chymiiying  action  of  the  stomach;  and  he  concluded, 
that  the  fluid,  which  is  sometimes  contained  in  the  empty  stomach, 
instead  of  being  a  menstruum  kept  in  reserve  for  chymification,  is 
nothing  more  than  the  saliva  continually  sent  down  into  that  viscus, 
and  that  its  purity  or  acidity  depends  upon  the  chymifying  action  of 
the  stomach.' 

As  regards  the  fluid  met  with  in  the  stomach  of  fasting  animals, 
M.  Montegre's  remarks  may  be  true  in  the  main;  but  we  have  too 
many  evidences  in  favour  of  the  chemical  action  of  some  secretion 
from  the  stomac-h  during  digestion  to  permit  us  to  doubt  the  fact  for  a 
moment.  Besides,  some  of  M.  Montegre's  experiments  have  been  re- 
peated with  opposite  results.-  MM.  Leuret  and  Lassaigne,^  and  Dr. 
Beaumont^  performed  those  relating  to  digestion  after  the  manner  of 
Spallanzani,  and  succeeded  perfectly;  whilst  they  failed  altogether  in 
producing  chymification  with  saliva,  either  in  its  pure  state,  or  when 
acidulated  with  vinegar. 

By  steeping  the  mucous  membrane  of  an  animal's  stomach  in  an 
acid  liquor,  a  solution  is  obtained,  to  which  Eberle"*  gave  the  name 
pepsin.  This  solution  has  the  property  of  dissolving  organic  matter 
in  a  much  higher  degree  than  diluted  acids.  It  dissolves  coagulated 
albumen,  muscular  fibre,  and  animal  matters  in  general.  In  an  experi- 
ment, one  grain  of  the  digestive  matter  dissolved  one  hundred  grains 
of  coagulated  white  of  egg.     Eberle  thought  that  all  mucus  has  the 

'  Chaussior  and  Adelon,  in  Diet,  des  Sci.  Medicales,  xx.  422. 

*  Reclierclies  sur  la  Digestion,  Paris,  1825.  "  Op.  citat.,  p.  139. 

*  Phjsiologie  der  Verdauung  nach  Versuclien,  ii.  s.  w.,  Wiirzburg,  1834;  Miiller, 
Axchiv.,  Heft  1,  183t),  or  Loudou  Lancet,  p.  19,  Marcli  31,  1838. 


CHYMIFICATIOX.  157 

property,  when  acidulated,  of  inducing  decomposition  and  subsequent 
solution  of  tlie  food;  but  it  would  appear,  that  no  other  mucus  than 
that  of  the  gastric  raucous  membrane,  when  acidulated,  possesses  it,^ 
and,  consequently,  that  there  must  be  a  peculiar  substance,  j^ejjsin  or 
gastric  ferment,  which  may  be  regarded  as  a  true  digestive  principle.^ 
This  principle  was  not  obtained  by  Schwann  in  a  pure  state;  but  M. 
Wasmann^  would  appear  to  have  succeeded  better.  A  solution,  con- 
taining only  5  Olio 0  P^^'^  ^^  pepsin  and  slightly  acidulated,  is  said  to  dis- 
solve the  white  of  an  egg  in  six  or  eight  hours,''  It  is  not  generally 
considered,  however,  to  be  a  distinct  substance — an  immediate  prin- 
ciple; but  rather  to  be  the  product  of  an  alteration  of  the  nitrogenized 
matters  of  the  parietes  of  the  stomach/ 

An  artificial  digestive  fluid  is  sometimes  made  which  resembles 
that  of  the  human  stomach,  by  macerating  in  water  portions  of  fresh 
or  dried  mucous  membrane  of  the  stomach  of  a  pig  or  other  omnivor- 
ous animal,  or  of  the  fourth  stomach  of  the  calf,  and  adding  to  the 
infusion  a  few  drops  of  chlorohydric  acid,  about  3.3  grains  to  half  an 
ounce  of  the  mixture  according  to  Schwann.  Portions  of  food  placed 
in  this  fluid,  and  the  mixture  kept  at  a  temperature  of  about  100°,  are 
softened  and  changed,  much  in  the  same  manner  as  they  would  be  in 
the  stomach.^ 

Even  were  the  evidence  adduced  less  positive  in  favour  of  the  exist- 
ence of  some  gastric  secretion  concerned  in  the  digestive  changes  in 
that  organ,  the  following  phenomena  would  be  overwhelming.  Be- 
sides the  fact  of  the  most  various  and  firm  substances  being  reduced 
to  chyme  in  the  stomach,  we  find  the  secretions  from  its  lining  mem- 
brane possessing  the  power  of  coagulating  albuminous  fluids.  It  is 
upon  the  coagulating  property  of  these  secretions,  that  the  method  of 
making  cheese  is  dependent.  Eennet,  employed  for  this  purpose,  is 
an  infusion  of  the  digestive  stomach  of  the  calf,  which,  on  being  added 
to  milk,  converts  the  albuminous  portion  into  curd;  and  it  is  surprising 
how  small  a  quantity  is  necessary  to  produce  this  effect.  Messrs.  For- 
dyce^  and  Young,^  of  Edinburgh,  found  that  six  or  seven  grains  of 
the  inner  coat  of  a  calf's  stomach,  infused  in  water,  afforded  a  liquid, 
which  coagulated  more  than  one  hundred  ounces  of  milk, — that  is, 
more  than  six  thousand  eight  hundred  and  fifty-seven  times  its  own 
weight;  and  yet  its  weight  was  probably  but  little  diminished.  The 
substance  that  possesses  this  property  does  not  appear  to  be  very  solu- 
ble in  water;  for  the  inside  of  a  calf's  stomach,  after  having  been 
steeped  in  water  for  six  hours,  and  well  washed,  still  furnishes  a  liquor 
or  infusion,  which  coagulates  milk.    Liebig^  has  denied,  that  the  fresh 

'  Mi'iller,  Elements  of  Physiology,  by  Baly,  pp.  518  and  542,  London,  1838. 

*  Miiller  and  Schwann,  in  Milller's  Archiv.,  Heft  1,  1836  ;  and  Miiller,  op.  citat. 

3  Journ.  de  Pharmacie  ;  and  American  Journal  of  Pharmacy,  for  Oct.,  1840,  ]).  192. 
<  Graham's  Elements  of  Chemistry,  Amer.  edit.,  p.  695,  Philad.,  1843,  and  Tliomson's 
Animal  Chemistry,  p.  229,  Edinb.,  1843. 

*  Robin  and  Verdeil,  Traite  de  Chiniie  Anatomique,  &c.,  iii.  555,  Paris,  1853;  and 
Becquerel  and  Rodier,  Traite  de  Chimie  Pathologique,  p.  470,  Paris,  1853. 

*  Kirkes  and  Paget,  Manual  of  Physiology,  2d  Amer.  edit.,  p.  173,  Philad.,  1853. 
'  A  Treatise  on  the  Digestion  of  Food,  p.  57,  2d  edit.,  Lond.,  1791. 

^  Thomson's  System  of  Chemistry,  6tli  edit.,  iv.  596.  ' 

3  Animal  Chemistry,  Webster's  Amer.  edit.,  Cambridge,  1842. 


158  DIGESTION. 

lining  membrane  of  the  stomacli  of  the  calf,  digested  in  weak  chloro- 
hydric  acid,  gives  to  that  fluid  the  power  of  dissolving  boiled  flesh  or 
coagulated  white  of  egg;  but  Dr.  Pereira'  affirms,  that  he  has  found, 
by  experiment,  that  a  digestive  liquor  can  be  prepared  from  the  fresh 
Tindried  stomach  of  a  cfilf.  This  had,  indeed,  been  shown  on  the  best 
authority  long  ago.  Mr.  Hunter,  for  example,  made  numerous  expe- 
riments upon  the  coagulating  power  of  the  secretions  of  the  stomach, 
which  show,  that  it  is  found  in  the  stomachs  of  animals  of  very  differ- 
ent classes.  The  lining  of  the  fourth  stomach  of  the  calf  is  in  com- 
mon use,  in  a  dried  state,  for  the  purpose  mentioned  above;  and  it  has 
been  proved,  that  every  part  of  the  membrane  possesses  the  same  pro- 
perty. Mr.  Hunter  found,  by  experiment,  that  the  mucus  of  the  fourth 
cavity  of  a  slink  calf,  made  into  a  solution  with  a  small  quantity  of 
water,  had  the  power  of  coagulating  milk ;  but  that  found  in  the 
three  first  cavities  possessed  no  such  power.  The  former,  even  after 
it  had  been  kept  several  days,  and  was  beginning  to  be  putrid,  re- 
tained the  property.  The  duodenum  and  jejunum,  with  their  contents, 
likewise  coagulated  milk ;  but  the  process  was  so  slow  as  to  give  rise 
to  the  suggestion,  that  it  might  have  occurred  independently  of  the 
intestines  employed  for  the  purpose.  He  found,  that  the  inner  mem- 
brane of  the  fourth  cavity  in  the  calf,  when  old  enough  to  be  killed 
for  veal,  had  t1ie  same  property.  Portions  of  the  cuticular,  of  the 
massy  glandular  part,  and  of  the  portion  near  the  pylorus  of  the  boar's 
stomach,  being  prepared  as  rennet,  it  was  found,  that  no  part  had  the 
effect  of  producing  coagulation  but  that  near  the  pylorus,  whei'e  the 
gastric  glands  of  the  animal  are  especially  conspicuous.  The  crop 
and  gizzard  of  a  cock  were  salted,  dried,  and  afterwards  steeped  in 
water.  The  solution,  thus  obtained,  was  added  to  milk :  the  portion 
of  the  crop  coagulated  it  in  two  hours;  that  of  the  gizzard  in  half  an 
hour.  The  contents  of  a  shark's  stomach  and  duodenum  coagulated 
it  instantaneously.  Pieces  of  the  stomach  were  washed  clean,  and 
steeped  in  water  for  sixteen  hours.  The  solution  coagulated  milk 
immediately.  Pieces  of  the  duodenum  produced  the  same  effect. 
When  the  milk  was  heated  to  96°,  the  coagulation  took  place  in  half 
an  hour;  when  cold,  in  an  hour  and  a  quarter.  The  stomachs  of  the 
salmon  and  thornback,  made  into  rennet,  coagulated  milk  in  four  or 
five  hours. 

But  those  experiments  of  Mr.  Hunter  do  not  inform  us  of  the  par- 
ticular secretions  that  are  productive  of  the  effect.  They  would, 
indeed,  rather  seem  to  show,  that  it  is  a  general  property  of  the  whole 
internal  membrane.  To  discover  the  exact  seat  of  the  secretion,  and 
especially  whether  it  be  not  in  the  gastric  glands.  Sir  Everard  Home^ 
selected  those  of  the  turkey ;  which,  from  their  size,  are  better  adapted 
for  such  an  experiment  than  those  of  any  other  bird,  except  the  ostrich. 
A  young  turkey  was  kept  a  day  without  food,  and  then  killed.  The 
gastric  glands  were  carefully  dissected  separately  from  the  lining  of 
the  cardiac  cavity;  cutting  off  the  duct  of  each  before  it  pierced  the 
membrane,  so  that  no  part  but  the  glands  themselves  were  removed. 

'  Treatise  on  Food  and  Diet,  Ainer.  edit.,  p.  36,  New  York,  1843. 

2  Lectures  on  Comparative  Anatomy,  i.  299,  Lond.,  1814,  and  iii.  134,  Lond.,  1823. 


J 


CHYMIFICATIOX. 


159 


Forty  grains,  by  weight,  of  these  glands  were  added  to  two  ounces  of 
new  milk ;  and  similar  experiments  were  made  with  rennet ;  with  the 
lining  of  the  cardiac  cavity  of  the  turkey ;  and  with  the  inner  mem- 
brane of  the  fourth  cavity \)f  the  calf's  stomach.  Coagulation  and 
separation  into  curds  and  whey  were  first  effected  by  the  rennet. 
Next  to  this,  and  simultaneously,  came  the  gastric  glands,  and  the 
fresh  stomach  of  the  calf;  and  lastly,  the  cardiac  membrane  of  the 
turkey.  From  these  experiments.  Sir  Everard  concluded,  that  the 
power  of  coagulation  is  in  the  secretion  of  the  gastric  glands;  and 
that  the  power  is  communicated  to  other  parts,  by  their  becoming 
more  or  less  impregnated  with  it. 

The  marginal  figure,  copied  from  an  engraving  of  the  microscopic 
observations  of  Mr.  Bauer,  exhibits  the  gastric  glands — as  he  regarded 
them — of  the  human  oesophagus  magnified  fifteen  times.  These  glands 
are  in  the  lining  of  the  lower  part  of  the  oesophagus';  and  have  the  ap- 
pearance of  infundibular 
cells,  whose  depth  does 
not  exceed  the  thickness 
of  the  membrane.  This 
structure,  although  differ- 
ent from  that  of  the  gas- 
tric glands  of  birds,  is  a 
nearer  approach  to  it  than 
is  to  be  met  with  in  any 
part  of  the  inner  surface 
of  the  stomach  or  duode- 
num. It  also  resembles 
them,  in  the  secretion 
which  it  produces  coagu- 
lating milk,  whilst  none 
of  the  inspissated  juices, 
met  with  in  these  cavities, 
according  to  Sir  Everard,  affect  milk  in  the  same  way.  Erom  these 
facts,  he  thinks,  there  can  be  no  longer  any  doubt  entertained,  that  the 
gastric  glands  have  the  same  situation  respecting  the  cavity  of  the 
stomach  as  in  birds.  No  histologist,  however,  agrees  with  him  in  this 
location  of  the  gastric  glands. 

In  some  experiments,  undertaken  by  M.  J.  E.  Simon^  with  a  view 
to  determine,  whether  the  stomach  of  the  child  possesses  the  same 
properties  of  coagulating  milk  as  that  of  the  calf,  he  found  that  cow's 
milk  was  not  coagulated  by  it,  but  that,  when  a  quantity  of  the  colos- 
trum of  the  mother  of  a  child,  which  died  when  five  days  old,  was 
obtained,  and  a  piece  of  calf's  stomach  was  introduced  into  it,  the  milk 
coagulated. 

Another  property,  manifestly  possessed  by  the  secretion  in  question, 
is  that  of  preventing  putrefaction,  or  of  obviating  it  in  substances  ex- 
posed to  its  action.  Mont^gre  and  Thackrah^  deny  it  this  property, 
but  there  can  be  no  doubt  of  its  existence.     Spallanzani,  Eordyce,  and 


Gastric  Glands  of  tho  Oesophagus  magnified  fifteen  times. 


'  Mailer's  Archiv.,  Heft  1, 1839,  cited  in  Brit,  and  For.  Med.  Rev.,  Oct.,  1839,  p.  549. 
^  Lectures  on  Digestion  and  Diet,  p.  14,  Lond.,  1824. 


160  DIGESTION. 

others,  liave  ascertained,  that  in  those  animals  wliich  frequentl}^  take 
their  food  in  a  half  putrid  state,  the  first  operation  of  the  stomach  is 
to  disinfect,  or  remove  the  factor  from  the  aliment  received  into  it. 
We  have  already  alluded  to  many  facts  elucidative  of  this  power. 
Helm  of  Vienna,'  in  the  case  of  a  female  who  had  a  fistulous  opening 
in  her  stomach,  observed,  that  substances  which  were  swallow^ed  in  a 
state  of  acidity  or  putridity,  sooft  lost  those  qualities  in  the  stomach ; 
and  the  same  power  of  resistuig  and  obviating  putrefaction  has  been 
exhibited  in  experiments  made  out  of  the  body.  Nothing  could  be 
more  unequivocal,  as  regards  the  possession  of  this  property  by  the 
gastric  fluid,  than  the  experiments  of  Dr.  Beaumont  and  the  author,* 
with  the  secretion  obtained  from  the  subject  of  his  varied  investigations. 
In  the  presence  of  the  author's  friend,  N.  P.  Trist,  Esq. — then  consul 
of  the  United  States  at  Havana, — the  odour  of  putrid  food  was  as 
speedily  removed  by  it  as  by  chlorinated  soda  employed  at  the  same 
time  on  other  portions.  The  explanation  of  this  property,  as  well  as 
that  of  coagulation,  has  been  a  stumbling-block  to  the  chemical  phy- 
siologist. "We  can  only  say  concerning  it,"  says  Dr.  Bostock,^  "that 
it  is  a  chemical  operation,  the  nature  of  which,  and  the  successive  steps 
by  which  it  is  produced,  we  find  it  difiicult  to  explain ;  at  the  same 
time,  that  we  have  very  little,  in  the  way  of  analogy,  which  can  assist 
us  in  referring  it  to  any  more  general  principle,  or  to  any  of  the  estab- 
lished laws  of  chemical  affinity." 

The  cases  of  what  are  termed  digestion  of  the  stomach  after  death  afford 
us,  likewise,  remarkable  examples  of  the  presence  of  some  powerful 
agent  in  the  stomach;  as  well  as  of  the  resistance  to  chemical  action, 
offered  hj  living  organs.  Powerful  as  the  action  of  the  gastric  juice 
may  be,  in  dissolving  alimentary  substances,  it  does  not  exert  it  upon 
the  coats  of  the  stomach  during  life.  Being  endowed  with  vitality, 
they  effectually  resist  it.  But  when  that  viscus  has  lost  its  vitality, 
its  parietes  yield  to  the  chemical  power  of  the  contained  juices,  and 
become  softened,  and,  in  part,  destroyed.  Mr.  Hunter^  found  the  lining 
membrane  of  the  stomach  destroyed,  in  several  parts,  in  the  body  of  a 
criminal,  who,  for  some  time  before  his  execution,  had  been  prevailed 
upon,  in  consideration  of  a  sum  of  money,  to  abstain  from  food.  Since 
Hunter's  time,  numerous  examples  have  occurred,  and  been  recorded 
by  Messrs.  Baillie,  Allan  Burns,  Haviland,  Grimaud,  Pascalis,  Cheese- 
man,  J.  B.  Beck,  Chaussier,  Yelloly,  Gardner,  Treviranus,  Godecke, 
Jager,  Carswell,  and  others.*  The  fact  is  of  importance  in  medical 
jurisprudence;  and,  until  a  better  acquaintance  with  the  subject,  would, 
doubtless,  have  been  set  down  as  strong  corroborative  evidence  in  cases 

'  Rudolplii,  Griinclriss  der  Physiologie,  2er  Band,  2te  Abtheil.,  s.  114,  Berlin,  1828. 

2  See  the  author's  Elements  of  Hygiene,  p.  216,  Philad.,  1835. 

3  Edit,  cit.it.,  p.  571. 

*  Phil.  Transact.,  Ixii.  ;  and  Observations  on  certain  parts  of  the  Animal  Economy, 
with  notes  by  Prof.  Owen,  Amer.  edit.,  p.  144,  Philad.,  1840. 

*  Beck's  Medical  Jurisprudence,  6th  edit.,  ii.  311,  Albany,  1838  ;  Carswell's  Path. 
Anat.,  No.  5,  Loud.,  1833;  and  T.  Wilkinson  King,  Guy's  Hospital  Reports,  vii.  139, 
Lond.,  1842  ;  and  a  case  communicated  to  the  author  by  Dr.  Thomas  M.  Flint,  in  which 
the  stomach  had  separated  from  the  oesophagus,  recorded  in  Med.  Examiner,  p.  715,  for 
December,  1848 ;  also,  Dr.  George  Budd,  on  the  Organic  Diseases  and  Functional  lOis-  ' 
orders  of  the  Stomach,  Amer.  edit.,  p.  19,  Philad.,  1856. 


CHYMIFICA.TION.  161 

of  suspected  poisoning.  It  is  now  established  that  solution  of  the  sto- 
mach may  take  place  after  death,  without  there  being  reason  for  sup- 
posing that  any  thing  noxious  had  been  swallowed. 

The  experiments  of  Dr.  Wilson  Philip'  and  Sir  Robert  CarswelP  are 
corroborative  of  this  physiological  action  of  the  gastric  juice.  On 
opening  the  abdomen  of  rabbits,  that  had  been  killed  immediately  after 
having  eaten,  and  allowed  to  lie  undisturbed  for  some  time  before 
examination,  the  former  found  the  great  end  of  the  stomach  soft,  eaten 
through,  and  sometimes  altogether  consumed;  the  chyme  being  covered 
only  by  the  peritoneal  coat,  or  lying  quite  bare  for  the  space  of  an  inch 
and  a  half  in  diameter:  and,  in  this  last  case,  a  part  of  the  contiguous 
intestines  was  also  destroyed  ;  whilst  the  cabbage,  which  the  animal 
had  just  taken,  lay  in  the  centre  of  the  stomach  unchanged,  if  we  ex- 
cept the  alteration  that  had  taken  place,  in  the  external  parts  of  the 
mass  it  had  formed,  in  consequence  of  imbibing  gastric  fluid  from  the 
half-digested  food  in  contact  with  it.  Why  the  perforation  takes  place, 
without  the  food  being  digested,  is  thus  explained  by  Dr.  Philip.  Soon 
after  death,  the  motions  of  the  stomach,  which  are  constantly  carrying 
on  the  most  digested  food  towards  the  pylorus,  cease.  The  food,  that 
lies  next  to  the  surface  of  the  stomach,  thus  becomes  fully  saturated 
with  gastric  fluid;  neutralizes  no  more;  and  no  new  food  being  pre- 
sented to  the  fluid  it  acts  on  the  stomach  itself,  now  deprived  of  life, 
and  equally  subjected  to  its  action  with  other  dead  animal  matter.  It 
is  extremely  remarkable,  however,  that  the  gastric  fluid  of  the  rab- 
bit, which,  in  its  natural  state,  refuses  animal  food,  should  so  completely 
digest  the  stomach,  as  not  to  leave  a  trace  of  the  parts  acted  upon. 
Dr.  Philip  remarks,  that  he  has  never  seen  the  stomach  eaten  through 
except  at  the  larger  end ;  but,  in  other  parts,  the  external  membrane 
has  been  injured.  Mr.  A.  Burns,^  however,  affirms,  that  in  several 
instances  he  found  the  forepart  of  the  stomach  perforated  about  an 
inch  from  the  pylorus,  and  midway  between  the  smaller  and  larger 
curvatures. 

From  all  these  facts,  then,  we  are  justified  in  concluding,  that  the 
food  in  the  stomach  is  subjected  to  the  action  of  secretions,  which  alter 
its  properties,  and  are  the  principal  agents  in  converting  it  into  chyme. 

But  many  physiologists,  whilst  they  admit,  that  the  change  efl'ected 
in  the  stomach  is  of  a  chemical  character,  contend,  that  the  nature  of 
the  action  is  unlike  what  takes  place  in  any  other  chemical  process,  and 
is,  therefore,  necessarily  organic  and  vital^  and  appertaining  to  vital 
chemistry.  Such  are  the  sentiments  of  Messrs.  Fordyce,"*  Broussais,* 
Chaussier,  and  Adelon,^  and  others.  Dr.  Prout  suggests,  that  the  sto- 
mach must  have,  within  certain  limits,  the  power  of  organizing  and 
vitalizing  the  different  alimentary  substances  ;  so  as  to  render  them  fit 
for  being  brought  into  more  intimate  union  with  a  living  body,  than 

'  Treatise  on  Indigestion,  Lond.,  1821. 

^  Ibid,  and  Edinb.  Med.  and  Surg.  Journal,  Oct..  1830;  and  art.  Perforation  of  the 
Hollow  Viscera,  in  Cyclopaedia  of  Practical  Medicine,  P.  xvi.  p.  272,  Loud.,  1833. 
'  Edinb.  Med.  and  Surg.  Journal,  vi.  132. 

*  On  the  Digestion  of  Food,  2d  edit.,  Lond.,  1791. 

*  Traite  de  Physiologie,  &c.,  translated  by  I)rs.  Bell  and  La  Roche,  p.  323. 

*  Diet,  des  Sciences  Medicales,  ix. 

VOL.  I.— 11 


162  DIGESTION. 

tlie  crude  aliments  can  be  supposed  to  be.  It  is  impossible,  he  con- 
ceives, to  imagine,  that  this  organizing  agency  of  tlie  stomach  can  be 
chemical.  It  is  vital,  and  its  nature  completely  unknown.  The  physi- 
ologist should  not,  however,  have  recourse  to  this  explanation,  until 
every  other  has  failed  him.  It  is,  in  truth,  another  method  of  expressing 
his  ignorance,  when  he  afl&rms,  that  any  function  is  executed  in  an  or- 
ganic or  vital  manner;  nor  is  this  mode  of  explaining  the  conversion 
of  the  aliment  into  chyme  necessary;  the  secretion  of  the  matters  that 
are  tlie  great  agents  of  chymification  is  doubtless  vital;  but  when  once 
secreted,  the  changes,  effected  upon  the  food,  are  probably  unmodified 
by  any  vital  interference,  except  what  occurs  from  temperature,  agita- 
tion, &c.,  which  can  only  be  regarded  as  auxiliaries  in  the  function.  It 
is  in  this  way,  that  digestion  is  influenced  by  the  nervous  system. 

The  effect  of  the  diflerent  emotions  on  the  digestive  function  is  often 
evinced,  and  has  already  been  alluded  to ;  but  the  importance  of  the 
nervous  influence  to  it  has  been  elucidated,  in  an  interesting  manner  to 
the  physiologist,  of  late  years  chiefly.  Baglivi,^  having  tied  the  nerves 
of  the  eighth  pair  on  dogs,  found  that  they  were  ai&cted  with  nausea 
and  vomiting,  and  obstinately  refused  food.  Since  Baglivi's  time,  the 
same  results  have  been  obtained  by  many  physiologists.  M.  De  Blain- 
ville,  having  repeated  the  operation  on  pigeons,  found  the  vetch  in  their 
crops  entirely  unchanged,  and  chymification  totally  prevented.  Legal- 
lois,^  Sir  Benjamin  Brodie,^  Messrs.  Philip,"  Dupuy,  Clarke  Abel,  Hast- 
ings,^ and  others — on  carefully  repeating  the  experiments — announced, 
that,  after  this  operation,  the  digestive  process  was  entirely  suspended.* 
The  result  of  these  experiments  was,  however,  contested  by  several 
physiologists  of  eminence,  who  affirmed,  that,  after  the  division  of  the 
eighth  pair,  digestion  continued  nearly  in  the  natural  state,  or,  at  most, 
was  only  slightly  impeded.  Mr,  Broughton^  asserted,  that  he  had  made 
the  section  on  eleven  rabbits,  one  dog,  and  two  horses ;  and  that  diges- 
tion was  not  destroyed.  M.  Magendie^  expresses  his  belief,  that  the 
arrest  of  chymification,  where  it  Avas  observed,  was  owing  to  the  dis- 
turbance of  respiration  caused  by  the  division  of  the  nerves;  and  he 
states  that  digestion  continued  when  care  was  taken  to  cut  the  nerve 
within  the  thorax,  lower  down  than  the  part  which  furnishes  the  pul- 
monary branch.  MM.  Leuret  and  Lassaigne  assert,^  that  they  found 
chymification  continue,  notwithstanding  the  division  of  these  nerves; 
and  Dr.  G.  C.  Holland'"  thinks  he  has  proved,  that  the  suspension  of  the 
digestive  function  is  not  produced  by  the  influence  of  the  nerves  being 
withdrawn  from  the  stomach,  but  by  the  disturbance  of  the  circulatory 
system;  for  when  the  natural  conditions  of  this  system  were  maintained, 
after  the  division  of  the  nerves,  the  function  of  digestion  still  continued 
to  be  properly  performed;  showing  that  the  nervous  connexion  between 

'  Opera  Omnia,  Lngd.  Bat.,  1745. 

2  Sur  le  Principe  de  la  Vie,  p.  214,  Paris,  1842.  s  Pliil.  Trans,  for  1814. 

*  Experimental  Inquiry,  &c.,  Lond.,  1817. 
^  Journal  of  Science  and  Arts,  vii.  ix.  x.  xi.  and  xii. 
6  Ley,  in  App.  to  Laryngismus  Stridulus,  p.  447,  Lond.,  1836. 
'  Ibid.,  X.  292.  8  prgcis,  &c.,  ii.  102. 

'  Edinburgh  Med.  and  Surg.  Journal,  sciii.  305  ;  and  Reoterches  sur  la  Digestion, 
Paris,  1825. 
'"  Inquiry  into  tlie  Principles,  &c.,  of  Medicine,  i.  444,  Lond.,  1834. 


CHYMIFICATION.  163  , 

the  brain  and  stomach  is  not  essential  to  the  process  of  digestion,  the 
secretion  of  the  gastric  solvent,  or  the  possession  of  contractility  by 
the  muscular  fibres  of  the  stomach. 

In  opposition  to  these  experiments,  those  of  M.  Dupuytren  may  be 
adduced.  He  divided,  separately,  the  portions  of  the  eighth  distributed 
to  the  pulmonary,  circulatory,  and  digestive  apparatuses,  and  always 
found,  when  the  section  was  made  below  the  pulmonary  plexus,  that 
chymification  was  suspended.  But  how  are  we  to  explain  the  discre- 
pancy between  these  results,  and  those  of  Messrs.  Broughton  and  Ma- 
gendie?  M.  Adelon'  has  supposed,  that  as  the  eighth  pair  is  not  the 
only  nerve  distributed  to  the  stomach, — the  great  sympathetic  sending 
numerous  filaments  to  it, — these  filaments,  in  the  experiments  of  Messrs. 
Broughton  and  Magendie,  might  have  been  sufficient  to  keep  up  for 
some  time  the  chymifying  action  of  the  stomach ;  and,  again,  he  sug- 
gests, whether  the  nervous  influence  may  not  have  still  persisted  for  a 
time  after  the  section  of  the  nerve,  like  other  nervous  influences,  which, 
he  conceives,  continue  for  some  time  even  after  death ;  and,  lastly,  he 
thinks  it  probable,  that,  in  the  cases  in  which  chymification  continued, 
the  experiment  was  badly  performed.  Most  of  these  reasons,  however, 
would  apply  with  as  much  force  to  the  experiments  on  the  other  side 
of  the  question.  Why  were  not  the  agency  of  the  great  sympathetic, 
and  the  continuance  of  the  nervous  influence  for  some  time  after  the 
section  of  the  nerve,  evidenced  in  the  experiments  of  Dupuytren,  Wil- 
son Philip,  Hastings,  and  others? 

More  recent  experiments  by  Messrs.  Wilson  Philip,^  Breschet,  Milne 
Edwards,  and  Yavasseur,^  have  shown,  that  the  mere  division  of  the 
nerves,  and  even  the  retraction  of  the  divided  extremities  for  the  space 
of  one-fourth  of  an  inch,  does  not  prevent  the  influence  from  being 
transmitted  along  them  to  the  stomach  ;  but  that  if  a  portion  of  the 
nerve  be  actually  removed,  or  the  ends  folded  back,  chymification  is 
wholly  or  partly  suspended.''  Most  of  the  experimenters  agree  with 
Sir  Benjamin  Brodie  in  the  opinion,  that  chymification  is  suspended 
owing  to  the  secretion  of  the  gastric  juice  having  been  arrested  by  the 
division  of  the  nerves  under  whose  presidency  it  is  accomplished.  MM. 
Breschet  and  Milne  Edwards,  however,  conceive,  that  the  efifect  is 
owing  to  paralysis  of  the  muscular  fibres  of  the  stomach  produced  by 
the  section  of  the  nerves  ;  in  consequence  of  which  the  different  por- 
tions of  the  alimentary  mass  are  not  brought  properly  into  contact 
with  the  coats  of  the  stomach,  so  as  to  be  exposed  to  the  action  of  its 
secretions ;  and  they  affirm,  that  when  the  galvanic  influence  is  made 
to  pass  along  the  part  of  the  nerve  attached  to  the  stomach,  its  effect 
is  to  restore  the  due  action  of  the  fibres ;  and,  that  a  mechanical  irri- 
tant, applied  to  the  lower  end  of  the  divided  nerves,  produces  a  similar 
kind  of  change  on  the  food  in  the  organ;  from  which  they 'conclude, 
that  the  use  of  the  ^ar  vagum,  as  connected  with  the  functions  of  the 
stomach,  is  to  bring  the  alimentary  mass  into  necessaiy  contact  with 
the  gastric  secretions.     These  experiments  were  repeated  in  London  by 

'  Physiologie  de  I'Homme,  &c.,  2de  edit.,  vol.  ii.,  Paris,  1829. 

*  Philos.  Transact,  for  1822.  »  Archives  Geiierales  de  Med.,  Aout,  1823. 

*  Ware,  North.  American  Medical  and  Surgical  Journal,  I'hilad.,  lb2S. 


.164  DIGESTION. 

Mr.  Cutler,  under  the  inspection  of  Dr.  Philip  and  Sir  B.  Brodie;  but 
the  effects  of  mechanical  irritation  of  the  lower  part  of  the  divided 
nerve  did  not  correspond  with  those  observed  by  MM.  Breschet  and 
Milne  Edwards.^ 

The  experiments  of  F.  Arnold,^  and  of  MM.  Bouchardat  and  San- 
dras,^  led  them  also  to  infer,  that  the  nerves  of  the  stomach  appear  to 
influence  chvmification  in  so  far  as  the  process  depends  upon  the 
various  motions  of  the  organ. 

M.  Longet^  has  endeavoured  to  reconcile  these  discordant  results. 
Having  opened  many  dogs,  he  ascertained,  that  in  the  greater  number, 
irritation  of  the  pneumogastric  nerves  induced  contraction  of  the 
stomach.  Frequently,  during  his  experiments,  he  saw  the  stomach 
assume  the  hour-glass  form.  In  a  few  dogs,  the  movements  of  the 
stomach,  on  the  irritation  of  the  nerve,  were  scarcely  perceptible.  After 
repeating  his  experiments  on  fort}'  dogs,  he  recognized  that  the  differ- 
ence in  the  results  obtained  depended  on  the  condition  of  the  stomach 
itself.  Thus,  if  the  animal  was  opened  when  it  was  full,  irritation  of 
the  pneumogastric  nerves  caused  manifest  movement;  but,  when  empty, 
scarcely  any  was  excited :  the  movements,  in  fact,  were  feeble  in  pro- 
portion to  the  time  that  had  elapsed  from  the  period  of  chymification, 
or  of  filling  the  stomach.  M.  Longet  thinks,  that  these  facts  account 
for  the  different  results  arrived  at  by  experimentalists  in  regard  to  the 
influence  of  the  pneumogastric  nerves  over  the  movements  of  the 
stomach ;  for,  if  the  same  experiments  were  made  when  the  stomach 
was  in  different  states,  they  might  readily  lead  to  opposite  conclusions. 
He  was  never  able  to  excite  any  movement  of  the  coats  of  the  stomach, 
by  irritating  or  galvanizing  the  filaments  of  the  great  sympathetic  or 
the  semilunar  ganglia. 

On  the  whole,  the  proposition  of  Dr.  Philip, — that  if  the  eighth  pair 
be  divided  in  such  a  manner  as  to  effectually  intercept  the  passage  of 
the  nervous  influence,  digestion  is  suspended, — is  generall}'^  considered 
to  be  established;  although  it  must,  we  think,  be  admitted  with  Mr. 
Mayo,*  that  the  rationale  of  the  subject  remains  involved  in  great  un- 
certainty. Like  other  secretions,  that  of  the  gastric  juice,  although 
capable  of  being  modified  by  the  nervous  influence,  cannot  be  regarded 
as  immediately  dependent  upon  it.  The  secretion,  of  the  true  acid  cha- 
racter and  solvent  powers,  is  not  always  checked  by  the  section  of  the 
nerves,  and  the  experiments  of  Dr.  John  Peid^  and  others  have  suffi- 
ciently shown,  that  the  integrity  of  those  nerves  is  not  a  condition 
absolutely  necessary  for  secretion  in  the  stomach,  whilst  at  the  same 
time  they  prove,  that  the  amount  of  secretions  usually  poured  into  the 
interior  of  that  organ  may  be  modified  in  an  important  manner  by  causes 

*  Bostock's  Physiology,  3d  edit.,  p.  .'523,  London,  1836. 

*  Lelirbuch  der  Physiologic  des  Menschon,  Zurich,  1836-7  >  noticed  in  British  and 
Foreign  Medical  Review  for  Oct.,  1839,  p.  478. 

*  Annuaire  de  Therapeutiqiie,  pour  1848,  p.  283,  Paris,  1848. 

*  Comptes  Rendus,  Fevr.,  1842.  See,  also,  Bischolf,  in  Miillers  Archiv.,  Berlin,  1843, 
and  Prof.  E.  Weber,  art.  Muskelbewegung,  in  Wagner's  Handworterbuch  der  Physio- 
logie,  15te  Lieferung,  s.  41,  Braunschweig,  1846. 

°  Outlines  of  Human  Physiology,  4th  edit.,  p.  122,  Lond.,  1837. 

^  Edinb.  Med.  and  Surg.  Journal,  April,  1839  ;  and  art.  Par  Vagum,  in  Cyclop,  of 
Anat.  and  Physiol.,  pt.  xxviii.  p.  899,  Lond.,  April,  1847. 


CHYMIFICATION.  165 

acting  through  those  nerves.^  It  is  denied,  however,  by  Professor  J. 
Miiller,  that  galvanism  has  any  influence  in  re-establishing  the  gastric 
secretion,  when  it  has  been  checked  by  their  division. 

Finally: — Dr.  Philip  found,  that  every  diminution  of  the  nervous 
influence, — the  section  of  the  medulla  spinalis  at  the  inferior  part,  for 
example, — deprives  the  stomach  of  its  digestive  faculty ;  and  MM. 
Edwards  and  Vavasseur  obtained  the  same  result  by  the  removal  of  a 
certain  portion  of  the  hemispheres  of  the  brain,  or  by  the  injection  of 
opium  into  the  veins  in  sufficient  quantity  to  throw  the  animal  into 
deep  coma.  Much  must,  of  course,  be  dependent  on  the  deranging 
influence  of  the  experiments.  By  means  of  the  fistulous  openings  into 
the  stomachs  of  dogs,  first  instituted  by  M.  Blondlot,  (see  page  153,)  M. 
Bernard^  undertook  fresh  experiments  on  this  unsettled  topic.  A  dog's 
digestion  was  watched  for  eight  days,  and  found  to  be  well  accomplished. 
On  the  ninth  day,  after  twenty-four  hours'  fast,  M.  Bernard  sponged 
out  the  stomach,  which  contracted  on  the  contact  of  the  sponge,  and 
at  once  secreted  a  large  quantity  of  gastric  fluid.  He  then  divided 
the  pneumogastric  nerves  in  the  middle  of  the  neck,  and  immediately 
the  mucous  membrane,  which  had  been  turgid,  became  pale,  as  if 
exanguious ;  the  movements  of  the  stomach  ceased ;  the  secretion  of 
gastric  fluid  was  instantaneously  arrested,  and  a  quantity  of  neutral 
ropy  mucus  was  soon  produced  in  its  place.  After  this,  digestion  was 
not  duly  performed;  milk  was  no  longer  coagulated ;  raw  meat  remained 
unchanged;  and  the  food,  consisting  of  meat,  milk,  bread,  and  sugar, 
which  the  dog  had  before  thoroughly  digested,  remained  for  a  long 
time  neutral,  and  at  length  acquired  acidity  only  from  its  transforma- 
tion into  lactic  acid.  In  the  stomachs  of  other  dogs,  after  the  division 
of  the  nerves,  he  traced  the  transformation  of  cane  sugar  into  grape 
sugar  in  three  or  four  hours ;  and  in  ten  or  twelve  hours,  the  trans- 
formation into  lactic  acid  was  complete.  In  others,  when  the  food  was 
not  capable  of  an  acid  transformation,  it  remained  neutral  to  the  last. 
In  no  case  did  any  part  of  the  food  pass  through  the  peculiar  changes 
of  chymification.  More  recently,  MM.  Bouchardat  and  Sandras,^  from 
the  results  of  a  series  of  experiments  instituted  by  them,  believe  they 
have  established,  that  stomachal  digestion  and  the  movements  of  the 
organ  are  interrupted  by  the  simultaneous  section  of  both  pneumogas- 
trics  on  a  level  with  the  larynx ;  and  farther,  that  intestinal  digestion, 
and  the  production  and  absorption  of  a  very  laudable  chyle  persist 
notwithstanding  such  section;  and  M.  Longet^  concludes,  that  the  sec- 
tion of  the  pneumogastrics  seriously  affects  chymification,  chiefly  by 
paralysing  the  proper  movements  of  the  stomach,  but  partly  by  dimi- 
nishing the  secretion  of  the  gastric  solvent ;  and  Professor  Berard,* 
after  examining  the  different  experiments  and  inferences  of  preceding 
inquirers,  infers: — that  "the  mixed  cords  of  the  pneumogastrics  and 
the  branches  furnished  by  the  great  sympathetic  to  the  stomach  beneath 

*  Longet,  Traite  de  Physiologie,  ii.  330,  Paris,  1850. 

*  Gazette  Medicale  de  Paris,  1  Juin,  1844. 

'  Bouchardat,  Aimuaire  de  Therapeutique,  de  Matiere  Medicale,  &c.,  pour  1848,  p. 
306,  Paris,  1848.  f       ^     '  .        .  i-  >  i' 

*  Traite  de  Pliysiologie,  ii.  340,  Paris,  1850. 

'  Cours  de  Pliysiologie,  12o  livraisou,  p.  235,  Paris,  1849. 


166  DIGESTION. 

the  diapTiragm,  contribute  to  the  maintenance  of  tlie  contractility  of 
the  stomach  and  the  secretion  of  the  gastric  jnice.  A  greater  share, 
however,  ought  to  be  assigned  to  the  cords  of  the  pneumogastric  than 
to  the  sub-diaphragmatic  branches  of  the  great  sympathetic.  More- 
over, the  motor  influence  of  the  pneumogastric  appears  to  predominate 
over  the  secretory ;  in  other  words,  the  resection  of  the  nerve  paralyses 
the  movements  more  than  it  diminishes  the  secretion." 

The  experiments  of  Professor  Bouley,'  of  Alfort,  exhibit,  that  the 
results  of  dividing  the  pneumogastric  nerves  are  very  different  in  dif- 
ferent animals.  In  the  horse,  for  example,  but  little  absorption  is 
effected  from  the  mucous  membrane  of  the  stomach,  whilst  in  the  dog 
the  contrary  is  the  case;  hence,  if  the  pneumogastric  nerves  be  tied  in 
the  former  animal,  a  solution  of  nux  vomica  is  retained  in  the  stomach 
Tinabsorbed;  whilst  if  they  were  entire,  it  would  be  sent  on  rapidly  into 
the  small  intestine,  and  be  immediately  absorbed.  In  the  dog,  the  same 
toxical  agent,  on  the  other  hand,  rapidly  destroys,  whether  the  pneumo- 
gastric nerves  be  tied  or  not, — because  the  lining  membrane  of  the  sto- 
mach of  the  dog  rapidly  absorbs.  The  experiments  of  Prof.  Bouley 
were  repeated  by  Prof  Bcrard,  and  with  identical  results.  It  is  proper, 
also,  to  remark,  that  there  are  certain  toxical  agents,  which  are  not 
absorbed  by  the  mucous  membrane  of  the  stomach  when  the  nerves 
are  entire.  This  appears  to  be  the  case  with  the  curare,  which  can  be 
swallowed  with  impunity.  It  has  been  supposed,  that  this  is  owing  to 
some  change  produced  in  it  by  the  gastric  secretions;  but  such  would 
not  seem  to  be  the  case,  as  the  poison,  if  digested  for  24  or  48  hours  in 
gastric  juice,  is  as  virulent  as  ever;  and  such  appears  to  be  the  fact 
when  the  various  intestinal  secretions  are  added  to  it.  The  experi- 
ments of  M^[.  Bernard  and  Pelouze^  exhibit,  that  the  gastro-enteric 
mucous  membrane  refuses  the  passage  of  the  curare  under  such  cir- 
cumstances, even  when  the  experiment  is  made  with  a  portion  of  the 
dead  membrane  adapted  to  an  endosmometer.  Such,  too,  appears  to 
be  the  fact  with  other  mucous  membranes,  except  the  pulmonary.  If 
the  poison  be  applied  to  it,  absorption  takes  place  in  the  same  manner 
as  when  it  is  placed  in  the  subcutaneous  areolar  tissue. 

"We  can  thus  comprehend  an  experiment  made  by  Professor  Bernard, 
who  gave  to  each  of  two  dogs,  on  one  of  which  he  had  divided  the  pneu- 
mogastric nerves,  a  dose  of  emulsin;  and,  half  an  hour  afterwards,  one 
of  amygdalin;  which  are  inert  when  taken  alone,  but,  by  mixture,  pro- 
duce hydrocyanic  acid.  The  dog  whose  nerves  were  cut,  died  in  a 
quarter  of  an  hour;  the  emulsin  having  been  detained  in  the  stomach 
until  the  amygdalin  reached  it.  In  the  other,  the  emulsin  was  removed 
by  absorption,  so  that  no  hydrocyanic  acid  could  be  formed  when  the 
amygdalin  was  taken.^  It  is  proper  to  remark,  however,  that  the  results 
of  these  distinguished  observers  do  not  exactly  accord  with  those  of 
Prof  Brainard,  of  Chicago,  on  curare  furnished  to  him ;  and  the  active 
principle  of  which  he  believed  to  be  the  venom  of  serpents.    Its  effects 

'  Archives  Generales  de  Medeoine,  Juillet,  1S52,  p.  357. 

2  L'Union  Medicale,  1850,  No.  125  ;  aud  Brit,  arrd  For.  Med.-Chir.  Rev.,  April,  1851, 
p.  532. 

3  Frericlis,  art.  Verdaming,  in  Wagner's  Handworterbucli  der  Physiologie,  S.  658,  Ster 
Baud,  Iste  Abth.,  Braunschweig,  1846. 


CHYMIFICATION.  167 

on  animals  were  strikingly  like  those  cansed  by  tlie  venom  of  tlie 
rattlesnake,  and  in  many  cases  no  difference  could  be  perceived  be- 
tween tbem.  He  found,  too,  that  like  the  venom  of  serpents  it  was 
innocuous  when  taken  into  the  stomach,  "except,  perhaps,  when  used 
in  very  large  quantities,  or  in  circumstances  very  peculiar.  This  is 
not  the  case  with  any  known  vegetable  poison."  Dr.  Brainard  adds, 
that  "it  is  now  well  known,  that  the  poison  employed  by  the  North 
American  Indians  for  their  arrows  is  that  of  the  rattlesnake,"^  He 
affirms,  moreover,  that  the  curare  or  woorara  poison  may  be  taken  into 
the  stomach  "and  absorbed  without  any  ill  effects."  If  this  be  the 
case,  some  change  must  be  produced  in  the  venom  before  or  during 
absorption.  Dr.  Brainard  agrees,  that  the  gastric  juice  has  no  power 
over  it — "at  least,  that  there  is  no  evidence  of  its  possessing  such  a 
power,  and  that  all  the  facts  that  we  are  acquainted  with  go  to  disprove 
it."  If  absorbed,-  then,  by  what  agency  is  it  decomposed,  for  if  injected 
into  the  bloodvessels  it  destroys  rapidly? 

Of  all  these  theories  of  chymification,  that  of  chemical  action,  aided 
by  the  collateral  circumstances  to  be  mentioned  presently,  can  alone  be 
embraced ;  yet,  how  difficult  is  it  to  comprehend,  that  any  one  secretion 
can  act  upon  the  immense  variety  of  animal  and  vegetable  substances 
employed  as  food !  The  discovery  of  the  chlorohydric  and  acetic  acids 
and  of  pepsin  in  the  secretion,  aids  us  in  solving  the  mystery  expressed 
by  the  well-known  pithy  and  laconic  observation  of  Dr.  William  Hunter 
in  his  lectures:  "Some  physiologists  will  have  it,  that  the  stomach  is  a 
mill;  others,  that  it  is  a  fermenting  vat;  others,  again,  that  it  is  a  stew- 
pan; — but,  in  my  view  of  the  matter,  it  is  neither  a  mill,  a  fermenting 
vat,  nor  a  stewpan ; — but  a  stomach,  gentlemen,  a  stomach." 

Allusion  has  been  already  made  to  ^^e/vsw? — an  organic  compound  or 
"ferment"  thrown  off  from  the  stomach — which  is  an  active  agent  in 
digestion.  It  had  been  observed  in  the  experiments  of  Eberle  and 
Schwann,  that  although  acids  alone  have  little  power  in  digesting  food, 
they  act  energetically  when  combined  with  the  mucus  of  the  stomach. 
Eberle  thought,  that  the  acidulated  mucus  of  any  membrane  would 
produce  the  effect,  but  J.  Miiller  and  Schwann  found  it  to  be  restricted 
to  that  of  the  stomach.  The  agency  of  pepsin  is  regarded  by  Liebig^ 
to  be  similar  to  that  of  diastase  in  the  germination  of  seeds.  Both  are 
.  bodies  in  a  state  of  transformation  or  decomposition;  the  latter  effecting 
the  solution  of  starch  by  its  conversion  into  sugar;  and  the  former  the 
formation  of  alimentary  matter  into  chyme.  The  present  belief  amongst 
physiologists  and  chemists — from  all  these  experiments,  as  well  as  those 
of  Wasraann  and  others — is,  that  pepsin,  by  inducing  a  new  arrange- 
ment of  the  elementary  particles  or  atoms  of  alimentary  matter,  dis- 
poses it  to  dissolve  in  the  gastric  acids.  Chlorohydric  acid,  indeed, 
dissolves  white  of  egg  by  ebullition,  just  as  it  does  under  the  influence 
of  pepsin;  so  that  pepsin  replaces  the  effect  of  a  high  temperature  in 
the  stomach.^   Liebig,  consequently,  does  not  believe  that  the  digestive 

'  Essay  on  a  New  Mctliod  of  Tre.ating  Serpent  Bite  and  other  Poisoned  Wounds,  p.  8, 
Chicago,  1854. 

*  Animal  Chemistry,  Gregory  and  Webster's  edit.,  p.  lOl),  Cambridge,  Mass.,  1S42. 

*  Graham's  Elements  of  Chemistry,  Amer.  edit.,  by  Dr.  Bridges,  p.  69(3,  Fhilad.,  1843. 


168  DIGESTION". 

process  is  a  simple  solution,  but  a  species  of  fermentation,  not  identical, 
however,  with  any  of  the  known  processes  of  fermentation  occurring 
in  organic  matters  out  of  the  body.  It  differs  from  ordinary  fermenta- 
tion in  being  unattended  with  the  formation  of  carbonic  acid ;  in  not 
requiring  the  presence  of  oxygen,  and  in  not  being  accompanied  by  the 
reproduction  of  the  ferment.' 

The  deductions  of  MM.  Bernard  and  Barreswil,^  from  numerous  and 
varied  experiments  related  to  the  Academie  Royale  des  Sciences,  of  Paris, 
have  been  referred  to  already.  From  these,  it  would  seem,  that  an  or- 
ganic compound  of  like  nature  exists  in  the  saliva,  gastric  juice,  and 
pancreatic  fluid;  and  that  its  digestive  powers  vary  according  as  it  is 
associated  with  fluid  having  an  acid  or  an  alkaline  reaction.  Thus  in 
the  gastric  juice,  which  is  acid,  it  readily  dissolves  nitrogenized  sub- 
stances,— fibrin,  gluten,  albumen,  &c.,  whilst  it  is  altogether  without 
action  on  starch.  These  gentlemen  affirm,  that  if  we  destroy  this  acid 
reaction,  and  render  the  gastric  juice  alkaline  by  the  addition  of  car- 
bonate of  soda,  the  active  organic  matter  being  in  presence  of  an  alka- 
line fluid  changes  its  physiological  action,  and  becomes  able  to  modify 
starch  rapidly,  whilst  it  loses  the  power  of  digesting  nitrogenized  sub- 
stances. As  the  saliva  and  pancreatic  juice  are  alkaline,  it  was  interest- 
ino-  to  know  whether  a  chano;e  in  the  chemical  reaction  of  these  fluids 
would  produce  in  them  the  same  change  of  properties  as  in  the  case  of 
the  gastric  juice.  Experiment  proved  such  to  be  the  flict.  By  rendering 
the  pancreatic  fluid  or  saliva  acid,  their  ordinary  action  was  inverted: 
they  acquired  the  power  of  dissolving  meat  and  other  nitrogenized 
substances,  whilst  they  lost  their  influence  on  starch. 

Certain  of  the  positions  of  these  gentlemen  received  support  from 
the  investigations  of  M.  Blondlot.^  He  is  of  opinion — and  most  of  the 
physiologists  of  the  present  day  accord  with  him — that  of  all  the  simple 
alimentary  substances,  those  that  are  fluid  at  the  ordinary  temperature 
of  the  stomach,  and  those  that  are  readily  soluble  in  its  secretions,  as 
fluid  albumen,  sugar,  gum,  pectin,  &c.,  are  at  once  absorbed  by  the 
veins.  It  would  seem,  indeed,  that  in  cases  of  scirrhus  of  the  pylorus, 
and  where  a  cancerous  communication  has  existed  between  the  stomach 
and  colon,"*  nutritious  matter  must  necessarily  be  absorbed  from  the 
stomach:  except,  however,  in  such  cases,  the  view,  that  digestion  can 
be  accomplished  by  the  gastric  veins,  independently  of  the  action  of 
any  gastric  secretions,  can  scarcely  be  maintained.^  It  would  seem,, 
moreover,  that  certain  aliments,  after  having  experienced  the  necessary 
stomachal  and  intestinal  changes,  are  received  by  imbibition  into  the 
veins  of  the  intestines.  MM.  Bouchardat  and  Sandras  affirm,  that  after 
herbivorous  animals  have  been  fed  on  farinaceous  substances,  more 
-dextrin,  grape  sugar  and  lactic  acid  are  detected  in  the  blood  of  the 
vena  porta  than  in  that  of  any  other  bloodvessel.^     Trommer,  also 

'  Kirkes  and  Paget,  Manual  of  Physiology,  2d  Amer.  edit.,  p.  173,  Philad.,  1853. 

2  Comptes  Rendus,  9  Decemb.,  1844,  and  7  Juillet,  1845. 

^  Traite  Analytique  de  la  Digestion,  Paris,  1S44. 

*  Such  a  case  is  given  by  Dr.  William  Waters,  in  Philadelphia  Med.  Examiner,  p. 
201,  April,  1845. 

'  A  Physiological  Essay  on  Digestion,  by  Nathan  Pi.  Smith,  M.D,,  &c.,  New  York, 
1825. 

^  Gazette  Medicale  de  Paris,  Jan.,  1845. 


CHYMIFICATION.  169 

detected  grape  sugar  in  the  blood  of  the  portal  vein,  but  not  in  that  of 
the  hepatic  vein  in  animals  to  which  that  substance  had  been  given 
with  their  food.^  The  bearing  of  such  observations  on  the  production 
of  sugar  bj  the  liver  will  be  shown  hereafter. 

In  conclusion: — Let  us  inquire  into  the  various  agencies  to  which 
the  food  is  exposed  during  the  progress  of  chymification.  First.  It 
becomes  mixed  with  the  secretions,  already  existing  in  the  stomach,  as 
well  as  with  those  excited  by  its  presence.  Secondly.  It  is  agitated  by 
the  peristaltic  motion  of  the  stomach  itself,  and  the  movement  of  the 
neighbouring  organs.  Thirdly.  It  is  exposed  to  a  temperature  of  at 
least  100°  of  Fahrenheit,  which,  during  the  ingestion  of  food,  does  not 
rise  higher:  exercise  elevates,  whilst  sleep,  or  rest,  or  a  recumbent 
posture,  depresses  it.^  After  food  has  been  subjected  to  these  influ- 
ences, the  conversion  into  chyme  commences.  This  always  takes  place 
from  the  surface  towards  the  centre :  the  nearer  it  lies  to  the  surface 
of  the  stomach,  the  more  it  is  acted  on ;  and  the  part  that  is  in  contact 
with  the  lining  membrane  is  more  digested  than  any  other ; — appear- 
ing as  if  corroded  by  some  chemical  substance  capable  of  dissolving  it. 
Dr.  Wilson  Philip^  asserts,  that  the  new  food  is  never  mixed  with  the 
old ;  the  former  being  always  found  in  the  centre,  surrounded  on  all 
sides  by  the  latter.  If  the  old  and  new  be  of  different  kinds,  the  line 
of  separation  between  them  is  so  evident,  that  the  former  may  be  com- 
pletely removed  without  disturbing  the  latter;  and  if  they  be  of  differ- 
ent colours,  the  line  of  demarcation  can  frequently  be  distinctly  traced 
through  the  parietes  of  the  stomach  before  they  are  laid  open.  Dr. 
Beaumont,^  however,  affirms,  that  this  statement  is  not  correct ;  that, 
in  a  very  short  time,  the  food,  already  in  the  stomach,  and  that  subse- 
quently eaten,  become  commingled.  In  the  subject  of  his  experi- 
ments, he  invariably  found  that  the  old  and  new  food,  if  in  the  same 
state  of  comminution,  were  readily  and  speedily  combined. 

The  conversion  of  the  food  into  chyme,  it  has  been  conceived,  com- 
mences in  the  splenic  portion,  is  continued  in  the  body  of  the  viscus, 
and  completed  in  the  pyloric  portion.  On  this  point,  the  observations 
of  Dr.  Philip  differ  somewhat  from  those  of  M.  Magendie,*  the  former 
appearing  to  think,  that  chymification  is  chiefly  accomplished  in  the 
splenic  portion  and  middle  of  the  stomach ;  whilst  the  latter  affirms, 
that  it  is  mainly  in  the  pyloric  portion  that  chyme  is  formed ; — the 
alimentary  mass  appearing  to  pass  into  it  by  little  and  little,  and 
during  its  stay  there  to  undergo  transformation.  He  further  affirms, 
that  he  has  frequently  seen  chymous  matter  at  the  surface  of  the  ali- 
mentary mass  filling  the  splenic  half;  but  that  it  commonly  preserves 
its  properties  in  this  part  of  the  organ. 

The  precise  steps  of  the  change  into  chyme  cannot  be  indicated. 
Some  of  the  results,  at  different  stages  of  the  process,  have  been  ob- 
served on  animals ;  and  pathological  cases  have  occasionally  occurred, 
which  enabled  the  physiologist  to  witness  what  was  going  on  in  the 
interior  of  the  stomach ;  but,  with  perhaps  one  exception,  those  oppor- 

'  Kirkes  and  Taget,  Manual  of  Physiology,  2d  Amer.  edit.,  p.  194,  Philad.,  1853. 

*  Beaumont,  On  the  Gastrio  Juice,  p.  274. 

'  Exper.  Inquiry,  oh.  vii.  sect.  1 ;  and  Treatise  on  Indigestion,  Lond.,  1821. 

*  Oi).  dtat.,  p.  89.  *  PrGcis,  &c.,  edit,  oit.,  ii,  88. 


170  DIGESTION", 

tunities  have  not  been  mncli  improved.  Dr.  Burrows^  relates  a  case 
of  fistulous  opening  into  the  organ.  The  subject  of  the  case  was  not 
seen  by  him  until  twenty-seven  years  after  the  injury,  at  which  time 
the  man  was,  to  all  appearance,  healthy ;  but  he  was  drunken,  and 
dissipated,  and  the  following  year  died.  A  case  is  related  by  Shenck  ;* 
and  Louis''  refers  to  similar  cases  that  occurred  to  Foubert  and  Covil- 
lard.  Helm,  of  Vienna,''  published  a  case,  to  which  reference  has 
already  been  made  ;  and  one  of  an  interesting  character  occurred  at  the 
Hospital  La  Gharite  of  Paris,  which  sheds  some  little  light  on  the 
subject.*  The  aperture,  which  was  more  than  an  inch  and  a  half  long, 
and  an  inch  broad,  exposed  the  interior  of  the  organ.  At  the  admis- 
sion of  the  female  into  the  hospital,  she  ate  three  times  as  much  as 
ordinary  persons.  Three  or  four  hours  after  a  meal,  an  irresistible 
feeling  compelled  her  to  remove  the  dressings  from  the  fistulous  open- 
ing, so  as  to  allow  the  escape  of  food  which  the  stomach  could  no 
longer  contain, — when  the  contents  came  out  quickly,  accompanied  by 
more  or  less  air.  They  possessed  a  faint  smell,  but  had  neither  acid 
nor  alkaline  properties;  and  the  grayish  paste,  of  which  they  consisted, 
when  diluted  with  distilled  water,  did  not  affect  vegetable  blues. 
Digestion  was  far  from  complete ;  yet,  frequently  the  odour  of  wine 
was  destroyed ;  and  bread  was  reduced  to  a  soft,  viscid,  thick  sub- 
stance, resembling  fibrin  recently  precipitated  by  acetous  acid,  and 
swimming  in  a  stringy  fluid  of  the  colour  of  common  soup.  Experi- 
ments, made  on  this  half-digested  food,  at  the  Ecole  de  Medecine^  showed 
that  the  changes,  which  it  had  undergone,  were  an  increase  of  gelatin; 
the  formation  of  a  substance  like  fibrin ;  and  a  considerable  portion  of 
chloride  of  sodium,  phosphate  of  soda  and  phosphate  of  lime.  The 
patient  could  never  sleep  until  she  had  emptied  her  stomach,  and 
washed  it  out  by  drinking  infusion  of  chamomile.  In  the  morning,  it 
contained  a  small  quantity  of  thick,  frothy  liquid,  analogous  to  saliva, 
which  did  not  affect  vegetable  blues ;  with  matters  of  greater  con- 
sistence, and  some  opaque,  albuminous  flocculi  mingled  with  the  liquid 
portion.  The  results  of  chemical  experiments  on  this  liquid  were 
similar  to  those  obtained  on  the  analysis  of  saliva. 

But  the  most  interesting  case  in  its  observed  phenomena  is  one  that 
occurred  to  Dr.  Beaumont,^  of  the  United  States  Army,  now  of  Saint 
Louis,  which  the  author  had  an  opportunity  of  examining.  To  this 
case,  reference  has  already  been  made  repeatedly.  A  Canadian  lad, 
Alexis  San  Martin,  eighteen  years  of  age,  received  a  charge  of  buck- 
shot in  his  left  side,  which  carried  away  integuments  and  muscles  of 
the  size  of  the  hand;  fracturing,  and  removing  the  anterior  half  of 
the  sixth  rib;  fracturing  the  fifth;  lacerating  the  lower  portion  of  the 
left  lobe  of  the  lung  and  the  diaphragm,  and  perforating  the  stomach. 
When  Dr.  Beaumont  saw  the  lad,  twenty-five  or  thirty  minutes  after 

'  Transactions  of  the  Royal  Irish  Academy,  vol.  iv. 

'  Observ.  Medic,  liar.,  Nov.,  &c.,  lib.  iii.  I'rancof.,  1609. 

3  Memoir,  de  TAcadtmie  Royale  de  Chirurgie,  vol.  iv.  p.  213,  Paris,  1819. 

*  Rudolphi,  Grundriss  der  Physiologic,  2ter  Band,  2te  Abtheil,  s.  114,  Berlin,  1828. 

*  Richerand's  Elemens  de  Physiologic,  edit,  cit.,  p.  72. 

^  Op.  citat.,  Introduction,  p.  10  ;  and  the  Author's  Elements  of  Hygiene,  p.  216,  Philad., 
1835. 


CHYMIFICATION".  171 

the  accident,  lie  found  a  portion  of  the  lung,  as  large  as  a  turkey's 
egg,  protruding  through  the  external  wound,  lacerated  and  burnt;  and, 
immediately  below  this,  another  protrusion,  which,  on  inspection, 
proved  to  be  a  portion  of  the  stomach,  lacerated  through  all  its  coats, 
and  suffering  the  food  he  had  taken  at  breakfast  to  escape  through  an 
aperture  large  enough  to  admit  the  forefinger.  It  need  scarcely  be 
said,  that  numerous  untoward  symptoms  occurred  in  the  cicatrization 
of  so  formidable  a  wound.  Portions  of  the  ribs  exfoliated;  abscesses 
formed  to  allow  the  exit  of  extraneous  substances ;  and  the  patient 
was  worn  down  by  febrile  irritation.  Ultimately,  however,  the  care 
and  attention  of  Dr.  Beaumont  were  crowned  with  success,  and  the 
instinctive  actions  of  the  system  repaired  the  extensive  injury.  The 
wound  was  received  in  1822,  and  on  the  6th  of  June,  1823,  one  year 
from  the  date  of  the  accident,  the  injured  parts  were  sound,  and  firmly 
cicatrized,  with  the  exception  of  the  perforation  leading  into  the  sto- 
mach, which  was  about  two  inches  and  a  half  in  circumference.  Until 
the  winter  of  1823-4,  compresses  and  bandages  were  needed  to  pre- 
vent the  escape  of  the  food.  At  this  period,  a  small  fold  or  doubling 
of  the  inner  coat  of  the  stomach  appeared  forming  at  the  superior 
margin  of  the  orifice,  slightly  protruding,  and  increasing  in  size  until 
it  filled  the  aperture.  This  valvular  formation  adapted  itself  to  the 
opening  into  the  organ,  so  as  to  completely  prevent  the  escape  of  the 
contents,  when  the  stomach  was  full;  but  it  could  be  readily  depressed 
by  the  finger.  Since  the  spring  of  1824,  San  Martin  had  enjoyed 
general  good  health;  he  was  active,  athletic,  and  vigorous;  eating  and 
drinking  like  a  healthy  individual.  From  the  summer  of  1825,  Dr. 
Beaumont  had  been  engaged  in  the  prosecution  of  numerous  experi- 
ments upon  him ;  some  of  the  results  of  which  he  has  given  to  the 
world.  In  the  winter  of  1833,  he  was  in  Washington,  when  the  author — 
at  the  time.  Professor  of  Medicine  in  the  University  of  Virginia — was 
politely  invited  to  examine  San  Martin  for  physiological  purposes. 
Many  of  the  results  of  this  examination  are  given  by  Dr.  Beaumont, 
and  have  already  been,  or  will  be,  referred  to  in  the  present  work. 
Dr.  Beaumont's  researches  into  the  comparative  digestibility  of  differ- 
ent alimentary  substances  belong  to  another  department  of  medical 
science,  and  have  accordingly  received  attention  from  the  author  else- 
where. 

What,  then,  it  may  be  asked,  are  the  changes  wrought  on  the  food 
in  the  stomach  by  the  gastric  secretions  ?  Dr.  Prout'  classes  them 
Tinder  three  operations ; — the  reducing,  converting,  and  organizing  and 
vitalizing.  The  first  of  these  is  probably  the  main  operation.  In 
order  to  decide,  whether  the  action  of  the  stomach  in  digestion  be  a 
simple  solution,  or  a  total  or  partial  conversion,  certain  compounds  of 
organization,  easy  of  detection — as  gelatin,  albumen,  and  fibrin — were 
introduced,  at  the  author's  sug^o-estion,  into  the  stomach  through  the 
fistulous  opening  in  the  subject  of  Dr.  Beaumont's  case ;  whilst  other 
portions  were  digested  artificially  in  gastric  juice  obtained  from  the 
same  individual.  The  solutions  presented  the  same  appearance,  and 
were  similarly  affected   by  reagents;  and  in  all  cases,  whether  the 

*  Bridgewater  Treatise,  Amer.  edit.,  p.  235,  Pliilad.,  1834. 


172  DIGESTION. 

digestion  was  artificial  or  rea.l^  the  proximate  principles  could  be 
thrown  down  in  tlie  state  of  gelatin^  fibrin  or  albumen^  as  the  case 
might  be.  These  experiments,  so  far  as  they  went,  justified  the  con- 
clusion, that  the  digestive  process  in  the  stomach  is  a  simple  solution  or 
division  of  alimentary  substances,  and  an  admixture  with  the  mucous 
secretions  of  that  organ,  and  the  various  fluids  from  the  supra-dia- 
phragmatic portion  of  the  digestive  tube.  With  regard  to  the  exist- 
ence of  the  other  gastric  operations  described  by  Dr.  Prout,  well- 
founded  doubts  may  be  entertained.  To  his  proposition  that,  what- 
ever may  be  the  nature  of  the  food,  the  general  composition  and 
character  of  the  chyle  remain  always  the  same,  no  objection  can  be 
urged ;  but,  admitting  its  accuracy,  it  by  no  means  follows,  that  the 
conversion  must  be  effected  in  the  stomach,  or  that  any  organizing  or 
vitalizing  powers  are  exerted  upon  the  chyme  in  that  organ.  On  the 
contrary,  it  appears  that  the  essential  changes  effected  on  solid  aliment 
in  the  stomach  are  of  a  purely  physical  character,  so  as  to  adapt  it  for 
the  separation  of  the  chylous  portion  in  the  intestines  by  organs  whose 
vital  endowments  and  influences  cannot  be  contested.  Dr.  T.  J.  Todd' 
is  disposed  to  believe,  from  his  experiments  on  artificial  digestion,  that 
the  various  vegetable  and  animal  substances  subjected  to  the  action  of 
the  digestive  fluids  at  the  ordinary  temperature  of  the  atmosphere  are, 
in  all  instances,  reduced — not  to  their  chymical^  but  to  their  organic 
elements ;  and  he  is  of  opinion,  that  this  applies  equally  to  digestion 
in  the  stomach,^ 

From  what  has  been  already  shown  of  the  close  approximation  to 
each  other  in  chemical  composition  of  several  of  the  compounds  of 
organization,  it  may  be  understood,  that  many  vegetable  principles 
might  be  converted  into  animal  principles  without  any  material  change 
of  composition.  They  might  all  perhaps  be  changed  into  albumen, 
from  which,  as  elsewhere  seen,  fibrin  differs  but  little  except  in  its 
organizable  power.  Saccharine  matters — it  has  been  conceived — may 
be  converted,  in  the  digestive  tube,  partly  into  albumen,  and  partly 
into  oleaginous  matter,  the  nitrogen  of  the  former  being  furnished, 
according  to  some,  by  the  pepsin  or  by  some  highly  nitrogenized  sub- 
stance secreted  in  the  stomach,  or  duodenum,  or  both;^  but  whether 
such  conversion  really  occurs  there  is  more  than  questionable.  The 
oleaginous  matters  themselves  are  absorbed  by  simple  imbibition  as 
an  emulsion  formed  by  their  union  with  the  alkali  of  the  pancreatic 
fluid." 

Most  physiologists  now  agree,  that  animal  food  is  converted  into  a 
modification  of  albumen,  called  albuminose^^  which,  when  it  enters  the 
vessels,  is  more  easily  assimilated  than  albumen.  AVhilst  a  solution 
of  the  latter,  indeed,  if  injected  into  the  bloodvessels,  is  separated  by 
the  kidney  ;  the  former  undergoes  assimilation  in  the  system  of  nutri- 

'  Brit.  Annals  of  Medicine,  Jan.,  1837. 

'  See,  on  the  action  of  the  gastric  juice  on  aliments,  Beaumont,  op.  cit. ;  and  Beraud, 
Manuel  de  Physiologie,  p.  134,  Paris,  18r)3. 

*  Prout,  on  the  Stomach  and  Urinary  Diseases,  p.  xxviii.,  note. 

*  Matteucci,  Lectures  on  the  Physical  Phenomena  of  Living  Beings,  by  Pereira,  Amer. 
edit.,  p.  110,  Philad.,  1848,  and  C.  Bernard,  Archives  Ui  nerales,  xix.  tiO,  cited  in  Bri- 
tish and  Foreign  Medico-Chirurgical  Review,  p.  528,  April,  1849. 

*  See  page  48. 


CHYMIFICATION.  173 

tion.  On  cane  sugar  a  similar  effect  appears  to  be  induced  by 
admixture  with  the  gastric  secretions.  It  is  converted  into  glucose, 
which  when  absorbed  is  more  readily  appropriated,  or  a  portion  of  it 
may  be  converted  into  lactic  acid. 

On  the  whole,  in  the  present  state  of  our  knowledge  of  this  import- 
ant function,  we  are  perhaps  justified  in  concluding: — First.  That  by 
the  operation  of  the  gastric  secretions  the  nitrogenized  principles  of 
the  food,  whether  animal  or  vegetable,  are  dissolved  in  the  stomach. 
Secondly.  That  amylaceous  matters  are  converted  by  the  buccal  secre- 
tions into  saccharine,  and  these  last  are  absorbed ;  or  they  undergo  a 
farther  change,  by  which  they  are  partly  converted  into  lactic  acid, 
and  partly  into  oleaginous  matter  [?].  Thirdly.  That  the  oleaginous 
matters  undergo  no  change  in  the  stomach ;  and  Fourthly.  That  with 
the  exception  of  certain  mineral  substances,  matters  that  cannot  be 
reduced  to  either  of  these  forms  are  sent  on  into  the  intestinal  canal, 
to  be  rejected  as  excrement. 

In  proportion  as  the  food  is  digested,  it  passes  through  the  pylorus. 
After  the  layer,  that  lies  next  to  the  mucous  membrane,  has  experi- 
enced the  requisite  change,  and  is  propelled  onwards  by  the  muscular 
action  of  the  organ,  the  portion  lying  next  to  it  becomes  subjected  to 
the  same  process.  The  gastric  fluid,  at  the  same  time,  penetrates,  in 
a  greater  or  less  degree,  the  entire  alimentary  mass,  so  that,  when  the 
central  portion  comes  in  contact  with  the  surface  of  the  stomach,  its 
conversion  is  already  somewhat  advanced.  The  chyme,  thus  success- 
ively formed,  does  not  remain  in  that  organ,  until  the  whole  alimentary 
mass  has  undergone  chymification ;  but  as  it  is  completed,  it  is  trans- 
mitted, by  the  peristaltic  action,  through  the  pylorus  into  the  duode- 
num. In  the  early  stages  of  digestion,  the  passage  of  the  chyme  from 
the  stomach  is  more  slow  than  in  the  later.  At  first,  it  is  more  mixed 
with  the  undigested  portions  of  food,  and,  as  Dr.  Beaumont^  suggests, 
is  probably  separated  with  difficulty  by  the  powers  of  the  stomach.  In 
the  more  advanced  stages,  as  the  whole  mass  becomes  chymified,  the 
process  is  more  rapid,  and  is  accelerated  by  the  peculiar  contraction  of 
the  stomach,  already  described.  After  the  expulsion  of  the  last  parti- 
cles of  chyme,  the  organ  becomes  quiescent,  and  no  more  gastric  secre- 
tion takes  place,  until  a  fresh  supply  of  food  is  received,  or  some  me- 
chanical irritation  is  produced  in  its  inner  coat. 

The  time,  required  for  the  complete  chymification  of  a  meal,  is  stated 
by  the  generality  of  physiologists  to  be  about  four  or  five  hours.  In 
Dr.  Beaumont's  case,^  a  moderate  meal  of  meat,  with  bread,  &c.,  was 
digested  in  from  three  hours  to  three  hours  and  a  half.  We  believe 
that,  in  by  far  the  majority  of  cases,  a  longer  time  than  this  is  neces- 
sary ;  and  in  laborious  digestions,  the  presence  of  food  can  be  distin- 
guished by  eructations  for  more  than  double  the  time.  It  is  manifest, 
that  no  fixed  period  can  be  established  for  the  production  of  this  effect. 
It  must  vary,  according  to  the  digestive  capability  of  the  individual ; 
the  state  of  his  general  health ;  and  the  relative  digestibility  of  the  ali- 
ments employed ;  all  which,  as  we  have  already  seen,  admit  of  great 
diversity.     It  would  seem  that  the  most  digestible  aliments  should  be 

'  On  the  Gastric  Juice,  p.  96.  2  Ibid.,  p.  275. 


174  DIGESTION. 

most  speedily  sent  on  into  the  duodenum;  yet  sucli  is  not  perhaps  the 
case.  Certain  it  is,  that  many  articles  pass  the  pylorus  after  having 
experienced  little  or  no  change ;  and  in  cases  of  artificial  anus,  Pro- 
fessor Lallemand,  of  Montpellier,  observed  that  the  least  nutritive  and 
least  digestible  presented  themselves  first.  Vegetable  substances  ap- 
peared before  animal ;  and  totally  indigestible  substances — as  pieces  of 
money — are  known  to  clear  the  stomach  rapidly.^ 

During  chymification  only  a  very  small  quantity  of  air  is  found  in 
the  stomach;  sometimes,  none.  "When  met  with,  it  is  near  the  cardiaxj 
orifice,  or  at  the  upper  part  of  the  splenic  portion.  M.  Magendie 
examined  the  gases  in  the  stomach  and  intestines  of  executed  crimi- 
i'lals,  and  obtained  the  following  results :  a,  in  the  case  of  an  individual 
who  had  taken  food  in  moderation  an  hour  previous  to  death ;  6,  in  the 
case  of  one  who  had  eaten  two  hours  previously ;  and  c,  in  the  case  of 
one  who  had  done  so  four  hours  previous  to  execution. 

100  volumes  of  the  gas  contained 

Oxygen. 

!From  tlie  stomacli, 
small  intestines, 
large         do. 

!  From  the  stomach, 
small  intestines, 
large         do. 

!From  the  stomach, 
small  intestines, 
large        do. 

From  these  results  it  appears,  that  when  the  execution  occurred  not 
longer  than  an  hour  after  a  meal,  oxygen  was  found  in  the  stomach ; 
and  when  not  until  two  hours,  it  had  entirely  disappeared,  and  a  large 
quantity  of  nitrogen  was  found  in  the  intestines,  with  an  entire  absence 
of  oxygen ;  whence  it  is  inferred,  that  the  oxygen  of  the  air  is  sepa- 
rated from  the  nitrogen  in  the  stomach;  and  the  former  is  employed  in 
digestion.  The  view  of  Liebig  is,  that  the  oxygen  occasions  a  mole- 
cular action  in  the  pepsin  or  animal  matter  in  the  stomach,  and  that 
this  intestine  motion  is  communicated  to  the  molecules  of  the  albumen 
or  protein  of  the  food,  so  that  the  latter  is  rendered  soluble  in  the  gas- 
tric acid.^  The  oxygen  he  refers  to  atmospheric  air  enclosed  in  the 
saliva  during  mastication,  and  in  that  way  introduced  into  the  stomach. 

The  small  quantity  of  air,  discovered  in  the  stomachs  of  animals, 
disproves  the  idea  of  M.  Chaussier,  that  we  swallow  a  bubble  at  each 
effort  of  deglutition.  If  so,  the  stomach  ought  to  be  always  inflated, 
especially  after  eating,  which  is  not  the  case.  MM.  Leuret  and  Las- 
saio-ne'*  found  the  air,  obtained  from  the  stomach  of  a  dog  fed  on  meat, 
to  consist  of  carbonic  acid,  43  parts ;  sulpliuretted  hydrogen,  2  parts ; 
oxygen,  4  parts;  nitrogen,  31  i^arts;  carburetted  hydrogen,  20  parts. 
Whence  these  gases  proceed  will  be  a  subject  of  future  inquiry. 

In  a  robust  individual,  chymification  is  effected  without  conscious- 
ness of  the  process.     He  finds,  especially  if  the  stomach  be  over-dis- 

•  Beraud,  Manuel  de  Physiologic,  p.  148,  Paris,  1853. 

2  Liebig,  op.  cit.,  p.  2?9.  *  Ancell,  Lond.  Lancet,  Dec.  16,  1842,  p.  419. 

«  Recherches  sur  la  Digestion,  Paris,  1825. 


Oxvgen. 

Azote. 

Carbonic  Acid. 

Inflammable  Gas. 

ll.OO 

71.45 

14.00 

3.55 

00.00 

20.08 

24.39 

55.33 

00.00 

51.03 

43.50 

5.47 

00.00 

00.00 

00.00 

00.00 

,  00.00 

8.85 

40.00 

51.15 

00.00 

18.40 

70.00 

11.60 

00.00 

00.00 

00.00 

00.00 

,  00.00 

66.60 

25.00 

8.40 

00.00 

45.96 

42.86 

11.18' 

CHYMIFICATION.  175 

tended,  tbat  the  feeling  of  fulness  and  the  oppression  of  respiration, 
produced  bj  the  distension  of  the  organ,  gradually  disappear.  It  is 
not  uncommon,  however,  for  slight  shivering  or  chilliness  to  be  felt  at 
this  time ;  for  the  sensations,  and  mental  and  moral  manifestations  to 
be  blunted;  and  a  disposition  to  sleep  to  be  experienced.  "This  con- 
centration of  the  whole  vital  activity,"  according  to  M.  Adelon,^  "is 
so  natural  to  the  animal  economy,  that  there  is  always  danger  in  oppos- 
ing or  crossing  it  by  any  extraneous  or  organic  influence ;  as  by  bath- 
ing, the  use  of  medicine,  violent  exercise,  mental  emotions,  intense 
intellectual  effort,  &c."  Gentle  exercise,  however,  would  seem  to  favour 
digestion.  Such  is  the  conviction  of  Dr.  Beaumont,^  from  his  observa- 
tions. In  the  subject  of  his  experiment,  he  found  the  temperature  of 
the  stomach  generally  raised  by  it  a  degree  and  a  half,  and  chymifica- 
tion  expedited.  Where  digestion  is  imperfect,  the  signs,  already  men- 
tioned, will  be  accompanied  by  the  disengagement  of  air  and  consequent 
eructations ;  a  sense  of  weight,  or  of  heat,  or  of  unusual  distension 
in  the  epigastric  region,  &c. ;  but  these,  as  well  as  the  developement  of 
sulphuretted  hydrogen,  discharged  by  eructation,  are  the  products  of 
ordinary  decomposition  or  fermentation,  and  appertain  to  the  morbid 
condition  of  the  function  or  to  indigestion.  Yet,  as  M.  Magendie^  has 
remarked,  it  does  not  seem,  that  these  laborious  digestions  are  much 
less  profitable  than  others.  The  food,  habitually  received  into  the 
stomach,  contains  far  more  nutritive  matter  than  is  necessary  to  sup- 
ply the  wants  of  the  system ;  and,  in  the  cases  in  question,  enouo-h 
chyle  is  always  separated  in  the  small  intestine  to  supply  the  losses, 
and  even  to  add  to  the  bulk  of  the  body. 

It  has  been  already  remarked,  that  the  chyme,  first  formed,  does  not 
continue  in  the  stomach  until  the  whole  meal  has  undergone  chymifi- 
cation ;  but  that,  as  soon  as  it  has  experienced  the  necessary  changes, 
it  passes  through  the  pylorus  into  the  duodenum.  It  would  appear, 
that  the  accumulation  of  chyme  in  the  pyloric  portion  of  the  stomach 
never  exceeds  four  ounces  at  any  one  time.  M.  Magendie  states,  that, 
in  the  numerous  experiments,  in  which  he  has  had  an  opportunity  of 
noticing  it,  he  uniformly  found,  when  the  quantity  amounted  to  about 
two  or  three  ounces,  it  was  permitted  to  pass  through  the  pylorus  into 
the  duodenum.  This  passage  of  the  chyme  is  effected  by  the  peris- 
taltic action.  At  the  commencement  of  digestion,  the  duodenum  con- 
tracts inversely,  and  the  pyloric  portion  of  the  stomach,  at  the  same 
time,  drives  its  contents  into  the  sj^lenic.  This  movement  is,  however, 
soon  followed  by  one  in  an  opposite  direction ;  and,  after  a  time,  the 
inverted  action  ceases,  and  the  movement  is  altogether  in  one  direc- 
tion;— from  the  stomach  towards  the  intestine.  The  movement  by 
which  the  chyme  is  immediately  sent  into  the  duodenum,  is  thus 
effected : — the  longitudinal  fibres,  which  pass  from  the  cardiac  to  the 
pyloric  orifice,  contract,  and  approximate  the  two  orifices ;  the  pyloric 
portion  then  contracts,  not  so  as  to  direct  the  chyme  into  the  splenic 
portion,  but  towards  the  duodenum:  in  this  manner,  the  chyme  passes 
from  the  stomach :  and,  as  fresh  portions  are  formed,  they  are  success- 

'  Pliysiologie  de  I'lTomme,  edit,  cit.,  ii.  433. 

^  On  the  Gastric  Juice,  p.  93.  "  Precis,  &c.,  ii.  104. 


176  DIGESTION. 

ively  sent  onwards ;  the  peristaltic  action  becoming  more  and  more 
marked  and  frequent,  and  extending  over  a  larger  portion  of  the 
organ,  as  clijmification  approaches  its  termination.  As  the  chyme  is 
discharged  into  the  small  intestine,  the  stomach  gradually  returns  to 
its  former  dimensions  and  situation. 

f.  Action  of  the  Small  Intestine. 

The  changes  in  the  alimentary  mass  in  the  small  intestine  are  not 
less  important  than  those  already  considered.  They  consist  in  a 
farther  change  of  the  chyme  into  a  substance,  whence  chyle  can  be  ex- 
tracted by  the  action  of  the  chyliferous  vessels  or  lacteals.  Whether 
chyle  be  separated  in  the  intestine,  in  a  state  fit  for  chyliferous  absorp- 
tion, or  be  formed  by  those  vessels,  will  have  to  be  canvassed  hereafter. 
In  common  language,  however,  it  is  said  to  be  separated  there,  and 
the  process,  by  which  this  is  accomplished,  is  called  chylification. 

As  the  chyme  proceeds  into  the  duodenum,  it  readily  finds  space, 
until  towards  the  end  of  chymification,  when  the  intestine  not  unfre- 
quently  experiences  considerable  dilatation.  The  presence  of  the 
alimentary  mass  augments  the  secretion  from  the  mucous  membrane; 
and  occasions  a  greater  flow  of  the  biliary  and  pancreatic  juices.  IvIM. 
Leuret  and  Lassaigne'  found,  when  \\\qj  applied  vinegar,  diluted  with 
water,  to  the  external  surface  of  the  small  intestine  in  a  living  animal, 
that  a  considerable  quantity  of  serous  fluid  was  immediately  exhaled. 
The  same  application,  made  to  the  follicles  of  the  intestine,  excited 
the  secretion  of  a  greater  quantity  of  mucus;  and  its  application  to 
the  mouths  of  the  choledoch  and  pancreatic  ducts  caused  the  orifices 
to  dilate,  and  a  greater  discharge  of  bile  and  pancreatic  juice.  It  is  in 
this  local  manner  that  many  of  the  cholagogue  purgatives  produce 
their  effect.  Calomel  exerts  its  agency  on  the  upper  part  of  the  intes- 
tinal canal  more  especially;  and  the  irritation  it  induces  in  the  mucous 
membrane  at  the  mouth  of  the  ductus  communis  choledochus  is  propa- 
gated along  the  biliary  ducts  to  the  liver,  the  secretion  of  which  is 
thus  augmented — but  not  by  any  specific  action  exerted  on  the  organ, 
as  has  been  often  imagined.  As  the  chyme  is  acid,  it  induces  the  same 
effects  on  the  follicles  as  the  acid  employed  in  the  experiments  of  MM. 
Leuret  and  Lassaigne. 

The  chyme  does  not  remain  so  long  in  the  intestine  as  food  does  in 
the  stomach.  The  successive  arrival  of  fresh  portions  propels  the  first 
onwards;  and  the  same  effect  is  induced  by  the  peristaltic  action  of 
the  intestines — an  involuntary,  muscular  movement  of  an  irregular, 
undulatory,  oscillatory  or  vermicular  character,  which  consists  in  an 
alternate  contraction  and  dilatation  of  the  organ,  proceeding  generally 
from  above  to  below,  so  as  to  propel  the  chyme  downwards.  When  it 
reaches  any  point  of  the  intestine,  its  contact  excites  the  contraction 
of  the  circular  fibres  of  the  part;  so  that  it  is  sent  forwards  to  another 
portion  of  the  canal;  the  circular  fibres  of  which  contract,  whilst  the 
former  are  relaxed;  and  this  occurs  successively  through  the  whole 
tract  of  the  intestines.  The  longitudinal  fibres,  by  their  contraction, 
shorten  the  intestine,  and  in  this  manner  meet  the  chyme,  so  as  to 

'  Recherclies  sur  la  Digestion,  Paris,  1825. 


ACTION   OF   THE   SMALL   INTESTINE.  177 

facilitate  its  progress;  but  their  effect  cannot  be  considerable.  When 
digestion  is  not  going  on,  the  peristaltic  action  occurs  only  at  inter- 
vals; always  slowly  and  irregularly;  and  perhaps,  as  has  been  sug- 
gested, only  when  sufficient  mucous  secretion  has  collected  on  the 
inner  coat  of  the  intestine  to  provoke  it.  During  digestion,  it  is  much 
more  energetic  and  frequent,  and  more  marked  in  the  duodenum  and 
small  intestine  than  in  the  large;  occurring  not  continuously,  but  at 
intervals,  as  the  chyme  arrives  and  excites  it.  When  the  small  intes- 
tine is  surcharged,  it  may  take  place  in  several  parts  of  the  canal  at 
once ;  and,  at  times,  the  action  is  inverted. 

The  secretions  poured  into  the  intestinal  canal  lubricate  it,  and 
facilitate  the  progress  of  the  chyme.  This  is  aided  by  the  free  and 
floating  condition  of  the  intestine;  and  by  the  agitation  of  the  diaphragm 
and  abdominal  muscles  in  respiration.  Yet  its  course  along  the  small 
intestine  is  slow.  The  chjmie  is  not  transmitted  from  the  stomach 
continuously ;  and  the  peristaltic  action  of  the  intestines  occurs  only 
at  intervals.  Moreover,  owing  to  the  convolutions  of  the  intestinal 
canal,  the  chyme  must,  in  many  cases,  proceed  against  its  own  gravity; 
and  be  retarded  by  the  numerous  valvulse  conniventes,  which  bury 
themselves  in  it,  when  the  canal  is  contracted  by  the  action  of  the 
circular  fibres.  All  these  circumstances  must  cause  it  to  proceed 
slowly  along  this  part  of  the  tube — a  point  of  some  importance,  when 
we  reflect,  that  an  essential  change  is  effected  on  it  through  the  influ- 
ence chiefly  of  the  bile  and  pancreatic  juice,  and  that  its  nutritive 
portion  is  here  absorbed.  In  the  duodenum,  the  course  of  the  chyme 
is  slow.  In  the  jejunum  it  is  more  rapid,  hence  the  name,  which  indi- 
cates, that  it  is  almost  always  found  "empty."  in  the  ileum  again  it  is 
slower  on  account  of  the  greater  consistence  acquired  by  the  absorp- 
tion of  the  chylous  portion.  Whilst  the  food  is  in  progress  along  the 
small  intestine,  it  experiences  the  change  in  its  physical  properties, 
which  enables  the  chyle  to  be  separated  from  it  by  absorption.  These 
two  actions  have  been  termed  respectively  cUyVfication  and  the  alsorp- 
tion  of  chyle;  although  by  some  the  former  term  has  been  applied  to 
both  processes. 

Above  the  point  at  which  the  common  choledoch  and  pancreatic 
ducts  open  into  the  duodenum,  no  change  is  observable  in  the  chyme. 
It  preserves  its  color,  semi-fluid  consistence,  sour  smell,  and  slightly 
acid  taste;  having  been  simply  mixed  with  the  exhaled  and  follicular 
secretions  of  the  lining  membrane ;  but,  immediately  after  it  has  passed 
the  part,  at  which  the  hepatic  and  cystic  bile  and  the  pancreatic  juice 
are  poured  into  the  intestine,  it  assumes  a  different  appearance;  its 
color  is  found  to  be  changed;  it  becomes  yellowish;  of  a  bitter  taste; 
its  sour  smell  diminishes;  and  chyle  can  now  be  separated  by  the  lac- 
teals.  Accordingly,  at  this  part  of  the  canal,  chyliferous  vessels  are 
first  perceptible. 

The  change  effected  upon  the  chyme  in  the  small  intestine  is, — 
like  that  produced  on  the  food  in  the  stomach, — of  an  entirely  phy- 
sical character.  The  chyle  itself,  we  shall  endeavour  to  show  here- 
after, is  formed  by  an  action  of  elaboration  and  selection  exerted  by 
the  chyliferous  vessels.  No  difference  is  observable  between  the 
chylous  and  excrementitious  portions  of  the  chyme  in  any  part  of  the 
VOL.  I.— 12 


178  DIGESTION". 

small  intestine ;  nor  can  it  be  separated  by  pressure  or  by  any  other 
physical  process,  M,  Magendie,^  indeed,  has  affirmed,  that  if  the 
chyme  proceeds  from  animal  or  vegetable  substances  that  contain  fat 
or  oil,  irregular  filaments  are  observed  to  form,  here  and  there,  on  the 
surface, — sometimes  of  a  flat,  at  others,  of  a  round  shape, — which 
speedily  attach  themselves  to  the  surface  of  the  valvule,  and  appear 
to  be  brute  chyle;  but  this  is  not  observed  when  the  chyle  proceeds 
from  food,  that  does  not  contain  fat.  In  this  case,  a  grayish  layer,  of 
greater  or  less  thickness,  adheres  to  the  mucous  membrane,  and  ap- 
pears to  contain  the  elements  of  chyle.  MM.  Leuret  and  Lassaigne^ 
state,  that  if  an.  animal  be  opened  while  digestion  is  going  on, — on 
the  surface  of  the  chyme,  between  the  pjdorus  and  the  orifice  of  the 
ductus  communis  choledochus,  a  grayish-white,  homogeneous,  dense, 
fluid,  and  acid  substance  is  perceived  on  the  villi  of  the  intestine. 
Neither  of  these,  however,  is  chyle.  It  is  merely  the  substance  whence 
chjde  is  obtained  by  the  action  of  the  chyliferous  vessels.  The  fact, 
mentioned  by  M.  Magendie, — regarding  the  appearance  of  irregular 
filaments,  when  animal  or  vegetable  substances,  containing  fat  or  oil, 
have  been  taken  as  diet, — has  been  the  occasion  of  erroneous  deduc- 
tions of  a  pathological  character.  Frank'  asserts,  that  he  was  re- 
quested to  see  a  prince,  who  was  attacked  with  epilepsy.  His  phy- 
sician,— a  respectable  old  practitioner, — assured  Frank,  that  he  could 
make  his  patient  void  thousands  of  filiform  worms  at  pleasure.  As 
he  was  unable  to  define  either  the  genus  or  species  of  these  worms, — 
the  quantity  of  which,  from  his  account,  seemed  to  be  prodigious, — 
Frank  requested  to  be  a  witness  of  the  phenomenon.  The  physician 
administered  a  dose  of  castor  oil,  which  produced  numerous  evacua- 
tions, containing  thousands  of  whitish  filaments  similar  to  small  eels ; 
but  on  an  attentive  examination  of  these  pretended  worms,  they  were 
found  to  consist  entirely  of  the  castor  oil,  in  a  state  of  fine  division. 

The  alteration  of  the  aliment  in  the  small  intestine  is  probably  of  a 
chemical  nature ;  yet  it  has  been  conceived  to  be  organic  and  vital. 
The  same  remarks  are  applicable  here  as  were  indulged  upon  the 
supposed  organic  and  vital  action  of  the  stomach  exerted  in  the  for- 
mation of  chyme.  The  agents  of  this  alteration  are: — the  fluids 
secreted  from  the  mucous  membrane  of  the  small  intestine,  and  the 
biliary  and  pancreatic  juices,  aided  by  the  temperature  of  the  parts, 
and  the  peristole.  Haller*  was  of  opinion,  that  the  first  of  these  is  a 
principal  agent.  Eeflecting  on  the  extensive  surface  of  the  small 
intestine,  on  the  number  of  arteries  distributed  to  the  organ,  and  on 
the  size  of  these  arteries,  that  distinguished  physiologist  asserted,  that 
the  lining  membrane  of  the  intestine,  at  the  time  of  chylification, 
secretes  a  juice,  which  he  estimated  at  the  enormous  quantity  of  eight 
pounds  in  the  twenty-four  hours.  To  this  he  gave  the  name  sulcus 
irdestinalis — succus  entericus — and  assigned  it  as  im]:)ortant  a  part  in 
chylification  as  he  attributed  to  the  gastric  juice  in  chymification.  It 
is  probable,  however,  that  the  fluids  secreted  by  the  mucous  mem- 
brane of  this  portion  of  the  canal  resemble  those  of  the  rest  of  the 

'  Precis,  &c.,  ii.  111.  2  Qp.  citat. 

'  De  Curandis  Homiuum  Morbis  Epitome,  lib.  vi.  p.  218.     '•  Element.  Physiol.,  xis.  5. 


ACTION   OF  THE   SMALL   INTESTINE.  179 

intestinal  mucous  membrane;  and  that  a  main  function  is  that  of 
lubricating  the  intestine,  and  of  still  further  diluting  the  chymous 
mass.  MM.  Leuret  and  Lassaigne  endeavoured  to  procure  some  of 
them  by  making  animals,  whilst  fasting,  swallow  small  sponges,  en- 
veloped in  fine  linen,  and  killing  them  twenty -four  hours  afterwards. 
Some  of  these  sponges  had  not  gone  further  than  the  stomach,  and 
were  filled  with  gastric  juice ;  others,  which  had  reached  the  small 
intestine,  had  imbibed  the  succus  intestmalis,  which  was  more  yellow, 
and  manifestly  less  acid  than  the  gastric  secretion.  On  attempting  to 
dissolve  a  crumb  of  bread  in  each  of  these  juices,  they  discovered  tliat 
the  gastric  secretion  communicated  a  sour  sjnell  to  the  bread ;  but 
that  the  intestinal  secretion  allowed  the  bread  to  be  precipitated,  and 
dissolved  no  part  of  it.  From  this  experiment,  it  has  been  concluded, 
that  the  succus  intestinalis  is  not  a  great  agent  in  chylification.  No 
weight,  however,  can  be  placed  upon  results  obtained  in  so  unsatis- 
factory a  manner ;  for  it  is  obvious,  that  no  certainty  could  exist  as  to 
the  identity  between  the  gastric  and  intestinal  juices  and  the  fluids 
found  in  the  respective  sponges. 

We  have  strong  reason,  indeed,  for  believing,  that,  even  if  food 
should  escape  the  action  of  the  stomach,  it  is  capable  of  being  digested 
in  the  small  intestine.  This  may  be  owing  to  some  of  the  true  gastric 
juice  passing  into  the  intestinal  canal,  and  impregnating  it ;  or  it  may 
be  a  similar  secretion  from  follicles  seated  there.  Experiments  by 
Bidder  and  Schmidt  on  living  animals  have  shown,  that  albuminous 
matters  inserted  into  the  ileum,  when  all  excess  of  gastric  juice  was 
prevented,  were  acted  upon  in  the  same  manner  as  in  the  stomach ; 
and  Dr.  C.  11.  Jones  proved  the  correctness  of  their  inferences,  on 
repeating  the  experiments.'  The  lining  membrane  of  the  small  intes- 
tine possesses  the  property  of  coagulating  milk;  and  pathological 
cases  occur  in  which  the  stomach  is,  to  all  appearance,  completely  dis- 
organized ;  yet  patients  survive  so  long  as  to  compel  us  to  presume, 
that  digestion  must  have  been  eft'ected  elsewhere  than  in  that  organ. 
M.  Magendie^  placed  a  piece  of  raw  meat  in  the  duodenum  of  a  healthy 
dog.  At  the  expiration  of  an  hour  it  had  reached  the  rectum,  and  its 
weight  was  found  to  be  but  slightly  diminished ;  the  only  change  ap- 
peared to  be  at  its  surface,  which  was  discoloured.  In  another  experi- 
ment, he  fixed  a  piece  of  muscle  with  a  thread,  so  that  it  could  not 
pass  out  of  the  small  intestine.  Three  hours  afterwards,  the  animal 
was  opened.  The  piece  of  meat  had  lost  about  half  its  weight.  The 
fibrin  was  especially  attacked;  and  what  had  resisted,  which  was 
almost  all  areolar  tissue,  was  extremely  fetid.  In  experiments  by  M. 
Voisin,^  aliment  was  introduced  into  the  small  intestines  of  animals, — 
in  one  case  masticated  and  mixed  with  saliva ;  in  another  without  any 
preparation.  In  a  few  hours,  in  the  first  instance,  and  after  a  longer 
period  in  the  second,  the  food  was  as  completely  chymified  as  if  the 
process  had  taken  place  in  the  stomach.  The  same  experiments  Avere 
repeated  upon  animals  whose  pylorus  had  been  secured  by  ligature, 
and  with  similar  results.     One  of  them  lived  for  a  month  after  the 

'  Til.  K.  Chambers,  Brit.  &  For.  Med.-Chir.  Rev.,  Oct.  1855,  p.  311. 

2  Precis,  &c.,  ii.  113. 

^  Nourel  Aper^u  sur  la  Physiologie  du  Foie,  etc.,  Paris,  1833. 


180  DIGESTION. 

ligature,  nourished  for  that  period  bj  food  introduced  into  the  duo- 
denum. These  facts  sufficiently  show,  that  a  solvent  action  is  exerted 
in  the  small  intestine;  and  there  is  reason  for  ascribing  to  the  mixed 
fluid  poured  into  it  a  great  power  of  reducing  alimentary  substances 
to  a  condition  in  which  they  may  be  absorbed.  MM.  CI.  Bernard 
and  De  Chaniac'  found  it  act  energetically  on  all  alimentary  prin- 
ciples; it  emulsified  fatty  bodies;  modified  albuminous  substances, 
and  transformed  starch  into  sugar;  and  Bidder  and  Schmidt  are  of 
opinion  that  in  addition  to  the  succus  intestinalis  exerting  a  solvent 
action  on  albuminous  substances  scarcely  less  than  that  of  the  gastric 
juice,  it  has  a  power  of  converting  starch  into  sugar  scarcely  less  than 
that  of  saliva  or  pancreatic  fluid.  Dr.  Ayres,^  indeed,  from  his  "micro- 
chernical  researches  on  the  digestion  of  starch  and  amylaceous  foods" 
is  disposed  to  assign  almost  the  whole  action  to  the  succus  intestinalis, 
since  he  found  the  conversion  into  glucose  to  occur  after  the  ligature 
of  the  common  choledoch  duct,  and  after  the  ligature  of  both  the  bile 
and  pancreatic  ducts  in  the  same  animal;  and  a  farther  proof  was 
afforded  of  the  activity  of  the  intestinal  mucus  taken  from  the  upper 
part  of  the  duodenum,  above  the  entrance  of  the  pancreatic  duct,  after 
ligature  of  that  duct  and  of  the  common  bile-duct,  by  its  capability  of 
converting  a  large  quantity  of  fresh-boiled  starch  into  glucose  out  of 
the  body. 

The  biliary  and  pancreatic  juices  are  usually  esteemed  great  agents 
in  chylification.  It  has  been  already  remarked,  that  the  chyliferous  ves- 
sels do  not  begin  to  appear  above  the  part  at  which  these  juices  are 
poured  into  the  duodenum  ;  that  in  the  rest  of  the  small  intestine  they 
are  less  and  less  numerous  as  we  recede  from  the  duodenum ;  and  that 
the  chyme  does  not  exhibit  any  marked  change  in  its  properties,  until 
after  its  admixture  with  those  fluids.  Direct  experiments  have  been 
made  for  the  purpose  of  testing  the  use  of  the  bile  in  digestion.  Sir 
Benjamin  Brodie  tied  the  ductus  communis  choledochus  in  young  cats, 
so  as  to  prevent  both  hepatic  and  cj'stic  bile  from  reaching  the  intes- 
tine. He  found,  that  chjdification  was  interrupted,  and  there  were 
neither  traces  of  chyle  in  the  intestines  nor  in  the  chyliferous  vessels. 
The  former  contained  onl}^  chyme,  similar  to  that  of  the  stomach,  which 
became  solid  at  the  termination  of  the  ileum ;  and  the  latter,  a  trans- 
parent fluid,  which  appeared  to  be  a  mixture  of  l^nnph,  and  of  the  more 
liquid  portion  of  the  cliyme.  Mr.  Mayo,^  likewise,  found,  that  when 
the  ductus  communis  choledochus  was  tied  in  the  cat  or  dog,  and  the 
animals  were  killed  at  various  intervals  after  eating,  there  was  no  trace 
whatever  of  chyle  in  the  lacteals.  M.  Magendie,'*  however,  repeated 
these  experiments  on  adult  animals,  and  with  dissimilar  results.  The 
greater  part  died  of  the  consequences  of  opening  the  abdomen,  and 
of  the  operation  required  for  tying  the  duct.     But  in  two  cases,  in 

'  Art.  Digestion,  p.  231,  in  SnppL'ment  au  Dictionnaire  des  Dictionnaires  de  Mede- 
cine,  par  Fabre,  Paris,  1S51;  and  Bidder  and  Schmidt,  Die  Verdauungssafte  und  der 
Stott'wechsel,  S.  272,  Mitau  und  Leipzig,  1852.  See  also,  Lehmann,  Physiological 
Chemistry,  Amer.  edit,  by  Dr.  R.  E.  Rogers,  i.  512,  Philad., 1855. 

^  Proceedings  of  the  Royal  Society ;  and  Quarterly  Journal  of  Microscopical  Science, 
April,  1855,  p.  251. 

•*  Lond.Med.  and  Physical  Journal,  Oct.,  1S26;  and  Outlines  of  Physiology,  4th  edit., 
p.  125,  London,  1837.  ••  Op.  citat.,  ii.  117. 


ACTION   OF   THE   SMALL   INTESTINE.  181 

whicli  they  survived  some  days,  lie  discovered  that  digestion  had  per- 
sisted; white  chyle  had  been  formed,  and  stercoraceous  matter  pro- 
duced. This  last  had  not  the  usual  colour ;  but  this,  as  he  remarks, 
is  not  surprising,  as  it  contained  no  bile.  The  experiment  was  repeated 
by  MM.  Leuret  and  Lassaigne,^  and  with  results  similar  to  those  ob- 
tained by  M.  Magendie.  In  the  duodenum  and  jejunum,  a  whitish  chyme 
adhered  to  the  parietes  of  the  organ;  and  in  the  thoracic  duct  there 
was  a  fluid  of  a  rosy-yellow  colour,  which  afforded,  on  analysis,  the 
same  constituents  as  chyle  ;  although  the  subjects  of  the  operation  had 
been  kept,  for  some  time,  without  food. 

The  experiments  of  Messrs.  Tiedemann  and  Gmelin^  on  this  subject 
were  marked  by  the  usual  care  and  accuracy  of  those  observers.  They 
found,  that  the  animals  were  attacked  with  vomiting,  soon  after  the 
operation,  and  afterwards  with  thirst  and  aversion  for  food ;  on  the 
second  or  third  day,  the  conjunctiva  became  yellow,  the  evacuations 
chalky,  and  very  fetid,  and  the  urine  yellow.  Some  of  the  animals 
died ;  others  were  killed  :  of  the  latter,  some  had  previously  recovered 
from  the  jaundice,  owing  to  a  singular  recuperative  phenomenon,  no- 
ticed by  Dr.  BlundelP  and  Sir  B.  Brodie  in  their  experiments — to  the 
re-establishment  of  the  choledoch  duct,  by  the  effusion  of  lymph  around 
the  tied  part,  and  the  subsequent  dropping  off"  of  the  ligature.  Like 
Sir  B.  Brodie,  Mayo,  Leuret  and  Lassaigne,  and  Voisin,  they  observed 
that  chymification  went  on  as  in  the  sound  animal. 

The  thoracic  duct  and  chyliferous  vessels,  in  animals  fed  a  short  time 
before  death,  always  contained  an  abundant  fluid,  which  was  generally 
of  a  yellowish  colour.  It  coagulated  like  ordinary  chyle ;  the  crassa- 
mentum  acquired  the  usual  red  colour;  and  the  only  difference  between 
it  and  the  chyle  of  a  sound  animal  was,  that  after  tying  the  duct  it  was 
never  white.  They  conceived  the  reason  of  the  difference  to  be,  that 
the  white  colour  is  owing  to  fatty  matter  taken  up  from  the  food  by  the 
agency  of  the  bile,  which  possesses  the  power  of  dissolving  fat ;  and 
may  probably,  therefore,  aid  in  effecting  its  solution  in  the  chyle  in  the 
radicles  of  the  chyliferous  vessels.  Sir  Benjamin  Brodie  and  Mr.  Mayo 
are  considered  to  have  been  misled  by  the  absence  of  the  white  colour, 
usually  possessed  by  the  chyle,  but  which  is  wanting  in  ordinary  diges- 
tion, if  the  food  does  not  contain  fatty  matter.''  The  experiments  of 
Dr.  Beaumont  showed,  that  oil  undersroes  but  little  chano;e  in  the  sto- 
mach,  and  that  bile  is  probably  necessary  to  give  it  the  requisite  physical 
constitution,  in  order  that  chyle  may  be  separated  from  it.  Messrs. 
Tiedemann  and  Gmelin  restrict  the  agency  of  the  bile  in  chylification 
to  the  accomplishing  of  the  solution  of  the  fatty  matter,  and  to  the 
nitrogenizing  or  animalizing  of  food  that  does  not  contain  nitrogen. 
The  experiments  of  M.  Voisin  equally  show,  that  the  ligature  of  the 
choledoch  duct  does  not  prevent  the  formation  of  chyle,  provided  the 
passage  of  the  pancreatic  fluid  is  not  at  the  same  time  prevented.     In 

•  Recherclies  sur  la  Digestion,  p.  147,  Paris,  1825. 

*  Recherclies  Experimentales,  &c.,  sur  la  Digestion,  ii.  53,  Paris,  1827. 

^  Researches,  Physiological  and  Pathological,  London,  1825 ;  and  Elliotson's  Physio- 
logy, p.  124,  London, 1840. 

'  Edinb.  Me  1.  and  Surg.  Journal,  xciii. ;  ami  Mayo,  Outlines  of  Human  Physiology, 
4th  edit.,  p.  130,  London,  1837. 


182  DIGESTION. 

a  number  of  dogs,  a  ligature  was  applied  so  as  to  completel}'  prevent 
the  passage  of  bile  into  the  intestine.  Two  lived  three  months  after 
the  experiment:  three,  six  weeks  ;  and  five  died  shortly  after  the  appli- 
cation of  the  ligature.  In  no  instance  did  death  appear  to  be  owing 
to  the  suspension  of  digestion  or  assimilation.  Almost  all  the  animals 
had  begun  to  eat ;  and,  in  the  majority,  fopd  perfectly  chymified  was 
found  in  the  duodenum ;  and  well  elaborated  chyle  in  the  chyliferous 
vessels.  It  would  appear,  therefore,  that  the  bile,  although  an  import- 
ant, is  not  an  essential 'agent  in  digestion  in  the  duodenum.  This  is 
signally  corroborated  by  the  cases  of  two  infants,  four  or  five  months 
old,  recorded  by  Dr.  Blundell.  The  hepatic  ducts  in  both  cases  ter- 
minated blindly,  so  that  no  bile  entered  the  intestines ;  the  evacuations 
were  white  like  spermaceti,  and  the  skin  jaundiced.  Yet  they  grew 
rapidly,  and  throve  tolerably. 

No  certain  knowledge  exists,  whether  any  of  the  elements  of  the 
bile  are  absorbed  in  the  form  of  chyle  ;  or  whether  it  acts  mainly  as  a 
precipitate,  and  is  thrown  off  with  the  excrement.  As  elsewhere  shown, 
however,  it  is  largely  excrementitious  or  depurative. 

As  to  the  mode  in  which  the  biliary'-  and  pancreatic  fluids  act  on  the 
chyme,  we  have  not  had,  until  recently,  much  more  than  conjectures 
to  guide  us.  MM.  Tiedemann  and  Gmelin  suggest,  that  the  soda  of 
the  bile  unites  with  the  chlorohydric  and  acetic  acids  of  the  chyme ; 
and  simultaneously  the  latter  precipitates  the  mucus  of  the  bile  and 
its  colouring  principle  and  resin,  which  are  evacuated  with  the  excre- 
ments. The  majority  of  physiologists  believe,  that  bile  is  divided  into 
two  parts  by  the  action  of  the  chyme;  the  one — containing  the  alkali, 
salts,  and  a  part  of  the  animal  matter — uniting  with  the  chyle ;  the 
other — containing  the  coagulated  albumen,  the  coloured,  concrete, 
acrid,  and  bitter  oil — uniting  with  the  faeces,  to  be  discharged  along 
with  them.  According  to  this  view,  the  action  of  the  bile  would  be 
purely  chemical;  a  part  would  be  recrementitial  or  taken  up  again; 
and  a  part  excrementitial,  giving  to  the  excrements  their  smell  and 
colour;  and,  according  to  some,  the  necessary  stimulating  property  for 
exciting  the  flow  of  the  intestinal  fluids,  and  soliciting  the  peristaltic 
action  of  the  intestines  so  as  to  produce  their  evacuation.  It  is  more 
than  doubtful,  however,  whether  the  bile  have  any  such  influence  as 
the  last.  It  is  a  law  in  the  economy,  that  no  secretion  irritates  the 
part  over  which  it  passes,  or  is  naturally  destined  to  pass,  unless  such 
part  is  in  a  morbid  condition ;  and  were  it  otherwise,  the  mucous  mem- 
brane of  the  intestine  would  be  soon  accustomed  to  the  stimulation; 
and,  the  effect  be  null.  MM.  Tiedemann  and  Graelin  further  suggest, 
that  from  the  abundance  of  highly  nitrogenized  principles,  which  the 
bile  contains,  it  probably  contributes  to  animalize  those  articles  of 
food,  that  do  not  contain  nitrogen;  and  that  it  may  tend  to  prevent 
the  putrefaction  of  the  food  in  its  course  through  the  intestines,  inas- 
much as  when  it  is  prevented  from  flowing  into  them,  their  contents 
appear  much  farther  advanced  in  decay  thnn  in  the  healthy  state. 
M.  Bernard,'  too,  has  shown  experimentally,  that  in  the  living  body 

'  Amer.  Journ.  of  tlie  Med.  Sciences,  Oct.  1851,  p.  351. 


^  ACTION   OF   THE   SMALL   INTESTINE.  183 

it  checks  the  process  of  fermentation,  which  it  had  been  found  to  do 
out  of  the  body. 

It  has  been  held  of  late,  that  bile  has  the  power  of  transforming 
saccharine  aliments  into  fat ;  a  circumstance,  which  is  favoured  by  the 
discovery  of  H.  Meckel,'  that  when  sugar  is  mixed  with  bile  out  of 
the  body  a  part  of  it  is  converted  into  fatty  matter.  Admixture  with 
the  pancreatic  juice  would  then  render  its  absorption  easy.  (See 
Secretion  of  Bile.) 

We  were  not  instructed  until  of  late  in  regard  to  the  precise  uses 
of  the  pancreatic  juice ;  although  many  have  been  assigned  to  it.  which, 
being  founded  in  ignorance  of  its  nature  and  properties,  it  would  be  a 
waste  of  time  to  notice.  Messrs.  Tiedemann  and  Gmelin  affirm,  that 
it  yields  to  the  chyme  the  richly  nitrogenized  principles,  that  enter 
into  its  composition;  and,  consequently,  aids  in  assimilation.  In  tes- 
timony of  this,  they  remark,  that  the  pancreas  is  larger  in  herbivorous 
than  in  carnivorous  animals;  and  that,  in  proportion  as  the  chymous 
matter  proceeds  along  the  intestinal  canal,  it  exhibits  itself  less  rich 
in  albumen  and  other  nitrogenized  matters,  which  have  probably  been 
abstracted  from  it  by  absorption.  Dr.  Marcet^  discovered  in  the  chyme 
of  the  small  intestine  a  notable  developement  of  albumen,  which  was 
first  perceptible  a  few  inches  from  the  pylorus,  and  did  not  exist  in 
the  large  intestine ;  and  Messrs.  Tiedemann  and  Gmelin  found  in  the 
intestinal  contents  of  animals,  that  had  swallowed  pebbles  while  fast- 
ing, more  albumen  than  the  pancreatic  juice  could  account  for.  If 
such  be  the  fact,  albumen  must  be  either  developed  from  the  food,  or 
secreted  from  the  mucous  membrane. 

There  is  a  striking  resemblance  in  chemical  properties  between  the 
pancreatic  juice  and  saliva;  and  the  views  applicable  to  both  one  and 
the  other,  embraced,  as  the  result  of  numerous  experiments  by  MM. 
Bernard  and  Barreswil,  have  been  already  stated.  The  experiments 
of  M.  C.  Bernard''  have  shed  important  light  on  this  matter.  Ex- 
posure of  fatty  bodies  to  the  pancreatic  juice  out  of  the  body  produced 
at  once  a  complete  emulsion,  whilst  no  such  effect  was  produced  on 
such  bodies  by  admixture  with  other  fluids — saliva,  gastric  juice,  or 
serum  of  the  blood,  for  example.  These  experiments  were  frequently 
repeated  with  like  results  in  the  presence  of  distinguished  observers — 
MM.  Magendie,  Berard,  Andral,  &c.  When  dogs  to  which  fatty  sub- 
stances had  been  given  were  killed  during  digestion,  these  substances 
were  found  unaltered  until  they  came  in  contact  with  the  pancreatic 
fluid ;  and  if  the  duct  of  the  pancreas  was  tied  all  change  was  pre- 
vented. It  would  seem,  therefore,  that  although  the  pancreatic  fluid 
resembles  the  saliva  in  many  respects — so  much  so,  indeed,  that  the 
pancreas  has  been  styled  "  the  abdominal  salivary  gland," — it  is  pos- 
sessed of  properties  as  a  digestive  fluid  which  the  saliva  has  not.     In 

'  Henle  und  Pfeuflfer,  Zeitschrift  fur  rationelle  Medicin  ;  cited  by  Mr.  Paget  in  Report 
in  British  and  Foreign  Medical  Review,  p.  261,  July,  1846. 

^  Medioo-Cliirurgical  Trans.,  vi.  618. 

^  Archives  Generales,  xiv.  ;  translated  in  the  Provincial  Medical  and  Surgical  Jour- 
nal for  March  31, 1849.  For  an  account  of  M.  Bernard's  investigations,  see  Dr.  Donald- 
son in  Amer.  .Journ.  of  the  Med.  Sciences,  Oct.  1851;  and  H.  Ludlou-,  Brit,  and  For. 
Med.-Chir.  Rev.,  Jan.  1854,  p.  62, 


184  DIGESTION". 

a  remark  upon  a  subsequent  memoire  bj  M.  Bernard — the  commis- 
sion, consisting  of  MM.  Magendie,  Milne  Edwards  and  Dumas — do 
not  hesitate  to  conclude,  that  M.  Bernard  has  completely  established 
the  ]Dhysiological  office  of  the  pancreas  and  made  known  the  mechanism 
of  the  digestion  of  fatty  matters.'  It  has  been  shown,  however,  by 
the  experiments  and  observations  of  Frerichs,^  Lehmann,  Lenz,  Herbst^ 
and  others,  that  digestion  of  fatty  matters  takes  place  after  the  pan- 
creatic duct  has  been  tied — sufficient  time  having  been  permitted  for 
the  evacuation  of  any  pancreatic  fluid,  which  may  have  been  in  the 
intestine  prior  to  the  operation — and  even  in  the  lower  portion  of  the 
small  intestine,  into  which  these  substances  have  been  conveyed  by 
injection  after  entire  isolation,  by  means  of  a  ligature,  from  the  part  of 
the  canal  into  which  the  pancreatic  secretion  had  been  discharged.  It 
would  seem,  too,  from  the  results  of  the  experiments  of  those  ob- 
servers, that  a  mixture  of  ttie  fluid  of  the  pancreas  with  bile  and  the 
succus  intestinalis  has  a  greater  emulsifying  power  than  the  first  of 
these  fluids  alone.  The  succus  intestinalis  would  seem,  indeed,  to  be 
an  important  adjuvant  in  the  action.'* 

The  influence  of  the  temperature  of  the  interior  of  the  intestine, 
and  of  the  peristaltic  motion,  on  chylification,  can  be  looked  upon  as 
onh^  accessory  and  indirect. 

Whilst  the  chyme  is  passing  through  the  small  intestine,  it  is  sub- 
jected to  the  action  of  the  chyliferous  vessels,  which  extract  from  it 
the  nutritious  part  or  chyle, — a  fluid  especially  destined  for  the  reno- 
vation of  the  blood.  How  this  is  accomplished  will  be  treated  of 
under  the  head  of  Absorption.  In  proportion  as  this  absorption  is 
effected,  the  chyme  changes  its  properties.  In  the  commencement  of 
the  jejunum,  it  is  the  same  as  in  the  duodenum;  but,  lower  down,  the 
grayish  layer,  that  existed  at  its  surface,  is  observed  to  gradually  dis- 
appear. It  assumes  greater  consistence;  its  yellow  colour  becomes 
more  marked;  and,  in  the  ileum,  it  has  a  greenish  or  brownish  tint; 
and  from  being  acid  becomes  alkaline,  until,  at  the  lower  part  of  the 
small  intestine,  it  seems  to  be  the  useless  residue  of  the  alimentary 
matter,  and  of  the  various  secretions  from  the  upper  portion  of  the 
digestive  apparatus.  It  is  now  mere  excrementitious  matter  or  fieces, 
although  not  possessing  the  entire  fiecal  odour.  Its  alkaline  character 
has  generally  been  ascribed  to  admixture  with  the  bile,  pancreatic 
fluid,  and  the  secretion  from  the  intestinal  glandulas.  The  agency  of 
the  bile  was  supposed  to  be  through  its  free  soda,  or  the  carbonate  or 
tribasic  phosphate  of  soda.  The  bile,  however,  as  shown  elsewhere, 
is  neutral ;  and  accordingly  it  has  been  suggested  as  more  probable, 
that  the  chyme  is  made  alkaline  by  the  ammonia,  which  is  one  of  the 

•  Gazette  Medicale,  No.  9,  Paris,  1849. 

2  Wagner's  Haudworterb.  der  Physiologie,  art.  Verdauung,  3ter  Band,  S.  845,  Braun- 
schweig, 1846  ;  and  Bidder  and  Scliniidt,  Die  Verdauungssiifte  und  der  StofFwechsel,  S. 
246,  Mitau  und  Leipz.,  1852. 

3  Henle  and  Pfeutfer's  Zeitsclirift,  Bd.  iii.,  S.  389-91;  and  Canstatt's  Jalxresbericht, 

1853,  S.  148,  Wiirzburg,  1854. 

•*  Todd  and  Bowman,  The  Physiological  Anatomy  and  Physiology  of  Man,  Pt.  iv.,  Sect. 
1,  p.  246,  Lond.,  1852;  and  Prof.  S.  Jackson,  Amer.  Jouru.  of  the  Med.  Sciences,  Oct. 

1854,  p.  307. 


ACTION   OF   THE   LARGE    INTESTINE.  185 

products  of  the  spontaneous  decomposition  of  bile  in  the  intestines.' 
The  pancreatic  juice  is  certainly  alkaline. 

During  the  formation  of  chyle,  gases  are  almost  always  present  in 
the  small  intestine.  They  were  first  examined  by  Jurine ;  but  chemical 
analysis  was  by  no  means  as  advanced  at  that  day  as  it  is  now ;  MM. 
Magendie^  and  Clievreul  have  more  recently  analyzed  those,  which  they 
found  in  the  small  intestines  of  three  criminals;  all  young  and  vigorous. 
The  results  of  this  analysis  have  been  given  already  (p.  174).  The 
gases  might  originate  in  various  ways.  They  might  pass,  for  example, 
from  the  stomach  with  the  chyme.  There  is  this  objection,  however, 
to  the  view;  that  the  air  in  the  stomach  contains  oxygen  and  very  little 
hydrogen ;  whilst  a  considerable  quantity  of  the  latter  gas  is  almost 
always  found  in  the  small  intestine,  and  never  oxygen.  Again,  they 
might  be  secreted  by  the  mucous  membrane  of  the  intestine.  So  far 
as  we  know,  however,  carbonic  acid  and  nitrogen  are  alone  exhaled 
from  the  tissues.  We  would  still  have  to  account  for  the  hydrogen. 
Lastly,  they  might  arise  from  the  reaction  of  the  elements  of  the  chyme 
upon  each  other,  and  this  has  been  considered  the  most  probable  origin. 
M.  Magendie^  has  frequently  seen  bubbles  of  gas  escaping  from  the 
chymous  mass,  between  the  mouth  of  the  ductus  communis  choledochus 
and  the  ileum ;  but  never  from  that  of  the  ileum,  the  upper  part  of  the 
duodenum,  or  stomach;  and  he  affirms,  that  Chevreul,  in  prosecuting 
some  experiments,  found  that  when  the  mass  obtained  from  the  small 
intestine  was  suffered  to  ferment  for  some  time  in  a  stove,  at  the  tem- 
perature of  the  body,  the  same  gases  were  obtained  as  those  met  with 
in  the  small  intestine.  The  presence  of  air  in  the  intestines  has  its 
positive  advantages.  It  preserves  the  canal  in  a  condition  adapted  for 
the  ready  exercise  of  its  functions : — thus,  it  facilitates  the  progress  of 
the  contained  matters,  as  it  is  more  easy  for  the  intestine,  when  it  con- 
tracts, to  propel  substances  contained  in  a  hollow  space,  than  in  a  canal 
whose  sides  are  in  contact.*  The  absorption  of  chyle  is,  doubtless,  also 
favoured  by  it.* 

When  the  food  has  attained  the  lower  part  of  the  ileum,  the  process 
of  chylification  has  been  accomplished,  and  the  residuary  matter  is 
transmitted,  by  the  peristaltic  action,  into  the  large  intestine.  The 
movement,  however,  recurs  irregularly  and  at  long  intervals.  In  the 
living  animal  it  can  rarely  be  perceived;  but  may  be  noticed  in  one 
recently  killed,  and  appears  to  have  no  coincidence  with  that  of  the 
pylorus. 

g.  Action  of  the  Large  Intestine. 

The  large  intestine  acts  as  a  reservoir  and  excretory  canal  for  the 
faeces.  The  residue  of  the  alimentary  matter  is  sent  on  through  the 
valve  of  Bauhin  by  the  peristaltic  action  of  the  ileum.  This  valve,  we 
have  seen,  is  so  situate  at  the  point  of  union  between  the  ileum  and 
caecum  as  to  permit  a  free  passage  from  the  former  to  the  latter,  but  to 

■  Valentin,  Lehrbuch  der  Physiologie  des  Mensclien,  i.  338,  Braunschweig,  1844. 
2  Precis,  ii.  115.  ^  Iljid.,  117. 

^  Berand,  Manuel  de  Physiologie,  p.  217,  Paris,  1853. 

^  Kornback,  De  Necessitate  Aeris  Atmosphserici  ad  Sorbitionem  Chyli  Adjuvandum, 
Hal.,  1848  ;  cited  in  Thomas,  Die  Physiologie  des  Menschen,  p.  281,  Leipzig,  1853. 


186  DIGESTION. 

prevent  return.  The  chymoiis  mass  is  sufficiently  soft  to  pass  readily ; 
and  the  quantity  of  mucus  poured  out  from  the  lining  membrane  facili- 
tates its  course.  When  it  has  reached  the  large  intestine,  it  first  ac- 
cumulates in  the  caecum,  which — being  cellular  or  pouched  like  the 
colon — necessarily  detains  it  for  some  time.  In  proportion,  however, 
as  the  caecum  becomes  filled,  the  peristaltic  action  is  extended  from  the 
small  intestine,  and  the  matter  is  sent  into  the  colon,  the  cells  of  which 
are  successively  filled;  first,  those  of  the  ascending,  and  then  those  of 
the  transverse  and  descending  colon,  as  far  as  the  annulus  or  com- 
mencement of  the  rectum.  The  whole  of  its  progress  through  the 
large  intestine  is  slowly  accomplished.  Independently  of  the  pouched 
arrangement,  which  retards  it,  a  part  of  the  colon  ascends,  so  that  the 
foecal  matter  must  often  proceed  contrary  to  gravity.  It  becomes, 
moreover,  more  and  more  inspissated  in  its  progress  towards  the  out- 
let ;  and  the  peristaltic  action  recurs  at  greater  intervals  than  in  the 
upper  portions  of  the  tube.  The  importance  of  such  a  reservoir  as 
the  large  intestine  is  obvious.  "Without  it,  we  should  be  subjected  to 
the  inconvenience  of  evacuating  the  fasces  incessantly. 

Before  the  excrementitious  matter  reaches  the  lower  portion  of  the 
small  intestine,  it  has  not  the  full  fiscal  odour;  but  acquires  it  after 
having  remained  there  for  a  short  time.  The  brownish-yellow  hue 
becomes  deeper ;  but  its  consistence,  smell,  and  colour,  vary  consider- 
ably, according  to  the  character  of  the  alimentary  matter ;  the  mode 
and  degree  in  which  chymification  and  chylification  have  been  accom- 
plished ;  the  habit  of  the  individual,  &c.  &c.  The  ftecal  matter,  as  we 
find  it,  consists  of  the  excrementitious  part  of  the  food,  as  well  as  of 
the  juices  of  the  upper  part  of  the  canal,  that  have  been  subjected  to 
the  digestive  process ;  of  the  secretions,  poured  out  from  the  lower 
part  of  the  intestine,  and  also,  of  substances,  that  have  escaped  the 
digestive  actions  of  the  stomach  and  small  intestine,  and  are  often  per- 
ceptible in  the  evacuations.  The  peculiar  fiecal  impregnation  is  pro- 
bably mainly  dependent  upon  a  secretion  from  appropriate  follicles; 
and  we  can  thus  understand,  if  we  take  into  consideration  the  digestion 
of  the  different  secretions,  why  ftecal  evacuations  may  exist,  when  the 
individual  has  not  eaten  for  some  time,  or  taken  but  little  nourishment. 
Professor  Bcrard,'  however,  is  of  opinion,  that  it  is  the  bile,  more  than 
any  other  liquid  poured  into  the  intestine,  which  gives  the  excrements 
their  special  characters,  and  especially  the  fiBcal  odour,  and  Leuret  and 
Lassaigne  had  already  remarked,  that  if  bile  be  heated,  it  gives  off  a 
faecal  smell. 

Some  phj^siologists  have  believed,  that  chylification  takes  place  even 
in  the  large  intestine,  and  that  chylous  absorption  is  more  or  less 
effected  there.  M.  Viridet^  asserted,  that  the  cxecum  is  a  second  sto- 
mach, in  which  a  last  effort  is  made  to  separate  from  the  food  the 
digestible  and  soluble  portions  it  may  still  contain.  In  herbivorous 
animals,  according  to  him,  an  acid  solvent  is  secreted  in  it.  MM. 
Tiedemann  and  Gmelin  seem  to  admit  the  fact;  and  likewise  tliink, 
that  the  fluid,  secreted  by  the  inner  membrane  of  the  intestine,  assists 

'  Cours  de  Physiologie,  ii.  373,  Paris,  1S49. 

*  Tractatus  Novus  de  Prima  Coctione,  &c.,  Genev,,  1691. 


ACTION   OF   THE   LARGE   INTESTINE.  187 

in  the  assimilation  of  tlie  food  by  means  of  the  albumen  it  contains, 
and  that  ftecal  matter  is  formed  there.  From  various  experiments 
instituted  by  Professor  Schultz/  of  Berlin,  he  infers,  that  the  food  in 
the  caecum  becomes  not  only  a  second  time  sour,  but  that  the  acid 
chyme  is  there  neutralized  by  the  access  of  bile  in  the  same  way  as  in 
the  duodenum.  M.  Blondlot,^  however,  states,  that  in  many  herbi- 
vorous animals  and  granivorous  birds,  as  sheep,  goats,  pigeons  and 
chickens,  the  contents  of  the  caecum  were  never  acid  unless  sugar  in 
some  form  had  been  mixed  with  their  food.  The  acidity  of  the  caecum 
which  then  ensues,  he  thinks  is  the  result  of  that  part  of  the  starch  or 
sugar,  which  had  not  been  absorbed  in  the  small  intestine,  being  trans- 
formed into  lactic  acid.  The  fact  of  the  separation  of  chyle  in  the 
caecum  and  colon  is  proved  by  the  experiments  of  M.  Voisin,^  which 
consisted  in  introducing  food  into  these  intestines  after  the  ileo-caecal 
valve  had  been  closed  by  ligature. 

The  physical  characters  of  the  feces  have  been  already  described. 
When  extruded,  they  have  the  shape  of  the  large  intestine,  or  of  the 
aperture,  through  which  they  have  been  evacuated.  If  the  form  of 
either  of  these  be  modified,  that  of  the  excrement  will  be  so  likewise. 
In  stricture  of  the  colon — especially  about  the  sigmoid  flexure — and  of 
the  rectum,  the  fseces  are  squeezed  through  the  narrowed  portions,  and 
often  evacuated  in  the  shape  of  ribands.  The  biliary  secretion  appears 
to  modify  the  appearance  of  the  fieces  greatly.  If,  as  in  jaundice,  it  be 
prevented  from  flowing  into  the  intestine,  they  are  clay -coloured.  M, 
Adelon'*  affirms,  that,  under  such  circumstances,  they  are  more  fre- 
quent. This  is  not  the  result  of  our  experience,  nor  does  it  appear  to 
be  deduced  from  his  own;  as,  a  few  pages  before,  he  remarks,  "it  is 
certain,  that  if  the  bile  does  not  flow,  the  excrements  are  dry,  devoid 
of  colour,  and  there  is  constipation."  On  the  other  hand,  if  the  bile 
flows  in  too  great  quantity  the  fa3ces  are  darker  coloured.  It  is  doubt- 
ful, whether  the  varying  quantity  of  the  biliary  secretion  have  much 
influence  on  the  number  of  evacuations,  unless  the  canal,  through 
which  it  has  to  pass,  is  in  a  morbid  condition.  Many  of  the  appear- 
ances in  the  fasces,  which  are  conceived  to  be  owing  to  a  morbid  con- 
dition of  the  biliary  secretion,  are  the  effect  of  admixture  with  products 
of  morbid  changes  in  the  stomach  or  intestines.  In  elucidation  of  this, 
it  may  be  observed,  that  the  green  evacuations  of  children  are  often 
referred  to  some  pathological  condition  of  the  biliary  secretion; 
whereas  the  colour  is  commonly  owing  to  unusual  formation  of  acid 
in  the  stomach,  the  admixture  of  which  with  healthy  bile  produces  the 
colour  in  question. 

The  chemical  properties  of  the  faeces  have  been  repeatedly  inquired 
into.  They  must,  of  course,  vary  according  to  the  nature  of  the  food, 
its  quantity,  the  kind  of  digestion,  &c.  Human  fasces  were  examined 
by  Eawitz*  after  animal  and  vegetable  food  had  been  taken.     But  few 

'  London  Med.  and  Surg.  Joum.,  Oct.  31,  1835  ;  cited  in  American  Journal  of  tlie 
Medical  Sciences,  Nov.,  1836,  p.  203. 

^  Traite  Analytique  de  la  Digestion,  p.  103,  Paris,  1844. 

^  Nouvel  Aper.u  sur  la  Physiologie  du  Foie,  &c.,  Paris,  1833.  ■•  Op.  citat. 

^  Ueber  die  Einfaclien  Nahruntrsmittel.  Breslau,  1846,  cited  by  Kirkes  and  Paget, 
Manual  of  Physiology,  2d  Amer.  edit.,  p.  176,  Philad.,  1853. 


188  DIGESTION. 

fragments  of  muscular  tissue  were  met  with;  but  the  cells  of  cartilage 
and  iibro-cartilage — excepting  those  of  fish — were  found  unchanged. 
Elastic  fibres  and  fatty  matters,  which  had  escaped  absorption,  appeared 
to  be  unchanged;  for  fat  cells  were  sometimes  unaltered  in  the  fieces; 
and  crystals  of  cholesterin  might  generally  be  obtained  from  them, 
especially  after  the  use  of  pork  fat  as  diet. 

Of  vegetable  aliments,  large  quantities  of  cell  membrane  were  unal- 
tered; and  starch  cells  were  commonly  deprived  of  only  part  of  their 
contents;  the  green  colouring  matter — chlorophyll — was  unaffected,  and 
the  walls  of  sap  vessels  and  spiral  vessels  were  usually  found  in  large 
quantities  in  the  faeces, — their  contents  having  been  probably  removed 
durino;  digestion. 

The  average  quantity  of  faecal  matter  discharged  by  the  adult  in  the 
twenty-four  hours,  has  been  estimated  at  about  five  or  six  ounces.' 
Wehsarg,^  indeed,  makes  it  less  than  this.  The  mean  of  seventeen  ob- 
served cases  was  not  much  more  than  four  ounces ;  so  that  if,  accord- 
ing to  the  diet-scale  of  the  Navy  of  the  United  States,^  forty-five  ounces 
of  solid  food  are  taken  in  the  twenty-four  hours,  about  forty  ounces 
must  be  appropriated  by  the  system  daily.  The  discharged  five  ounces 
of  fasces  consist,  almost  wholly,  of  substances  that  are  rebellious  to  the 
action  of  the  gastric  and  intestinal  secretions.  It  is  estimated,  that  aa 
much  as  seventy-five  per  cent,  of  the  fteces  is  water,  so  that  the  solid 
matter  in  them  is  not,  probably,  more  than  an  ounce,  or  an  ounce  and 
a  half. 

The  faeces  differ  in  each  animal  species.  Those  of  the  herbivora  con- 
tain less  animal  matter  than  those  of  the  carnivora  and  omnivora;  and 
the  agriculturist  is  well  aware,  that  the  excrements  of  all  animals  are 
not  equally  valuable  as  manure.  The  dung  of  the  pigeon  is  alkaline 
and  caustic ;  and  hence  has  been  employed  in  tanning  for  softening 
skins.  The  excrement  of  dogs,  that  have  fed  only  on  bones,  is  white, 
and  appears  to  be  almost  wholly  composed  of  the  earthy  matter  of 
bone.  It  has  not,  however,  been  examined  by  modern  chemists.  This 
white  excrement  is  the  album  grcecum,  cynocoprus^  spodiwin  Grcecoruni^ 
album  cams  or  stercus  caninwm  album,  of  the  older  writers.  It  was 
formerly  employed  as  a  discutient  in  quinsies,  and  as  an  anti-epileptic 
agent,  but  is  now  justly  discarded. 

M.  Vauquelin,'*  on  comparing  the  nature  and  quantity  of  the  earthy 
parts  of  the  excrements  of  fowls  with  those  of  the  food  on  which  they 
subsisted,  arrived  at  some  results  that  are  of  interest  to  the  physiolo- 
gist. He  found  that  a  hen  devoured,  in  ten  days,  lilll"8-i8  grains 
troy  of  oats.  These  contained  of  phosphate  of  lime  136*509  grains; 
and  of  silica  219-548  grains;  in  the  whole  356-057  grains.  During 
these  ten  days  she  laid  four  eggs,  the  shells  of  which  contained  98*779 
grains  of  phosphate,  and  58*191  grains  of  carbonate  of  lime;  and 

*  Todd  and  Bowman,  Physiological  Anatomy,  &c.  Pt.  iv.  Sect.  i.  p.  267,  Lond.  1852; 
and  Budfije,  Memoranda  der  Speciellen  Pliysiologie  des  Menschen,  5te  Autiage,  S.  99, 
Weimar,  1853. 

2  Mikroskopische  und  Cliemisclie  Untersuclmngen  der  Fseces  Gesunder  Erwachsener 
Menschen,  Giessen,  1853 ;  and  Scherer  in  Canstatt's  Jahresbericht,  1853,  S.  121 ;  see, 
also,  Ehring,  ibid. ;  and  Marcet,  Proceedings  of  the  Royal  Society,  June  15,  1854. 

*  See  page  119.  *  Annales  de  Chimie,  tom.  xxix.  p.  3. 


ACTION   OF   THE   LAEGE   INTESTINE.  189 

passed  185.266  grains  of  silica.  The  fixed  parts,  thrown  out  of  the 
system  during  the  time,  consisted  of: — 

Phosphate  of  lime, 274*305  grains. 

Carbonate  of  lime,     ........         511"911 

Silica, 185-206 

Given  out, 971-482 

Taken  in, 356-057 

Surplus, 615-425 

The  quantity  of  fixed  matter,  therefore,  given  out  of  the  system  in. 
ten  days,  exceeded  the  quantity  taken  in  by  this  last  amount. 

Tlie  phosphate  of  lime,  taken  in,  amounted  to  .         .         .         136*509  grains. 
That  given  out,  to 274-305 

137-796 

There  must,  consequently,  have  been  formed  137.796  grains  of  phos- 
phate of  lime,  besides  511.911  grains  of  the  carbonate.  The  inferences, 
deduced  from  these  experiments,  were,  that  lime,  and  perhaps  also 
phosphorus,  is  not  a  simple  substance,  but  a  compound  formed  of  in- 
gredients that  exist  in  oats,  water,  or  air ;  the  only  substances  to  which 
the  fowl  had  access ;  and  that  silica  must  enter  into  its  composition,  as 
a  part  had  disappeared.  Before,  however,  we  adopt  these  conclusions, 
the  experiments  ought  to  be  repeated  more  than  once.  The  chicken 
should  be  fed  on  oats  some  time  before  the  excrements  and  shells  are 
subjected  to  analysis;  as  the  carbonate  of  lime,  and  the  excess  of  phos- 
phate detected  on  analysis,  might  have  proceeded,  not  only  from  the 
food,  but  from  earthy  matters  previously  swallowed.  Care  should  also 
be  taken,  that  it  has  no  access  to  any  calcareous  earth;  and  w^e  must 
be  certain,  that  it  has  not  diminished  in  weight;  as,  in  such  case,  the 
earth  may  have  been  supplied  from  its  own  body.  These  precautions 
are  the  more  requisite,  seeing,  that  experiments  have  shown,  that  cer- 
tain birds  cannot  produce  eggs  unless  they  have  access  to  calcareous 
earth. 

There  are  some  very  remarkable  instances  of  chemical  changes,  in 
mysterious  actions  more  immediately  concerned  in  the  decomposition 
and  renovation  of  the  frame;  or,  in  what  has  been  abstractedly 
termed — the  function  of  nutrition.  Dr.  Henry'  has  announced,  that 
the  following  substances  have  been  satisfactorily  proved  to  exist  in 
healthy  urine ; — water,  free  phosphoric  acid,  phosphate  of  lime,  phos- 
phate of  magnesia,  fluoric  acid,  uric  acid,  benzoic  acid,  lactic  acid, 
urea,  gelatin,  albumen,  lactate  of  ammonia,  sulphate  of  potassa,  sul- 
phate of  soda,  fluoride  of  calcium,  chloride  of  sodium,  phosphate  of 
soda,  phosphate  of  ammonia,  sulphur,  and  silex; — yet  we  have  no 
proof  that  these  substances  are  obtained  from  any  other  source  than 
the  food ;  and  some  of  them  are  with  difficulty  obtained  any  where. 
Every  one  of  them  is  necessary  for  the  constitution  of  the  urine;  and 
many  must  be  formed  by  a  chemical  union  of  their  elements  under 
the  vital  agency.     Some  are  met  with  in  the  animal  body  exclusively. 

'  Elements  of  Chemistry,  9th  edit.,  ii,  435,  Lond.,  1823. 


190  DIGESTION. 

Berzelius^  found,  in  100  parts  of  human  fosces: — water,  73-3 ;  unal- 
tered residue  of  animal  and  vegetable  substances,  7'0 ;  bile,  0*9 ;  albu- 
men, 0*9;  peculiar  extractive  matter,  2'7;  substance,  formed  of  altered 
bile,  resin,  animal  matter,  &c.,  14 ;  salts,  1-2.  Seventeen  parts  of  these 
salts  contained,  of  carbonate  of  soda,  5;  chloride  of  sodium,  i;  sul- 
phate of  soda,  2 ;  ammoniaco-magnesian  phosphate,  2 ;  phosphate  of 
lime,  4.  The  excrements  have  likewise  been  examined  by  MM.  Leuret 
and  Lassaigne,  and  others ;  but  none  of  the  analyses  have  shed  much 
light  on  the  physiology  of  digestion.  Analyses  of  the  ashes  of  firm 
human  feces  by  Enderlin^  yielded  the  following  results: — chloride  of 
sodium  and  alkaline  sulphate,  1-307;  tribasic  phosphate  of  soda,  2-633 ; 
phosphate  of  lime,  and  phosphate  of  magnesia,  81-272;  phosphate  of 
iron,  2-091 ;  sulphate  of  lime,  4-56 ;  silica,  7-97. 

In  the  large  intestine,  gases  are  met  with,  along  with  the  feeces. 
These  were  examined  by  MM.  Magendie'  and  Chevreul  in  the  three 
criminals  already  referred  to  (page  174).  The  results  accord  with 
those  of  Jurine,^  obtained  long  ago,  as  regards  the  nature  of  the  gases; 
but  they  do  not  correspond  with  what  he  says  relating  to  the  carbonic 
acid,  the  quantity  of  which,  according  to  him,  goes  on  decreasing 
from  the  stomach  to  the  rectum.  The  analyses  of  MM.  Magendie  and 
Chevreul  show,  that  the  proportion  instead  of  decreasing,  increases. 
Concerning  the  origin  of  these  gases,  the  remarks  made  on  those  in 
the  small  intestine  are  equally  applicable  here.  Marchand  made  two 
analyses  of  air  discharged  from  the  rectum.  These  yielded  carbonic 
acid,  44-5  and  36'5;  nitrogen,  14-0  and  29-0;  hydrogen,  25'8  and  13-5; 
carburetted  hj^drogen,  15-5  and  22*0;  and  sulphuretted  hydrogen,  1.^ 

When  the  fecal  matter  has  accumulated  to  the  necessary  extent  in 
the  rectum,  its  expulsion  follows ;  and  to  this  function  the  term  defeca- 
tion has  been  assigned.  The  faeces  collect  gradually  in  the  large  intes- 
tine, without  any  consciousness  on  the  part  of  the  individual.  Sooner 
or  later,  the  desire  or  want  to  evacuate  them  arises.  This  is  usually 
classed  among  the  internal  sensations  or  desires.  It  is,  however,  of  a 
mixed  character.  It  is  not  always  in  a  ratio  with  the  quantity  of 
fa3ces,  as  is  shown  by  the  fact,  that  occasionally  the  intestine  is  filled 
without  the  want  arising;  and,  if  the}^  be  unusually  thin  or  irritating, 
the  desire  is  developed,  when  an  extremely  small  quantity  is  present, — 
as  in  cases  of  tenesmus.  The  period,  at  which  the  desire  returns,  is 
variable,  according  to  the  amount  and  character  of  the  food  employed, 
as  well  as  the  habit  of  the  individual.  "Whilst  the  generality  of  per- 
sons evacuate  the  bowels  at  least  once  a-day, — and  this  at  a  period 
often  regulated  by  custom, — others  pass  a  week  or  two  without  any 
alvine  discharge,  and  yet  may  be  in  perfect  health.  Nay,  some  of  the 
collectors  of  rare  cases^  have  affirmed,  on  the  authority  of  Ehodius, 
Panarolus,  Salmuth,  and  others,  that  persons  may  remain  in  health, 

'  Traite  do  Cliimie,  trad,  par  Jourdan  et  Esslinger,  torn,  vii.,  and  Simon's  Animal 
Cliemistry,  Sydenham  Society  edit.,  ii.  372,  Lond.,  184(5,  or  Amer.  edit.,  Philad.,  1846. 

2  Annaleu  der  Chemie  und  Pharmacie,  Mars,  1844,  cited  by  Mr.  Paget,  Brit,  and  For. 
Med.  Kev.,  Jan.  1S45,  p.  277. 

3  Precis,  &c.,  ii.  126.  *  Memoir,  de  la  Soc.  Royale  de  Med.,  x.  72. 

"  Rudolph  Wagner's  Lehrbuch  der  Speciellen  Physiologic,  Iste  Lieferuug,  S.  228, 
Leipz.,  1854. 
^  Art.  Cas  Rares,  in  Diet,  des  Sciences  Medicales. 


DEFECATION".  191 


with  tlie  bowels  moved  not  oftener  than  once  a  month,  three  months, 
half  a  year,  two  years,  and  even  seven  years !  Sir  Everard  Home^ 
refers  to  the  case  of  General  Grose,  who  was  in  the  Dutch  service, 
under  the  Duke  of  Cumberland,  in  the  Flanders  war;  and  who  for 
thirty  years  had  no  passage  through  the  bowels.  General  Gage 
noticed  that  he  ate  heartily;  but  in  two  hours  left  the  table  and  re- 
jected his  meal.  He  was  healthy,  and  capable  of  exercise  like  other 
men.  Dr.  Heberden^  mentions  the  case  of  a  person,  who  had  naturally 
an  evacuation  once  a  month  only;  and  another  who  had  twelve  eva- 
cuations every  day  during  thirty  years,  and  then  seven  every  day  for 
seven  years,  and  grew  fat  rather  than  otherwise.  A  young  lady,  re- 
ferred to  by  M.  Fouteau,^  had  no  evacuation  for  upwards  of  eight 
years ;  although  during  the  last  year  she  ate  abundantly  of  fruit,  and 
drank  coffee,  milk,  tea,  and  broth  with  yolks  of  eggs ;  but  she  had 
copious  greasy  sweats; — and  many  similar  extraordinary  cases  have 
been  recorded  by  Dr.  Chapman''  of  Philadelphia.  TVhen  the  desire 
to  evacuate  has  once  occurred,  it  generally  persists  until  the  fasces  are 
expelled.  Sometimes,  however,  it  disappears  and  recurs  at  an  uncer- 
tain interval;  and,  if  again  resisted,  may  become  the  source  of  pain, 
and  ultimately  command  implicit  obedience.  That  the  pressure  and 
irritation  of  the  fteces  develope  the  sensation  is  evidenced  by  the  fact, 
that  the  momentary  relief  experienced  at  times,  when  the  desire  is 
urgent,  is  usually  accompanied  by  a  manifest  upward  return  of  the 
faecal  matters  from  the  sigmoid  flexure  into  the  colon. 

In  evacuating  the  fteces,  the  object  to  be  accomplished  is, — that  the 
contents  of  the  large  intestine  shall  be  pressed  upon  with  a  force  supe- 
rior to  the  resistance  presented  by  the  annulus  or  upper  extremity  of 
the  contracted  rectum,  and  the  muscles  of  the  anus.  The  contraction 
of  the  rectum  is  generally  insufficient  to  effect  this  last  object,  notwith- 
standing the  great  thickness  of  its  muscular  layer.  In  cases,  however, 
of  irritability  of  the  rectum,  the  sphincter  is  incapable  of  resisting  the 
force  developed  by  the  proper  muscular  fibres  of  the  gut.  Under  or- 
dinary circumstances,  the  aid  of  the  diaphragm  and  abdominal  mus- 
cles is  invoked,  and  it  is  chiefly  through  these  muscles,  that  volition 
influences  the  act  of  defecation, — suspending,  deferring,  or  accelerating 
it,  as  the  case  may  be.  After  a  full  inspiration,  the  muscles  that  close 
the  glottis ;  and  the  expiratory  muscles, — especially  those  of  the  ante- 
rior part  of  the  abdomen, — contract  simultaneously.  The  air  cannot 
escape  from  the  lungs ;  the  diaphragm  is  depressed  upon  the  abdo- 
minal viscera,  and  the  whole  thorax  presents  a  resisting  body ;  so  that 
all  the  expiratory  power  of  the  muscles  bears  upon  the  viscera,  and 
presses  them  against  the  vertebral  column.  In  this  way,  considerable 
force  is  exerted  upon  the  contents  of  the  colon  and  rectum ;  the 
resistance  of  the  sphincter, — already  diminished  by  the  direct  exercise 
of  volition, — is  surmounted ;  it  yields,  and  the  fasces  are  extruded. 
The  levator  ani  and  ischio-coccygeus,  aided  by  the  transversus  perinei 
muscle,  support  the^  anus  during  the  expulsory  efforts,  and  restore  it 

'  Lect.  on  Comp.  Anat.,  v.  12,  Lond.,  1828.  2  Commentarii,  p.  14. 

3  ffiuvres  Posthumes,  i.  27,  Paris,  1783. 

*  Lectures  on  the  more  important  Diseases  of  the  Thoracic  and  Abdominal  Viscera, 
p.  294,  PhiLad.,  1844. 


192  DIGESTION. 

to  its  place  after  tbe  efforts  have  ceased.  Astruc  maintained,  that  the 
abdominal  muscles  had  nothing  to  do  with  the  act  of  defecation, 
which  gave  occasion  to  the  jocose  remark  of  Pitcairn/ — "Mihi  videtur 
Astruccium  nunquam  cacasse  alioquin  sensisset  musculos  abdominis 
et  se  contrahere  et  alia  exprimere  posse." 

Whilst  straining  is  effected  by  the  diaphragm  and  abdominal  mus- 
cles, the  longitudinal  muscular  fibres  of  the  rectum  contract,  so  as  to 
shorten  the  intestine,  and,  consequently,  the  space  over  which  the 
fgeces  have  to  pass.  At  the  same  time,  the  circular  fibres  contract 
from  above  to  below,  so  as  to  propel  the  excrement  downwards,  and 
to  cause  the  mucous  membrane  to  extrude,  and  form  a  ring  or  hour- 
relet,  like  that  which  occurs  at  the  cardiac  orifice  of  the  stomach,  when 
the  food  is  passing  from  the  oesophagus  into  that  organ.  If  this  ex- 
trusion occurs  to  a  great  extent,  it  constitutes  the  disease  called 
prolapsus  ani. 

Dr.  O'Beirne,^  of  Ireland,  guided  by  the  following  facts  and  argu- 
ments ; — that  great  irritation  would  be  produced  in  the  sphincter  ani, 
and  bladder,  if  the  fteces  descended  readily  into  the  rectum  ; — that  the 
difficulty  experienced  in  throwing  up  an  injection  is  inconsistent  with 
the  idea  of  the  gut  being  open,  and  proves  that  it  is  firmly  contracted 
and  closed; — that  when  the  surgeon  has  occasion  to  pass  his  finger  up 
the  rectum,  he  rarely  encounters  either  solid  or  fluid  fseces; — that  the 
two  sphincter  muscles  of  the  anus  are  weakened  in  certain  diseases, 
and  divided  in  operations,  and  yet  it  rarely  happens,  that  the  power  of 
retaining  the  fieces  is  destroyed; — that  on  passing  a  stomach-tube  to 
the  height  of  half  an  inch  up  the  rectum,  in  a  number  of  healthy  per- 
sons, it  was  found,  that  nothing  escaped,  and  that  the  tube  could  be 
moved  about  freely  in  a  space,  which,  on  introducing  the  finger,  was 
ascertained  to  be  the  pouch  of  the  rectum ;  but  that  from  the  highest 
part  of  the  pouch  to  the  upper  extremity  of  the  gut — generally  a 
distance  of  from  six  or  seven  to  eight  inches — it  could  not  be  passed 
upwards  without  meeting  with  considerable  resistance,  and  without 
using  a  degree  of  force  to  mechanically  dilate  the  intestine,  which  was 
plainly  felt  to  be  so  contracted  as  to  leave  no  cavity  for  this  extent; — ■ 
that  when  the  instrument  reached,  in  this  way,  the  highest  point  of  the 
rectum,  the  resistance  to  its  passage  upward  was  felt  to  be  sensibly 
increased,  until,  at  length,  by  using  a  proportionate  degree  of  pressure, 
it  passed  rapidly  forward,  as  if  through  a  ring,  into  a  space  in  which 
its  extremity  could  be  moved  with  great  freedom,  and  as  instantly  a 
rush  of  flatus,  of  fluid  fgeces,  or  of  both,  took  place  through  the  tube; — 
and  that  in  every  instance,  where  the  tube  presented  the  least  appear- 
ance of  fieces  after  being  removed,  this  appearance  was  confined  to 
that  portion  which  had  entered  the  sigmoid  flexure : — guided  by  these 
and  other  facts.  Dr.  O'Beirne  concluded,  that  in  the  healthy  and 
natural  state,  all  the  part  of  the  rectum  above  its  pouch  is  at  all 
times,  with  the  single  exqeption  of  a  few  minutes  previous  to  the  eva- 
cuation of  the  bowels,  firmly  contracted,  and  perfectly  empty,  at  the 

'  Opuscula  medica  (Lector)  Roterodam,  1714. 

2  New  Views  of  the  Process  of  Defecation,  &c.,  Dublin,  1833 ;  reprinted  in  this 
country,  Washington,  1834. 


DEFECATION.  193 

same  time  that  tlie  poucb.  itself,  as  well  as  tte  sigmoid  flexure  of  the 
colon,  is  always  more  or  less  open,  and  pervious, — and  that  the 
sphincter  ani  muscles  are  but  subsidiary  agents  in  retaining  the  faeces. 
When  the  fasces  are  firm,  considerable  muscular  effort  is  necessary  to 
expel  them;  but  when  they  are  of  a  softer  consistence,  the  contraction 
of  the  rectum  is  sufficient. 

The  sphincters — as  elsewhere  shown — afford  examples  of  reflex 
action.  After  sensation  and  volition  are  suspended,  they  contract 
under  direct  irritation.  Yet,  like  the  respiratory  muscles,  they  are  of 
a  mixed  character, — partly  voluntary  and  partly  involuntary.  They 
are  involuntary,  but  capable  of  being  aided  or  impeded  by  a  voluntary 
effort.  The  state  of  gentle  contraction,  in  which  they  constantly  are, 
is  evidently  dependent  upon  their  connexion  with  the  spinal  cord ;  for 
the  experiments  of  Dr.  Marshall  Hall  have  exhibited,  that  it  ceases, 
when  the  connexion  is  destroyed. 

Air,  contained  in  the  intestinal  canal,  readily  moves  about  from 
place  to  place,  and  speedily  reaches  the  rectum  by  the  peristaltic 
action  alone.  Its  expulsion,  however,  is  commonly  accomplished  by 
the  aid  of  the  abdominal  muscles ;  when  it  issues  with  noise.  If  dis- 
charged by  the  contraction  of  the  rectum  alone,  it  is  generally  in 
silence.  Children  are  extremely  subject  to  flatulence;  in  the  adult  it 
is  not  so  common.  Certain  kinds  of  diet  favour  its  production  more 
than  others,  especially  in  those  of  weak  digestive  powers,  of  which 
condition  its  undue  evolution  is  generally  an  indication.  The  legu- 
minous and  succulent  vegetables  in  general  belong  to  this  class. 
Where  digestion  is  tardily  accomplished,  they  give  occasion  to  the 
copious  disengagement  of  gas.  Too  often,  however,  the  disgusting 
habit  of  constantly  discharging  air  streperously  from  the  bowels  is 
encouraged,  rather  than  repressed;  and  there  are  persons,  who  are 
capable  of  effecting  the  act  almost  as  frequently  as  they  attempt  it. 

The  noise,  made  by  the  air,  as  it  passes  backwards  and  forwards  in 
the  intestinal  canal,  constitutes  the  affection  called  horlorygmus. 

So  much  for  the  digestion  of  solid  food.  In  so  delicate  and  compli- 
cated an  apparatus,  it  would  seem,  that  mischief  ought  more  frequently 
to  result  from  the  various  heterogeneous  substances  that  are  received 
into  the  digestive  tube.  Its  resistance,  however,  to  morbific  agencies 
is  astonishing.  In  the  Museum  of  the  Boston  Society  for  Medical  Im- 
provement^ an  open  penknife  is  preserved,  which  was  swallowed  b}^  a 
child  between  three  and  four  years  of  age,  and  passed  from  the  bowels 
after  the  expiration  of  fifty-one  hours;  the  child,  in  the  meantime, 
playing  about  as  usual,  and  not  seeming  to  suffer.  The  story  of  the 
lunatic,  under  the  care  of  Dr.  Fox  of  Bristol,  who  swallowed  "some 
inches"  of  a  poker,  which  came  away  without  any  suffering,  is  regarded 
as  authentic;^  and  there  is  no  question  in  regard  to  the  authenticity  of 
the  case  of  the  sailor  recorded  by  Dr.  Marcet,^  who  swallowed  a  num- 

'  J.  B.  S.  Jackson,  A  Descriptive  Catalogue  of  the  Anatomical  Museum  of  the  Boston 
Society  for  Medical  hnprovement,  p.  158,  Boston,  1847. 
2  Southey,  The  Doctor,  iv.  297,  Lond._,  1837. 
^  Medico-Chirurgical  Transactions,  xii.  52,  Lond.,  1822. 
VOL.  I.— 15 


194  DIGESTION". 

ber  of  clasp  knives  witli  impunity,  but  ultimately  fell  a  victim  to  his 
idle  temerity, — having  swallowed,  in  the  whole,  thirty-seven ! 

5.    DIGESTIOIf  OF  LIQUIDS. 

In  inquiring  into  the  digestion  of  liquids,  we  shall  follow  the  same 
order  as  that  observed  in  considering  the  digestion  of  solids ;  but  as 
many  of  the  acts  are  accomplished  in  the  same  manner,  it  will  not  be 
necessary  to  dwell  upon  them. 

Thirst  or  the  desire  for  drink  is  an  internal  sensation ;  in  its  essence 
resembling  that  of  hunger,  although  not  referred  to  the  same  organs. 
It  arises  from  the  necessities  of  the  system ;  from  the  constant  drain  of 
the  fluid  portions  of  the  blood;  and  is  instinctive  or  essentially  allied 
to  organization.'  The  sensation  differs  in  different  persons,  and  is  rarely 
alike  in  the  same.  Usually,  it  consists  of  a  feeling  of  dryness,  constric- 
tion, and  heat  in  the  back  part  of  the  mouth,  pharynx,  oesophagus,  and 
occasionally  in  the  stomach;  and,  if  prolonged,  redness  and  tumefaction 
of  the  parts  supervene,  with  a  clammy  condition  of  the  mucous  follicu- 
lar— and  diminution  and  viscidity  of  the  salivary — secretions.  These 
phenomena  are  described  as  being  accompanied  by  restlessness,  general 
heat,  injected  eyes,  disturbed  mind,  acceleration  of  the  circulation,  and 
short  breathing,  the  mouth  being  frequently  and  largely  open,  so  as  to 
admit  the  air  to  come  in  contact  with  the  irritated  parts,  and  thus  afford 
momentary  relief. 

Thirst  is  a  very  common  symptom  of  febrile  and  inflammatory  dis- 
eases, in  which  fluid — especially  cold  fluid — is  desired  in  consequence 
of  the  local  relief  it  affords  to  the  parched  and  heated  membrane  of  the 
alimentary  canal.  It  is  also  developed  by  extraneous  circumstances, 
as  in  summer,  when  the  body  sustains  considerable  loss  of  fluid ;  as 
well  as  in  those  diseases — dropsy,  diabetes,  &c. — which  produce  the 
same  effect.  There  are  many  other  circumstances,  however,  that  excite 
it; — long  speaking  or  singing;  certain  kinds  of  diet  as  the  saline  and 
spicy, — and  especially  the  habit,  acquired  by  some,  of  drinking  fre- 
quently. Whilst  individuals,  thus  circumstanced,  may  need  several 
gallons  a  day  to  satisfy  their  wants ; — others,  who  have,  by  resistance, 
acquired  the  habit  of  using  very  little  liquid,  may  be  enjoying  health, 
and  not  experiencing  the  slightest  inconvenience  from  the  privation  of 
liquid ;  so  completely  are  M'e,  as  regards  the  character  and  quantity  of 
our  aliment,  the  creatures  of  habit.  This  privation,  it  is  obvious,  can- 
not be  absolute  or  pushed  beyond  a  certain  extent.  There  must  always 
be  fluid  enough  taken  to  administer  to  the  necessities  of  the  system. 

As  in  the  production  of  all  sensations,  three  acts  are  required  for 
accomplishing  that  of  thirst; — impression,  conduction,  and  perception. 
The  last,  as  in  every  similar  case,  is  effected  by  the  brain ;  and  the 
second  by  the  nerves  passing  between  the  part  impressed  and  that 
organ.  The  act  of  impression — its  seat  and  cause — will  alone  arrest 
our  attention,  and  it  will  be  found  that  we  are  still  less  instructed  on 
these  points  than  on  the  physiology  of  hunger.  Even  with  regard  to 
the  seat  of  the  impression,  we  are  in  a  state  of  uncertainty.  It  appears 
to  be  chiefly  in  tlie  back  part  of  the  mouth  and  fauces;  but  \vbether 

'  J.  BC'clard,  Traite  Lleraentaire  de  Physiologie,  p.  28,  Paris,  1855. 


LIQUIDS.  195 

primarily  there,  or  experienced  there  by  sympathy  with  the  condition 
of  the  stomach,  is  by  no  means  clear.  The  latter  opinion,  however, 
appears  the  more  probable.  In  a  remarkable  case,  published  by  Dr. 
Gairdner  of  Edinburgh,  it  was  found  impracticable  to  allay  thirst  by 
merely  supplying  the  mouth,  tongue,  and  fauces  with  fluid.  A  man 
had  cut  through  the  oesophagus.  An  insatiable  thirst  arose;  several 
pailfuls  of  water  were  swallowed  daily,  and  discharged  through  the 
wound  Avithout  removing  the  desire  for  drink;  but  on  injecting  water, 
mixed  with  a  little  spirit,  into  the  stomach,  it  was  soon  quenched. 
That  the  sensation  is  greatly  dependent  upon  the  quantity  of  fluid  cir- 
culating in  the  vessels  is  shown  by  the  fact,  mentioned  by  M.  Dupuy- 
tren,  that  he  succeeded  in  allaying  the  thirst  of  animals,  by  injecting 
milk,  whey,  water  or  other  fluids  into  the  veins;  and  M.  Orfila  states, 
that,  in  his  toxicological  experiments,  he  frequently  allayed  in  this 
way  the  excessive  thirst  of  animals,  to  which  he  had  administered 
poison;  and  which  were  incapable  of  drinking,  owing  to  the  oesopha- 
gus having  been  tied.  He  found,  also,  in  his  experiments,  that  the 
blood  of  animals  was  more  and  more  deprived  of  its  watery  portions 
as  the  abstinence  from  liquids  was  more  prolonged.-' 

Like  all  other  sensations,  that  of  thirst  arises  from  an  inappreciable 
modification  of  the  nerves  of  the  organ:  hence,  all  the  hypotheses 
proposed  to  account  for  it  have  been  mere  fantasies  undeserving  of 
enumeration. 

The  jyrehens ion  of  liquids  differs  somewhat  from  that  of  solids.  The 
fluid  may  be  simply  poured  into  the  mouth,  or  a  vacuum  may  be 
formed  in  it:  the  pressure  of  the  atmosphere  then  forces  it  in.  When 
we  drink  from  a  vessel,  the  mouth  is  applied  to  the  surface  of  the  fluid; 
the  chest  is  then  dilated,  so  as  to  diminish  the  pressure  of  the  atmo- 
sphere on  the  portion  of  the  surface  of  the  liquid  intercepted  by  the 
lips;  and  the  atmospheric  pressure  on  the  surface  of  the  fluid  in  the 
vessel  forces  it  into  the  mouth,  to  replace  the  air  that  has  been  drawn 
from  the  mouth  by  the  dilatation  of  the  thorax.  In  sucking^  the  mouth 
may  be  compared  to  an  ordinary  syringe;  the  nozzle  of  which  is  repre- 
sented by  the  lips;  the  body  by  the  cheeks,  palate,  &c.,  and  the  piston 
by  the  tongue.  To  put  this  in  action,  the  lips  are  accurately  adjusted 
around  the  body  from  which  the  liquid  has  to  be  extracted.  The 
tongue  is  likewise  applied,  contracts,  and  is  carried  backwards ;  so 
that  an  approach  to  a  vacuum  is  formed  between  its  upper  surface 
and  the  palate.  The  fluid,  no  longer  compressed  equally  by  the  atmo- 
sphere, is  displaced,  and  enters  the  mouth. 

As  neither  mastication  nor  insalivation  is  required  in  the  case  of 
liquids,  they  do  not  remain  long  in  the  mouth,  unless  their  temperature 
is  too  elevated  to  admit  of  their  being  passed  down  into  the  stomach 
immediately,  or  they  are  of  so  luscious  a  character,  that  their  prolonged 
application  to  the  organ  of  taste  affords  pleasure.  Their  deglutition  is 
effected  by  the  same  mechanism  as  that  of  solids;  and,  as  they  yield 
readily  to  the  slightest  pressure,  with  less  difficulty.  Their  accumula- 
tion in  the  stomach  takes  place  in  much  the  same  manner.  They  arrive 
by  successive  mouthfuls;  and,  as  they  collect,  the  thirst  disappears 

'  Adelon,  Pliysiologie  de  I'lloiume,  2de  edit.,  ii.  525,  Paris,  1829. 


196  DIGESTIOX. 

with  all  its  local  and  general  attendants.     If,  however,  the  organ  be 
over-distended  a  disposition  to  vomiting  is  induced. 

The  changes,  which  liquids  undergo  in  the  stomach,  are  of  different 
kinds.  All  acquire  the  temperature  of  that  viscus,  and  become  mixed 
with  the  secretions  from  its  internal  surface,  as  well  as  from  that  of 
the  supra-diaphragmatic  portion  of  the  digestive  tube.  Some,  however, 
undergo  the  operation  of  chymification ;  others  not.  To  the  latter 
class  belong, — water,  weak  alcoholic  drinks,  the  vegetable  acids,  &c. 
Water  experiences  the  admixture  already  mentioned ;  becomes  turbid, 
and  gradually  disappears,  without  undergoing  any  transformation. 
Part  passes  into  the  small  intestine ;  the  other  is  directly  absorbed. 
When  any  strong  alcoholic  liquor  is  taken,  the  effect  is  different.  Its 
stimulation  causes  the  stomach  to  contract,  and  augments  the  secre- 
tion from  the  mucous  membrane ;  whilst,  at  the  same  time,  it  coagu- 
lates all  the  albuminous  portions ;  mixes  with  the  watery  part  of  the 
mucous  and  salivary  fluids,  and  rapidly  disappears  by  absorption ; 
hence,  the  speedy  supervention  of  inebriety,  or  death,  after  a  large 
quantity  of  alcohol  has  been  taken  into  the  stomach.  The  sub- 
stances, that  have  been  coagulated  by  the  action  of  the  alcohol,  are 
afterwards  digested  like  solid  food.  We  can  thus  understand  the  good 
effects  of  a  small  quantity  of  alcohol,  taken  after  a  substance  difficult 
of  digestion, — a  custom  which  has  existed  from  high  antiquity,  and  has 
physiology  in  its  favour.  It  is,  in  such  cases, — to  use  the  language  of 
the  eccentric  Kitchener,' — a  good  "^^eris^aZ^/c  j3ersz<.«(^r." 

Oil  remains  longer  in  the  stomach  than  any  other  liquid,  experiences 
little  change  there,  but  passes  into  the  small  intestine,  where  it  forms 
an  emulsion  and  enters  the  veins  and  chyliferous  vessels.  Milk,  as  is 
well  known,  coagulates  in  the  stomach  soon  after  it  is  swallowed,  after 
which  the  clot  is  digested,  and  the  whey  absorbed.  Yet  the  existence 
of  coagula  in  the  stomach  is  constantly  regarded  by  the  unprofessional 
as  a  pathological  condition !  Where  the  liquid,  aqueous  or  spirituous, 
holds  in  suspension  the  immediate  principles  of  animals  or  vegetables, 
as  gelatin,  albumen,  osmazome,  sugar,  gum,  fecula,  colouring  matter, 
&c.,  there  is  reason  to  believe  that  they  enter  immediately  into  the 
veins  of  the  stomach  and  small  intestine,  having  become  modified  and 
rendered  fit  for  assimilation  by  admixture  with  the  gastric  and  intes- 
tinal secretions.  The  salts,  united  with  these  fluids,  are  taken  up  along 
with  them.  Ked  wine,  according  to  M.  Magendie,^  first  becomes  turbid 
by  admixture  with  the  juices  formed  in,  or  carried  into,  the  stomach ; 
the  albumen  of  these  fluids  speedily  undergoes  coagulation,  and  be- 
comes flocculent;  and,  subsequently,  its  colouring  matter — entangled, 
perhaps,  with  the  mucus  and  albumen — is  deposited  on  the  mucous 
membrane  of  the  stomach.  The  aqueous  and  alcoholic  portions  soon 
disappear. 

Liquids  reach  the  small  intestine  in  two  forms; — in  the  state  of 
chyme;  and  in  their  unaltered  condition.  In  the  former  case,  they 
proceed  like  the  chyme  obtained  from  solid  food.     In  the  latter,  they 

'  Directions  for  Invigorating  and  Prolonging  Life;  or  the  Invalid's  Oracle, &c.,  Amer. 
edit.,  from  the  6th  London,  hy  T.  S.  Barrett,  New  York,  1831. 
*  Precis,4&c.,  ii.  143. 


EUMINATION.  197 

undergo  no  essential  cliange;  being  simply  nnited  with  the  fluids  poured 
into  the  small  intestine,' — the  mucous  secretions,  bile  and  pancreatic 
juice.  Their  absorption  goes  on  as  they  proceed,  so  that  very  little,  if 
any,  attains  the  large  intestine.  The  mode  in  which  they  are  expelled 
is  the  same  as  in  the  case  of  solids. 

6.    EEUCTATION,  KKGUEGITATION,  KUMINATIOIi,  AND  VOMITING. 

Although  the  contraction  of  the  oesophagus  generally  prevents  the 
return  of  matters  from  the  stomach,  occasionally  this  occurs,  giving 
rise  to  eructation,  regurgitation,  or  vomiting. 

a.  Eructation. — Eructation  or  belching  is  the  escape  of  gas  from 
the  stomach.  If  air  exists  in  the  organ,  it  is  necessarily  situate  near 
the  cardiac  orifice.  When  the  aperture  relaxes,  it  passes  out,  and, 
unless  forced  back  by  the  contraction  of  the  oesophagus,  speedily 
reaches  the  pharynx,  causing  the  edges  to  vibrate,  hence  the  sound  by 
which  it  is  accompanied. 

b.  Regurgitation. — If,  instead  of  air,  liquid  or  solid  food  ascends 
from  the  stomach  into  the  mouth,  the  action  is  called  regurgitation. 
Of  this  we  have  an  instance  in  the  puking  of  the  infant  at  the  breast; 
and  in  the  adult,  when  the  stomach  is  surcharged.  Occasionally,  too,  it 
occurs  when  the  organ  is  empty, — in  the  morning,  for  example, — when 
it  is  frequently  preceded  by  eructations,  by  which  the  air,  contained  in 
the  organ,  is  got  rid  of.  The  mode  in  which  it  takes  place  is  analo- 
gous to  that  of  eructation.  The  substances,  contained  in  the  stomach 
become  accidentally  engaged  in  the  cardiac  orifice,  during  the  open 
state  of  the  orifice,  and  the  relaxation  of  the  lower  part  of  the  oeso- 
phagus, owing  to  the  direct  pressure  of  the  stomach  on  its  contents, 
and  the  abdominal  muscles  contracting  and  compressing  that  viscus. 
When  they  have  once  passed  into  the  oesophagus,  the  latter  contracts 
upon  them  but  inversely,  or  from  below  to  above.  In  this  way  they 
ascend  into  the  pharynx,  and  ultimately  into  the  mouth.  Generally, 
regurgitation  takes  place  in  an  involuntary  manner;  but  there  are 
some  who  are  capable  of  effecting  it  at  will;  and  can  discharge  the  con- 
tents of  their  stomachs  at  pleasure.  To  accomplish  this, — a  deep  inspi- 
ration is  taken,  by  which  the  diaphragm  is  forcibly  depressed  upon  the 
stomach ;  the  abdominal  muscles  are  then  contracted  so  as  to  compress 
the  organ ;  and  this  effect  is  occasionally  aided  by  pressing  strongly 
with  the  hands  on  the  epigastric  region.  When  these  efforts  are  simul- 
taneous with  the  relaxation  of  the  lower  third  of  the  oesophagus,  the 
alimentary  matters  pass  into  the  oesophagus.  This  voluntary  regurgi- 
tation seems  to  be  what  is  called  vomiting  at  pleasure. 

Professor  Berard^  has  remarked,  that  when  food  passes  from  the 
mouth  into  the  pharynx,  in  the  act  of  deglutition,  the  reflex  action  of 
the  second  stage  precipitates  it  into  the  oesophagus  without  any  act  of 
the  will ;  but  when  food  ascends  from  the  oesophagus  into  the  pharynx, 
it  can  be  introduced  at  will  into  the  mouth,  or  be  swallowed, 

c.  Rumination. — Some  individuals  have  taken  advantage  of  this 
power  to  chew  the  food  over  again,  and  subject  it  to  a  second  degluti- 
tion.    The  function  of  rumination  is  peculiar  to  certain  animals ;  yet 

'  Cours  de  Pliysiologie,  ii.  275  (note),  Paris,  1S49. 


"198  DIGESTION". 

man  has  occasionally  possessed  it.  Peyer,'  as  well  as  Percy  and  Lau- 
rent,^ has  given  numerous  examples.  The  wife  of  afrottenr  or  rubber 
of  the  floors,  in  the  establishment  of  the  then  Duke  of  Orleans — after- 
wards King  Louis  Phihppe — could  bring  up  a  glassful  of  water  into 
her  mouth  immediately  after  she  had  swallowed  it.  Dr.  Copland^  ap- 
pears to  have  seen  more  than  one  instance  of  human  rumination,  and 
he  describes  it  as  an  affection  rather  to  be  courted  than  shunned,  so 
far  as  resrards  the  sensations  of  the  individual.'*  Under  usual  circum- 
stances,  according  to  him,  rumination  commences  from  a  c^uarter  of  an 
hour  to  an  hour  and  a  half  after  a  meal.  The  process  is  never  accom- 
panied with  the  smallest  degree  of  nausea,  pain,  or  disagreeable  sensa- 
tion. The  returned  alimentary  bolus  is  attended  with  no  unpleasant 
flavour;  is  in  no  degree  acidulous  [?] ;  is  agreeable;  and  masticated  with 
additional  pleasure,  and  greater  deliberation  than  at  first.  The  whole 
of  the  food  swallowed  at  a  meal  is  not  returned  in  order  to  undergo 
the  process ;  but  chiefly  the  part  that  has  been  insufficiently  masticated. 
The  more  fluid  portions  are  sometimes,  however,  regurgitated  along 
with  the  more  solid;  and  when  the  stomach  is  distended  by  a  copious 
meal  the  fluid  contents  are  frequently  passed  up  to  be  again  swal- 
lowed.* 

d.  Vomiting. — This  inverted  action  of  the  stomach,  preceded — as  it 
always  is — by  manifest  local  and  general  disturbance,  cannot  properly 
be  regarded  as  within  the  domain  of  physiology.  In  the  language  of 
Haller,  vomitus  totus  morbosus  est.  It  is,  however,  so  nearly  allied  to 
the  phenomena  we  have  just  considered,  and  has  engaged  so  much  of 
the  time  of  the  physiologist,  as  well  as  pathologist,  that  it  requires 
mention  here.  From  regurgitation  it  differs  essentially, — in  the  sensa- 
tion that  precedes;  the  retching  that  accompanies;  and  the  fatigue 
that  generally  succeeds  it;  in  short,  whilst  in  regurgitation  no  indispo- 
sition may  be  felt,  in  vomiting  it  is  always  present  to  a  greater  or  less 
extent. 

The  sensation  of  the  desire  to  vomit  is  termed  nausea.  It  is  an  inde- 
scribable feeling  of  general  indisposition;  sometimes  accompanied 
with  one  of  circumgyration,  either  in  the  head  or  epigastric  region; 
trembling  of  the  lower  lip,  and  copious  flow  of  saliva.  Along  with 
these  signs,  there  is  manifest  diminution  of  the  powers  of  the  vascular 
and  nervous  systems ;  hence  the  utility  of  nauseating  remedies  when 
these  systems  are  inordinately  excited.  The  causes,  which  produce 
nausea,  show  that  it  may  be  either  an  external  or  internal  sensation. 
Those,  that  occasion  it  directly  or  externally,  are  emetics ;  too  great 
distension  of  the  stomach,  or  the  presence  of  food  that  disagrees  by  its 
quality;  morbid  secretions;  reflux  of  bile  from  the  duodenum,  &c.  All 
these  are  so  many  immediate  irritants,  which  develope  the  sensation, 

'  Merycologia,  &c.,  Basil,  1685. 

*  Art.  Merycisme,  in  Diet,  des  Sciences  Medicales;  and  Berard,  Cours  de  Pliysiologie, 
13te  livraison,  p.  274,  Paris,  1849. 

3  Edition  of  De  Lys's  translation  of  Richcrand's  Physiology. 

*  See  also  Bifraud,  Manuel  de  Ph^^siologie,  p.  152,  Paris,  1853. 

*  An  interesting  case  of  rumination  is  citeil  from  tlie  London  Lancet,  in  the  Phila- 
delphia Med.  Examiner,  p.  315,  for  May,  1845.  On  the  sensible  phenomena  of  rumi- 
nation, see  Colin,  Comptes  Reudus,  xxxv.,  130,  1852;  and  Scherer,  Canstatt's  Jahres- 
bericht,  1852,  S.  133. 


VOMITING.  199 

as  external  sensations  in  general  are  developed.  In  other  cases,  the 
cause  acts  at  a  distance.  Between  the  stomach  and  various  organs  oi 
the  body,  such  extensive  sympathetic  relations  exist,  that  if  one  be 
long  and  painfully  affected,  the  stomach  sooner  or  later  sympathizes; 
and  nausea,  or  vomiting,  or  both  are  induced.  In  many  instances,  in- 
deed, the  cause  is  much  more  remote  than  this ;  the  sight  of  a  disgust- 
ing object,  an  offensive  smell,  or  a  nauseous  taste,  will  as  certainly  pro- 
duce the  sensation  as  any  of  the  more  direct  agents.  To  this  class  of 
causes  belongs  the  nausea  produced  by  riding  in  a  carriage  with  the 
back  to  the  horses,  by  swinging,  and  particularly  by  sailing  on  the 
ocean.  How  the  motion,  which  obviously  excites  the  nausea  in  these 
cases,  acts,  has  been  the  subject  of  many  speculations,  especially  as 
regards  sea-sickness.  Darwin'  refers  it  to  an  association  with  some 
affection  of  the  organs  of  vision,  which,  in  the  first  instance,  produces 
vertigo;  and  M.  Bourru,  in  his  French  translation  of  the  work  of  Gil- 
christ, "  On  the  utility  of  sea  voyages  in  the  cure  of  different  dis- 
eases,"— ascribes  it  to  irritation  of  the  optic  nerves,  caused  by  the 
impossibility  of  fixing  the  eyes  on  objects  soon  after  embarking. 
The  objections  to  these  views  are,  that  it  ought  to  be  prevented  by 
simply  covering  the  eyes,  and  that  the  blind  ought  to  be  exempt  from 
it,  which  is  not  the  case.  Dr.  Wollaston^  attempted  to  explain  it,  by 
some  change  in  the  distribution  of  the  blood ; — the  descending  motion 
of  the  vessel  causing  an  accumulation  in  the  brain,  as  it  causes  the 
mercury  to  rise  in  the  tube  of  a  barometer.  But  the  explanation  is 
too  physical.  The  mercury,  in  an  unyielding  tube,  is  readily  influ- 
enced by  the  motions  of  the  vessel;  but  the  blood  in  the  living  ani- 
mal is  circumstanced  far  otherwise.  It  is  under  the  influence  of  a 
vital  force,  which  interferes  greatly  with  the  action  of  purely  physical 
causes.  Were  it  otherwise,  we  should  be  liable  to  alarming  accidents, 
whenever  the  body  is  exposed  to  the  slightest  concussion. 

The  generality  of  pathologists  consider,  that  the  first  effect  is  upon 
the  brain,  the  sensation  being  produced  consecutively  through  the  in- 
fluence of  that  organ  on  the  stomach ;  and  it  is  difficult  not  to  accord 
with  this  view;  whilst  it  must  be  admitted,  that  the  precise  mode,  in 
which  it  is  effected — as  in  the  case,  indeed,  of  every  other  phenome- 
non of  the  nervous  system,  is  beyond  our  cognizance.  In  nausea,  pro- 
duced by  the  sight  of  a  disgusting  object,  we  have  this  catenation  of 
actions  somewhat  more  clearly  evidenced.  The  impression  is  mani- 
festly conveyed  to  the  brain  by  the  optic  nerves,  and  from  that  organ 
the  sensation  must  emanate.  It  is  probable,  too,  that  when  emetics 
are  injected  into  the  veins,  the  first  effect  takes  place  on  the  brain,  and 
the  stomach  is  affected  secondarily. 

When  the  state  of  nausea,  howsoever  induced,  continues  for  any 
length  of  time,  it  is  usually  followed  by  vomiting.  The  rejected  mat- 
ters are  generally  from  the  stomach ;  but  if  the  retching  or  violent 
contractile  efforts  of  the  muscles  concerned  be  long  continued,  the  con- 
tents of  the  small  intestine  also  form  part ;  hence,  we  account  for  the 
universality  of  the  presence  of  bile  in  the  rejected  matters  after  an 
emetic  has  been  taken.     Its  presence  is,  therefore,  in  the  generality  of 

•  Zoonomia.  iv.  252,  3d  edit.,  Loud.,  IbOl.  '  Philos.  Trausact.  for  1810. 


200  DIGESTION. 

cases,  no  evidence  of  the  person's  being  wliat  is  termed  hilioics.  The 
contents  of  the  small  intestine  are  returned  into  the  stomach  by  the 
antiperistaltic  action.  The  longitudinal  fibres  take  their  fixed  point 
below,  and  contract  from  above  downwards;  so  that  the  chymous  mass 
is  forced  towards  the  upper  part  of  the  canal,  whilst  the  circular  fibres 
contract  from  below  to  above.  In  cases  of  colica  ileus  or  iliac  j^ccssion, 
the  inverted  action  extends  through  the  whole  intestinal  canal ;  so  that 
fecal  matters,  and  even  substances  injected  into  the  rectum,  pass  the 
ileo-crecal  valve,  and  are  discharged  by  the  mouth. 

Of  old,  it  was  universally  maintained,  that  vomiting  is  caused  by  the 
sudden  and  convulsive  inverted  contraction  of  the  stomach ;  and  they, 
who  admitted  that  the  diaphragm  and  abdominal  muscles  take  part  in 
the  action,  looked  upon  them  simply  as  accessories.  Francis  Bayle,* 
Professor  in  the  LTniversity  of  Toulouse,  in  1681,  appears  to  have  been 
the  first  who  suggested,  that  the  stomach  is  nearly  passive  in  the  act; 
and  that  vomiting  is  caused  almost  exclusively  by  the  pressure  exerted 
upon  that  organ  by  the  diaphragm  and  abdominal  muscles.  His  reason 
for  the  belief  was  founded  on  the  fact,  that  having  introduced  his  finger 
into  the  abdomen  of  a  living  animal  whilst  it  was  vomiting,  he  could 
not  perceive  any  contraction  of  the  stomach.  In  1686,  M.  Chirac  re- 
peated the  experiment  with  similar  results ;  after  which,  the  views  of 
Bayle  were  embraced  by  many  of  the  most  eminent  physiologists  and 
pathologists, — Senac,  Van  Swieten,  and  Schwartz,^  and,  at  a  later  period, 
by  the  celebrated  John  Hunter,^  who  maintained,  that  the  contraction 
of  the  muscular  fibres  of  the  stomach  is  not  essential  to  the  act.  Many 
distinguished  physiologists  ranged  themselves  on  the  opposite  side. 
M.  Littre  maintained,  that  the  stomach  is  provided  with  considerable 
muscular  bands,  capable  of  powerful  contraction;  and  that  vomiting, 
as  in  the  case  of  ruminant  animals,  is  often  caused  without  the  partici- 
pation of  the  abdominal  muscles.  We  have  seen,  however,  that  the 
rumination  of  animals  more  resembles  regurgitation.  M.  Lieutaud* 
argued,  that,  according  to  Bayle's  theory,  vomiting  ought  to  be  a  vo- 
luntary phenomenon;  that  the  stomach  is  too  deeply  seated  to  be  com- 
pressed, so  as  to  empty  it  of  its  contents,  by  the  neighbouring  muscles; 
and  he  details  the  singular  case  of  a  female,  who,  whilst  labouring  under 
an  affection,  forwdiich  emetics  seemed  to  be  required,  resisted  the  action 
of  the  most  powerful  substances  of  that  nature.  After  her  death,  M. 
Lieutaud,  feeling  desirous  to  detect  the  cause  of  this  resistance,  had 
the  body  opened  in  his  presence ;  the  stomach  was  found  enormously 
distended,  but  its  structure  unaffected.  He,  consequently,  inferred, 
that  the  stomach  had  become  paralyzed  from  over-distension,  and  that 
the  effect  produced  was  similar  to  that,  so  often  met  with  in  the  bladder, 
when  it  has  been  long  and  largely  distended.  This  case  seemed  to  prove 
to  him,  that  the  stomach  is  most  concerned  in  the  act  of  vomiting,  as 
the  abdominal  muscles  and  diaphragm  appeared  healthy,  and  no  obsta- 
cle existed  to  their  contraction.     It  is  singular,  however,  that  emetics 

'  Prohlemata  Medico-physica  ot  Medica,  Hagje  Comitis,  1678. 

*  Ilaller,  Elemeiita  Physiol.,  lib.  xix.  ^  4,  Bern.,  17o4. 

*  Observations  on  certain  parts  of  the  Animal  Economy,  with  Notes  by  Prof.  Owen, 
Amer.  edit.,  p.  121,  Philad.,  1840. 

*  MOmoir.  de  PAcad.  pour  1752,  p.  223. 


VOMITING.  201 

should  not  have  excited  the  contraction  of  the  diaphragm  and  abdominal 
muscles;  especially  as  there  is  reason  for  believing,  that  many  of  them 
at  least,  under  ordinary  circumstances,  are  taken  into  the  bloodvessels, 
and  affect  the  brain  first,  and  through  its  agency  the  muscles  con- 
cerned in  the  act  of  vomiting.  The  case  seems  to  have  been  one  of 
unusual  resistance  to  the  ordinary  effects  of  nauseating  substances,  and 
cannot  be  looked  upon  as  either  favourable  or  unfavourable  to  the  views 
of  Bayle.  We  find,  that  vomiting  does  not  follow  the  exhibition  of  the 
largest  doses  of  the  most  powerful  emetics,  if  the  energy  of  the  nervous 
system  be  suspended  by  the  inordinate  use  of  narcotics,  or  by  violent 
injuries  of  the  head.  M,  Lieutaud  farther  remarks,  that  according  to 
Bayle's  theory  vomiting  occurs  at  the  time  of  inspiration ;  but  this 
cannot  be,  as  the  lower  part  of  the  oesophagus  is  then  contracted,  and 
if  the  vomited  matters  could  reach  the  pharynx,  they  would  pass  into 
the  larynx. 

Dr.  Marshall  HalP  has  attempted,  and  successfully,  to  show,  that  the 
larynx  is  closed  during  vomiting;  and  has  concluded,  that  the  act  is  a 
modification  of  expiration, — or  that  the  muscles  of  expiration,  by  a  sud- 
den and  violent  contraction,  press  upon  the  contents  of  the  stomach,  and 
project  them  through  the  oesophagus.  Perhaps — as  Dr.  Hall  has  re- 
marked— no  act  affords  a  better  illustration  of  the  action  of  the  excito- 
motory  or  reflex  system  of  nerves  than  this.  If  the  upper  part  of  the 
throat  be  tickled  with  a  feather,  vomiting  results;  but  if  the  feather  be 
passed  too  far  down,  deglutition  is  induced  and  not  vomiting.  The  ex- 
citor  nerves,  in  the  former  case,  are  the  glosso-pharyngeal,  and  perhaps 
the  fifth  pair.  When  vomiting  is  caused  by  an  emetic,  the  pneumogas- 
tric  is  the  excitor.  When  the  impression  is  first  made  on  the  brain, 
the  stimulus  must  be  conveyed  by  the  medulla  oblongata  and  medulla 
spinalis  to  the  muscles  concerned. 

Haller^  maintained  the  ancient  doctrine,  that  the  stomach,  alone,  is 
competent  to  the  operation.  His  views  were  chiefly  founded  on  his 
theory  of  irritability,  which  compelled  him  to  admit  contraction  wherever 
there  are  muscular  fibres;  and  on  certain  experiments  of  Wepfer,^  who 
asserted,  that  when  he  produced  vomiting  by  mineral  substances,  he 
observed  the  stomach  contract.  The  Acaderaie  des  Sciences  of  Paris, 
unsatisfied  with  the  results  of  previous  observations,  appointed  M. 
Duverney''  to  examine  into  the  question,  experimentally  and  otherwise; 
who — although  he  did  not  adopt  the  whole  theory  of  Chirac — confirmed 
the  accuracy  of  the  facts  on  which  it  rested.  He  demonstrated,  that 
the  stomach  is  but  little  concerned  in  the  act;  and  that  it  is  chiefly  de- 
pendent upon  the  contraction  of  the  diaphragm  and  abdominal  muscles, 
which  enclose  the  stomach  as  in  a  press,  so  that  its  contents  are  com- 
pelled to  return  by  the  oesophagus.  On  the  other  hand,  in  1771,  M. 
Portal,*  in  his  lectures  at  the  College  of  France,  endeavoured  to  show, 
that  the  stomach  is  the  great  agent.  He  administered  to  two  dogs 
arsenic  and  nux  vomica,  which  produced  vomiting.  The  abdomen  was 
immediately  opened;  and,  according  to  Portal,  the  contractile  move- 

'  .Tournal  of  Science  and  Arts,  xv.  388. 

*  Loo.  citat.  *  Cicut?e  Aquaticre  Historia,  &c.,  Basil,  1679. 

*  Memoir  de  I'Academ.  pour  1700,  Hist.,  p.  27. 
'  Courri  d'Anatomie  Medicale,  Paris,  1S04. 


202  DIGESTION. 

ments  of  the  stomacli  could  be  both  seen  and  felt ;  and  it  was  noticed, 
that  instead  of  the  vomiting  being  dependent  upon  the  pressure  of  the 
diaphragm  on  the  stomach,  it  occurred  at  the  time  of  expiration ;  and 
was  arrested  during  inspiration,  because  the  depressed  diaphragm  then 
closes  the  inferior  extremity  of  the  oesophagus  with  such  strength,  that 
the  contents  cannot  be  forced  into  the  oesophagus  when  we  press  upon 
the  organ  with  both  hands.  The  views  of  Portal  were  confirmed  by 
the  experiments  of  Dr.  Haighton.^  lie  opened  several  animals  during 
the  eftbrts  of  vomiting  ;  and  states  that  he  distinctly  saw  the  contrac- 
tions of  the  stomach. 

In  more  recent  times,  the  physiological  world  has  been  again  agitated 
with  this  question.  In  1813,  M.  Magendie^  presented  to  the  French 
Institute  tlie  results  of  a  series  of  experiments  on  dogs  and  cats, — 
animals,  that  vomit  with  facility.  Six  grains  of  tartrate  of  antimony 
and  potassa  were  given  to  a  clog,  and,  when  he  became  affected  with 
nausea,  the  linea  alba  was  divided,  and  the  finger  introduced  into  the 
abdomen  to  detect  the  state  of  the  stomach.  No  contraction  was  felt; 
the  organ  appeared  simply  pressed  upon  by  the  liver  and  intestines 
crowded  upon  it  by  the  contracted  diaphragm  and  abdominal  muscles. 
Nor  was  any  contraction  of  the  stomach  perceptible  to  the  eye;  on  the 
contrary,  it  appeared  full  of  air,  and  three  times  its  usual  size.  The 
air  manifestly  came  from  the  oesophagus,  as  a  ligature,  applied  round 
the  cardia,  completely  shut  it  oK  From  this  experiment,  M,  Magendie 
inferred,  that  the  stomach  is  passive  in  vomiting.  A  solution  of  four 
grains  of  tartrate  of  antimony  and  potassa  in  two  ounces  of  water  was 
injected  into  the  veins  of  a  dog;  and,  as  soon  as  nausea  took  place,  an 
incision  was  made  into  the  abdomen,  and  the  stomach  drawn  out  of  the 
cavity.  Although  the  retching  continued,  the  viscus  remained  im- 
movable ;  and  the  efforts  were  vain.  If,  on  the  other  hand,  the  anterior 
and  posterior  surfaces  of  the  stomach  were  pressed  upon  by  the  hands, 
vomiting  occurred,  even  when  no  tartrate  was  administered, — the  pres- 
sure provoking  the  contraction  of  the  diaphragm  and  abdominal  mus- 
cles, and  thus  exhibiting  the  close  sympathetic  connexion,  existing 
between  those  acts.  A  slight  pull  at  the  oesophagus  was  attended  with 
a  similar  result.  In  another  dog,  the  abdomen  was  opened ;  the  vessels 
of  the  stomach  tied;  and  the  viscus  extirpated.  A  solution  of  two 
grains  of  tartrate  of  antimony  and  potassa  in  an  ounce  and  a  half  of 
water  was  then  injected  into  the  veins  of  the  animal,  when  nausea  and 
fruitless  efforts  to  vomit  supervened.  The  injection  was  repeated  six 
times:  and  alwaj^s  with  the  same  results. — In  another  dog,  the  stomach 
was  extirpated,  and  a  hog's  bladder  fitted  to  the  oesophagus  in  its  stead, 
containing  a  pint  of  water,  which  distended  but  did  not  fill  it.  The 
whole  was  then  put  into  the  abdomen;  the  parietes  of  which  were 
closed  by  suture.  A  solution  of  tartrate  of  antimony  and  potassa  was 
now  injected  into  the  jugular  vein:  nausea — and,  afterwards,  vomit- 
ing— supervened,  and  the  fluid  was  forced  from  the  bladder. — In  an- 
other dog,  the  phrenic  nerves  were  divided ;  by  which  three-fourths  of 
the  diaphragm  were  paralysed;  the  dorsal  being  the  only  nerves  of 

'  MeTQ-oirs  of  the  Lond.  Med.  Society,  vol.  ii.  , 

*  Mcnioiw  sur  le  Vomissemeut,  Paris,  1813 ;  and  Pr6cis  El^meutaire,  edit,  cit.,  ii.  152. 


VOMITING.  203 

motion  remaining  untouched.  When  tartrate  of  antimony  and  potassa 
was  injected  into  the  veins  of  this  animal,  but  slight  vomiting  occurred; 
and  this  ceased,  when  the  abdomen  was  opened,  and  the  stomach  forcibly 
pressed  upon, — In  another  dog,  the  abdominal  muscles  were  detached 
from  the  sides  and  linea  alba; — the  only  part  of  the  parietes  remaining 
being  the  peritoneum.  A  solution  of  tartrate  of  antimony  and  potassa 
was  now  injected  into  the  veins:  nausea  and  vomiting  supervened; 
and,  through  the  peritoneum,  the  stomach  was  observed  immovable; 
whilst  the  diaphragm  pressed  down  the  viscera  so  strongly  against  the 
peritoneum,  that  it  gave  way,  and  the  linea  alba  alone  resisted. — In  a 
final  experiment,  he  combined  the  last  two.  He  cut  the  phrenic  nerves 
to  paralyse  the  diaphragm ;  and  removed  the  abdominal  muscles.  Yo- 
miting  was  no  longer  excited. 

From  these  different  results,  M.  Magendie  decided,  that  vomiting 
takes  place  independently  of  the  stomach;  and,  on  the  other  hand,  that 
it  cannot  occur  without  the  agency  of  the  diaphragm  and  abdominal 
muscles;  and  he  concluded,  that  the  stomach  is  almost  passive  in  the 
act; — that  the  diaphragm  and  abdominal  muscles,  especially  the  first, 
are  the  principal  agents; — that  air  is  constantly  swallowed  at  the  time 
of  vomiting,  to  give  the  stomach  the  bulk  which  is  necessary,  in  order 
that  it  may  be  compressed  by  those  muscles;  and  lastly,  that  the  dia- 
phragm and  abdominal  muscles  are  largely  concerned  in  vomiting,  as 
is  indicated  by  their  evident  and  powerful  contractions,  and  by  the 
fatigue  felt  in  them  afterwards.  In  corroboration  of  his  view,  M.  Ma- 
gendie refers  to  cases  of  scirrhous  pylorus,  in  which  there  is  constant 
vomiting,  although  a  part  of  the  tissue  of  the  stomach  has  become  of 
cartilaginous  hardness,  and,  consequently,  incapable  of  contraction. 

Clear  as  the  results  obtained  by  this  practiced  experimenter  seem  to 
be,  they  have  been  controverted;  and  attempted  to  be  overthrown  by 
similar  experiments.  Soon  after  the  appearance  of  his  memoir,  M. 
Maingault^  laid  before  the  Society  of  the  Faculte  de  Medccine  of  Paris, 
a  series  of  experiments,  from  which  he  deduced  very  different  results. 
In  all,  vomiting  was  produced  without  the  aid  of  the  diaphragm  and 
abdominal  muscles.  The  vomiting  was  excited  by  pinching  a  portion 
of  intestine,  which  acts  more  speedily  than  the  injection  of  substances 
into  the  veins.  The  abdomen  of  a  dog  was  opened,  and  a  ligature 
passed  round  a  portion  of  intestine,  which  was  returned  nito  the  abdo- 
men, and  the  Avound  closed  by  suture :  vomiting  took  place.  All  the 
abdominal  muscles  were  next  extirpated, — the  skin,  alone,  forming  the 
parietes  of  the  cavity.  This  was  brought  together,  and  the  vomiting 
continued.  On  another  dog,  three-quarters  of  the  diaphragm  were 
paralysed  by  the  section  of  the  phrenic  nerves.  The  abdomen  was 
now  opened,  and  a  ligature  placed  round  a  portion  of  intestine.  Vomit- 
ing occurred.  Lastly  ; — these  two  experiments  were  united  into  one. 
The  abdominal  muscles  were  cut  crucially,  and  removed;  the  phrenic 
nerves  divided ;  and  the  diaphragm  was  cut  aw^ay  from  its  fleshy  por- 
tion towards  its  tendinous  centre ;  leaving  only  a  portion  as  broad  as 
the  finger  under  the  sternum.  The  integuments  were  not  brought 
together ;  yet  vomiting  continued. 

'  Memoire  sur  le  Vomissement,  Paris,  1813. 


204  DIGESTION. 

As  these  results  were  obtained  on  numerous  repetitions  of  the  ex- 
periment, M.  Maingault  conceived  himself  justified  in  deducing  infer- 
ences opposite  to  those  of  M,  ISragendie,  namely, — that  the  contraction 
of  the  diaphragm  and  abdominal  muscles  is  only  accessory  to  the  act 
of  vomiting;  that  the  action  of  the  stomach  is  its  principal  cause; — 
that  the  latter  is  not  a  convulsive  contraction,  which  strikes  the  eye, 
but  a  slow,  antiperistaltic  action  ;  and  that  the  only  convulsive  move- 
ment is  the  contraction  of  the  oesophagus,  which  drags  the  stomach 
upwards.  He  adduces,  moreover,  various  considerations  in  favour  of 
his  deductions.  If  the  stomach,  he  asks,  be  passive,  why  does  it  pos- 
sess nerves,  vessels,  and  muscular  fibres?  Why  is  vomiting  more 
energetic,  when  the  stomach  is  pinched  nearer  to  its  pyloric  orifice  ? 
Why  are  the  rugas  of  the  mucous  membrane  of  the  stomach,  during 
vomiting,  directed  in  a  divergent  manner  from  the  cardiac  and  pyloric 
orifices  towards  the  middle  portion  of  the  organ?  If  the  diaphragm 
does  all,  why  do  we  not  vomit  whenever  that  muscle  contracts  for- 
cibly ?  Why  does  not  the  diaphragm  produce  the  discharge  of  urine 
in  paralysis  of  the  bladder?  Why  is  vomiting  not  a  voluntary  phe- 
nomenon? And,  lastly,  how  is  it  that  it  occurs  in  birds,  which  have 
no  diaphragm  ? 

The  minds  of  physiologists  were  of  course  distracted  by  these  con- 
flicting results.  M.  Kicherand^  embraced  the  views  of  M.  Magendie; 
and  affirmed,  that  he  had  never  observed  contraction  of  the  stomach ; 
and  that  it  seemed  to  him  the  least  contractile  of  any  part  of  the 
intestinal  canal.  With  regard  to  the  experiments  of  M.  ^^laingault,  he 
considered,  that  the  stomach  had  not  been  wholly  separated  from  the 
surrounding  muscles ;  that  the  action  of  the  pillars  of  the  diaphragm, 
and  the  spasmodic  constriction  of  the  hypochondres  are  sufficient  to 
compress  the  viscus ;  that  nothing  is  more  difficult  to  effect  than  the 
section  of  the  phrenic  nerves  below  their  last  root ;  and,  moreover, 
such  section  does  not  entirely  paralyse  the  diaphragm,  as  the  muscle 
still  receives  twigs  from  the  intercostal  nerves  and  great  sympathetic; 
that  the  cardia,  being  more  expanded  than  the  pjdorus,  the  passage 
of  substances  through  it  is  rendered  easy ;  and  that  it  is  incorrect  to 
say,  that  the  cardiac  orifice,  during  inspiration,  is  closed  between  the 
pillars  of  the  diaphragm.  Again,  to  object  that,  according  to  the 
theory  of  M.  !^[agendie,  vomiting  ought  to  be  a  voluntary  phenomenon, 
is  a  feeble  argument;  for  it  is  admitted,  that  the  muscles,  which,  at 
the  time,  compress  the  stomach,  act  convulsively.  If  the  diaphragm, 
in  paralysis  of  the  bladder,  cannot  effect  the  excretion  of  the  urine,  it 
is  because  that  reservoir  is  not  favourably  situate  as  regards  the 
muscle  ;  and,  lastly,  the  arguments  deduced  from  birds,  that  they  are 
capable  of  vomiting,  although  they  have  no  diaphragm,  is  equally 
insufficient,  for  it  is  not  absolutely  necessary  that  it  should  be  a  dia- 
phragm, but  any  muscle  that  can  compress  the  stomach. 

When  the  Memoir  of  M,  Maingault  was  presented  to  the  society  of 
the  Faculle  de  Mklecine^  M.  Legallois  and  Professor  Bdclard  were 
named  reporters.  The  experiments  were  repeated  before  them  by  M. 
Maingault ;  but,  instead  of  appearing  contradictory  to  those  of  Ma- 

'  Nouveaux  Elemens  de  Phjsiologie,  7eme  edit.,  Paris,  1817. 


\ 

VOMITING.  205 

gendie,  these  gentlemen  declared,  that  they  were  not  sufficiently  mul- 
tiplied, nor  sufficiently  various,  to  lead  to  any  positive  conclusion. 
MM,  Legallois  and  Beclard  subsequently  repeated  and  varied  them ; 
and  instituted  others,  from  which  they  deduced  corollaries,  entirely 
conformable  to  those  of  M.  Magendie  ;^  and  lastly,  M.  Begin^  boldly 
affirms,  "  without  fear  of  being  contradicted  by  facts,  that  there  is  no 
direct  or  authentic  experiment,  that  demonstrates  the  activity  of  the 
stomach  during  vomiting :" — and  he  adds,  "  I  have  repeated  the  greater 
part  of  the  experiments  of  Magendie ;  he  has  performed  all  in  presence 
of  a  great  number  of  spectators,  of  whom  I  was  one ;  and  I  can  say, 
with  the  commissioners  of  the  Academie  des  Sciences,  that  I  have  seen, 
examined,  touched,  and  my  conviction  is  full  and  entire."  Still,  many 
eminent  physiologists  have  adhered  to  the  idea,  that  the  stomach  is 
the  main  agent  in  vomiting ;  and  among  these  was  M.  Broussais.^  He 
manifestly,  however,  confounded  the  phenomena  of  regurgitation  with 
those  of  vomiting;  which,  we  have  endeavoured  to  show,  are  distinct. 

A  case  of  wound  of  the  left  hypochondrium  with  escape  of  the  sto- 
mach was  described  to  the  Academie  Royale  de  Medecine,  by  M.  Lepine, 
and  reported  upon  by  MM.  Lagneau,  Gimelle,  and  Bcrard,^  which 
confirms  the  views  adopted  by  M.  Magendie.  During  the  whole  of 
the  period,  that  the  stomach  remained  out  of  the  abdominal  cavity, 
there  was  no  apparent  contraction  of  the  muscular  fibres  of  the  organ, 
and  none  of  its  contents  were  expelled,  although  the  patient  made 
violent  efforts  to  vomit.  As  soon,  however,  as  the  stomach  had  been 
returned  into  the  abdomen,  the  efforts  were  followed  by  the  expulsion 
of  its  contents.  M.  Lepine  confirms  the  observations  of  Magendie  in 
another  point.  After  each  act  of  vomiting,  the  patient  appeared  to 
swallow  air.  "I  observed  him,"  says  M.  Lupine,  "execute  repeated 
acts  of  deglutition,  each  of  which  was  accompanied  by  a  noise,  that 
seemed  to  be  owing  to  the  passing  back  of  air."* 

On  the  whole,  we  are,  perhaps,  justified  in  concluding,  that  the  an- 
cient doctrine  regarding  vomiting  is  full  of  error,  and  ought  to  be 
discarded;  that  the  inverted  action  of  the  stomach,  although  not  ener- 
getic, is  necessary, — that  the  pressure,  exerted  on  the  parietes  of  the 
stomach  by  the  diaphragm  and  abdominal  muscles,  is  a  powerful  cause, 
— and  that  the  more  or  less  complete  paralysis  of  the  diaphragm,  or 
destruction  of  the  abdominal  muscles,  renders  vomiting  more  feeble 
and  more  slow  in  manifesting  itself.  The  deep  inspiration  preceding 
the  act  of  vomiting,  is  terminated  by  the  closure  of  the  glottis:  after 
this  the  diaphragm  cannot  move  without  expanding  or  compressing  the 

'  Bulletin  de  la  Faculte  et  de  la  Societe  de  Med.,  1813,  No.  s,,  and  (Euvres  de  Le- 
gallois, Paris,  1824. 

*  Traite  de  Therapeiitique,  Paris,  1825. 

^  Traite  de  Physiologie,  etc,  translated  by  Drs,  Bell  and  La  Roche,  p.  345,  Philad., 
1832. 

*  Bulletin  de  I'Academie  Royale  de  Medecine,  1844.  See  cases  cited  in  Pliilad. 
Med.  Examiner,  April  20,  1844,  p,  92;  also  a  case  of  Wound  of  Abdomen,  in  Amer. 
Journ.  of  the  Med.  Sciences,  Oct.  1846,  p.  379. 

*  The  case  described  by  Lepine  has,  a.s  properly  remarked  by  Dr.  Brinton,  (Cyclop, 
of  Anat.  and  Physiology,  art.  Stomach  and  Intestines,  Pt.  40,  p,  317,  Lond.,  1855,) 
"been  strangely  misquoted  by  many  English  authors."  See  Kirkos  and  Paget, 
Manual  of  Physiology,  2d  Amer.  edit.,  p,  180,  Philad.,  1853;  and  Carpenter,  Principles 
of  Human  Physiology,  Amer.  edit.,  p.  96,  Philad,,  1855. 


206  ABSORPTION. 

air  in  the  lungs.  It,  consequently,  presents  a  resisting  surface,  against 
which  the  stomach  may  be  pressed  by  the  contracting  abdominal  mus- 
cles. The  order  of  the  phenomena  seems  to  be  as  follows.  The  brain 
is  affected  directly  or  indirectly  by  the  cause  exciting  vomiting ; — 
through  the  brain  and  medulla,  the  glottis  is  closed,  and  the  diaphragm 
and  abdominal  muscles  are  thrown  into  appropriate  contraction,  and 
press  upon  the  stomach ;  this  organ  probably  contracts  from  the 
pylorus  towards  the  cardia ;  and,  by  the  combination  of  efforts,  the 
contents  are  propelled  into  the  oesophagus,  and  out  of  the  mouth. 
These  efforts  are  repeated  several  times  in  succession,  and  then  cease, 
— to  reappear  at  times.  Whilst  the  rejected  matters  pass  through  the 
pharjmx  and  mouth,  the  glottis  closes;  the  velum  palati  rises  and  be- 
comes horizontal  as  in  deglutition ;  but  owing  to  the  convulsive  action 
of  the  parts,  these  apertures  are  less  accurately  closed,  and  more  or 
less  of  the  vomited  matter  passes  into  the  larynx  or  nasal  fossae.  On 
account  of  the  suspension  of  respiration  impeding  the  return  of  blood 
from  the  upper  parts  of  the  body,  and  partly  owing  to  the  force  with 
which  the  blood  is  sent  through  the  arteries,  the  face  is  flushed,  or 
livid,  the  perspiration  flows  in  abundance,  and  the  secretion  of  tears  is 
largely  augmented. 


CHAPTER  11. 

ABSORPTION. 

In  the  consideration  of  the  preceding  functions,  we  have  seen  the 
alimentary  matter  subjected  to  various  actions  and  alterations;  and  at 
length,  in  the  small  intestine,  possessed  of  the  necessary  physical  con- 
stitution for  the  chyle  to  be  separated  from  it.  Into  the  mode  in  which 
this  separation, — which  we  shall  find  is  not  simply  a  secerning  action, 
but  one  of  vital  elaboration, — is  effected,  we  have  now  to  inquire.  It 
constitutes  the  function  of  absorption,  and  its  object  is  to  convey  the 
nutritive  fluid,  formed  from  the  food,  into  the  current  of  the  circula- 
tion. Absorption  is  not,  however,  confined  to  the  formation  of  this 
fluid.  Liquids  can  pass  into  the  blood  directly  through  the  coats  of 
the  containing  vessel,  without  having  been  subjected  to  any  elabora- 
tion ;  and  the  different  constituents  of  the  organs  are  constantly  sub- 
jected to  the  absorbing  action  of  cells,  by  which  their  decomposition  is 
effected,  and  their  elements  conveyed  into  the  blood;  whilst  antago- 
nizing cells  elaborate  from  the  blood,  and  deposit  fresh  particles  in  the 
place  of  those  that  have  been  removed.  These  various  substances, 
— bone,  muscle,  hair,  nail,  as  the  case  may  be, — are  never  found,  in 
their  compound  state,  in  the  blood;  and  the  inference,  consequently,  is 
that  at  the  very  radicles  of  the  absorbents  and  exhalants,  the  substance 
on  which  absorption  or  exhalation  has  to  be  effected,  is  reduced  to  its 
constituents,  and  this  by  an  action,  to  which  we  know  nothing  similar 
in  physics  or  chemistry ;  hence,  it  has  been  inferred,  that  the  opei-ation 
is  one  of  the  acts  of  vitality. 

All  the  various  absorptions  may  be  classed  under  two  heads: — the 
external  and   the  internal ;  the  former  including  those  that  take  place 


CHYLIFEROUS   APPARATUS.  207 

on  extraneous  matters  from  the  surface  of  the  body  or  its  prolongation 
— the  mucous  membranes;  and  tlie  latter,  those  that  are  effected  inter- 
nally, on  matters  proceeding  from  the  body  itself,  by  the  removal  of 
parts  already  deposited.  By  some  physiologists,  the  action  of  the  air 
in  respiration  has  been  referred  to  the  former  of  these ;  and  the  whole 
function  of  absorption  has  been  defined; — the  aggregate  of  actions,  by 
which  nutritive  substances— external  and  internal — are  converted  into 
fluids,  which  serve  as  the  basis  of  arterial  blood.  The  function  of  respi- 
ration will  be  investigated  separately.  Our  attention  will,  at  present, 
be  directed  to  the  other  varieties;  and,  first  of  all  to  that  which  occurs 
in  the  digestive  tube. 

I.  DIGESTIVE  ABSORPTION. 

The  absorption,  effected  in  the  organs  of  digestion,  is  of  two  kinds ; 
according  as  it  concerns  liquids  of  a  certain  degree  of  tenuity,  or  solids. 
The  former,  it  has  been  remarked,  are  subjected  to  no  digestive  action, 
but  disappear  chiefly  from  the  stomach,  and  in  part  from  the  small 
intestine.  The  latter  undergo  conversion,  before  they  are  fitted  to  be 
taken  up  from  the  intestinal  canal. 

a.  Absorption  of  Chyle  or  Chyhsis. 

1.    ANATOMY  OF  THE  CHYLIFEKOUS  APPARATUS. 

In  the  lower  animals,  absorption  is  effected  over  the  whole  surface  of 
the  body,  both  as  regards  the  materials  necessary  for  nutrition  and  the 
supply  of  air.  No  distinct  organs  for  the  performance  of  these  functions 
are  perceptible.  In 

the  upper  classes  Fig-  54. 

of  animals,  how-  ^~J^~"^ 
ever,  we  find  an 
apparatus,  mani- 
festly intended  for 
the  absorption  of 
chyle,  and  con- 
stituting a  vas- 
cular communica- 
tion between  the 
small  intestine  and 
left  subclavian. 
Along  this  chan- 
nel, the  chyle 
passes,  to  be  emp- 
tied into  that  ve- 
nous trunk. 

The    chyliferOUS  Chyliferous  Vessels.  . 

apparatus  consists 

of  chyliferous  vessels,  mesenteric  glands,  and  thoracic  duct.  The  chy- 
liferous vessels  or  lacteals  arise  from  the  inner  surface  of  the  small  intes- 
tine ; — in  the  villi,  which  are  at  the  surface  of,  and  between,  the  valvulee 
conniventes.     Prof.  E.  H.  Weber'  has,  however,  seen  them  distributed 

'  Miiller's  Archiv.,  u.  s.  w.,  s.  400,  Berlin,  1847. 


208  ABSORPTION". 

in  tlie  interspaces  between  the  villi ;  the  lacteals  and  bloodvessels  form- 
ing a  close  network;  but  he  could  not  detect  them  in  the  parietes  of 
the  follicles  of  Lieberkuhn.  Their  origin  is  almost  imperceptible;  and, 
accordingly,  the  nature  of  their  arrangement  has  given  occasion  to 
much  diversity  of  sentiment  amongst  anatomists.  Lieberkiihn^  affirms, 
that,  by  the  microscope,  it  may  be  shown  that  each  villus  terminates 
in  an  ampullula  or  oval  vesicle,  which  has  its  apex  perforated  by 
lateral  orifices,  through  which  the  chyle  enters ;  and  Bruch^  affirms, 
that  there  is  a  ceecal  ampulla  or  excavation  in  the  tissue  at  the  extre- 
mity of  each  villus,  in  which  its  lacteal  commences ;  but  he  does  not 
regard  the  ampulla  as  perforated. 

The  doctrine  of  open  mouths  of  lacteals  and  Ij^mphatics  was  embraced 
by  Hewson,^  Sheldon,"*  Cruikshank,^  Hedwig,*  and  Bleuland,^  and  by 
some  of  the  anatomists  and  ]3hysiologists  of  the  present  day ;'  but,  on 
the  other  hand,  it  has  been  contested  by  Mascagni,'  and  others ;  whilst 
Eudolphi,^°  Meckel,'^  and  numerous  others'^  believed,  that  the  lacteals 
have  not  free  orifices;  but  that  in  the  villi,  in  which  absorption  is 
effected,  a  spongy  or  sort  of  gelatinous  tissue  exists,  which  accomplishes 
absorption,  and,  being  continuous  with  the  mouths  of  chyliferous  ves- 
sels, conveys  the  product  of  absorption  into  them,  a  view  not  unlike 
that  of  Professor  Briicke  to  be  mentioned  presently.  Bich at  conceived 
them  to  commence  by  a  kind  of  sucker  or  absorbing  mouth,  the  action 
of  which  he  compared  to  that  of  the  puncta  lachrymalia  or  of  a  leech 
or  cupping-glass ;  and  lastly, — from  the  observation,  often  made,  that 
different  coloured  fluids,  with  which  the  lymphatics  have  been  injected, 
have  never  spread  themselves,  either  into  the  areolar  tissue,  or  the 
parenchyma  of  the  viscera, — M.  Mojon,^-'  of  Genoa,  affirmed,  that  lym- 
phatics have  no  patulous  orifice,  and  that  they  take  their  origin  from 
a  cellular  filament,  which  progressively  becomes  a  villosity,  an  areolar 
spongiole,  a  capillary,  and,  at  length,  a  Ijnnphatic  trunk  ; — the  absorbent 
action  of  these  vessels  being  a  kind  of  imbibition.  Professor  Miiller''' 
affirms,  that  he  has  never  perceived  any  opening  at  the  extremity  of 
the  villi  :  in  his  earlier  examinations,  he  was  unable  to  see  appearances 
of  foramina  on  any  part  of  their  surface ;  but  he  has  observed,  in  por- 
tions of  the  intestines  of  the  sheep  and  the  ox,  which  had  been  exposed 
for  some  time  to  the  action  of  water,  that  over  the  whole  surface  of 

'  Dissert,  de  Fabric.  Villor.  Intest.  (passim.)  Lugd.,  Bat.,  1745. 

*  Siebold  and  KiiUikcr's  Zeitschrift,  April,  1853. 

'  Experimental  Inquiries  ;  edited  by  Falconer,  Lond.,  1774,  1777,  and  1780,  or  Hew- 
son's  Works,  Sydenham  Society's  edit.,  p.  181,  Lond.,  184(3. 

*  Tlie  History  of  the  Absorbent  System,  &c.,  p.  1,  Lond.,  1784. 
^  Anatomy  of  the  Absorbing  Vessels,  2d  edit.,  Loud.,  1790. 

*  Disquisit.  AmpuU.  Lieberkiihnii,  Lips.  1797. 

"  Exper.  Auatom.,  1784;  aud  Descript.  Vasculor.  in  Intestinor.  Teuuium  Tunicis, 
Ultraj.,  1797. 

*  See  Ileule,  Allgemeine  Anatomic,  u.  s.  w.  s.  5(59,  Leipz.,  1841. 

^  Vasorum  Lymphaticorum  Corporis  Humani  Historia,  &c.,  Senis,  1787  ;  and  Pro- 
dromo  d'un  Opera  sul  Sistemo  de  Vase  Linfatice,  Siena,  1784. 

'"  Anatomisch.  Physiologisch.  Abhandluug.,  Berlin,  1802. 

"  Handbuch,  u.  s.  w.  translated  by  Jourdan  and  Breschet,  p.  179,  Paris,  1805. 

'^  F.  Arnold,  Lehrbuch  der  Plivsioloifie  des  Menschen,  Zurich,  1836-7 ;  noticed  in 
Brit,  and  For.  Med.  Rev.,  Oct.,  1839,  p.  479. 

"  Journal  de  la  Societe  des  Sciences  Physiques,  &c.,  Nov.,  1833. 

"  Handbuch  der  Physiologie,  u.  s.  w.,  and  Baly's  translation,  p.  269,  Lmd.,  1838. 


CHYLIFEEOUS   APPARATUS. 


209 


the  villi  indistinct  depressions  were  scattered,  which  might  be  regarded 
as  oblique  openings.  He  adds,  however,  that  he  makes  this  observa- 
tion with  great  hesitation  and  distrust. 

Fig.  55. 


Chyliferous  Apparatus. 

A,  A.  A  portion  of  the  jejnnnm.  h,h,h,h.  Superficial  lacfpals.  c,  c,  c.  Mesentery,  d,  d,  d.  First  row 
of  mesenteric  glands.  e,e,e.  Second  row.  /,/.  Keceptaculum  chyli.  g.  Thoracic  duct.  h.  Aorta,  t,  t. 
Lymphatics. 

In  conversation  with  the  author,  in  July,  1854,  he  expressed  the 
same  views  in  regard  to  the  closed  condition  of  the  villi,  and  his  con- 
sequent dissent  to  those  promulged  by  Professor  Briicke,'  of  Vienna, 
who  affirms,  that  the  epithelial  cells  covering  the  villi  are  open  towards 
the  intestine ;  the  apertures  being  covered  with  a  mucous  {scldeimig) 
substance ;  and  at  the  opposite  surface  they  open  into  the  lacteals,  which 
he  regards,  at  their  commencement,  as  mere  cavities  in  the  centre  of  the 
villus  without  any  distinct  walls,  the  true  lacteals  originating  from  these 
spaces  in  the  substance  of  the  villi.     Prof.  Briicke's  views  are  also  con- 


'  Ueber  die  Cliylusgefiisse  uud  die  Resorption  des  Clijlus,  Wieii,  1853. 
VOL.  I. — 14 


210 


ABSORPTION. 


tested  by  Kcilliker,  Bruch,  Henle/  and  others;  and  if  we  admit,  with 
him,  that  such  an  arrangement  might  enable  us  to  explain  more  readily 
how  fatty  and  insoluble  substances  pass  into  the  circulation ;  the  dif- 
ficulty which  applies  to  every  doctrine  of  the  open  mouths  of  the  chy- 
liferous  vessels,  as  to  the  mode  in  which  chylosis  is  accomplished,  would 
still  remain.  As  hereafter  remarked,  instead  of  any  act  of  elaboration 
being  executed,  the  chyle  would  necessarily  have  to  be  formed  in  the 
alimentary  canal.  Professor  Briicke,  it  is  true,  states,  that  as  the  chjde 
in  the  villi  surrounds  the  bloodvessels,  an  interchange  of  some  of  the 
elements  takes  place;  the  blood  gives  fibrin  to  the  chyle;  and  the  chyle 
a  portion  of  its  soluble  materials  to  the  blood.^ 

It  has  been  elsewhere  remarked  (page  85),  that  numerous  muscular 
fibre-cells  have  been  observed  in  the  villi, — an  arrangement  which 
accounts  anatomically  for  the  movement  observed  in  them  by  difierent 
histologists. 

The  marginal  illustration.  Fig.  57,  from  Krause,  exhibits  the  appear- 
ance presented  by  the  incipient  chyliferous  vessels  in  the  villi  of  the 
jejunum  of  a  young  man,  who  had  been  hanged  soon  after  taking  a  full 

meal  of  farinaceous  food.    The 
Fig-  57.  chyliferous  vessel  issuing  from 

each  villus  appeared  to  arise 
by  several  small  branches,  in 
some  of  which  free  extremities 
could  be  traced,  whilst  others 
anastomosed  with  each  other. 
The  arrangement  of  the  differ- 
ent anatomical  constituents  i? 
well  seen  in  Fig.  56,  which  re- 
presents an  injected  intestinal 
villus  of  a  cat,  which  was  killed 
during  digestion.  When  they 
become  perceptible  to  the  eye, 
they  are  observed  as  in  Fig. 
54,  communicating  frequently 
with  each  other;  and  forming  a 
minute  network,  first  between 
the  muscular  and  mucous  mem- 
branes, and  afterwards  between 
the  muscular  and  peritoneal,  until  they  terminate  in  larger  trunks,  a,  a, 
a,  a.  When  they  attain  the  point  at  which  the  peritoneal  coat  quits 
the  intestine,  they  also  leave  it;  creep  for  an  inch  or  two  in  the  sub- 
stance of  the  mesentery ;  and  enter  a  first  row  of  mesenteric  glands. 
From  these  they  issue,  of  a  greater  size  and  in  less  number ;  proceed 
still  farther  along  the  mesentery,  and  reach  a  second  row,  into  which 
they  enter.  From  these,  again,  they  issue,  larger  and  less  numerous; 
anastomosing  with  each  other;  and  proceeding  towards  the  lumbar 
portion  of  the  spine,  where  they  terminate  in  a  common  reservoir, — 

'  Canstatt's  Jahresliericlit,  1853,  Ister  Band.  s.  24,  Wiirzburg,  1854. 
2  For  an  abstract  of  Prof.  Briicke's  views,  see  a  note  by  Dr.  I)a  Costa,  in  his  Amer. 
edit,  of  KoUiker's  Manual  of  Unman  Histology,  p.  510,  Pliilad.,  1S54. 


Section  of  Intestinal 
Villus. 

a.  Artery,  b.  Vein.  c. 
Lymphatic.  —  Maguifiod 
aX)  diameters. 


Intestinal  Villus  with  the 
ccMnmenceuient  of  a 
Lacteal. 


CHYLIFEROUS   APPARATUS. 


211 


the  reservoir  of  Pecquet,  receptaculura  seu  cisterna  chyli  (Figs.  55  and 
60)  —which  is  the  commencemeut  of  the  thoracic  duct.    This  reservoir 

Fig.  58.  , 


Fig.  59. 


Extremity  of  Intestinal  Villus. 

A.  During  absorption,   showing  absorbent  cells  and  lacteal  trunks,  distended  with  chyle.     B.  During 
interval  of  digestion,  showing  the  supposed  peripheral  network  of  lacteals. 

is  situate  about  the  third  lumbar  vertebra;  behind  the  right  pillar  of 
the  diaphragm,  and  the  right  renal  vessels.  The  chyliferous  vessels 
generally  follow  the  course  of  the  arteries; 
but  sometimes  proceed  in  the  spaces  between 
them.  They  exist  in  the  lower  part  of  the 
duodenum,  throughout  the  whole  of  the  jeju- 
num, and  in  the  upper  part  of  the  ileum.  M. 
Yoisin^  affirms,  that  all,  or  at  least  the  major 
part,  of  them  pass  through  the  substance  of 
the  liver,  before  they  empty  their  contents  into 
the  thoracic  duct.  After  proceeding  a  certain 
distance,  they  anastomose,  he  says,  with  each 
other,  enlarge  in  size,  and  are  collected  to- 
gether so  as  to  form  a  kind  of  plexus  below 
the  lobe  of  Spigelius,  towards  which  they  con- 
verge. From  this  point,  they  penetrate  the 
substance  of  the  liver,  through  which  they 
ramify  with  great  minuteness,  and  finally 
empty  themselves  into  the  receptaculum  chyli. 
To  prove,  that  the  chyliferous  vessels  do  pass 
through  the  liver,  he  put  a  ligature  around 
the  duct  below  the  diaphragm,  in  a  dog  which 
had  eaten  largely,  and  when  digestion  was  in 
full  activity.  The  chyliferous  vessels  were 
observed  to  swell,  and  their  whitish  colour  was 
distinctly  perceived.  They  could  be  traced, 
without  much  difficulty,  from  the  interior  of  the  intestinal  canal,  through 
the  mesenteric  glands,  as  far  as  their  entrance  into  the  liver. 

The  chyliferous  vessels  are  composed  of  two  coats;  the  outer  of  a 
fibrous  and  firm  character,  into  whose  composition  muscular  fibre-cells 
have  been  found,  by  Ktilliker,  to  enter  largely;  the  inner  very  thin,  epi- 
thelial, and  generally  considered  to  form,  by  its  duplicatures,  valves. 
These  are  of  a  semilunar  form,  arranged  in  pairs,  and  with  the  convex 
side  towards  the  intestine.  Their  arrangement  has  appeared  to  be  well 
adapted  for  permitting  the  chyle  to  flow  from  the  intestine  to  the  tho- 


Extremity  of  an  Intestinal  Vil- 
lus during  absorption. 

a.  Marginal  layer  of  opithelinm- 
cells,  b.  Epitholium-colls  turgid 
with  oleaginous  matter,  c.  Adher- 
ent oil-globules. 


'  Nouvel  Apei\u  sur  la  Physiologie  du  Foie,  &c.,  Paris,  1833. 


212  ABSOEPTION. 

racic  duct,  and  for  preventing  its  retrograde  course;  but  M.  Magendie* 
affirms,  that  their  existence  is  by  no  means  constant.  These  reputed 
valves  are  considered  by  M.  Mojon^  to  be  true  sphincters.  By  phicing 
the  lymphatic  vessels  on  a  glass  plate,  and  opening  them  through  their 
entire  length,  he  observed  by  the  microscope,  that  they  are  formed  of 
circular  fibres,  which,  by  diminishing  the  size  of  the  vessel  at  different 
points,  give  rise  to  the  nodosities  observed  externally.  If  the  ends  of 
a  varicose  lymphatic  be  drawn  in  a  contrary  direction,  these  nodosities 
disappear,  as  well  as  the  supposititious  valves.  Mojon  observed,  more- 
over, that  the  fibrous  membrane  of  the  lymphatics  has  longitudinal,  as 
well  as  oblique,  filaments  passing  from  one  narrow  portion  to  another. 
The  longitudinal  fibres  have  their  two  extremities  attached  to  the  trans- 
verse fibres,  which,  according  to  him,  constitute  the  sphincters  or  con- 
tractors of  the  lymphatics.  He  explains  the  difficulty  often  experienced 
in  attempting  to  inject  the  lymphatic  vessels  in  a  direction  contrary  to 
the  course  of  the  lymph,  by  the  circumstance,  that  the  little  pouches 
formed  by  the  sphincters,  and  the  relaxation  or  distension  of  their  pa- 
rietes  on  filling  them  with  injected  matter,  diminish  the  calibre  of  the 
tube,  and  can  even  close  it  entirely.  The  smallest  lacteals  appear  to 
be  destitute  of  valves;  but  valves  are  perceptible  in  those  of  less  than, 
one-third  of  a  line  in  diameter,  and  they  have  the  same  structure  as 
those  of  the  veins.  The  minute  lacteals  in  the  villi  are  said  to  consist 
of  a  single  membrane  with  elongated  cell-nuclei,  corresponding  to  the 
longitudinal  fibrous  membrane  of  the  veins,  but  not  lined  by  epithe- 
lium. Some  anatomists  describe  an  external  coat,  formed  of  condensed 
areolar  tissue,  which  unites  the  chjdiferous  vessels  to  the  neighbouring 
parts. 

The  mesenteric  glands  or  ganglions  are  small,  irregularly  lenticular 
organs;  varying  in  size  from  the  sixth  of  an  inch  to  an  inch;  nearly 
one  hundred  in  number,  and  situate  between  the  two  laminae  of  the 
mesentery.  Tn  them,  the  lymphatic  vessels  of  the  abdomen  terminate; 
and  the  chyliferous  vessels  traverse  them  in  their  course  from  the  in- 
testine to  the  thoracic  duct.  Their  substance  is  of  a  pale  rosy  colour ; 
and  their  consistence  moderate.  By  pressure,  a  transparent  and  in- 
odorous fluid  can  be  forced  from  them;  which  has  never  been  examined 
chemically.  Anatomists  differ  with  regard  to  their  structure.  Accord- 
ing to  some,  they  consist  of  a  pellet  of  chyliferous  vessels,  folded  a 
thousand  times  upon  each  other;  subdividing  and  anastomosing  almost 
ad  infinitum;  united  by  areolar  tissue,  and  receiving  a  number  of  blood- 
vessels. In  the  opinion  of  others,  again,  cells  exist  in  their  interior, 
into  which  the  afferent  ch3diferous  vessels  open;  and  whence  the  efferent 
set  out.  These  are  filled  with  a  milky  fluid,  carried  thither  by  the  lac- 
teals or  exhaled  by  the  bloodvessels.  Notwithstanding  the  labours  of 
Nuck,^  Hewson,  Abernethy,  Mascagni,  Cruikshank,  Haller,'*  Beclard,* 
and  other  distinguished  anatomists,  the  texture  pf  these,  as  well  as  of 
the  lymphatic  glands  or  ganglions  in  general,  is  not  demonstrated.   The 

'  Precis  Eltmentaire,  2de  edit.,  ii.  177,  Paris,  1825. 

*  Op.  citat.  and  Amer.  Journal,  &c.,  for  Aug.  1834,  p.  465. 

*  Adenologia,  Lugd.  Bat.,  llJt»ti. 

*  Element.  Physiol.,  lib.  ii.  §3,  Lansan.,  1757. 

*  Addit.  a  Biciiat,  p.  128,  Paris,  1821. 


CHYLIFEROUS   APPARATUS. 


213 


chvliferous  and  sanguiferous  vessels  become 
extremely  minute  in  their  substance;  and  the 
communication  between  the  afferent  and  effe- 
rent vessels  is  very  easy ;  as  mercurial  injec- 
tions pass  readily  from  the  one  to  the  other. 
According  to  Mr.  Goodsir,  the  absorbent  ves- 
sels within  the  chyliferous  and  lymphatic 
glands  lay  aside  all  but  their  internal  coat; 
and  the  epithelium,  instead  of  forming  a  thin 
lining  of  flat  transparent  scales,  as  in  the  ex- 
tra-glandular lymphatics,  acquires  an  opaque 
granular  aspect,  and  is  converted  into  a  thick 
irregular  layer  of  spherical  nucleated  cor- 
puscles, measuring  on  an  average  5  o'o  o^-^  P^^^ 
of  an  inch  in  diameter,  so  as  to  suggest  the 
idea  of  lymph  or  chyle  corpuscles  generated 
on  the  internal  membrane  after  the  ordinary 
manner  of  epithelium  cells,  and  about  to  be 
thrown  off  into  the  vessel.  This  layer,  accord- 
ing to  Mr,  Goodsir,  is  thickest  in  those  lymph- 
atics that  are  situated  towards  the  centre  of 

Fig.  61. 


Diagram  of  a  lymphatic  gland,  showing  the  intra-glandiilar  net- 
Work,  and  the  transition  from  the  scale-like  epithelia  of  the  extra- 
glandular  lymphatics,  to  the  nucleated  cells  of  the  iutra-glandular. 

the  gland,  becomes  gradually  thinner  towards 
the  afferent  and  efferent  vessels,  and  passes 
continually  into  the  ordinary  epithelium. 

Fig.  62. 


Portion  of  the  intra-glandular  lymphatic,  showing  along  the  lower 
edge  the  thickness  of  tlie  germinal  memhraue,  and  upon  it  the  thick 
layer  of  glandular  epithelial  cells. 

More  recently,  the  morphology  of  these 
glands  has  been  investigated  by  Prof.  Briicke 
and  Prof.  Kolliker,'  who  state  that  each  gland 


Thoracic  Duct. 

1.  Arch  of  aorta.  2.  Thoracic 
aorta.  3.  Abdominal  aorta,  show- 
ing its  principal  branches  divided 
near  their  origin.  4.  Arteria  iuuo- 
minata,  divided  into  right  carotid 
and  right  subclavian  arteries.  5. 
Left  carotid.  6.  Left  subclavian.  7. 
Superior  cava,  formed  by  the  union 
of  8,  the  two  venjB  innominat<e  ;  and 
these  by  the  junction  9  of  internal 
jugular  and  subclavian  vein  at  each, 
side.  10.  Greater  vena  azygos.  11. 
Termination  of  the  lesser  in  greater 
vena  azygos.  12.  Heceptaculum 
chyli  ;  several  lymphatic  trunks 
are  seen  opeuing  into  it.  1.'?.  Tho- 
racic duct,  dividing  opposite  middle 
of  dor.sal  vertebrre  into  two  branch- 
es, which  soon  reunite ;  course  of 
duct  behind  arch  of  aorta  and  left 
subclavian  artery  is  shown  by  a 
dotted  line.  14.  The  duct  making 
it.s  turn  at  root  of  tho  neck  and  re- 
ceiving several  lymphatic  trunks 
previously  to  terminating  in  poste- 
rior aspect  of  junction  of  internal 
jugular  aud  subclavian  vein.  lo. 
Termination  of  trunk  of  ductu.s 
lymphaticus  dexter. 


is  enclosed  in  a  fibrous 


'  Mikroskopisclie  Anatomie,  2ter  Band,  S.  528,  Leipzig,  1854;   or  Amer.  edit,  of  Dr. 
Day's  translation  of  liis  Human  Histology,  by  Dr.  Da  Costa,  p.  695,  Pliilad.,  1^54. 


21-i 


ABSORPTIO]Sr. 


slieatli  or  capsule,  c-liicli  sends  iiiAvards  a  number  of  thin  laraellne,  so 
as  to  constitute  a  tolerably  regular  areolated  tissue  in  the  whole  gland. 
The  alveoli,  thus  formed,  are  filled  with  a  grayish-white  pulp,  which 
agrees,  in  all  its  characters,  with  that  in  the  glands  of  Peyer,  and  is 
penetrated,  like  the  latter,  by  a  fine  vascular  plexus.     The  afierent 

Fig.  63. 


(i         ■-  d 

Section  of  Lymphatic  Gland. 

a,  a.  The  fibrous  tissue  which  forms  its  exterior,  h, 
h.  Superficial  vasa  inferentia.  c,  c.  Larger  alveoli  near 
the  surface,  d,  d.  Smaller  alveoli  of  the  interior,  e,  e. 
Fibrous  walls  of  the  alveoli. 


Section  of  one  of  the  Alveoli  of  a  Lymph- 
atic Gland. 

a,  a.  Its  fibrous  envelope,  ft,  6.  Prolonga- 
tions from  this,  intersecting  and  subdividing 
the  general  cavity,  c,  c.  Xuclei  of  the  fibre- 
cells,    d.  Separate  fibre-cells. 


and  efferent  chyliferous  vessels  appear  to  communicate  freely  with  these 
alveoli;  and  the  fluid,  brought  to  the  glands  by  the  former,  must  pass 
through  their  pulp  before  entering  the  latter. 

It  was  before  remarked,  that  the  Peyerian  glands  may  be  regarded 
as  belonging  to  the  lacteal  or  lymphatic  system.  They  resemble  greatly 
in  structure  the  mesenteric  glands;  and  a  greater  number  of  chyliferous 
vessels  may  be  traced  from  them  during  digestion  than  from  other  parts 
of  the  intestine.  Brlicke,  too,  found,  that  he  could  fill  them  by  injec- 
tion from  the  absorbents. 

The  thoracic  duct,  g,  Fig.  55,  and  13,  Fig.  60,  is  formed  by  the  junction 
of  the  chyliferous  trunks  with  the  lymphatic  trunks  from  the  lower 
extremities.  The  receptaculum  ch?jli,  already  described,  forms  its  com- 
mencement. After  passing  from  under  the  diaphragm,  the  duct  pro- 
ceeds, in  company  with  the  aorta,  along  the  right  side  of  the  spine, 
until  it  reaches  the  fifth  dorsal  vertebra ;  where  it  crosses  over  to  the 
left  side  behind  the  oesophagus.  It  then  ascends  behind  the  left  carotid 
artery;  runs  up  to  the  interstice  between  the  first  and  second  vertebraa 
of  the  chest;  where,  after  receiving  the  lymphatics,  which  come  from 
the  left  arm  and  left  side  of  the  head  and  neck,  it  suddenly  turns  down- 
wards, and  terminates  at  the  angle  formed  by  the  meeting  of  the  sub- 
clavian and  internal  jugular  vein  of  the  left  side. 

To  observe  the  chyliferous  apparatus  to  the  greatest  advantage,  it 
should  be  examined  in  an  individual  recently  executed,  or  killed  sud- 
denly two  or  three  hours  after  having  eaten;  or  in  an  animal,  destroyed 
for  the  purpose  of  experiment,  under  similar  circumstances.  The  lac- 
teals  are  then  filled  with  ch34e,  and  may  be  readily  recognised,  espe- 
cially if  the  thoracic  duct  has  been  previously  tied.   These  vessels  were 


CHYLE.  215 

unknown  to  the  ancients.  The  honour  of  their  discovery  is  due  to 
Gaspard  Aselli,^  of  Cremona,  who,  in  1622,  at  the  solicitation  of  some 
friends,  undertook  the  dissection  of  a  living  dog,  which  had  just  eaten, 
in  order  to  demonstrate  the  recurrent  nerves.  On  opening  the  abdo- 
men, he  perceived  a  multitude  of  white,  very  delicate  filaments  crossing 
the  mesentery  in  all  directions.  At  first,  he  took  them  to  be  nerves; 
but  having  accidentally  cut  one,  he  saw  a  quantity  of  a  white  liquor 
exude,  analogous  to  cream.  Aselli  also  noticed  the  valves,  but  he  fell 
into  an  important  error  regarding  the  destination  of  the  lacteals;  be- 
lieving them  to  collect  in  the  pancreas,  and  from  thence  proceed  to  the 
liver.  In  1628,  the  human  lacteals  were  discovered.  Gassendi^  had 
no  sooner  heard  of  the  discovery  of  Aselli,  than  he  spoke  of  it  to  his 
friend  Nicholas-Claude-Fab  rice  de  Peiresc,  senator  of  Aix;  who  seems 
to  have  been  a  most  zealous  propagator  of  scientific  knowledge.  He 
immediately  bought  several  copies  of  the  work  of  Aselli,  which  had 
only  appeared  the  year  previously;  and  distributed  them  amongst  his 
professional  friends.  Many  experiments  were  made  upon  animals,  but 
the  great  desire  of  De  Peiresc  was,  that  the  lacteals  should  be  found 
in  the  human  body.  Through  his  interest,  a  malefactor,  condemned  to 
death,  was  given  up,  a  short  time  before  his  execution,  to  the  anato- 
mists of  Aix;  who  made  him  eat  copiously;  and,  an  hour  and  a  half 
after  execution,  opened  the  body,  in  which,  to  the  great  satisfaction  of 
De  Peiresc,  the  vessels  of  Aselli  were  perceived  in  the  clearest  manner. 
Afterwards,  in  163-1,  John  Wesling^  gave  the  first  graphic  representa- 
tion of  them  as  they  exist  in  the  human  body;  and  subsequently  pointed 
oat  more  clearly  than  his  predecessors  the  thoracic  duct  and  lymphatics. 
Prior  to  the  discovery  of  the  chyliferous  and  lymphatic  vessels,  the 
veins,  which  arise  in  immense  numbers  from  the  intestines,  and,  by 
their  union  with  other  veins,  form  the  vena  porta,  were  esteemed  the 
agents  of  absorption;  and,  even  at  the  present  day,  they  are  considered, 
by  some  phj^siologists,  to  participate  with  the  chyliferous  vessels  in  the 
function; — with  what  propriety  we  shall  inquire  hereafter. 

2.    CHYLE. 

The  chyle,  as  it  circulates  in  the  chyliferous  vessels,  has  only  been 
submitted  to  examination  in  comparatively  recent  times.  It  varies  in 
different  parts  of  its  course.  The  best  mode  of  obtaining  it  is  to  feed 
an  animal;  and,  when  digestion  is  in  full  progress,  to  strangle  it,  or 
divide  the  spinal  marrow  beneath  the  occiput.  The  thorax  must  then 
be  opened  through  its  whole  length,  and  a  ligature  be  passed  round 
the  aorta,  oesophagus,  and  thoracic  duct,  as  near  the  neck  as  possible. 
If  the  ribs  of  the  left  side  be  now  turned  back  or  broken,  the  thoracic 
duct  is  observed  lying  against  the  oesophagus.  By  detaching  the  upper 
part,  and  cutting  into  it,  the  chyle  flows  out,  A  small  quantity  only 
is  thus  obtained ;  but,  if  the  intestinal  canal  and  chyliferous  vessels  be 
repeatedly  pressed  upon,  the  flow  may  be  sometimes  kept  up  for  a 
quarter  of  an  hour.     It  is  obviously  impossible,  in  this  way,  to  obtain 

'  De  Lactibus  seu  Lacteis  Venis,  &c.,  Mediol.,  1G27;  also,  in  Collect.  Oper,  Spigelii, 
edit.  Van  der  Linden ;  and  in  Manget.  Tlieatr.  Anatom. 

^  Vita  Peirescii,  in  Op.  omnia,  v.  300.  *  Syntagm,  Anatom.,  viii.  170. 


216  ABSORPTION". 

the  cbj^le  pure;  inasmucli  as  tlie  lymphatics,  from  various  parts  of  the 
body,  are  constantly  pouring  their  fluid  into  the  thoracic  duct. 

From  the  concurrent  testimony  of  various  experimenters,  chyle  is  a 
liquid  of  a  milky-white  appearance ;  limpid  and  transparent  in  herbi- 
vorous animals,  but  opaque  in  the  carnivorous;  neither  viscid  nor  glu- 
tinous to  the  touch ;  of  a  consistence,  varying  somewhat  according  to 
the  nature  of  the  food ;  a  spermatic  smell ;  sweet  taste,  not  dependent 
on  that  of  the  food  ;  neither  acid  nor  alkaline:  and  of  a  specific  gravity 
greater  than  distilled  water,  but  less  than  the  blood.  Magendie,^ 
Tiedemann  and  Gmelin,^  and  Miiller,^  however,  state  it  to  possess  a 
saline  taste ;  to  be  clammy  on  the  tongue ;  and  sensibly  alkaline.  Its 
milky  colour  is  generally  supposed  to  be  owing  to  oily  matter  which 
occurs  in  it  in  the  form  of  globules  of  various  sizes,  from  05^150^^  ^^ 
2o'oo^^  of  ^^  ^^ch  in  diameter,  and  which  are  more  abundant  in  the 
chyle  of  man  and  of  the  carnivora,  than  in  that  of  the  herbivora.  Mr. 
Gulliver^  has,  however,  afl&rmed,  that  the  colour  is  due  to  an  immense 
multitude  of  minute  particles,  which  he  regards  as  forming  the  matrix 
or  molecular  base  of  the  chyle.  These  are  generally  spherical  and 
extremely  small, — their  diameter  being  estimated  at  from  -jg^oo^^  ^^ 
54^0 (jth  of  an  inch.  They  are  of  a  fatty  nature,  and  their  number 
appears  to  be  dependent  upon  the  amount  of  fatty  matter  in  the  food. 
Their  fatty  nature  is  shown  by  their  solubility  in  ether,  and,  when  the 
ether  evaporates,  by  their  forming  dro{)S  of  oil.  As,  however,  they  do 
not  run  together,  it  has  been  suggested,  that  each  molecule  consists  of 
oil  coated  with  albumen,  a  view  which  is  supported  by  the  fact,  that 
when  water  or  dilute  acetic  acid  is  added  to  chyle,  many  of  the  mole- 
cules are  lost  sight  of,  and  oil  drops  appear  in  their  place;  as  if  the 
envelopes  of  the  molecules  had  been  dissolved,  and  their  oily  contents 
had  run  together.^ 

The  chemical  character  of  the  chyle  of  animals  has  been  examined 
by  Emmert,^  Vauquelin,^  Marcet,^  Prout,^  Simon,^°  Nasse,"  and  Las- 
Baigne;'^  and  is  found  to  resemble  greatly  that  of  the  blood.  In  a  few 
minutes  after  its  removal  from  the  thoracic  duct  it  becomes  solid;  and, 
after  a  time,  separates,  like  the  blood,  into  two  parts;  a  coagulum,  and 
a  liquid.  The  coagulum  is  an  opaque  white  substance;  of  a  slightly 
pink  hue;  insoluble  in  water;  but  readily  soluble  in  the  alkalies,  and 
alkaline  carbonates.  M.  Yauquelin  regards  it  as  fibrin  in  an  imper- 
fect state,  or  as  intermediate  between  that  principle  and  albumen ;  but 

'  Precis,  &c.,  ii.  172. 

'^  Die  Verdauung  uach.  Versuchen,  1.  353,  Heidelb.,  1S26  ;  or  French,  translation,  by 
Jourdan,  Paris,  1827. 

3  Elements  of  Physiology,  by  Baly,  p.  258,  London,  1838. 

■*  Gerber's  General  Anatomj',  by  Gulliver,  Appendix,  p.  88,  London,  1842. 

^  Kirkes  and  Paget,  Manual  of  Physiology,  2d  Amer.  edit.,  p.  210,  Philad.,  1853. 

^  Annales  de  Chiuiie,  torn.  Ixxx.  p.  81. 

'  Ibid.,  Ixxx.  113;   and  Annals  of  Philosophy,  ii.  220. 

^  Medico-Chimrg.  Transactions,  vol.  vi.  (jIS,  London,  1815. 

^  Thomson's  Annals  of  Philosophy,  xiii.  121,  and  263. 

'°  Animal  Chemistry,  Sydenham  Soc.  edit.,  p.  354,  Loudon,  1845,  or  Amer.  edit., 
Pbilad.,  1846. 

"  Wagner's  Handworterbuch,  u.  s.  w.,  i.  235,  art.  Chyle ;  and  Simon,  op.  cit. 

''  Journ.  de  Chiraie  Med.,  p.  348,  Paris,  1853;  and  Soberer,  in  Canstatt's  Jaliresbe- 
richt,  1S53,  p.  Ill ;  and  Day,  Brit,  and  Foreign  Med.-Chir.  Eev.,  July,  1555,  p.  217. 


CHYLE. 


217 


M.  Brande'  tTiinks  it  more  closely  allied  to  the  caseons  matter  of  milk 
than  to  fibrin.  The  analyses  of  Drs.  Marcet  and  Prout  agree,  for  the 
most  part,  with  that  of  M.  Vauquelin.  The  existence  of  fibrin  in  it 
can  scarcely  be  doubted. 

Like  blood,  again,  chyle  often  remains  for  a  long  time  in  its  vessels 
without  coagulating,  but  coagulates  rapidly  on  being  removed  from 
them.^ 

Dr.  Prout  has  detailed  the  changes,  which  the  chyle  experiences  in 
its  passage  along  the  chyliferous  apparatus.  In  each  successive  stage, 
its  resemblance  to  blood  was  found  to  be  increased.  Another  point  of 
analogy  with  blood  is  the  fact,  observed  by  Mr.  Bauer,^  and  subse- 
quently by  MM.  Prevost  and  Dumas,"*  and  others,  that  the  chyle, 
when  examined  by  the  microscope,  contains  globules  or  corpuscles ; 
differing  from  those  of  the  blood  in  their  being  of  a  smaller  size,  the 
average  being  ^^^Q^th  of  an  inch,  and  devoid  of  colouring  matter. 


Fig.  64. 


Fig.  65. 


Chyle-Corpuscles  in  various  Phases. 
a,  a.  Stellate  form  occasionally  seen, 
after  escape  of  their  coutents.  b,  b. 
Free  nuclei,  c.  A  nucleus  surrounded 
by  a  few  granules,  d,  e.  Small  cells, 
some  with  distinct  nucleus,  f,  g.  Lar- 
ger cells,  one  with  a  visible  nucleus. 
h.  Similar  cell  after  addition  of  water. 
i.  Similar  cell  after  addition  of  acetic 
acid. 


Fluid  from  a  Mesenteric  Gi.uid  of  a  Ilabbit,  when  white 
Chyle  was  present  in  the  Lacteals. 

a.  Molecular  base.  6,  e,  d,  &c.  Various  organic  corpus- 
cles, b.  Appearance  of  the  majority  of  corpuscles.  The  con- 
tained granules  are  most  numerous  and  coarse  in  the  largest 
ones,  but  almost  entirely  disappear  under  the  action  of  acetic 
acid,  which  thereby  discloses  an  appearance  of  one.  or  two 
nuclei.  The  majority  of  the  corpuscles  are  either  large  or 
small,  and  but  few  of  intermediate  size.  d.  Exhibits  the 
effect  of  acetic  acid  in  rendering  the  corpuscles  more  clear 
and  their  nuclei  more  distinct,  e.  Large  lymph-corpuscle, 
showing  well  the  granulated  border.  /.  Large  corpuscle, 
apparoutly  enclosiug  three  smaller  ones,  each  of  which  has 
the  granulated  character.  This  appearance  of  enclosed  cells 
is  not  common. — Magnified  300  diameters. 

The  nature  and  source  of  these  globules,  as  well  as  of  those  of  the 
lymph  which  resemble  them  in  all  respects,  are  not  determined.  They 
have  been  supposed  to  be  the  nuclei  or  primordial  cells  from  which  all 
the  tissues  originate,^  of  which  there  is  no  sufficient  evidence:  and  to 
be  the  source  of  the  blood-corpuscle,  which — as  hereafter  shown — is 
probably  the  case.  These  corpuscles — it  has  been  generally  con- 
ceived— are  formed  mainly,  if  not  wholly,  in  the  mesenteric  ganglia; 

'  Phil.  Transact,  for  1812.  ^  Bouisson,  Gazette  Medicale  de  Paris,  1844. 

'  Sir  E.  Home,  Lectures  on  Comp.  Anat.,  iii.  25. 

*  llililiotli.  Universelle  de  (ieneve,  p.  221,  Juillet,  1821. 

^  GruUirer,  iu  Gerber's  Anatomy,  p.  83,  note. 


218  ABSORPTIOX. 

and  the  recent  researches  of  Yirchow,  Briicke,  Donders,  and  Kolliker, 
confirm  the  view,  that  the  principal  origin  of  the  cellasforni  elements 
of  the  chyle  are  formed  in  the  lymphatic  glands.  The  last  mentioned 
observer/  with  H.  Miiller,  found  in  all  the  chyliferous  vessels,  pro- 
ceeding from  the  Peyerian  glands,  a  considerable  amount  of  colourless 
cells :  the  chyle,  however,  from  the  other  vessels  of  the  small  intestine, 
not  connected  with  these  glands,  also  contained  cells, — in  general,  how- 
ever, in  smaller  number ;  but  no  cellteform  elements  could  be  detected 
in  the  lymph  proceeding  from  the  much  distended  lymphatic  vessels 
of  the  liver.  Upon  the  supposition,  therefore, — as  Kolliker  remarks — 
that  the  solitary  follicles  of  the  small  and  large  intestine  communi- 
cate with  lymphatic  vessels,  these  facts  would  appear  to  correspond 
with  the  hypothesis,  that  the  lymphatic  glands  and  the  analogous  fol- 
licles of  the  intestines  are  the  only  sites  of  formation  of  lymph  cells. 
On  the  other  hand,  he  invariably  found  in  the  large  lymphatics  of  the 
spermatic  cord  of  the  bull,  close  to  the  epididymis,  in  several  very 
carefully  examined  cases,  a  small  number  of  cells  which  could  not  be 
distinguished  from  lymph  corpuscles ;  and  he,  therefore,  suggests,  whe- 
ther the  epithelial  cells  of  the  smaller  lymphatics  may  not  participate 
in  this  cell-formation  more  than  has  hitherto  been  believed. 

Although  chyle  has  essentially  the  same  constituents,  whatever  may 
be  the  food  taken,  and  separates  equally  into  a  clot  and  serous  por- 
tion, the  character  of  the  aliment  may  have  an  effect  upon  the  relative 
quantity  of  those  constituents,  and  thus  exert  an  influence  on  its  com- 
position. That  it  scarcely  ever  contains  adventitious  substances  will 
be  seen  hereafter;  but  it  is  obvious,  that  if  an  animal  be  fed  on  diet 
contrary  to  its  nature,  the  due  proportion  of  perfect  chyle  may  not  be 
formed;  and  that,  in  the  same  way,  different  alimentary  articles  may 
be  very  differently  adapted  for  its  formation.  MM.  Leuret  and  Las- 
saigne,^  indeed,  affirm,  that  in  their  experiments  they  found  the  chyle, 
differ  more  according  to  the  nature  of  the  food  than  to  the  animal 
species ;  but  that,  contrary  to  their  expectation,  the  quantity  of  fibrin 
in  it  bore  no  relation  to  the  more  or  less  nitrogen ized  character  of  the 
aliment.  They  assign  it,  as  constituents,  fibrin,  albumen,  fatty  matter, 
soda,  chloride  of  sodium,  and  phosphate  of  lime. 

Messrs.  Tiedemann  and  Gmelin  have  communicated  the  following 
data  in  regard  to  the  influence  of  diet  on  the  chyle.  The  experiments 
were  made  on  dogs,  and  the  chyle  was  taken  from  the  thoracic  duct. 
First.  After  taking  cheese,  the  chyle  coagulated  very  slightly.  The 
clot  was  little  more  than  a  pale  red  transparent  film,  and  the  serum 
slightly  milky.  It  contained  water,  950*3 ;  clot,  1-71 :  residue  of 
serum,  48*0.  Secondly.  After  the  use  of  starch,  the  chyle  was  of  a  pale 
yellowish-white  colour,  and  coagulated  rapidly.  It  contained  water 
930-0;  clot  and  residue  of  serum,  70-0.  The  clot  was  of  a  pale  red 
colour.  Thirdly.  After  taking  flesh,  and  bread  and  milk,  it  was  of  a 
reddish-white  colour,  and  coagulated  rapidly,  the  clot  being  of  a  pale 
red  tint,  and  the  serum  very  milk}'.     It  consisted  of  water,  915-3; 

'  Zeitschrift  flir  Wissensch.  Zoolog.  vii.  182;  and  Quarterly  Journal  of  Microscopical 
Science,  July,  1^55,  p.  291. 

*  Reclieiclies  sur  la  Digestion,  Paris,  1825. 


CHYLE.  219 

clot,  2*7 ;  residue  of  serum,  83"8.  Fourtfily.  After  the  use  of  milk  it 
presented  a  milky  appearance,  and  the  clot  was  transparent,  and  of  a 
pale  red  colour.  Fifthly.  After  bread  and  milk,  it  contained  water, 
961'1;  clot  1'9;  residue  of  serum,  37"0.  Sixthly.  After  flesh,  bread, 
and  milk,  when  the  gall  duct  had  been  tied,  it  was  of  a  yellowish  red 
colour;  coagulated  firmly,  separating  into  a  bright  red  clot,  and  tur- 
bid yellow  serum ;  and  contained  water,  933'0 ;  clot,  5*6 ;  residue  of 
serum,  60'9.^ 

The  chief  object  of  Dr.  Marcet's  experiments  was  to  compare  the 
chyle  from  vegetable,  with  that  from  animal  food,  in  the  same  animal. 
The  experiments  made  on  dogs  led  him  to  the  following  results.  The 
specific  gravity  of  the  serous  portion  is  from  l'0i2  to  1*021,  whether 
it  be  formed  from  animal  or  vegetable  diet.  Vegetable  chyle,  when, 
subjected  to  analysis,  furnishes  three  times  more  carbon  than  animal 
chyle.  The  latter  is  highly  disposed  to  become  putrid;  and  this 
change  generally  commences  in  three  or  four  days ;  whilst  vegetable 
chyle  may  be  kept  for  several  weeks,  and  even  months,  without  being 
putrid.^  Putrefaction  attacks  rather  the  coagulum  of  the  chyle  than 
its  serous  portion.  The  chyle  from  animal  food  is  always  milky ;  and, 
if  kept  at  rest,  an  unctuous  matter  separates  from  it,  similar  to  cream, 
which  swims  on  the  surface.  The  coagulum  is  opaque,  and  has  a 
rosy  tint.  On  the  other  hand,  chyle  from  vegetable  food  is  almost 
always  transparent,  or  nearly  so,  like  ordinary  serum.  Its  coagulum 
is  nearly  colourless,  and  resembles  an  oyster ;  and  its  surface  is  not 
covered  with  the  substance  analogous  to  cream.  M.  Magendie,^  too, 
remarks,  that  the  proportion  of  the  three  substances,  into  which  chyle 
separates  when  left  at  rest; — namely,  the  fatty  substance  on  the  sur- 
face, the  clot,  and  the  serum,  varies  greatly  according  to  the  nature  of 
the  food; — that  the  chyle,  proceeding  from  sugar,  for  example,  has 
very  little  fibrin ;  whilst  that  from  flesh  has  more ;  and  that  the  fatty 
matter  is  extremely  abundant  when  the  food  contains  fat  or  oil ;  whilst 
scarcely  any  is  found  if  the  food  contains  no  oleaginous  matter. 

Lastly : — the  attention  of  Dr.  Prout"  has  been  directed  to  the  same 
comparison.  He  found,  on  the  whole,  less  difference  between  the  two 
kinds  of  chyle  than  had  been  noticed  by  Dr.  Marcet.  In  his  experi- 
ments, the  serum  of  chyle  was  rendered  turbid  by  heat,  and  a  few 
flakes  of  albumen  were  deposited;  but,  when  boiled,  after  admixture 
with  acetic  acid,  a  copious  precipitation  ensued.  To  this  substance, 
which  thus  differs  slightly  from  albumen,  Dr.  Prout  gave  the  inex- 
pressive name  of  incipient  albumen.  The  following  is  a  comparative 
analysis,  by  him,  of  the  chyle  of  two  dogs,  one  of  which  was  fed  on 
animal,  and  the  other  on  vegetable  substances.  The  quantity  of  pure 
albumen,  it  will  be  observed,  was  much  less  in  the  latter  case. 

'  Tiedemann  and  Gmelin,  Verdauung  u.  s.  w.,  2  B.  S.  75,  Heidelb.  und  Leipz., 
1827. 

^  M.  Thenard  lias  properly  remarked,  that  the  difference  in  the  time  of  putrefaction 
of  these  two  substances,  appears  very  extraordinary.  It  is,  indeed,  inexplicable. 
Traite  de  Chimie  Elementaire,  &c.,  5eme  edit.,  Paris,  1827. 

3  Op.  citat.,  p.  174. 

■•  Annals  of  Philosophy,  xiii.  22,  and  Bridgewater  Treatise,  Amer.  edit.,  p.  272, 
Philad.,  11534. 


220  ABSORPTION. 

Vegetable  Food.       Animal  Food. 

Water 93-6  89-2 

Fibrin 0-6  0-8 

Incipient  albumen      ......  4-6  4-7 

Albumen,  with  a  red  colouring  matter         .         .  0-4  4-6 

Sugar  of  milk a  trace. 

Oily  matter         .......  a  trace.  a  trace. 

Saline  matters 0-8  0-7 

100-0  100-0 

The  difference  between  the  chyle  from  food  of  such  opposite  cha- 
racter, as  indicated  by  these  experiments,  is  insignificant,  and  indica- 
tive of  the  great  uniformity  in  the  action  of  the  agents  of  absorption. 
Researches  by  Messrs.  Macaire  and  Marcet,'  tend,  indeed,  to  establish 
the  fact,  that  the  chyle  ajid  the  blood  of  herbivorous  and  carni- 
vorous quadrupeds  are  identical  in  their  composition,  in  as  far,  at 
least,  as  regards  their  ultimate  analysis.  They  found  the  same  pro- 
portion of  nitrogen  in  it,  whatever  kind  of  food  the  animal  consumed 
habitually ;  and  this  was  the  case  with  the  blood,  whether  of  the  car- 
nivora  or  herbivora ;  but  it  contained  more  nitrogen  than  the  chyle. 
These  results  are  not  so  singular,  now  that  we  know  that  the  animal 
and  vegetable  compounds  of  protein  are  almost  identical  in  compo- 
sition. 

All  the  investigations  into  the  nature  of  the  chyle  exhibit  the  inac- 
curacy of  the  view  of  Roose,^  that  eh}- le  and  milk  are  identical.^ 

With  regard  to  the  precise  quantity  of  chjde,  formed  after  a  meal, 
we  know  nothing  definite.  When  digestion  is  not  going  on,  there  can 
of  course  be  none  formed  except  from  the  digestion  of  the  secretions 
of  the  digestive  tube  itself;  and,  after  an  abstinence  of  twenty -four 
hours,  the  contents  of  the  thoracic  duct  are  chiefl}-  lymph.  During 
digestion,  the  quantity  formed  will  bear  some  relation  to  the  amount 
of  food  taken,  the  nutritive  qualities  of  the  food,  and  the  digestive  powers 
of  the  individual.  M.  Magendie,'*  from  an  experiment  made  on  a  dog, 
estimated,  that  at  leasi  half  an  ounce  was  conveyed  into  the  mass  of 
blood,  in  that  animal,  in  five  minutes :  and  the  flow  was  kept  up,  but 
much  more  slowly,  as  long  as  the  formation  of  chyle  continued.  In 
experiments  on  a  cat,  Professor  F.  Bidder^  found  the  amount  that  passed 
through  the  thoracic  duct  in  the  twenty-four  hours,  to  be  in  proportion 
to  the  weight  of  the  body  as  1  to  5.34 ;  or  about  that  which — as  else- 
where shown — the  mass  of  blood  has  been  generally  conceived  to  bear 
to  the  weight  of  the  body.  In  dogs,  the  proportion  was  as  1  to  6.66. 
It  is  difficult,  however,  to  establish  an  average  amount  where  so  many 
elements  have  to  enter  into  the  calculation,  and  so  much  variation  must 
occur,  according  to  the  greater  or  less  amount  of  aliment  taken,  and 
numerous  other  circumstances  f  but  that  so  large  a  quantity  passes  as 
is  stated  by  these  observers,  almost  exceeds  belief. 

'  Memoir,  de  la  Societe  de  Physique  et  de  I'Histoire  Naturelle  de  Geneve,  v.  389. 

^  Weber's  Hildebrandt's  Handbuch  der  Anatomie,  i.  102,  Braunschweig,  1830. 
See,  on  the  whole  subject  of  the  chyle,  Lelimann,  Lehrbuch  der  Physiologischen 
Chemie,  ii.  271,  Leipz.,  1850;  or  Amer.  edit,  of  Dr.  Day's  translation,  by  Dr.   Robt. 
E.  Rogers,  ii.  17,  Philad.,  1855.  *  Op.  citat.,  ii.  183. 

*  Miiller's  Archiv.  fiir  Anat.,  s.  46,  Berlin.  1845,  and  Bidder  and  Schmidt,  Die  Ver- 
dauunscssafte  und  der  StoflVechsel,  s.  283,  Mitau  und  Leipz..  1852. 

e  Prof.  Th.  L.  W.  Bischoff,  Miiller's  Archiv.,  IS'o.  (i,  s.  125,  Berlin,  1846. 


CHYLOSIS.  221 


3.    PHYSIOLOGY  OF  CHYLOSIS. 


The  facts  referred  to — regarding  the  anatomical  arrangement  of  the 
chyliferous  radicles  and  mesenteric  glands — will  sufficiently  account 
for  the  obscurity  of  our  views  on  many  points  of  chylosis.  The  diffi- 
culty in  detecting  the  extremities  of  the  chyliferous  radicles  has  been 
the  source  of  different  hypotheses ;  and,  according  as  the  view  of  open 
mouths  or  of  spongy  gehatinous  tissue  has  been  embraced,  the  chyle  has 
been  supposed  to  enter  immediately  into  the  vessels,  or  to  be  received 
through  the  medium  of  this  tissue ;  or,  again,  to  pass  through  the 
parietes  of  the  vessels  by  imbibition.  Let  it  be  borne  in  mind,  how- 
ever, that  the  action  of  absorption  is  seen  only  by  the  "  mind's  eye  ;" 
and  that  chyle  does  not  seem  to  exist  anywhere  but  in  the  chyliferous 
vessels.  In  the  small  intestine,  we  see  a  chymous  mass,  possessing  all 
the  properties  we  have  described,  but  containing  nothing  resembling 
true  chyle ;  whilst,  in  the  smallest  lacteal  that  can  be  detected,  it  always 
possesses  the  same  essential  properties.  Between  this  imperceptible 
portion  of  the  vessel,  then,  and  its  commencement — including  the 
latter — the  elaboration  must  have  been  effected.  MM.  Leuret  and 
Lassaigne,^  indeed,  affirm  that  they  have  detected  chyle  in  the  chymous 
mass  within  the  intestine,  by  the  aid  of  the  microscope.  They  state, 
that  globules  appeared  in  it  similar  to  those  that  are  contained  in  chyle, 
and  that  their  dissemination  amongst  so  many  foreign  matters  alone 
prevents  their  union  in  perceptible  fibrils.  These  globules  they  regard 
as  true  chyle — for  the  reason,  that  they  observed  similar  globules  in 
artificial  digestions;  and,  on  the  other  hand,  never  detected  them  in  the 
digestive  secretions.  In  their  view,  consequently,  chyliferous  absorption 
is  confined  to  the  separation  of  chyle,  ready  formed  in  the  intestine, 
from  the  excrementitious  matters  united  with  it.  But  we  must  have 
stronger  evidence  to  set  aside  the  overwhelming  testimony  in  favour  of 
an  action  of  selection  and  elaboration  by  the  absorbents  of  all  organ- 
ized bodies — vegetable  as  well  as  animal.  The  nutriment  of  the  vege- 
table may  exist  in  the  soil  and  the  air  around  it ;  but  it  is  subjected  to 
a  vital  agency  the  moment  it  is  laid  hold  of,  and  is  decomposed  to  be 
again  combined  to  form  sap.  A  like  action  is  doubtless  exerted  by  the 
chyliferous  radicles  f  and  hence  all  the  modes  of  explaining  this  part 
of  the  function,  under  the  supposition  of  their  being  passive,  mechanical 
tubes,  are  inadequate.  Boerhaave^  affirmed,  that  the  peristaltic  motion 
of  the  intestines  has  a  considerable  influence  in  forcing  chyle  into  the 
mouths  of  the  chyliferous  vessels ;  and  Briicke  is  of  opinion,  that  the 
contraction  of  the  muscular  fibres  of  the  canal  are  concerned  in  the 
entrance  of  the  chylous  matter  into  the  perforated  epithelial  cells  which 
he  depicts ;"  whilst  Dr.  Young^  is  disposed  to  ascribe  the  whole  effect 
to  capillar}^  attraction ;  and  he  cites  the  lachrymal  duct  as  an  analogous 
case,  the  conr.ents  of  which,  he  conceives — and  we  think  with  propriety 
— are  entirely  propelled  in  this  manner. 

'  Eeclierches  Physiologiques  et  Cliimiques,  pour  servir  i  I'Histoire  de  la  Digestion, 
p.  60,  Paris,  1825. 

^  F.  Arnold,  Lelirbucli  der  Physiologie  des  Mensclien,  Zurich,  1836-7  ;  noticed  in 
Brit,  and  For.  Med.  Review,  Oct.  1839,  p.  479. 

^  Pr?elect.  Academ.  in  Prop.  Instit.  liei  Med.,  §  103. 

^  Page  1:09.  =  Medical  Literature,  p.  42,  Lond.,  1813. 


222  ABSORPTION. 

The  objections  to  these  views,  as  regards  the  chylifcrous  vessels,  are 
sufficiently  obvious.  The  chyle  must,  according  to  them,  exist  in  the 
intestines  ;  and,  if  that  of  Boerhaave  were  correct,  we  ought  to  be  able 
to  obtain  it  from  the  chyme  by  pressure.  As  the  chyle  is  not  present, 
ready  formed,  in  the  intestine,  the  explanations  by  imbibition  and  by 
capillary  attraction  are  equally  inadmissible.  There  is  no  analogy 
between  the  cases  of  the  lachrymal  duct  and  the  chyliferous  vessels  ; 
even  if  it  were  admitted,  that  the  latter  have  open  mouths,  which  is 
not  the  case.  In  another  part  of  this  work,  it  was  affirmed,  that  the 
passage  of  the  tears  through  the  puncta  lachrymalia,  and  along  the 
lachrymal  ducts,  is  one  of  the  few  cases  in  which  capillary  attraction 
can  be  invoked,  with  propriety,  for  the  explanation  of  functions  exe- 
cuted by  the  human  frame.  In  that  case,  there  is  no  conversion  of  the 
fluid.  It  is  the  same  on  the  conjunctiva  as  in  the  duct ;  but,  in  the 
case  of  the  chyliferous  vessels,  a  new  fluid  is  formed:  there  must, 
therefore,  have  been  an  action  of  selection  exerted;  and  this  very 
action  would  be  the  means  of  the  entrance  of  the  new  fluid  into  the 
mouths  of  the  lacteals.  If,  therefore,  we  admit,  in  any  form,  the  doc- 
trine of  capillary  tubes,  it  can  only  be,  when  taken  in  conjunction 
with  that  of  the  elaborating  agency.  "  As  far  as  we  are  able  to  judge," 
says  Dr.  Bostock,^  "  when  particles,  possessed  of  the  same  physical 
properties,  are  presented  to  their  mouths  (the  lacteals),  some  are  taken 
up,  while  others  are  rejected ;  and  if  this  be  the  case,  we  must  con- 
ceive, in  the  first  place,  that  a  specific  attraction  exists  between  the 
vessel  and  the  particles,  and  that  a  certain  vital  action  must,  at  the 
same  time,  be  exercised  by  the  vessel,  connected  with,  or  depending 
upon,  its  contractile  power,  which  may  enable  the  particles  to  be 
received  within  the  vessel,  after  they  have  been  directed  towards  it. 
This  contractile  power  may  be  presumed  to  consist  in  an  alternation  of 
contraction  and  relaxation,  such  as  is  supposed  to  belong  to  all  vessels 
that  are  intended  for  the  propulsion  of  fluids,  and  which  the  absorbents 
would  seem  to  possess  in  an  eminent  degree."  This  is  specious  ;  but 
it  would  be  not  the  less  hypothetical  if  the  chyliferous  vessels  had  open 
mouths.  By  other  physiologists,  absorption  is  presumed  to  be  eftected 
by  virtue  of  the  peculiar  sensihiUty  or  insensible  organic  contractility  or 
irritability  of  the  mouths  [?]  of  the  absorbents ;  but  these  terms,  as  M. 
Magendie^  has  remarked,  are  the  mere  expression  of  our  ignorance, 
regarding  the  nature  of  the  phenomenon.  The  separation  of  the 
chyle  is,  doubtless,  a  chemical  process;  seeing  that  there  must  be  both 
an  action  of  decomposition  and  recomposition  ;  but  it  is  not  regulated 
solely  by  the  same  laws  that  govern  inorganic  chemistry. 

Professor  Goodsir,'  with  almost  all  modern  physiologists,  has  referred 
the  function  to  the  agency  of  cells.  Having  fed  a  dog  with  oatmeal, 
butter,  and  milk,  he  examined  the  intestinal  villi  three  hours  after- 
wards ;  when  the  chyliferous  vessels  were  turgid  with  chyle,  and  the 
intestine  was  full  of  milky  chyme  mingled  with  a  bilious-looking  fluid. 
In  the  white  portion  of  the  fluid,  which  was  situate  principally  towards 

'  Physiology,  edit,  cit.,  622,  Lond.,  183G.  *  Precis,  &c.,  ii.  179. 

'  Ediab.  New  Philosophical  . Journal,  July,  1842;  and  Anatomical  and  Pathological 
Observations,  p.  4,  Edinb.,  1845. 


OHYLOSIS.  .  223 

the  mucous  membrane,  numerous  epithelium  cells  were  found ;  some 
of  which  had  evidently — from  their  form — been  detached  from  the 
surface  of  the  villi ;  whilst  others  had  been  thrown  oft"  from  the  inte- 
rior of  the  follicles  of  Lieberkiihn.  The  villi  were  turgid,  and  destitute 
of  epithelium  except  at  their  bases.  Each  villus  was  covered  by  a 
very  fine,  smooth  membrane,  continuous  with  what  Mr.  Bowman  terms 
the  "basement  membrane"  of  the  mucous  surface,  which  is  reflected 
into  the  follicles.  The  villi  were  semitransparent,  except  at  their  free 
or  bulbous  extremities,  where  they  were  white  and  nearly  opaque. 
The  summit  of  each  villus  was  crowded  beneath  the  enveloping  mem- 
brane with  a  number  of  perfectly  spherical  vesicles,  varying  in  size 
from  T^'go^^^  ^^  2o'oB^^  of  an  inch  ;  the  matter  in  the  interior  of  which 
had  an  opalescent,  milky  appearance.  At  the  part  where  the  vesicles 
approached  the  granular  texture  of  the  substance  of  the  villus,  minute 
granular  or  oily  particles  were  situate  in  great  numbers.  The  trunks 
of  two  lacteals  could  be  easily  traced  up  the  centre  of  each  villus ;  and 
as  they  approached  the  vesicular  mass,  they  subdivided  and  looped ; 
but  in  no  instance  could  they  be  seen  to  communicate  directly  with 
any  of  the  vesicles.  These  vesicles,  in  Mr.  Goodsir's  opinion,  can 
scarcely  be  considered  in  any  other  light  than  cells,  whose  lives  have 
but  a  very  brief  duration,  which  select  from,  and  ajipropriate  the  mate- 
rials in  contact  with  the  surface  of  the  villi  into  their  own  substance, 
and  then  liberate  them,  by  solution  or  disruption  of  the  cell-wall,  in  a 
situation  where  they  can  be  absorbed  by  the  lacteals.  When  the  in- 
testine contains  no  more  chyme,  the  development  of  new  vesicles 
ceases ;  the  lacteals  empty  themselves,  and  the  villi  become  flaccid. 
During  the  interval  of  repose,  the  epithelium  is  renewed  for  the  protec- 
tion of  the  surface  of  the  villi,  and  for  the  secretion  function  of  the 
follicles  of  Lieberkiihn.  It  is  considered  by  Mr.  Goodsir,  that  the  epi- 
thelium cells  have  their  origin  in  certain  nuclei,  which  he  has  detected 
scattered  through  the  basement  membrane. 

These  views  were  embraced  by  Dr.  Carpenter;  but  they  are  by  no 
means  established.  It  is  denied,  indeed,  by  Eeichert,^  from  his  own 
and  Bidder's  observations,  that  the  epithelium  is  ever  so  shed  from  the 
digestive  canal,  in  or  after  any  act  of  digestion,  as  to  leave  any  portion 
of  the  subjacent  mucous  membrane  uncovered  or  raw  ;  and  Prof,  E,  H. 
Weber^  distinctly  observed  the  chyliferous  vessels  filled  with  chyle, 
although  the  mucous  membrane  was  covered  with  epithelium.  The 
materials  of  the  chyle,  therefore,  to  enter  the  vessels  must  have  passed 
through  the  epithelium.  During  absorption,  he  noticed  the  prismatic 
cells  of  the  cylinder  epithelium  experiencing  change  of  form  and  colour, 
and  in  rabbits  and  frogs  becoming  tumid,  and  containing  chyle  cor- 
puscles. In  man,  beneath  the  epithelium  is  a  second  layer  of  cells, 
which  are  neither  conical,  cylindrical,  nor  prismatic,  but  round ;  many 
of  which  are  filled  with  an  opaque  white ;  and  others  with  a  transpa- 
rent, oleaginous  fluid ;  so  that  different  cells  appeared  to  absorb  diflerent 
fluids.  Dr.  Carpenter,  indeed,  now  regards  Mr.  Goodsir's  views  as  to 
the  nature  of  those  cells  to  be  erroneous,  "for  several  excellent 
observers,"  he  says,  "agree  in  regarding  them  as  the  proper  epithe- 

'  Miiller's  Archiv.,  1844.  2  ii,i^\,^  3.  401^  Berlin,  1847. 


22-i  ABSOKPTION. 

Hum  cells  of  tlie  villi,  vrhicli  are  not  thrown  off  as  Prof.  Goodsir 
believed,  but  so  completely  change  their  aspect  in  consequence  of  the 
imbibition  of  oleaginous  fluid  (Fig.  59),  that  they  cease  to  be  recog- 
nizable as  such,  unless  their  intermediate  stages  be  traced.  It  may 
then,"  he  adds,  "  be  stated  with  some  confidence,  that  the  epithelium 
cells  covering  the  extremities  of  the  villi,  are  the  real  instruments  in 
the  selection  and  absorption  of  the  materials  of  the  chyle;  and  that, 
drawing  these  into  their  own  cell-cavities,  they  subsequently  deliver 
them  up  to  the  lacteals,  by  which  they  are  carried  towards  the  centres 
of  the  circulation."^ 

It  has  already  been  said,  that  chyle  alwavs  possesses  the  same 
essential  properties ;  that  it  may  vary  slightly  according  to  the  food, 
and  the  digestive  powers  of  the  individual ;  but  rarely  if  ever  contains 
any  adventitious  substance, — the  function  of  the  chyliferous  vessels 
being  restricted  to  the  formation  of  chyle.  The  facts  and  arguments, 
in  flivour  of  this  view  of  the  subject,  will  be  given  hereafter. 

The  course  of  the  chyle  is,  as  we  have  described,  along  the  chylife- 
rous vessels,  and  through  the  mesenteric  glands  into  the  receptaculum 
chyli  or  commencement  of  the  thoracic  duct ;  along  which  it  passes  into 
the  subclavian  vein.  The  chief  causes  of  its  progression  are, — first  of 
all,  the  inappreciable  action,  by  which  the  chyliferous  vessels  form  and 
receive  the  chyle  into  them.  This  formation  being  continuous,  the 
fresh  portions  must  propel  those  already  in  the  vessels  towards  the 
mesenteric  glands,  in  the  same  way  as  the  ascent  of  sap  in  plants, 
during  the  spring,  appears  to  depend  on  the  constant  absorbing  action 
of  the  roots.^  The  vessels  themselves,  too,  are  contractile  :^  such  was 
the  opinion  of  Messrs.  Sheldon,^  Schneider,  Cruikshank,^  and  J.  Muller. 
M,  ]\[andP  affirms,  that  it  can  no  longer  be  doubted  ;  and  that  the  irri- 
tabilit}^  continues  even  for  several  hours  after  death.  M.  ^lojon^  con- 
siders, that  when  the  longitudinal  fibres,  which  he  has  observed  in  the 
lymphatics,  contract,  they  draw  one  sphincter  nearer  to  another,  whilst 
the  oblique  fibres  diminish  the  diameter.  All  these  fibres,  taking  their 
point  cVappui  in  the  circular  fibres,  dilate  the  superior  sphincters  by 
drawing  the  circumference  downwards.  By  this  method,  the  fluid  that 
enters  a  lymphatic  irritates  the  vessel,  which  contracts  upon  itself, 
diminishes  its  cavity,  and  sends  on  the  fluid  through  the  open  sphinc- 
ter. A  kind,  of  peristaltic  action,  he  conceives, — and  in  this  view  he 
is  confirmed  by  MM.  Lacauchie,*  Gruby,  and  Delafond,^ — exists  in  the 
lymphatics  similar  to  that  of  the  intestines,  which  may  be  observed 
very  distinctly  in  the  lacteal  vessels  of  the  mesentery  of  animals,  if 
opened  two  or  three  hours  after  they  have  been  well  fed.  In  the  veins 
of  the  wing  of  the  bat,  a  regular  rhythmical  movement  has  been  ob- 
served by  Mr.  Wharton  Jones,'"  the  result  of  their  own  contractile 
power ;  and  the  existence  of  such  a  movement  of  the  veins  of  a  part 

'  Principles  of  Human  Physiology,  Amer.  edit.,  p.  136,  Philad.,  1855. 

2  Brescliet,  Le  Systeme  Lympliatique,  Paris,  1S30. 

3  Mailer's  Haiidl inch,  u.  s.  w.,  and  Baly"s  translation,  i.  284,  Lond.,  1838. 

*  History  of  the  Absorhent  System,  p.  28,  Lond.,  1784.  ^  Op.  citat.,  c.  12. 

^  Manuel  d'Anatomie  CxeU'  rale,  p.  211,  Paris,  1843. 
''  Jonrn.  de  la  Societ«  des  Sciences  Physiques,  etc.,  Nov.  1833. 
8  Comptes  Rendus.  15  Mai,  1843.  s  Ibid.,  5  Juin,  1843. 

'"  Proceedings  of  the  Royal  Society,  Feb.  1852,  and  Philosophical  Transactions  for 
1852,  p.  131.  ^ 


CHYLOSIS.  225 

as  an  auxiliary  propulsive  force,  Dr.  Carpenter^  thinks,  obviously 
strengthens  the  probability  of  its  occurrence  in  the  lymphatics  as  the 
principal  propelling  power,  where  no  central  impelling  organ  exists ; 
"just  as  a  like  movement  is  seen  in  the  bloodvessels  of  such  of  the 
lower  invertebrata  as  have  no  heart." 

In  the  absence  of  more  direct  observation  it  was  argued  that  the 
lacteals  and  lymphatics  are  possessed  of  a  power  of  contraction  for  the 
following  reasons: — First.  They  are  small;  and  tonic  contractions  are 
generally  admitted  in  all  capillary  vessels.  Secondly.  The  ganglions 
or  glands,  which  cut  them  at  intervals,  would  destroy  the  impulse 
given  by  the  first  action  of  the  radicles ;  and  hence  require  some  con- 
traction in  the  vessels  to  transport  the  chyle  from  one  row  of  these 
ganglions  to  another.  Thirdly.  If  a  chyliferous  vessel  be  opened  in 
a  living  animal,  the  chyle  spirts  out,  which  could  not  be  effected 
simply  by  the  absorbent  action  of  the  chyliferous  radicles;  and, 
Fourthly^  in  a  state  of  abstinence,  these  vessels  are  found  empty ; 
proving,  that  notwithstanding  there  has  been  an  interruption  to  the 
action  of  chylous  absorption,  the  whole  of  the  chyle  has  been  pro- 
pelled into  the  receptaculum  chyli.  It  is  obvious,  however,  that  most 
of  these  reasons  would  apply  as  well  to  the  elasticity  as  to  the  mus- 
cularity of  the  outer  coat  of  these  vessels.^  A  more  forcible  argument 
is  derived  from  an  experiment  by  Lauth.^  He  killed  a  dog  towards 
the  termination  of  digestion;  and  immediately  opened  its  abdomen, 
when  he  found  the  intestines  marbled,  and  the  chyliferous  vessels 
filled  with  chyle.  Under  the  stimulation  of  the  air,  the  vessels  began 
to  contract,  and,  in  a  few  minutes,  were  no  longer  perceptible.  The 
result  he  found  to  be  the  same,  whenever  the  dissection  was  made 
within  twenty-four  hours  after  death ;  but,  at  the  end  of  this  time,  the 
irritability  of  the  vessels  was  extinct ;  and  they  remained  distended 
with  chyle,  notwithstanding  the  admission  of  air.  Kcilliker'*  found, 
too,  that  when  the  wire  of  an  electro-magnetic  apparatus  was  applied 
to  some  well  filled  lymphatics  on  the  skin  of  a  dog's  foot  soon  after 
the  leg  had  been  removed  by  amputation,  their  diameter  was  dimin- 
ished at  least  one  half;  and  this  did  not  occur  suddenly,  but  in  the 
course  of  between  half  a  minute  and  a  minute. 

These  experiments  and  observations  led  to  a  deduction,  in  the  ab- 
sence of  less  direct  proof,  scarcely  doubtful ; — that  the  chyliferous 
vessels  possess  a  contractile  action,  by  the  aid  of  which  the  cbyle  is 
propelled  along  them.  In  addition  to  these  propelling  causes,  the 
pulsation  of  the  arteries  in  the  neighbourhood  of  the  vessels,  and 
the  pressure  of  the  abdominal  muscles  in  respiration  have  been  in- 
voked. The  former  has  probably  less  effect  than  the  latter.  It  is  not, 
indeed,  easy  to  see  how  it  can  be  possessed  of  any.  Of  the  agency  of 
the  latter  we  have  experimental  evidence.  If  the  thoracic  duct  be 
exposed  in  the  neck  of  a  living  animal,  and  the  course  of  the  chyle  be 
observed,  it  will  be  found  accelerated  at  the  time  of  inspiration,  when 
the  depressed  diaphragm  forces  down  the  viscera,  or  when  the  abdo- 

'  Principles  of  Human  Physiology,  Amer.  edit.,  p.  158,  Philad.,  1854. 
'  Adelon,  Physiologie,  etc.,  iii.  31. 
•*  Essai  sur  les  Vaisseaux  Lymphat.,  Strasb.,  1824. 
<  Kiilliker  and  Siebold's  Zeitschrift,  lb49. 
VOL.  I. — 15 


226  ABSORPTION. 

men  of  tlie  animal  is  compressed  by  the  bands.  We  sball  find,  too, 
hereafter,  that  the  mode  in  which  the  thoracic  duct  opens  into  the 
subclavian  exerts  considerable  eifect  on  the  progress  of  the  chyle.  We 
have  reason  to  believe  that  its  course  is  slow.  It  has  been  already 
stated,  that  in  an  experiment  on  a  dog,  which  had  eaten  animal  food 
at  discretion,  M.  Magendie^  found  half  an  ounce  of  chyle  discharged 
from  an  opening  in  the  thoi'acic  duct  in  five  minutes.  Still,  as  he 
judiciously  remarks,  the  velocity  will  be  partly  dependent  upon  the 
quantity  of  chyle  formed.  If  much  enters  the  thoracic  duct,  it  will 
probably  proceed  faster  than  under  opposite  circumstances.  In  the 
commencement  of  the  thoracic  duct  it  becomes  mixed  with  lymph ; 
and  under  the  head  of  lymphatic  absorption  we  shall  show  how  they 
proceed  together  into  the  subclavian,  and  the  effect  produced  by  the 
circumstances  under  which  the  thoracic  duct  opens  into  that  venous 
trunk. 

It  has  been  a  subject  of  inquiry,  Avhether  chyle  varies  materially  in 
different  parts  of  its  course;  and  what  is  the  precise  modification, 
impressed  upon  it  by  the  action  of  the  mesenteric  glands.  The  expe- 
riments of  Renss,  Emmert,^  and  others,  seem  to  show,  that  when  taken 
from  the  intestinal  side  of  the  glands  it  is  of  a  yellowish- white  colour; 
does  not  become  red  on  exposure  to  the  air,  and  coagulates  but  imper- 
fectly, depositing  only  a  small,  yellowish  pellicle.  It  is  said,  indeed, 
that  chyle,  drawn  from  the  chyliferous  vessels,  which  traverse  the  in- 
testinal walls,  contains  albumen  in  a  state  of  solution,  but  no  fibrin, 
and  abounds  in  oleaginous  matter ;  whilst  that  from  the  other  side  of 
the  glands,  and  near  the  thoracic  duct,  is  of  a  reddish  hue ;  contains 
chyle  globules;  coagulates  entirely,  and  separates  into  a  clot  and  serum. 
M.  Vauquelin,^  too,  affirms,  that  it  acquires  a  rosy  tint  as  it  advances  ^ 
in  the  apparatus;  and  that  the  fibrin  becomes  gradually  more  abund- 
ant. These  circumstances  have  given  rise  to  the  belief,  that  as  it  pro- 
ceeds it  becomes  more  and  more  animalized,  or  transformed  into  the 
nature  of  the  being.  This  efilect  has  generally  been  ascribed  to  the 
mesenteric  glands ;  and  it  has  been  presumed  by  some  to  be  produced 
by  the  exhalation  of  a  fluid  into  their  cells  from  the  numerous  blood- 
vessels with  which  they  are  furnished.  Others,  again,  consider,  that 
the  veins  of  the  glands  remove  from  the  chjde  every  thing  that  is 
noxious;  or  purify  it.  From  the  circumstance,  that  the  rosy  colour 
is  more  marked  on  the  thoracic,  than  on  the  intestinal  side  of  the 
glands;  that  the  fluid  is  richer  in  fibrin  after  having  passed  through 
those  glands;  and  that  the  rosy  colour  and  fibrin  are  less  when  the 
animal  has  taken  a  large  proportion  of  food,  MM.  Tiedemann  and 
Gmelin"*  infer,  that  it  is  to  the  action  of  the  glands,  that  the  chyle  owes 
those  important  changes  in  its  nature; — the  fluid,  in  its  passage 
through  them,  obtaining,  from  the  blood  circulating  in  them,  new  ele- 
ments, which  animalize  it. 

There  is  much  probability  in  the  view,  that  some  nitrogenized  ma- 
terial is  secreted  from  the  lining  membrane  of  the  chyliferous  vessels, 

'  Precis,  &c.,  ii.  183. 

2  Reil's  Arcliiv.,  viii.  s.  2;  and  Annales  de  Cliimie,  Ixxx.  81. 

s  Annales  de  Cbimie,  Ixxxi.  113  ;  and  Annals  of  Philosophy,  ii.  220. 

*  Die  Verdauung  nach  Versuchen,  u.  s.  w.,  or  Jourdau's  translat.,  Paris,  1S27. 


I.  lu  the  afferent  or  peripheral  lac- 
teals  (from  the  intestines  to  the 
mesenteric  glands). 


CHYLOSIS.  227 

in  the  mesenteric  glands  especially,  tlirougli  tlie  agency  of  the  nucle- 
ated cells  described  by  Professor  Goodsir,  which  may  be  a  great  agent 
in  the  changes  effected  on  the  chyle  in  its  course.  At  the  same  time — 
as  has  been  well  observed' — an  important  source  of  fallacy  attends  all 
deductions  founded  upon  the  differences  observed  in  the  chyle  in  the 
several  parts  of  its  course  through  the  lacteals, — which  is,  that  we 
cannot  be  at  all  sure  how  far  this  may  not  be  dependent  upon  an 
actual  interchange  of  ingredients  with  the  blood,  by  imbibition  through 
the  very  thin  parietes  of  the  contiguous  vessels.  The  whole  question, 
as  Dr.  Carpenter  properly  remarked,  offers  a  wide  scope  for  farther 
inquiry. 

The  following  table,  slightly  modified  from  one  by  Gerber,^  exhibits 
concisely  the  relative  proportions  of  the  three  main  ingredient-s  of  the 
chyle — fat,  albumen,  and  fibrin — in  various  parts  of  the  absorbent  sys- 
tem; and  affords  some  idea  of  its  change  in  the  process  of  assimilation. 

'  Fat  in  maximum  quantity  (numerous  fat  or  oil 
globules). 
Albumen  in  minimum  quantity  (few  or  no  chyle 

corpuscles'). 
Fibrin  almost  entirely  wanting. 
II    In  the  efferent  or  central  lacteals   f  ^"^  "'  medium  quantity  (fewer  oil  globules). 

XI*       111     tile    dlClCllt    \J1    ^jCHLXtH    ICH^LC'Cl'IiD        Ii77  •  •  I'l  y      1        1  7 

.c        .1  i.     ■      1      J    i    ii  ^«o«7?ien  m  maximum  quantity  (c/fwe  conjusc/es 

(from  the  mesenteric  glands  to  the  <  i    ^  •  /  \i     j       i       jx 

^,     _     .     ,       .  °  very  numerous,  but  imperfectly  developed). 

'*  [  Fibrin  in  medium  quantity. 

Fat  in  minimum  quantity  (fewer  or  no  oil  glo- 
bules). 

Albumen  in  medium  quantity  (chyle  corpuscles 
numerous  and  more  distinctly  cellular). 

Fibrin  in  maximum  quantity. 

In  another  place,  various  hypotheses,  that  have  been  indulged  re- 
garding the  functions  of  the  spleen,  will  be  noticed.  It  is  proper,  how- 
ever, to  refer,  here,  to  one  which  has  been  proposed  by  MM.  Tiede- 
mann  and  Gmelin.  They  consider  the  organ  a  dependent  ganglion  of 
the  absorbent  system,  which  prepares  a  fluid  destined  to  be  mixed  with 
the  chyle  to  effect  its  animalization  ;  and  assert,  that  the  chyle  coagu- 
lates little  or  not  at  all  before  it  has  jjassed  through  the  mesenteric 
glands;  but,  after  this,  fibrin  begins  to  appear,  and  is  much  more 
abundant  after  the  addition  of  the  lymph  from  the  spleen,  which  con- 
tains a  large  quantity  of  fibrin.  Before  passing  the  mesenteric  glands, 
the  chyle  contains  no  red  particles;  but  it  does  so  immediately  after- 
wards, and  more  particularly  after  it  is  mixed  with  the  Ijmiph  from 
the  spleen,  which  abounds  with  them,  and  with  fibrin.  M.  Voisin,^ 
who,  as  we  have  seen,  considers  that  the  chyliferous  vessels  ramify  in 
the  substance  of  the  liver,  is  of  opinion  that,  by  the  action  of  the  liver, 
a  species  of  purification  is  produced  in  the  chyle,  by  which  the  latter 
is  better  fitted  to  mingle  with,  and  form  part  of,  the  blood;  but  neither 
his  anatomical  nor  physiological  views  on  the  subject  have  met  with 
much  countenance. 

Prior  to  the  discovery  of  the  chyliferous  vessels,  the  mesenteric  veins 
were  regarded  as  agents  of  chylous  absorption ;  and  as  these  veins  ter- 

'  Carpenter,  Human  Physiology,  2d  Amer.  edit.,  p.  426,  Philad.,  1845  ;  and  last 
Amer.  edit.,  p.  156,  Philad.,  1855^ 

^  Ibid.,  2d  edit.  p.  427.     "  Nouvel  Aper;u  sur  la  Physiologie  du  Foie,  &c.,  Paris,  1833. 


III.  In  the  thoracic  duct. 


228  ABS0EPTI02T. 

minate  in  tlie  vena  porta,  wliicli  is  distributed  to  the  liver,  this  last  was 
considered  the  first  organ  of  sanguification ;  and  to  impress  upon  the 
chyle  a  primary  elaboration.  In  this  view,  the  great  size  of  the  organ 
compared  with  the  small  quantity  of  bile  furnished  by  it,  and  the  excep- 
tion, which  the  mesenteric  veins  and  vena  porta  present  to  the  rest  of 
the  venous  system, — as  well  as  the  large  size  of  the  liver  in  the  foetus, 
although  not  effecting  any  biliary  secretion,  and  the  fact  of  its  receiv- 
ing immediately  the  nutritive  fluid  from  the  placenta  were  accounted 
for.  The  idea  of  the  agency  of  the  mesenteric  veins  is  now  nearly 
exploded,  but  not  altogether  so.  There  are  yet  physiologists,  and  of 
no  little  eminence,  who  esteem  them  participators  in  the  functions  of 
chylosis  with  the  chyliferous  vessels  themselves. 

Some  of  the  arguments,  based  on  fallacious  data,  used  by  these  gen- 
tlemen, are: — First.  The  mesenteric  veins  form  as  much  an  integrant 
part  of  the  villi  of  the  intestine  as  the  chyliferous  vessels ;  and  they 
have  also,  free  orifices  [?]  in  the  cavity  of  the  intestine.  Lieberkuhn,' 
by  throwing  an  injection  into  the  vena  porta,  observed  the  fluid  ooze 
out  of  the  villi  of  the  intestine;  and  M.  Ribes^  obtained  the  same  result 
by  injecting  spirit  of  turpentine  coloured  black.  These  experiments — 
it  need  hardly  be  said — are  insufficient  to  establish  the  fact  of  open 
mouths.  Situate,  as  those  vessels  are,  in  an  extremely  loose  tissue, 
which  affords  them  but  little  support,  the  slightest  injecting  force  might 
be  expected  to  rupture  them.  Secondly.  Chyle  has  often  been  found 
in  the  mesenteric  veins.  Swammerdam  asserts,  that,  having  placed  a 
ligature  around  these  veins  in  a  living  animal,  whilst  digestion  was 
goina  on,  he  saw  whitish,  chylous  strise  in  their  blood;  and  Tiedemann 
and  Gmelin  afl&rm,  that  they  have  often,  in  their  experiments,  observed 
the  same  appearance.  If  the  fact  of  the  identity  of  these  striae  with 
chyle  were  well  established,  we  should  have  to  bend  to  the  weight  of 
evidence.  This  is  not,  however,  the  case.  No  other  reason  for  the 
belief  is  afforded  than  their  colour.  The  arguments  against  the  me- 
senteric veins  having  the  power  of  forming  chyle  we  think  irresistible. 
A  distinct  apparatus  exists,  which  scarcely  ever  contains  any  thing 
but  chyle;  and  consequently,  it  would  seem  unnecessary,  that  the 
mesenteric  veins  should  participate  in  the  function,  especially  as  the 
fluid  which  circulates  in  them  is  most  heterogeneous;  and,  as  we  shall 
see,  a  compound  of  various  adventitious  and  other  absorptions.  Grant- 
ing, however,  that  these  strife  are  true  chyle,  it  would  by  no  means  fol- 
low absolutely,  that  it  should  be  formed  by  the  mesenteric  veins.  A  com- 
munication may  exist  between  the  chyliferous  vessels  and  these  veins. 
Wall^eus^  asserts,  that  having  placed  a  ligature  on  the  lymphatic  trunks 
of  the  intestine,  chyle  passed  into  the  vena  porta.  Rosen,  Meckel,* 
and  Lobstein  affirm,  that  by  the  use  of  injections  they  detected  this 
inosculation.     Lippi*  states,  that  the  chyliferous  vessels  have  numerous 

*  Dissert,  de  Fabric.  Villor.  Intestin.,  Lugd.  Bat.,  1745. 

*  Memoir,  de  la  Socic'te  Medicale  d'Emulation,  viii.  621. 

'  Medica  Omnia,  &c.,  ad  Cliyli  et  Sanguinis  CircuL,  Lond.,  16G0. 

*  Diss.  Epist.  ad  Haller.  de  Vasis  Lymph.,  &c.,  Berol.,  1757  ;  Nov.  Exper.  de  Finibns 
Venarum  et  Vas.  Lymph.,  Berol.,  1772,  and  Manuel  d'Anatomie,  &c.,  French  edit.,  by 
Jourdan,  i.  179. 

^  Illustrazioni  Fisiologiche  e  Patologiehe  del  Sistema  Linfatico-Chilifero,  Firenze, 
1825. 


CHYLOSIS.  '  229 

anastomoses  witli  tbe  veins,  not  only  in  their  course  along  tlie  mesentery 
before  they  enter  the  mesenteric  glands,  but  also  in  the  glands  them- 
selves. Tiedemann  and  Gmelin  concur  in  the  existence  of  this  last 
anastomosis,  and  MM.  Leuret  and  Lassaigne  found  that  a  ligature  ap- 
plied round  the  vena  porta  occasioned  a  reflux  of  blood  into  the  tho- 
racic duct.  Professors  Meckel,  E.  H.  Weber,  Radolphi,  and  J.  Muller 
doubt,  however,  the  existence  of  an  actual  open  communication  between 
the  lymphatics  and  minute  veins  in  the  glands.  Meckel  states,  as  a 
reason  for  his  questioning  this,  that  when  the  seminal  duct  of  the  epi- 
didymis of  the  dog  is  injected,  the  veins  also  are  filled ;  and  Miiller' 
observes,  that  when  glands  are  injected  from  their  excretory  duct,  the 
small  veins  of  the  gland  also  frequently  become  filled  with  mercury; 
and  the  cases  in  which  this  occurred  to  him  were  always  those  in  which 
the  ducts  had  not  been  well  filled, — their  acini  not  distended.  Thirdly. 
That  the  ligature  of  the  thoracic  duct  has  not  always  induced  death, 
or  has  not  induced  it  speedily ;  and,  consequently,  the  thoracic  duct  is 
not  the  only  route  by  which  the  chyle  can  pass  to  be  inservient  to  nu- 
trition. In  an  experiment  of  this  kind  by  M.  Duverney,  the  dog  did 
not  die  for  fifteen  days.  M.  Flandrin  repeated  it  on  twelve  horses, 
which  appeared  to  eat  as  usual,  and  to  maintain  their  flesh.  On  killing 
and  opening  them  a  fortnight  afterwards,  he  satisfied  himself  that  the 
thoracic  duct  was  not  double.  Sir  Astley  Cooper  performed  the  expe- 
riment on  several  dogs:  the  majority  lived  longer  than  a  fortnight,  and 
none  died  in  the  first  two  days ;  although,  on  dissection,  the  duct  was 
found  ruptured,  and  chyle  eft'used  into  the  abdomen.  The  experiments 
of  M.  Dupuytren  have  satisfactorily  accounted  for  these  different  re- 
sults. He  tied  the  thoracic  duct  in  several  horses.  Some  died  in  five 
or  six  days,  whilst  others  continued  apparently  in  perfect  health.  In 
those  that  died  in  consequence  of  the  ligature,  it  was  impossible  to 
throw  any  injection  from  the  lower  part  of  the  duct  into  the  subclavian. 
It  was,  therefore,  presumable,  that  the  chyle  had  ceased  to  be  poured 
into  the  blood,  immediately  after  the  duct  was  tied.  On  the  other 
hand,  in  those  that  remained  apparently  unaffected,  it  was  always  easy 
to  send  mercurial  or  other  injections  from  the  abdominal  portion  of  the 
duct  into  the  subclavian.  The  injections  followed  the  duct  until  near 
the  ligature,  when  they  turned  off',  and  entered  large  lymphatic  vessels, 
which  opened  into  the  subclavian ;  so  that,  in  these  cases,  the  ligature 
of  the  thoracic  duct  did  not  prevent  the  chyle  from  passing  into  the 
venous  system;  and  thus  we  can  understand  why  the  animals  should 
not  have  perished.^ 

From  every  consideration,  then,  it  appears  that  the  chyliferous  ves- 
sels are  the  sole  organs  concerned  in  cbylosis;  and  we  shall  see  pre- 
sently, that  they  refuse  the  admission  of  other  substances,  which  must, 
consequently,  reach  the  circulation  through  a  different  cliannel. 

The  views  of  those  who  believe,  that  the  absorption  of  the  nutritive 
portion  of  most  aliments  takes  place  in  the  stomach, — fatty  matters 
only  being  absorbed  by  the  chyliferous  vessels, — have  been  referred  to 
elsewhere.     M.  Bernard,  who  properl}'-  ascribes  to  the  liver  a  most 

'  Handbucli,  u.^  s.  w.  ;  and  Balv's  translation,  p.  273,  Lond.,  1838. 
2  Kicheraud's  -hlemens  de  Physiologie,  edit,  oit.,  p.  9U. 


230  ABSOKPTIOX. 

important  assimilating  function,  agrees  with  those  gentlemen,  that 
albuminous  and  saccharine  matters  are  taken  up  by  the  gastro-intestinal 
veins,  by  which  they  are  conveyed  to  that  organ ;  and  that  the  cbyli- 
ferous  vessels  absorb  only  fat.  Chyle,  in  other  words,  he  regards  as 
lymph  holding  in  suspension  emulsified  fat  ;^  and  all  these  substances, 
according  to  him,  pass  into  veins  and  lacteals  by  a  simple  act  of  en- 
dosmose.  It  has  been  already  argued,  however,  that  the  formation  of 
chyle — and  the  same  may  be  said  of  that  of  lymph — is  an  action  of 
selection  and  elaboration, — the  product  being  always  essentially  the 
same;  and  exhibiting  the  same  constituents,  although  their  proportions 
vary  within  restricted  limits.  Fat,  moreover,  can  readily  pass  into  the 
intestinal  bloodvessels,  and  has  been  detected  in  them  in  such  quan- 
tity,— that,  according  to  Bruch,^  the  superficial  capillary  network  pre- 
sents, at  times,  an  opalescent  whiteness.  Moreover,  the  experiments 
of  Matteucci^  have  sufficiently  shown,  that  no  special  arrangement  of 
chyliferous  vessels  is  required  for  the  absorption  of  fat,  seeing  that  if 
an  emulsion  be  put  into  an  intestine,  and  the  intestine  be  plunged  into 
a  weak  alkaline  solution,  the  latter  becomes  turbid  from  the  passage 
of  the  oily  matter  through  the  membrane;  so  that  it  can  be  readily 
understood,  that  fatty  matter  may  be  found  both  in  the  chyliferous 
vessels  and  in  the  lymphatics. 

b.  Ahsorption  of  Drinks. 

It  has  been  already  stated,  that  a  wide  distinction  exists  between 
the  gastric  and  intestinal  operations  that  are  necessary  in  the  case  of 
solid  and  of  thin  liquid  food.     Whilst  the  for- 
Fig.  G6.  mer  is  converted  into  chyme  and  passes  into  the 

small  intestine,  to  have  its  chylous  part  sepa- 
rated from  it;  the  latter  is  usually  absorbed 
from  the  stomach  or  small  intestine. 
.  The  chyliferous  vessels,  we  have  seen,  are 

^         agents  and  exclusive  agents  of  the  absorption 
,\       of  chyle — the  nutritive  product  from  the  diges- 
-  ^      tion  of  solids.     What,  then,  are  the  agents  of 
*^,  jx. ,       the  absorption  of  liquids  ?     There  are  but  two 

\  '  " ')''  "^      sets  of  vessels  on  which  we  can  rest  for  a  mo- 

ment. These  are  the  lacteals  or  lymphatics  of 
.  ^  the  digestive  tube ;  and  the  veins  of  the  same 
canal.  But,  it  has  been  seen,  the  chyliferous 
vessels  refuse  the  admission  of  everything  but 
chyle.  It  would  necessarily  follow,  then,  that 
Villi  of  the  Human  Intestine,   i]^q  absorptiou  of  liouids  must  be  a  function  of 

with  their  Capillary  Plexus       ,  •  o       i    •       i  t       ■  p  ^     ^ 

injected.  the  vems.     Such  is  the  conclusion  ot  most  phy- 

siologists, and  on  inferences  that  are  logical. 
The  view  is  not,  however,  universally  admitted ;  some  assigning  the 

'  Comptes  Rendiis,  xxxi.  79S,  and  L'Union  Medicale,  1850.  See,  also,  Dr.  Donald- 
son, on  M.  Bernard  s  Discoveries  in  Amer.  Journ.  of  the  Med.  Sciences,  Oct.  1851,  and 
H.  Lndlow  in  Brit,  and  For.  Med.-Chir.  Rev.,  Jan.  1854,  p.  (35. 

^  Siebold  and  KoUiker's  Zeitsclirift,  Ajiril,  1853. 

3  Lectnres  on  the  Physical  Phenomena  of  Living  Beings,  by  Dr.  Pereira,  Amer.  edit., 
p.  110,  Philad.  1848. 


OF   DEINKS. 


231 


function  exclusively  to  tlie  lacteals;  others  sharing  it  between  them 
and  the  veins.     Let  us  inquire  into  the  facts  and  arguments  that  have 


Fig.  G7. 


Capillary  Plexus  of  the  Villi   of  the   Human  Small   Intestine,  as   seen  on  the  Surface,  after  a 
successful  injection,  magnified  50  diameters. 

been  brought  forward  from  time  to  time  in  support  of  these  different 
opinions.  The  advocates  for  the  exclusive  agency  of  the  chyliferous 
vessels  affirm,  First^  That  what- 
ever is  the  vascular  system,  that 
effects  the  absorption  of  drinks,  it 
must  communicate  freely  with  the 
cavity  of  the  intestine ;  and  that 
the  chyliferous  vessels  do  this. 
Secondly^  That  this  system  of  ves- 
sels is  the  agent  of  chylous  ab- 
sorption : — a  presumption,  that  it 
is  likewise  the  agent  of  the  ab- 
sorption of  drinks.  Thirdly,  That 
every  physiologist,  who  has  exa- 
mined the  chyle,  has  described  its 
consistence  to  bo  in  an  inverse 
ratio  with  the  quantity  of  drink 
taken ;  and,  lastly,  that  when  co- 
loured and  odorous  substances 
have  passed  into  the  intestine, 
they  have  been  found  in  the  chy- 
liferous vessels  and  not  in  the  me- 
senteric veins.  The  experiments, 
adduced  in  favour  of  this  last  po- 
sition are,  however,  so  few  and  in- 
adequate, that  it  is  surprising  they 
could  have,  for  a  time,  so  com- 
pletely overturned  the  old  theory, 
zeal  and  ability  of  the  Hunters,  and  of  the  Windmill  Street  School  in 


Vertical  Section  of  the  Coats  of  the  Small 
Intestine  of  a  Dog,  showing  only  the  com- 
mencing portions  of  the  Portal  Vein  and  the 
Capillaries.  The  injection  has  been  thrown 
into  the  Portal  Vein,  but  has  not  penetrated 
to  the  Arteries. 
a.  Vessels  of  the  villi,     b.  Those  of  LieberkCha's 

tubes,     c.  Those  of  the  muscular  coat. 


This  effect  was  greatly  aided  by  the 


232  ABSORPTION. 

general,  \v"ho  were  the  great  improvers  of  our  knowledge  regarding  the 
anatomy  of  the  lymphatic  system.  John  Hunter,^ — who  was  one  of  the 
first  that  positively  denied  absorption  by  the  veins,  and  maintained  that 
of  the  lymphatics, — instituted  the  following  ingenious  and  imposing  ex- 
periment. He  opened  the  abdomen  of  a  living  dog;  laid  hold  of  a  por- 
tion of  intestine,  and  pressed  out  the  matters  it  contained  with  his  hand. 
He  then  injected  warm  milk  into  it,  which  he  retained  by  means  of  liga- 
tures. The  veins,  belonging  to  the  portion  of  intestine,  were  emptied 
of  their  blood  by  puncturing  their  trunks;  and  were  prevented  from 
receiving  fresh  blood,  by  the  application  of  ligatures  to  the  correspond- 
ing arteries.  The  intestine  was  returned  into  the  cavity  of  the  abdo- 
men; and,  in  the  course  of  half  an  hour,  was  again  withdrawn  and 
scrupulously  examined;  the  veins  wei'e  still  found  empty,  whilst  the 
chyliferous  vessels  were  full  of  a  white  fluid.  Mr.  Hunter  subsequently 
repeated  the  experiment  with  odorous  and  coloured  substances,  but 
without  being  able  to  detect  them  in  the  mesenteric  veins.  It  may  be 
remarked,  also,  that  Musgrave,^  Lister,^  Blumenbach,"  Seller  and  Fici- 
nus*  assert,  that  they  have  detected  substances,  which  had  been  thrown 
into  the  intestines  of  animals,  in  the  chyle  of  the  thoracic  duct.  The 
experiments  of  Hunter,  however,  are  those,  on  which  the  supporters 
of  this  view  of  the  question  principally  relied. 

Physiologists,  who  believed  in  the  absorption  of  liquids  by  the  me- 
senteric veins,  advanced  similar  arguments  and  much  more  numerous 
experiments.  They  affirmed  that  the  mesenteric  veins,  like  the  chyli- 
ferous vessels,  form  constituent  portions  of  the  villi ; — that  if  the  chy- 
liferous system  is  manifestly  an  absorbent  apparatus,  the  same  may  be 
said  of  the  venous  system ; — that  if  the  chyle  has  appeared  more  fluid 
after  much  drink  has  been  taken,  the  blood  of  the  mesenteric  veins 
was  seen  by  Boerhaave  to  be  more  fluid  under  like  circumstances; 
and,  lastly,  against  the  experiments  of  Hunter,  numerous  others  were 
cited,  showing  clearly,  that  liquids,  injected  into  the  intestine,  have 
been  found  in  the  mesenteric  veins,  whilst  they  could  not  be  detected 
in  the  chyliferous  vessels. 

To  the  first  experiment  of  Hunter  it  was  objected ; — that  in  his 
time  the  art  of  performing  physiological  experiments  was  imperfect ; 
and  that,  in  order  to  deduce  useful  inferences  from  it,  we  ought  to 
know,  whether  the  animal  was  fasting,  or  digestion  was  going  on  at 
the  time  it  was  opened;  that  the  lymphatics  ought  to  have  been  exa- 
mined at  the  commencement  of  the  experiment,  to  see  whether  they 
were  full  of  chyle,  or  empty ;  as  well  as  the  milk,  to  notice  whether  it 
had  experienced  any  change  during  its  stay  in  the  intestine;  and 
lastly,  that  the  reasons  ought  to  have  been  assigned  for  the  belief,  that 
the  lacteals  were  filled  with  milk  at  the  end  of  the  experiment,  and 
not  with  chyle.  Moreover,  the  experiment  was  repeated  several  times 
by  !MM.  Flandrin  and  Magendie," — careful  and  accurate  observers, — 
yet,  in  no  case,  was  the  milk  found  in  the  chj^liferous  vessels.     The 

1  Observations  on  certain  parts  of  the  Animal  Economy,  with  notes  by  Richard 
Owen,  F.  R.  S.,  Bell's  Library  edit.,  p.  307,  Philad.,  1840. 

2  Philosoph.  Transact,  for  1701,  p.  996.  ^  n.jd.,  p.  819. 

*  Institut.  Physiol.,  §  422.  ^  Journal  Complement.,  xviii.  327. 

6  Precis,  &c.,  edit,  citat.,  ii.  201. 


OF   DEINKS.  233 

first  experiment  of  Hunter  could  not,  therefore,  be  looked  upon  as 
satisfactory.  Some  source  of  fallacy  must  have  occurred,  otherwise  a 
repetition  of  the  experiment  should  have  been  attended  with  like  re- 
sults, and  we  shall  find,  hereafter,  that  in  another  experiment,  by  that 
distinguished  individual,  a  source  of  illusion  existed,  of  which  he  was 
not  aware,  that  was  sufficient  to  account  for  the  appearance  he 
noticed. 

The  experiments  of  Hunter  with  odorous  and  coloured  substances 
were  repeated  by  many  physiologists,  and  found  even  less  conclusive 
than  that  with  the  milk.  M.  Flandrin,  who  was  professor  in  the  Vete- 
rinary School  at  Alfort,  in  France,  thought  that  he  could  detect,  in 
horses,  an  herbaceous  odour  of  the  blood  of  the  mesenteric  veins,  but 
not  of  the  chyle.  He  gave  a  horse  a  mixture  of  half  a  pound  of  honey, 
and  the  same  quantity  of  asafoetida ;  and,  whilst  the  smell  of  the  latter 
was  distinctly  perceptible  in  the  venous  blood  of  the  stomach  and  in- 
testine, no  trace  of  it  existed  in  arterial  blood  and  chyle.  Sir  Everard 
Home,^  having  administered  tincture  of  rhubarb  to  an  animal,  around 
whose  thoracic  duct  he  had  placed  a  ligature,  found  the  rhubarb  in  the 
bile  and  urine.  M.  Magendie  gave  to  dogs,  whilst  digesting,  a  quan- 
tity of  alcohol  diluted  with  water ;  and  solutions  of  camphor,  and  other 
odorous  fluids :  on  examining  the  chyle,  half  an  hour  afterwards,  he 
could  not  detect  any  of  those  substances;  but  the  blood  of  the  mesen- 
teric veins  exhaled  the  odour,  and  afforded  the  substances  by  distilla- 
tion. He  gave  to  a  dog  four  ounces  of  a  decoction  of  rhubarb ;  and, 
to  another,  six  ounces  of  a  solution  of  prussiate  of  potassa  in  water. 
Half  an  hour  afterwards,  no  trace  of  these  substances  could  be  detected 
in  the  fluid  of  the  thoracic  duct ;  whilst  they  could  be  in  the  urine. 
On  another  dog,  he  tied  the  thoracic  duct,  and  gave  it  two  ounces  of  a 
decoction  of  nux  vomica.  Death  occurred  as  speedily  as  in  an  animal 
in  which  the  thoracic  duct  was  pervious.  The  result  was  the  same, 
when  the  decoction  was  thrown  into  the  rectum,  where  no  proper  chy- 
liferous  vessels  exist.  Having  tied  the  pylorus  in  dogs,  and  conveyed 
fluids  into  their  stomachs,  absorption  equally  took  place,  and  with  the 
same  results.  Lastly,  with  M.  Delille,^  he  performed  the  following 
experiment  on  a  dog,  which  had  eaten  a  considerable  quantity  of  meat, 
in  order  that  the  chyliferous  vessels  might  be  easily  perceived.  An 
incision  was  made  through  the  abdominal  parietes ;  and  a  portion  of 
the  small  intestine  drawn  out,  on  which  two  ligatures  were  applied  at 
a  short  distance  from  each  other.  The  lymphatics,  which  arose  from 
this  portion  of  the  intestine,  were  very  white,  and  apparent  from  the 
chyle  that  distended  them.  Two  ligatures  were  placed  around  each  of 
them ;  and  they  were  divided  between  the  ligatures.  Every  precau- 
tion was  taken,  that  the  portion  of  intestine  drawn  out  of  the  abdomen 
should  have  no  connexion  with  the  rest  of  the  body  by  lymphatics. 
Five  mesenteric  arteries  and  veins  communicated  with  this  portion  of 
the  intestine.  Four  of  the  arteries  and  as  many  veins  were  tied,  and 
cut  in  the  same  manner  as  the  lymphatics.  The  two  extremities  of 
the  portion  of  intestine  were  now  divided,  and  separated  entirely  from 

'  Lectures  on  Comparative  Anatomj,  i.  221,  Lond.,  1814. 
^  Precis,  kc,  ii.  203. 


234  ABSORPTION'. 

the  rest.  A  portion,  an  inch  and  a  half  long,  thus  remained  attached 
to  the  body  by  a  mesenteric  artery  and  vein  only.  These  two  vessels 
were  separated  from  each  other  by  a  distance  of  four  fingers'  breadth ; 
and  the  areolar  coat  was  removed,  to  obviate  the  objection,  that  lym- 
phatics might  exist  in  it.  Two  ounces  of  a  decoction  of  nux  vomica 
were  now  injected  into  this  portion  of  intestine,  and  a  ligature  was 
applied  to  prevent  the  exit  of  the  injected  liquid.  The  intestine, 
surrounded  by  fine  linen,  was  replaced  in  the  abdomen ;  and,  in  six 
minutes,  the  effects  of  the  poison  were  manifested  with  their  ordinary 
intensity: — every  thing  occurred  as  if  the  intestine  had  been  in  its 
natural  condition.  M.  Scgalas^  performed  a  similar  experiment,  leav- 
ino-  the  intestine,  however,  communicating  with  the  rest  of  the  body 
by  chyliferous  vessels  only.  On  injecting  a  solution  of  half  a  drachm 
of  alcoholic  extract  of  nux  vomica  into  the  intestine;  the  poisoning, 
which,  in  the  experiment  of  M.  Magendie,  took  efl'ect  in  six  minutes, 
Lad  not  occurred  at  the  expiration  of  half  an  hour;  but  when  one  of 
the  veins  was  untied  and  the  circulation  re-established,  it  supervened 
immediately.  Westrumb^  mixed  rhubarb,  turpentine,  indigo,  prussiato 
of  potassa,  and  acetate  of  lead  with  the  food  of  rabbits,  sheep,  and 
dogs.  They  were  detected  in  the  veins  of  the  intestines  and  in  the 
urine,  but  not  in  the  chyle.  The  same  facts  were  observed  by  Mayer' 
when  rhubarb,  saffron,  and  prussiate  of  potassa  were  introduced  into 
the  stomach.  MM.  Tiedemann  and  Gmelin  likewise  observed  that  the 
absorption  of  different  colouring  and  odorous  substances  from  the  in- 
testinal canal  was  effected  exclusively  by  the  veins.  Indigo,  madder, 
rhubarb,  cochineal,  litmus,  alkanet,  camboge,  verdigris,  musk,  cam- 
phor, alcohol,  spirits  of  turpentine.  Dip  pel's  animal  oil,  asafoetida, 
garlic,  the  salts  of  lead,  mercury,  iron,  and  baryta,  were  found  in  the 
venous  blood,  but  never  in  the  chyle.  Prussiate  of  potassa  and  sul- 
phate of  potassa  were  the  only  substances,  w^hich,  in  their  experiments, 
had  entered  the  chyliferous  vessels. 

Such  are  the  chief  facts  and  considerations  on  which  the  believers 
in  the  chyliferous  absorption  and  venous  absorption  of  drinks  rested 
their  respective  opinions.  The  strength  was  manifestly  with  the  latter. 
Let  it  be  borne  in  mind,  that  no  sufficient  experiments  had  been  made, 
to  encourage  the  idea,  that  any  thing  is  contained  in  the  chyliferous 
vessels  except  chyle ;  and  that  nearly  all  were  in  favour  of  absorption 
by  the  mesenteric  veins.  An  exception  to  this,  as  regards  the  chjdife- 
rous  and  lymphatic  vessels,  seemed  to  exist  in  the  case  of  certain  salts. 
The  prussiate  and  the  sulphate  of  potassa — we  have  said — were  detected 
in  the  thoracic  duct  by  MM,  Tiedemann  and  Grmelin;  the  sulphate  of 
iron  and  the  prussiate  of  potassa  were  found  there  by  Messrs.  Harlan, 
Lawrence,  and  Coates''  of  Philadelphia ;  and  the  last  of  these  salts  by 
Dr.  Macneven,  of  Xew  York.     "  I  triturated,"  says  Dr.  Macneveu,* 

'  Magendie's  Journal  de  Pliysiologie,  torn.  ii. ;  and  Precis,  &c.,  ii.  208. 
2  De  Phaenomenis  qu»  ad  Vias  sic  dictas  Lotii  claudestinas  referuntur,  Gotling., 
1819. 

^  MeckePs  Arcliiv.,  Band.  iii. 

*  Philad.  Jouru.  of  IMed.  and  Phys.  Sciences,  vol.  ii.  ;  and  Harlan's  Medical  and 
Physical  Researches,  p.  458.     Philad.,  1835. 

*  JS'ew  York  Med.  and  Phys.  Journ.,  June,  1822. 


OF   DRINKS.  235 

"  one  draclim  of  crystallized  hydrocyanate  of  potassa  with  fresh  butter 
and  crumbs  of  bread,  which  being  made  into  a  bolus  the  same  dog 
swallowed  and  retained.  Betweeo  three  and  four  hours  afterwards,  Dr. 
Anderson  bled  him  largely  from  the  jugular  vein,  A  dose  of  hydro- 
cyanic acid  was  then  administered,  of  which  he  died  without  pain,  and 
the  abdomen  was  laid  open.  The  lacteals  and  thoracic  duct  were  seen 
well  filled  with  milk-white  chyle.  On  scratching  the  receptaculum, 
and  pressing  down  on  the  duct,  nearly  half  a  teaspoonful  of  chyle  was 
collected.  Into  this  were  let  fall  a  couple  of  drops  of  the  solution  of 
permuriate  of  iron,  and  a  deep  blue  was  the  immediate  consequence." 
Professor  J.  Muller'  placed  a  frog  with  its  posterior  extremities  in  a 
solution  of  prussiate  of  potassa,  which  reached  nearly  as  high  as  the 
anus,  and  kept  it  so  for  two  hours.  He  then  carefully  washed  the  ani- 
mal, and  having  wiped  the  legs  dry,  tested  the  lymph  taken  from  under 
the  skin  with  a  persalt  of  iron ;  it  immediately  assumed  a  bright  blue 
colour,  while  that  of  the  serum  of  the  blood  was  scarcely  affected  by 
the  test.  In  a  second  experiment,  in  which  the  frog  was  kept  only  one 
hour  in  the  solution,  the  salt  could  not  be  detected  in  the  lymph.  These 
exceptions  are  strikingly  corroborative  of  the  rule.  Of  the  various 
salts  employed,  only  those  mentioned  appear  to  have  been  detected  in 
the  chyle  of  the  thoracic  duct.  It  is,  therefore,  legitimately  presumable, 
that  they  entered  adventitiously,  and  probably  by  simple  endosmose — 
the  mode  in  which  venous  absorption  seems  to  be  etYected. 

The  property  of  endosmose  possessed  by  animal  tissues,  has  already 
been  the  subject  of  remark,^  It  was  then  shown,  that  they  are  not  all 
equally  penetrable  ;  and  that  different  fluids  possess  different  penetra- 
tive powers.  Such  was  proved  to  be  the  case  in  the  experiments  of 
MM.  Tiedemann  and  Gmelin  on  the  subject  under  discussion.  Although 
various  substances  were  placed  in  the  same  part  of  the  intestinal  canal, 
they  were  not  all  detected  in  the  blood  of  the  same  vessels.  Indigo 
and  rhubarb  were  found  in  the  blood  of  the  vena  porta.  Camphor, 
musk,  spirit  of  wine,  spirit  of  turpentine,  oil  of  Dippel,  asafoetida, 
garlic,  not  in  the  blood  of  the  intestines,  but  in  that  of  the  spleen  and 
mesentery ;  prussiates  of  iron,  lead,  and  potassa,  in  that  of  the  veins 
of  the  mesentery ;  those  of  potassa,  iron,  and  baryta,  in  that  of  the 
spleen  ;  prussiate  of  potassa,  and  sulphates  of  potassa,  iron,  lead,  and 
baryta,  in  that  of  the  vena  porta  as  well  as  in  the  urine  ;  whilst  mad- 
der and  camboge  were  found  in  the  latter  fluid  only. 

Experiments  by  MM,  Flaudin  and  Danger^  confirmed  the  general  rule 
of  the  absorption  of  poisons  from  the  digestive  canal  by  the  branches 
of  the  vena  porta,  and  the  diversity  of  locality  in  which  they  are  met 
with.  Their  latest  examinations  were  on  the  absorption  of  the  salts 
of  lead,  which  they  detected  in  the  digestive  tube,  liver,  spleen,  kidneys, 
and  lungs,  but  not  in  the  blood,  heart,  brain,  muscles,  or  bones. 

The  evidence  in  favour  of  the  action  of  the  chyliferous  vessels  being 
restricted  to  the  absorption  of  chyle,  whilst  the  intestinal  veins  take 
up  other  matters,  has  not  been,  however,  considered  by  some  as 
conclusive  as  it  is  by  us.     M.  Adelon,'^  for  example,  concludes,  that,  as 

'  Handbuch  der  Pliysiologie,  u.  s.  w.  Baly's  translation,  p.  279.     Lond.,  1838. 
2  Page  6(3.  ■  3  Gazette  Medicale,  3  Fevr.,  1844. 

*  Pliysiologie  de  I'Homme,  edit,  cit.,  iii.  111. 


236  ABSORPTION". 

the  sectators,  on  botli  sides,  employ  absolutely  tLe  same  arguments,  we 
are  compelled  to  admit,  that  the  two  vascular  systems  are  under  exactly 
similar  conditions;  and  both,  consequentl}'',  participate  in  the  function. 
"We  have  seen,  that  whatever  may  be  the  similarity  of  arguments,  the 
facts  are  certainly  not  equal.*  It  is  proper,  however,  to  remark,  that 
chemical  analysts  experience  great  difficulty  in  detecting  inorganic 
substances  when  these  are  mixed  with  certain  of  the  compounds  of 
organization ;  and  this  may  account  for  such  substances  not  having 
been  discovered  in  the  thoracic  duct,  even  when  present  there. 

With  regard  to  the  mode  in  which  the  absorption  of  fluids  is  effected, 
a  difference  of  opinion  has  existed,  and  chiefly  as  regards  the  question, 
— whether,  as  in  the  case  of  the  chjde,  any  elaboration  is  effected,  or 
whether  the  fluid,  when  it  attains  the  interior  of  the  vessel,  is  the  same 
as  without.  The  arguments  in  favour  of  these  different  views  will  be 
detailed  under  the  head  of  Venous  Absorption.  We  may  merely  ob- 
serve, at  present,  that  water, — the  chief  constituent  of  all  drinks, — is 
an  essential  component  of  every  circulating  fluid ; — that  we  have  no 
evidence  that  any  action  of  elaboration  is  exerted  upon  it :  and  that 
the  ingenious  and  satisfactory  experiments  of  Prof.  J.  K.  Mitchell,* 
have  shown,  that  it  penetrates  most,  if  not  all,  animal  tissues  better 
than  any  other  liquid ;  and,  consequentlj',  passes  through  them  to  accu- 
mulate in  any  of  its  own  solutions.  It  is  probably  in  this  way — that 
is,  by  imbibition, — that  all  venous  absorptions  are  effected. 

But  it  has  been  said: — if  fluids  pass  so  readily  through  the  coats  of 
the  veins, — by  reason  of  the  extensive  mucous  surface,  with  which 
they  come  in  contact,  a  large  quantitj^  of  extraneous  and  heteroge- 
neous fluid  must  enter  the  abdominal  venous  system  Avhen  we  drink 
freely,  and  the  composition  of  the  blood  be  consequently  modified; 
and,  if  it  should  arrive,  in  this  condition,  at  the  heart,  the  most  serious 
consequences  might  result.  It  has,  indeed,  been  affirmed  by  a  distin- 
guished member  of  the  profession^  in  this  country,  in  a  more  inge- 
nious than  forcible  argument  to  support  a  long-cherished — but  now 
almost  universally  abandoned — hypothesis,  that  "  it  must  at  least  be 
acknowledged,  that  no  substance,  in  its  active  state,  does  reach  the 
circulation,  since  it  is  shown,  that  a  small  portion  even  of  the  mildest 
fluid,  as  milk  or  mucilage,  oil  or  pus,  cannot  be  injected  into  the 
bloodvessels  without  occasioning  the  most  fatal  consequences."  But 
the  effects  are  here  greatly  dependent  on  the  mode  in  which  the  injec- 
tion is  made.  If  a  scruple  of  bile  be  sent  forcibly  into  the  crural 
vein,  the  animal  generally  perishes  in  a  few  moments.  The  same 
occurs,  if  a  quantity  of  atmospheric  air  be  rapidly  introduced  into  a 
venous  trunk.  The  animal,  according  to  Sir  Charles  Bell,*  dies  in  an 
instant,  when  a  very  little  air  is  blown  in : — and  there  is  no  suffering 
nor  struggle,  nor  any  stage  of  transition,  so  immediately  does  the 
stillness  of  death  take  })ossession  of  every  part  of  the  frame.  In  this 
way,  according  to  Beauchene,  Larrey,  Bupuytren,  Warren  of  Boston, 
Mott  and  Stevens  of  New  York,  Delpech,  and  others,  operations  at 

'  Bostock's  Physiol.,  3d  edit.,  p.  607.     Lond.,  1836. 

'  American  Journal  of  the  Medical  Sciences,  vii.  44,  58. 

'  Chapman,  Elements  of  Therajjeutics,  6th  edit.,  p.  47,  Philad.,  1831. 

*  Animal  Mechanics,  P.  ii.  p.  42,  London,  1829. 


OF   DRINKS.  237 

times  prove  fatal; — the  air  being  drawn  in  by  the  divided  veins.  If, 
however,  the  scruple  of  bile,  or  the  same  quantity  of  atmospheric  air 
be  injected  into  one  of  the  branches  of  the  vena  porta,  no  apparent 
inconvenience  is  sustained,  M,  Magendie^  concludes,  from  this  fact, 
that  the  bile  and  atmospheric  air,  in  their  passage  through  the  my- 
riads of  small  vessels  into  which  the  vena  porta  divides  and  subdivides 
in  the  substance  of  the  liver,  become  thoroughly  mixed  with  the 
blood,  and  thus  arrive  at  the  vital  organs  in  a  condition  to  be  unpro- 
ductive of  mischief.  This  view  is  rendered  the  more  probable  by  the 
fact,  that  if  the  same  quantity  of  bile  or  of  air  be  injected  very  slowly 
into  the  crural  vein,  no  perceptible  inconvenience  is  sustained.  Dr. 
BkindelP  injected  in  this  manner  five  drachms  into  the  femoral  vein 
of  a  very  small  dog,  with  only  temporary  inconvenience ;  and,  subse- 
quently, three  drachms  of  expired  air,  without  much  temporary  dis- 
turbance ;  and  M,  Lepelletier^  affirms,  that  in  the  amphitheatre  of  the 
Ecole  Pratique  of  Paris,  in  the  presence  of  upwards  of  two  hundred 
students,  he  injected  thrice  into  the  femoral  vein  of  a  dog,  of  middle 
size,  at  a  minute's  interval,  three  cubic  inches  of  air,  without  observ- 
ing any  other  effect  than  struggling,  whining,  and  rapid  movements 
of  deglutition ;  and  these  phenomena  existed  only  whilst  the  injection 
was  going  on.  Since  that  he  has  often  repeated  the  experiment  with 
identical  results, — "proving,"  he  observes,  "that  the  deadly  action  of 
the  air  is,  in  such  case,  mechanical,  and  it  is  possible  to  prevent  the 
fatal  effects  by  injecting  it  so  gradually,  that  the  blood  has  power  to 
disseminate,  and  perhaps  even  to  dissolve  it  with  sufficient  prompti- 
tude to  prevent  its  accumulation  in  the  cardiac  cavities."  From  the 
experiments  of  Mr.  Erichsen,  however,  the  cause  of  death  in  such 
cases,  would  appear  to  be  asphyxia.'' 

As  liquids  are  frequently  passed  off  by  the  urinary  organs  soon 
after  they  have  been  swallowed,  it  has  been  believed  by  some, — either 
that  there  are  vessels  which  form  a  direct  communication  between  the 
stomach  and  bladder ;  or  that  a  transudation  takes  place  through  the 
parietes  of  the  stomach  and  intestine,  and  that  the  fluids  proceed 
through  the  intermediate  areolar  tissue  to  the  bladder.  Both  these 
views,  we  shall  hereafter  show,  are  devoid  of  foundation. 

In  animals,  in  which  the  cutis  vera  is  exposed,  or  the  cuticle  very 
thin,  nutritive  absorption  is  effected  through  that  envelope.  In  the 
polypi,  medusae,  radiaria,  and  vermes,  absorption  is  active,  and  accord- 
ing to  Zeder  and  Rudolphi,^  entozoa,  that  live  in  the  midst  of  animal 
humours,  imbibe  them  through  the  skin.  A  few  years  ago,  Jacobson® 
instituted  experiments  on  the  absorbing  power  of  the  helix  of  the  vine 
{Limagon  des  vignes).  A  solution  of  prussiate  of  potassa  was  poured 
over  the  body.  This  was  rapidly  absorbed,  and  entered  the  mass  of 
blood  in  such  quantity,  that  the  animal  acquired  a  deep  blue  colour 
when  sulphate  of  iron  v.^as  thrown  upon  it.     In  the  frog,  toad,  sala- 

'  Precis  Elementaire,  2de  edit.,  ii.  433.         ^  Medico-Chinirg.  Trans,  for  1818,  p.  65. 
3  Physiologie  Medicale  et  Pliilosophique,  i.  494,  Paris,  1831. 
<  Berard,  Cours  de  Physiologie,  iv.  94,  Paris,  1855. 
*  Entozooriim  Histor.,  i.  252,  275,  Berlin,  1829. 

^  Memoir,  de  I'Acad.  des  Sciences  de  Berlin,  1825,  and  Tiedemann,  Traite  Complet 
de  Physiologie  de  PHomme,  edit.  Fr.,  p.  242,  Paris,  1831. 


238 


ABSORPTION. 


mander,  &c.,  cutaneous  absorption  is  so  considerable,  tbat  occasionally 
the  weight  of  water,  taken  in  this  way,  is  equal  to  that  of  the  whole 
body.  It  will  be  seen  hereafter,  that  the  nutrition  of  the  foetus  in 
utero  is  mainly,  perhaps,  accomplished  by  nutritive  absorption  effected 
through  the  cutaneous  envelope. 

II.   ABSORPTION  OF  LYMPH  OR  LYMPHOSIS. 

This  function  is  effected  by  agents,  that  strongly  resemble  those 
concerned  in  the  absorption  of  chyle.  One  part  of  the  vascular  appa- 
ratus is,  indeed,  common  to  both, — the  Ihoracic  duct.  We  are  much 
less  acquainted,  however,  with  the  physiology  of  lymphatic,  than  of 
chyliferous,  absorption. 

1.   ANATOMY  OF  THE  LYMPHATIC   APPARATUS. 

The  lymphatic  apparatus  consists  of  lymphatic  vessels,  lymphatic 

glands   or    ganglia, 
Fig.  69.  and    thoracic    duct. 

The  latter,  however, 
does  not  form  the 
medium  of  commu- 
nication between  all 
the  lymphatic  ves- 
sels and  the  venous 
system. 

1.  Lymphatic  ves- 
sels.— These  vessels 
exist  in  almost  all 
parts  of  the  body; 
and  have  the  shape 
of  cylindrical,  trans- 
parent, membranous 
tubes,  of  small  size, 
anastomosing  freely 
with  each  other,  so 
as  to  present,  every- 
where, a  reticular  ar- 
rangement. They 
are  never,  according 
to  Professor  M  tiller, 
so  small  as  the  arte- 
rial and  venous  ca- 
])illaries,  and  are,  al- 
most without  excep- 
-rr     ,       ,  T       ,    .    .,     ,  tion,  visible   to  the 

Vessels  and  Lymphatic  Glands  of  Axilla.  V    A  P      "R 

1.   The   axillary   artery.     2.    Axillary   vein.    3.    Brachial   artery.     4.  E.^        .       ^^^' 

Brachial  vein.     o.  Primitive  carotid  artery.     6.    Internal  jugular  vein.  TrCviraUUS      aSSCrtS, 

7.  Subcutaneous  lymphatics  of  arm  at  its  upper  part.     8.  Two" or  three  of  .i      ,    .-i      ■  11-,     Tlz 

the  most  inferior  and  superficial  glands  into  which  the  superficial  lyni-  tliat  tUCir  WaliS,   llKG 

phatics  empty.     9.   Deep-seated   lymphatics  which  accompany  brachial  iK„       orpnior       mpm- 

artery.     10.    Lymphatics  and  glands   which   accompany   infra-.scapular  ^^^^      clXt-Uldl        iiiciu- 

bloodvessels.  11.  Glands  and  lymphatics  accompanying  thoracica  longa  braUC  and  OtllCr  tiS- 
artery.     12.  Deeper-seated  lymphatics.     1.3.  Axillary  chain  of  glands.     14.  '  ,  p 

Acromial  branches  of  lymphatics.  1.5.  Jugular  lymphatics  and  glands.  SUCS,  are  made  Up  01 
16,  17.  Lymphatics  which  empty  into  subclavian  vein  near  its  junction  •        ,  i  ..„..„, 

with  right  internal  jugular  vein.  minutc    elementary 


LYMPHOSIS. 


239 


Fis.  70. 


cylinders,  of  a  diameter  of  from  O'OOl  to  0*006  millimetres,  placed  in  a 
series,  side  by  side  and  end  to  end,  so  as  to  constitute  tiibes  wbicli 
form  networks,  and  open  into  larger  lymphatic  trunks.  They  are  ex- 
tremely numerous;  more  so,  however,  in  some  parts  than  others. 
They  have  not  been  found  in  the  brain,  spinal  marrow,  eye,  or  internal 
ear,  bones,  cartilages,  or  any  non-vascular  parts;  but  this  is  not  a  posi- 
tive proof,  that  they  do  not  exist  in  some  of  them.  It  may  be,  that 
they  are  so  minute  as  to  escape  observation.  In  their  progress  towards 
the  venous  system,  they  go  on  forming  fewer  and  fewer  trunks;  yet 
always  remain  small.  This  uniformity  in  size  is  peculiar  to  them. 
When  an  artery  sends  oft'  a  branch,  its  size  is  sensibly  diminished ; 
and  when  a  vein  receives  a  branch,  it  is  enlarged ;  but  when  a  lym- 
phatic ramifies,  there  is  generally  little  change  of  size,  whether  the 
branch  given  off  be  large  or  small. 

The  lymphatics  consist  of  two  planes, — the  one  superficial^  the  other 
deep-seated.  The  former  creep  under  the  outer  covering  of  the  organ, 
or  of  the  skin,  and  accompany  the  subcutaneous  veins.  The  latter  are 
seated  more  deeply  in  the  interstices  of  the  muscles,  or  even  in  the 
tissue  of  parts ;  and  accompany  the  nerves  and  great  vessels.  These 
planes  anastomose  with  each  other. 

This  arrangement  occurs  not  only  in  the  limbs,  but  the  trunk, 
and  in  every  viscus.  In  the 
trunk,  the  superficial  plane 
is  beneath  the  skin;  and  the 
deep-seated  between  the  mus- 
cles and  the  serous  membrane 
that  lines  the  splanchnic  cavi- 
ties. In  the  viscera,  one 
plane  occupies  the  surface; 
the  other  appears  to  arise 
from  the  parenchyma. 

The  two  great  trunks  of  the 
lymphatic  system,  in  which 
the  lymphatic  vessels  of  the 
various  parts  of  the  body 
terminate,  are  the  thoracic 
duct,  and  the  great  lym- 
phatic trunk  of  the  right  side. 
The  course  of  the  thoracic 
duct  has  been  described  al- 
ready. It  is  formed  of  three 
great  vessels ; — one,  in  which 
all  the  lymphatics  and  lac- 
teals  of  the  intestines  termi- 
nate ;  and  the  other  two, 
formed  by  the  union  of  the 


Lympbatic  Vessels  and  Glands  of  the  Groin  of  the 
Right  Side. 

1.  Saphena  magna  vein.  2.  Veins  on  the  surface  of  abdo- 
men. 3.  External  pudic  vein.  4.  Lymphatic  ves.sels  col- 
lected iu  fasciculi  and  accompanying  the  sapheua  vein  on 
its  inner  side.  6.  External  trunks  of  the  same  set  of  vessels. 
6.  Lymphatic  gland  which  receives  all  these  vessels.  It 
_  .  is  placed  on  the  termination  of  the  saphena  vein.     7.  Ef- 

lymphaticS  of  the  lower  half     Cerent  trunks  from  this  gland;   they  become  deep-seated 
p     \         T       ^  r\  •  n  ^^^  accompany  the  femoral  artery.     8.  One  of  the  more 

01     the     body.       Occasionally,      external  lymphatic  glands  of  the  groin.     9.  A  chain  of  four 
+1-IQ    /-1n,^+  *■         e  1      or  five  inguinal  glands,  which  receive  the  lymphatics  from 

tne    aUCt    consists    OI    several     the  genltaU,  abdomen,  and  external  portion  of  the  thigh. 

trunks,  which  unite  into  one 

before  reaching  the  subclavian  vein;  but  more  frequently  it  is  double. 


240  ABSORPTION. 

In  addition  to  the  l3^rnphatics  of  the  lower  half  of  the  body,  the  thoracic 
duct  receives  a  great  part  of  those  of  the  thorax,  and  all  those  from 
the  left  half  of  the  upper  part  of  the  body.  At  its  termination  in  the 
subclavian,  there  is  a  valve  so  disposed  as  to  allow  the  lymph  to 
pass  into  the  blood ;  and  to  prevent  the  reflux  of  the  blood  into  the 
duct.  We  shall  see,  however,  that  its  mode  of  termination  in  the 
venous  system  possesses  other  advantages.  The  great  lymphatic 
trunk  of  the  right  side  is  formed  by  the  absorbents  from  that  side  of 
the  head  and  neck,  and  from  the  right  arm.  It  is  rery  short,  being 
little  more  than  an  inch,  and  sometimes  not  a  quarter  of  an  inch,  in 
length, — but  of  a  diameter  nearly  as  great  as  the  thoracic  duct.  A 
valve  also  exists  at  the  mouth  of  this  trunk,  which  has  a  similar  ar- 
rangement and  office  with  that  of  the  left  side. 

The  lymphatics  have  been  asserted  to  be  more  numerous  than  the 
veins;  by  some,  indeed,  the  proportion  has  been  estimated  at  fourteen 
superficial  lymphatics  to  one  superficial  vein ;  whence  it  has  been  de- 
duced, that  the  capacity  of  the  lymphatic  is  greater  than  that  of  the 
venous  system.  This  must  be  mere  matter  of  conjecture.  The  same 
may  be  said  of  the  speculations  that  have  been  indulged  regarding  the 
mode  in  which  the  l3nxiphatic  radicles  arise, — whether  by  open  mouths 
or  by  some  spongy  mediate  body.  The  remarks  made  regarding  the 
chylous  radicles  apply  with  equal  force  to  the  lymphatic. 

It  has  been  a  matter  of  some  interest  to  determine,  whether  the 
lymphatic  vessels  have  other  communications  with  the  venous  system 
than  by  the  two  trunks  just  described;  or,  whether,  soon  after  their 
origin,  they  do  not  open  into  the  neighbouring  veins, — an  opinion  held 
by  many  of  those,  who  believe  in  the  doctrine  of  absorption  by  the 
lymphatics  exclusively,  to  explain  why  absorbed  matters  are  found  in 
the  veins.  Several  of  the  older,  as  well  as  more  modern,  anatomists, 
have  professed  this  opinion;  whilst  it  has  been  strenuously  combated 
by  Sommering,  Eudolphi,^  and  others.  Yieussens  affirmed,  that,  by 
means  of  injections,  lymphatic  vessels  were  distinctly  seen  originating 
from  the  minute  arteries,  and  terminating  in  small  veins.  Sir  William 
Blizard^  asserts,  that  he  twice  observed  lymphatics  terminating  directly 
in  the  iliac  veins.  Mr.  Bracy  Clarke^  found,  that  the  trunk  of  the 
lymphatic  system  of  the  horse  had  several  openings  into  the  lumbar 
veins.  M.  Ribes,"  by  injecting  the  supra-hepatic  veins,  saw  the  sub- 
stance of  the  injection  enter  the  superficial  lymphatics  of  the  liver. 
M.  Alard*  considers  that  the  lymphatic  and  venous  systems  communi- 
cate at  their  origins.  Vincent  Fohmann^  thinks,  that  the  lymphatic 
vessels  communicate  directly  with  the  veins,  not  only  in  the  capillaries, 
but  in  the  interior  of  the  lymphatic  glands.  Lauth,^  of  Strasburg, — 
who  went  to  Heidelberg  to  learn  from  Fohmann  his  plan  of  injecting, — 
announced  the  same  facts  in  1824.     By  this  anatomical  arrangement, 

'  Gnindriss  der  Physiologie,  u.  s.  w.,  2ter  Band,  2te  Abtheilung,  S.  247,  Berlin,  1S28. 

^  Physiological  Observations  on  the  Absorbent  System  of  Vessels,  Lend.,  1787. 

'  Rees's  Cyclopedia,  art.  Anatomy,  Veterinary.  *  Magendie,  Precis,  etc.,  ii.  238. 

^  Du  Siege  et  de  la  Nature  des  Maladies,  ou  Nouvelles  Considerations  touchaut  la 
Veritable  Action  du  Systeme  Absorbant,  etc.,  Paris,  1821. 

^  Ueber  die  Verbindung  der  Saugadem  mit  den  Venen,  Heidelb.,  1821 ;  and  Das 
Saugadersystem  der  Wirbelthiere,  Heft  1,  Ileidelb.,  1824;  and  Mem.  sur  lea  Communi- 
cations des  Vaisseaux  Lymphatiques  avec  les  Veines,  Liege,  1832. 

^  Essai  sur  les  Vaisseaux  Lymphatiques,  Strasbourg,  1824. 


LYMPHATIC   APPARATUS.  241 

Lautli  explains  how  an  injection,  sent  into  the  arteries,  reaches  the 
lymphatics,  without  being  eiilised  into  the  areolar  tissne;  the  injection 
passing  from  the  arteries  into  the  veins,  and  thence,  by  a  retrograde 
route,  into  the  lymphatics.  M.  Beclard  believed,  that  this  communi- 
cation exists  at  least  in  the  interior  of  the  lymphatic  glands;  and  he 
supported  his  opinion  by  the  fact,  that  in  birds,  in  which  these  glands 
are  wanting,  and  are  replaced  by  plexuses,  the  lymphatic  vessels  in  the 
plexuses  are  distinctly  seen  opening  into  the  veins.  Lippi'  has  made 
these  communications  the  subject  of  an  express  work.  According  to 
him,  the  most  numerous  exist  between  the  lymphatic  vessels  of  the 
abdomen,  and  the  vena  cava  inferior  and  its  branches.  So  numerous 
are  they,  that  every  vein  receives  a  lymphatic  vessel,  and  the  sum  of 
all  would  be  sufficient  to  form  several  thoracic  ducts.  Opposite  the 
second  and  third  lumbar  vertebree,  the  lymphatic  vessels  are  manifestly 
divided  into  two  orders : — some  ascending,  and  emptying  themselves 
into  the  thoracic  duct;  others  descending,  and  opening  into  the  renal 
vessels  and  pelves  of  the  kidnej^s.  Lippi  admits  the  same  arrange- 
ment, as  regards  the  chyliferous  vessels;  and  he  adopts  it  to  explain 
the  promptitude  with  which  drinks  are  evacuated  by  the  urine. 

Subsequent  researches  have  not,  in  general,  confirmed  the  statements 
of  Lippi.  G.  Kossi,^  indeed,  maintains,  that  the  vessels,  which  Lippi 
took  for  lymphatics,  were  veins.  It  would  appear,  however,  that  when 
Eossi  was  in  Paris,  he  was  unable  to  demonstrate,  when  requested  to 
do  so  by  M.  Breschet,  the  very  things,  that  he  had  previously  figured 
and  described.  Panizza,  too,  af&rms,  that  no  direct  union  or  continuity 
between  the  venous  capillaries  and  lymphatics  has  ever  been  made 
manifest  to  the  eye,  either  in  the  human  subject  or  the  lower  animals:^ 
and,  on  the  whole,  the  observations  of  Lippi  as  to  the  alleged  termina- 
tion of  lymphatics  in  various  veins  of  the  abdomen  have  generally 
been  either  rejected  as  erroneous  or  held  to  refer  to  deviations  from 
the  normal  condition.'*  It  is  proper  to  remark,  however,  that,  recently, 
Dr.  A.  Nuhn,*  Prosector  at  Heidelberg,  has  maintained,  that  there  is  a 
regular  communication  between  the  abdominal  lymphatics  and  veins, 
and  describes  three  cases  of  the  kind  which  fell  under  his  own  observa- 
tion. In  two  of  these,  the  lymphatics  opened  into  the  renal  veins;  in 
the  third  into  the  vena  cava.  The  article  contains  a  good  history  of 
the  views  of  dififereut  observers  on  the  communication  between  the 
absorbents  and  veins. 

We  are  perhaps  justified  in  concluding  with  Panizza,  that  anatomy 
has  not  hitherto  succeeded  in  determining,  with  physical  certainty,  in 
what  relation  the  sanguiferous  and  lymphatic  systems  stand  to  each 
other,  at  their  extreme  ramifications.^     M.  Magendie^  conceives  the 

'  Illustrazioni  Fisiologiche,  etc.,  Firenz.,  1825. 

^  Omodei's  Annali  Universali,  Jan.,  1826. 

8  Osservazioiii  Antropo-zootomico-fisiologiche,  Pavia,  1833;  and  Breschet,  Sjsteme 
Lymphatiqtie,  Paris,  1836. 

'  Quain's  Human  Anatomy,  by  Quain  and  Sliarpey,  Amer.  edit.,  by  Dr.  Leidy,  ii.  43, 
Pliilad.,  1849. 

^  Miiller's  Archiv.  fiir  Anatomie,  u.  s.  w.,  Heft  2,  S.  173,  Berlin,  1848. 

^  See  on  both  sides  of  this  subject,  Miiller's  Handbuch,  u.  s.  w.,  Baly's  translation, 
p-  273,  Lond.,  1838  ;  and  Weber's  Hildebrandt's  Handbuch  der  Anatomie,  iii.  113, 
Braunschweig,  1831.  ^  Precis,  &c.,  ii.  194. 

VOL.  I. — 16 


242 


ABSORPTION. 


Fig.  71. 


most  plausible  view  regarding  tlie  lymphatics  to  be: — that  they  arise 
by  extremely  fine  roots  in  the  substance  of  the  membranes  and  areolar 

tissue,  and  in  the  parenchyma  of 
organs,  where  they  appear  con- 
tinuous with  the  final  arterial 
ramifications; — as  it  fi'equently 
happens,  that  an  injection  sent 
into  an  artery  passes  into  the 
lymphatics  of  the  part  to  whiti*i 
it  is  distributed.  By  some,  they 
are  described  as  commencing  ei- 
ther in  closely  meshed  networks, 
interspersed  among  the  bloodves- 
sels of  the  several  tissues,  or  else 
in  pointed  closed  tubes  or  pro- 
cesses, as  shown  in  the  marginal 
figure  of  the  lymph  and  blood- 
vessels in  a  part  of  the  tail  of  the 
tadpole; — the  bloodvessels  being 
denoted  by  the  corpuscles  in 
them.  In  this  state,  many  of  the 
extremities  of  the  lymphatics  ap- 
pear to  communicate  with  pointed 
or  star-shaped  cells;  but  this,  ac- 
cordins;  to  Messrs.  Kirkes  and 
Paget, ^  may  be  peculiar  to  the 
embryonic  state,  as  no  similar  cells  are  seen  in  the  adult;  nor  is  there 
any  appearance  of  the  existence  of  cells  for  the  elaboration  of  lymph, 
similar  to  those  described  as  existing  in  the  intestinal  villi. 

The  structure  of  the  lymphatic  vessels  is  like  that  of  the  lacteals. 
They  have  the  same  number  and  character  of  coats ;  the  same  crescen- 
tic  valves  or  sphincters,  occurring  in  pairs,  and  giving  them  the  knotted 
and  irregular  appearance,  for  which  they  are  remarkable  ; — every  con- 
traction indicating  the  presence  of  a  pair  of  valves,  or  sphincter.  The 
minutest  lymphatics  seem,  however,  to  be  destitute  of  valves :  but  they 
are  discernible  in  those  of  less  than  one-third  of  a  line  in  diameter, 
and  have  the  same  structure  as  those  of  the  veins.  In  man,  each 
lymphatic,  before  reaching  the  venous  system,  passes  through  a 
lymphatic  gland  or  ganglion,  formerly  called  a  conglobate  gland,  lliese 
organs  are  extremely  numerous;  and  in  shape,  structure,  and  probably 
in  function,  resemble  entirely  the  mesenteric  glands.  (See  page  217.) 
They,  therefore,  do  not  demand  distinct  notice.  They  exist  more  par- 
ticularly in  the  axillae,  neck,  neighbourhood  of  the  lower  jaw,  beneath 
the  skin  of  the  nape  of  the  neck,  and  in  the  groins,  and  pelvis  in  the 
neighbourhood  of  the  great  vessels.  The  connection  between  the 
lymphatics  and  those  glands  is  the  same  as  that  between  the  chyli- 
ferous  vessels  and  mesenteric  glands. 

M.  Chaussier  includes  in  the  lymphatic  system  certain  organs,  whose 
uses  in  the  econoni}"  are  not  manifest, — the  thymus  gland,  the  thyroid, 

•  Manual  of  Physiology,  2d  Amer.  edit.,  p.  209,  Philad.,  1853. 


Bloodvessels  and  Lymphatics  from  the  Tail  of  the 
"Tadpole. 


LYMPHATIC  APPARATUS. 


243 


t"he  supra-renal  capsules,  and  per-  Fig-  72. 

haps  the  spleen.  These  he  con- 
siders to  be  varieties  of  the  same 
species,  and  terms  them  all  glandi- 
form ganglions. 

The  thymus  gland  is  a  body 
consisting  of  distinct  lobes,  situate 
at  the  upper  and  anterior  part  of 
the  thorax  behind  the  sternum. 
It  has  been  considered  to  belong 
more  particularly  to  foetal  exist- 
ence, and  will  be  investigated 
hereafter. 

The  thyroid  gland  or  hody^  is, 
also,  a  lobated  organ,  situate  at  the 
anterior  part  of  the  neck  beneath 
the  skin  and  subcutaneous  mus- 
cles, and  resting  on  the  anterior 
and  inferior  part  of  the  larynx, 
and  first  rings  of  the  trachea.  It  is 
formed  of  lobes,  which  subdivide 
into  lobules  and  granula ;  is  of  a 
red,  and  at  times  yellow  colour ; 
and  presents,  internally,  cells  or 
vesicles,  filled  with  a  viscid  and 
colourless  or  yellowish  fluid, 
which,  collected  on  the  point  of  a 
knife  after  incising  the  gland,  ap- 
pears like  a  weak  solution  of  gum, 
and  is  almost  devoid  of  the  ropi- 
ness  of  white  of  egg.  Putintocom- 
mon  rectified  spirit,  it  seems  to  lose 
only  a  little  water ;  becomes  solid, 
but  not  opaque ;  and  loses  but 
little.  The  same  effects  result  in 
the  cells  when  the  gland  is  boiled 
for  a  quarter  of  an  hour  :  no  ap- 
parent solution  occurs.  The  thy- 
roid gland  has  no  excretory  duct ; 
and,  consequently,  it  is  difiicult  to 
imagine  its  use.  It  is  larger  in 
the  foetus  than  in  the  adult,  and 
has  been  supposed  to  be,  in  some 
way,  inservient  to  foetal  existence. 
It  continues,  however,  through 
life;  receives  large  arteries,  as 
well  as  a  number  of  nerves  and 
lymphatics,  and  hence,  it  has  been 
supposed,  fills  some  important  of&ce  through  the  whole  of  existence. 
This,  however,  is  conjectural.     Mr.  King*  has  affirmed,  what  had  been 

'  Guy's  Hospital  Eeports,  i.  437,  Lond.,  1836,  and  Sir  Astlej  Cooper.,  ibid.,  p.  448. 


A.  One  of  the  inguinal  lymphatic  glands  injpcted 
with  mercury,  a.  Atferent  lymphatic  vessel  fmm  the 
lower  extremity,  b.  Efferent  vessel.  Others  are  also 
seen. 

B.  One  of  the  superficial  lymphatic  trunlis  of  the 
thigh. 

C.  One  of  the  femoral  lymphatic  trunlis  laid  open 
longitudinally  to  display  the  valves  within  it.  c.  Sinus 
between  the  valve  and  tlie  wall  of  the  vessel,  d.  Sur- 
face of  one  valve,  directed  towards  the  opposite,  e. 
Semicircular  attached  margin  of  the  valve. 


Gronpof  Gland  Vesicles  from  the  Thyroid  Glavd  of 
a  child,  a.  Connective  tissue,  b.  Membrane  of  the 
vesicles,    c.  Epithelial  cells. 


244  ABSORPTION. 

already  imagined  by  many,  that  tlie  absorbent  vessels  of  tlie  thyroid 
convey  its  peculiar  secretion  to  the  great  veins  of  the  body.  It  is  the 
seat  of  goitre  or  hronchocele,  the  swelled  necl\  Derhysliire  nech^  ■pai)as,  &c., 
as  it  has  been  termed  in  different  quarters  of  the  globe, — a  singular 
affection,  which  is  common  at  the  base  of  lofty  mountains  in  all  parts 
of  the  world ;  and  for  the  cure  of  which,  we  have  a  valuable  remedy  in 
iodine.  The  eutrophic  agency  of  this  drug  is  particularly  exerted  on 
the  thyroid,  and  it  aflbrds  an  additional  instance,  to  the  many  already 
known,  of  remedial  agents  exerting  their  properties  upon  a  particular 
organ,  without  our  being  able,  in  the  slightest  degree,  to  account  for  the 
preference.  Iodine  stimulates,  perhaps,  the  absorbent  vessels  of  the 
gland  to  augmented  action ;  it  certainly  modifies  the  nutrition  of  the 
organ  ;  and  the  consequence  is  absorption  of  the  morbid  deposit. 

The  supra-renal  or  atrahiliary  capsules  or  glands  are  small  bodies 
in  the  abdomen,  behind  the  peritoneum,  and  above  each  kidney,  which 
are  larger  in  the  fcetus  than  in  the  adult.  The  arteries  distributed  to 
them  are  of  considerable  size.  They  are  lobular  and  granular,  and 
like  the  kidneys,  according  to  Kolliker,  consist  of  a  so-called  cortical^ 
and  a  medullary  portion,  the  former  being  principally  formed  of  a  stroma 
of  connective  tissue,  in  which  are  oval  spaces  filled  with  a  granular 
substance,  mixed  with  nuclei,  or  even  cells.  The  medullary  portion 
also  consists  of  a  stroma  of  connective  tissue  formed  of  lamince,  which 
are  prolonged  from  the  cortical  connective  tissue,  in  the  network  of 
which  lies  a  pale,  fine,  granular  substance,  containing  pale  cells,  and  a 
few  fat  or  pigment  granules,  the  cells  frequently  having  distinct  nucleoli, 
"with  large  nucleoli."^  Sir  Everard  Home^  described  their  interior  as 
filled  with  a  viscid  fluid  pulp  or  oil,  which  is  reddish  in  the  foetus,  yel- 
low in  childhood,  and  brown  in  old  age.  Under  the  microscope,  the  pulp 
has  been  found  to  consist  of  minute  oil-like  spheroids,  of  very  unequal 
size,  varying  from  ^^hoo^^  ^^  so'oo^^^  of  an  inch  in  diameter.^  They 
continue  during  life ;  but  with  their  precise  uses  we  are  unacquainted. 
By  the  ancients,  they  were  believed  to  be  the  secretory  organs  of  the 
imaginary  atrabilis  ;  hence  their  name.  Sir  Everard  Home  considers 
tliat  they  act  like  a  filter,  "by  which  any  oil  left  in  the  arterial  branches 
that  are  near  the  kidneys  may  be  separated,  and  prevented  from  making 
its  escape  by  the  tubee  uriniferge  of  these  glands."  Dr.  Carpenter* 
thought  the  only  function  that  can  be  assigned  them  with  anything 
like  probability,  is  that  of  serving  as  a  means  of  conveying  into  the 
veins  the  blood  sent  through  the  renal  artery,  when,  from  any  cause, 
the  secreting  function  of  the  kidneys  is  partly  or  wholly  checked,  and 
their  capillary  circulation  stagnates  in  consequence. 

All  these  bodies  are  probably  concerned  in  ha3matosis ;  but  at  the 
same  time — as  shown  hereafter, — they  may  act  under  special  circum- 
stances as  diverticula  to  the  blood  and  hence  merit  the  name — now 
generally  assigned  to  them — of  vascular  glands.  Their  functions  are 
treated  of  elsewhere. 

'  Mikroskopische  Anatomie,  2ter  Band,  s.  377,  Leipz.,  1854,  and  Amer.  edit,  of  the 
Sydenham  Society's  edit,  of  his  Manual  of  Histology,  by  Dr.  Da  Costa,  p.  615,  Phila- 
delphia, 1854. 

2  Lect.  on  Comp.  Anat.,  v.  2G2,  Lond.,  1828. 

3  Gulliver,  in  Gerher's  General  Anatomy,  p.  103. 

*  Principles  of  Human  Physiology,  §  710,  Lond.,  1842. 


LYMPH.  245 


Lympli  may  be  procarecl  in  two  ways,  either  by  opening  a  lym- 
pbatic  vessel,  and  collecting  the  fluid  that  issues  from  it, — but  this  is 
an  uncertain  method, — or  by  making  an  animal  fast  four  or  five  days, 
and  obtaining  the  fluid  from  the  thoracic  duct.  This  has  been  con- 
sidered pure  lymph ;  but  it  must  be  mixed  with  the  product  of  the 
digestion  of  the  dift'erent  secretions  from  the  portion  of  the  digestive 
tube  above  the  origin  of  the  chyliferous  vessels.  Chyle  itself  is 
nothing  more  than  lymph  of  the  intestines,  containing  matter  absorbed 
from  the  digested  food ;  and  in  the  intervals  of  digestion  lymph  alone 
is  found  in  the  chyliferous  vessels. 

The  fluid,  obtained  as  above-mentioned,  is  of  a  rosy,  slightly  opal- 
ine tint ;  a  markedly  spermatic  odour,  and  saline  taste.  At  times,  it 
is  of  a  decidedly  yellowish  colour ;  at  others,  of  a  madder  red ;  circum- 
stances which  may  have  given  occasion  to  erroneous  inferences  from 
experiments  made  on  the  absorption  of  colouring  matters.  Its  specific 
gravity  has  been  found,  by  some,  to  be  1022*28 :  by  others,  1*037.  Its 
colour  is  affirmed  to  be  more  rosy  in  proportion  to  the  length  of  time 
the  animal  has  fasted.  When  examined  by  the  microscope,  it  exhibits 
globules  or  corpuscles  like  those  of  the  chyle ;  and,  like  the  chyle, 
bears  considerable  analogy,  in  its  chemical  composition,  to  the  blood. 
Both  may,  indeed,  without  impropriety,  be  regarded  as  rudimental 
blood. 

Bodies  similar  to  these  lymjjh  corpuscles  are  seen  mingled  with  the 
blood,  occupying  generally  the  space  between  the  main  current  and 
the  parietes  of  the  vessel.  Some,  however,  regard  them  as  blood  cor- 
puscles in  process  of  solution  or  disintegration ;  and  M.  MandP  thinks 
they  do  not  exist  in  the  fluid  during  life,  but  are  owing  to  the  coagu- 
lation of  its  fibrin.  More  recently,  he  has  stated,  that  from  experi- 
ments made  with  M.  Breschet,  it  was  evidently  impracticable  to  pro- 
cure pure  lymph  by  opening  the  lymphatic  hearts  of  frogs.  Blood 
globules  always  existed  in  it;  and  this,  he  thinks,  throws  doubts  on 
the  view,  that  lymph  corpuscles  are  transformed  into  blood  corpuscles. 

When  left  at  rest,  lymph  separates  into  two  portions ; — the  one  a 
liquid,  nearly  like  the  serum  of  the  blood  ;  the  other  a  coagulum  or 
clot  of  a  deeper  rosy  hue ;  in  which  is  a  multitude  of  reddish  filaments, 
disposed  in  an  arborescent  manner;  and,  in  appearance,  very  analo- 
gous to  the  vessels  distributed  in  the  tissue  of  organs.  When  a  por- 
tion of  coagulated  lymph  is  examined,  it  seems  to  consist  of  two 
parts : — the  one  solid,  formed  of  numerous  cells,  which  contains  the 
other  or  more  liquid  part ;  and  if  the  former  be  separated,  the  latter 
coagulates.  Mr.  Brande^  collected  the  lymph  from  the  thoracic  duct 
of  an  animal,  that  had  been  kept  without  food  for  twenty-four  hours. 
He  found  its  chief  constituent  to  be  water,  besides  which,  it  contained 
chloride  of  sodium  and  albumen: — the  latter  being  in  such  minute 
quantity,  that  it  coagulated  only  by  the  action  of  galvanism.  The 
lymph  of  a  dog  yielded  to  M.  Chevreul,  water,  926-4;  fibrin,  4-2; 
albumen,  61"0;  chloride  of  sodium,  6*1;  carbonate  of  soda,  1*8;  phos- 
phate of  lime,  phosphate  of  magnesia,  and  carbonate  of  lime,  0*5. 


'  Anatom.  Microscop.,  i.  15.  ^  Turner's  Chemistry,  4tli  Amer.  edit.,  p.  567. 


246  ABSOEPTION. 

That  of  tlie  liorse  yielded  to  M.  Lassaigne,  water,  192"5  ;  fibrin,  0"33; 
albumen,  5*78 ;  chlorides  of  sodium  and  potassium,  with  soda  and 
phosphate  of  lime,  l"-43.  Total,  100,  MM.  Marchand  and  Colberg^ 
found  its  constituents  to  be, — water,  96'926;  fibrin,  0'520;  albumen, 
0*4:3-4;  osmazome  (and  loss),  0"312  ;  fatty  oil  and  crystalline  fat,  0*264; 
chloride  of  sodium,  chloride  of  potassium,  carbonate  and  lactate  of  an 
alkali,  and  sulphate  of  lime,  phosphate  of  lime,  and  oxide  of  iron, 
1"544.  Total,  lOO'OOO.  Gmelin  found,  in  1000  parts  of  human  lymph, 
water,  961'0;  solid  constituents,  30*74;  fibrin,  5*20;  albumen,  4*34; 
extractive  matter,  3*12;  fluid  and  crystalline  fat,  2*64;  chlorides  of 
sodium  and  potassium,  alkaline  sulphates  and  carbonates,  sulphate 
and  phosphate  of  lime,  and  peroxide  of  iron,  15*44.  M.  L'Hdritier* 
analyzed  the  lymph  obtained  from  the  thoracic  duct  of  a  man  who 
died  from  softening  of  the  brain,  and  took  nothing  bat  a  little  water 
for  thirty  hours  preceding  his  death.  It  contained  in  1000  parts, — 
water,  924*36;  fibrin,  3*20;  fat,  5*10;  albumen,  60*02;  salts,  8*25. 
Lymph,  collected  from  the  absorbent  vessels  of  the  neck  of  a  horse, 
was  elaborately  analyzed  by  Nasse,  and  found  to  contain  in  1000 
parts, — water,  950;  solid  residue,  50;  albumen  with  fibrin,  39*111; 
water  extract,  3*248;  spirit  extract,  0*877;  alcohol  extract,  0*755; 
ethereal  extract,  0*088;  oleate  of  soda,  0*575  ;  carbonate  of  soda,  0*560; 
phosphate  of  soda,  0*120 ;  sulphate  of  potassa,  0*233 ;  chloride  of 
sodium,  4123  ;  carbonate  of  lime,  0.104 ;  phosphate  of  lime  with  some 
iron,  0*095;  carbonate  of  magnesia,  0*044;  silica,  0*067.  He  com- 
pared the  lymph  with  the  serum  from  the  blood  of  a  healthy  horse; 
and  found  a  remarkable  coincidence  in  the  salts  of  the  two  fluids. 

Alkaline  chlorides         ..... 
Alkaline  carbonates  (oleate  of  soda  included)  . 
Alkaline  sulphates        ..... 
Alkaline  phosphates     ..... 

5-611  5-61P 

The  same  observer*  has  given  a  tabular  view  of  six  analyses  of  the 
lymph  of  the  horse  and  ass. 

Reuss  and 

Emmert.  Gmelin.  Gmelin.  Lassaigne.  Rees.       Nasse. 
I.  II. 


Serum. 

Lymph. 

4-055 

4.123 

1-130 

,    1-135 

0-311 

0-233 

0-115 

0-120 

Water           .... 

960-0  961-0  967-70  925-00  965-36    950-00 

Fibrin           .             .             .     nearly 

3-0 

2-5 

1-30       3-30      1-20)   „„,, 
14-85                  12-00  1  "^^-^^ 

Albumen       .... 

27*5 

Extractive  matter  soluble  only  in  water 

2-1 

2-58      57.36     13.19       3-25 

Extractive  matter  soluble  in  alcohol 

39-6 

6-9 

9-69                    2-40       1-63 

Fat    . 

0-0 

traces               a  trace     0-09 

Soluble  salts                    ")        contained  in 

Salts  of  lime,  magnesia  I              the 

14-34      5-85      5-61 

and  silica                     J  extractive  matters 

a  trace ) 

Oxide  of  iron              .             .             .             . 

j  0.31 

Loss   ..... 

0-4 

3.88 

'  Miiller's  Archiv.  Jahreang,  1838,  s.  129,  cited  in  V.  Bruns,  Lelirbuch  der  Allge- 
meinen  Anatoniie,  s.  135,  Braunschweig,  1841. 

2  Traite  de  Chimie  Pathologicjue,  p.  IS,  Paris,  1S42. 

3  Simon's  Animal  Chemistry,  Sydenham  Soc.   edit.,  p.  353,  Lond.,  1845,  or  Amer. 
edit.,  Philad.,  1846. 

^  Wagner's  Handworterbuch  der  Physiologic,  9te  Lieferuug,  s.  396,  Braunschweig, 
1845. 


Chyle. 

Lymph 

90-237 

96-536 

3-516 

1-200 

0-370 

0.120 

0-332 

0-240 

1-233 

1-319 

3-601 

a  trace. 

0-711 

0.585 

^         LYMPH.  247 

A  comparative  analj'sis  of  tlie  chyle  and  lympli  of  the  ass  has  been 
made  by  Dr.  G.  0.  Eees.^  The  fluids  were  obtained  from  the  chylife- 
rous  and  lymphatic  vessels  seven  hours  after  a  full  meal,  previous  to 
their  entrance  into  the  thoracic  duct. 

Water  ...... 

Albuminous  matter  .... 

Fibrinous  matter     ..... 
Animal  extractive  matter,  soluble  in  water  and  alcobol 
Animal  extractive  matter,  soluble  in  water  only   . 
Fatty  matter  ..... 

Salts  : — alkaline  chloride,  sulphate,  and  carbonate,  with  ) 
traces  of  alkaline  phosphate  and  oxide  of  iron  j" 

100-000  100-000 

The  chyle — it  will  be  observed — contains  a  larger  proportion  of  de- 
cidedly organizable  matters.  Dr.  Eees^  examined  the  contents  of  the 
thoracic  duct  of  a  human  subject,  procured  an  hour  and  a  quarter  after 
death  by  hanging.  They  amounted  to  six  drachms,  and  yielded  the 
following  results : — 

Water              ........  90-48 

Albumen,  with  traces  of  fibrinous  matter      .             .             .             .  7.08 

Aqueous  extractive  (zomodine)           .....  0-56 

Alcoholic  extractive  (osmazome)        .....  0-52 

Alkaline  chloride,  carbonate,  and  sulphate,  with  traces  of  phosphate,  )       ^. . . 

and  oxide  of  iron  ) 

Fatty  matters               .......  0-92 

100-00 

Messrs,  Gubler  and  Quevenne^  had  an  opportunity  of  examining 
human  lymph  obtained  from  a  varicose  dilatation  of  the  superficial 
lymphatic  network  of  the  skin,  and  found  it  to  consist  of — 

Fibrin.  ........         0-056 

Fatty  matter   .'  .  .  .  .  .  .  .         0-382 

Caseiform  matter,  containing  only  one  per  cent,  of  earthy  phosphate  ) 

with  traces  of  iron    ......  )     4*275    !-  6-013 

Ilydro-alcoholic  extract,  containing  sugar,  and  leaving,  by  incinera-  "1 
tion,  0-730  of  a  saline  mixture,  composed  of  chloride  of  sodium,  and  > 
phosphate  and  carbonate  of  soda      ....  J      1-300^ 

Water  .........      93-987 

Chyle  and  lymph  strikingly,  therefore,  resemble  each  other ;  and  ac- 
cording to  M.  Millon,^  when  taken  from  the  same  animal  at  one  time, 
the  analogy  in  composition  is  very  great.  AVithout  impropriety  they 
may,  indeed,  be  termed  rudimental  blood.^ 

It  is  impossible  to  estimate  the  quantity  of  lymph  contained  in  the 
body.  It  would  seem,  that  notwithstanding  the  great  capacity  of  the 
lymphatic  vessels,  there  is,  under  ordinary  circumstances,  little  fluid 
circulating  in  them.     Frequently,  when  examined,  thej  have  appeared 

'  Lond.  Med.  Gazette,  Jan.,  1841. 

"  Proceedings  of  the  Royal  Society,  Feb.  10, 1842. 

*  Comptes  Rendus  des  Seances  et  Memoires  de  la  Societe  de  Biologie,  Annee  1854, 
p.  50,  Paris,  1855. 

*  Archives  Generales  de  Medecine,  Fevr.,  1850,  p.  237. 

^  See,  on  the  whole  subject  of  the  lymph,  Lehmann,  Lehrbuch  der  Physiologischen 
Chemie,  ii.  290,  Leipz.,  1S50,  and  Amer.  edit,  of  Dr.  Day's  translation,  by  Dr.  Robt.  E. 
Rogers,  ii.  31,  Philad.,  1855. 


2-48  ABSORPTION. 

to  be  empty,  or  pervaded  by  a  mere  thread  of  Ij^mpli.  M.  Magendie^ 
endeavoured  to  obtain  the  whole  of  the  lymph  from  a  dog  of  large 
stature.  He  could  collect  but  an  ounce  and  a  half;  and  it  appeared 
to  him  that  the  quantity  increased  whenever  the  animal  was  kept  fast- 
ing ;  but  on  this  point  he  does  not  seem  to  express  himself  positively. 
On  the  other  hand,  M.  Collard  de  Martigny^  obtained  nine  grains  of 
lymph,  in  ten  minutes,  from  the  thoracic  duct  of  a  rabbit  which  had 
taken  no  food  for  twenty-four  hours ;  and  Geiger,  from  three  to  five 
pounds  of  Ijnuph  daily,  from  the  foot  of  a  horse  from  which  the  same 
.quantity  had  been  flowing  several  years,  without  injury  to  the  health. 
The  estimate  made  by  Bidder  has  been  referred  to  elsewhere.  (Page  220). 

3.    PHYSIOLOGY  OF  LYMPHOSIS. 

The  term  lymphosis  has  been  proposed  by  Chaussier  for  the  action 
of  elaboration  by  which  lymph  is  formed, — as  chylosis  has  been  used 
for  the  formation  of  chyle,  and  hcematosis  for  that  of  the  blood.  In 
describing  the  organs  concerned,  the  striking  similarity — we  might 
almost  say — identity  in  structure  and  arrangement  between  them  and 
the  chyliferous  organs  will  have  been  apparent.  A  part  of  the  vascu- 
lar apparatus  is  common  to  both ;  and  they  manifestly  constitute  one 
and  the  same  system.  This  would  be  sufficient  to  induce  us  to  assign 
them  similar  functions ;  and  it  would  require  powerful  and  positive 
testimony  to  establish  an  opposite  view.  At  one  period,  l3miph  was 
considered  to  be  simply  the  watery  portion  of  the  blood ;  and  the 
lymphatic  vessels  were  regarded  as  the  continuation  of  ultimate  arte- 
rial ramifications.  It  was  affirmed,  that  the  blood,  on  reaching  the 
terminal  branches  of  the  arteries,  separated  into  two  parts ;  the  red 
and  thicker  portion  returning  to  the  heart  by  the  veins ;  and  the  white, 
serous  portion — liquor  sanguinis — by  the  lymphatics.^  The  reasons 
for  this  belief  were,  the  great  resemblance  between  lymph  and  the 
serum  of  the  blood ;  and  the  facility  with  which  an  injection  passes, 
in  the  dead  body,  from  the  arterial  into  the  lymphatic  capillary  vessels. 
M.  Magendie  has  revived  the  ancient  doctrine ;  and,  of  consequence, 
no  longer  considers  the  lymphatics  to  form  part  of  the  absorbent  sys- 
tem ;  but  to  belong  to  the  circulatory  apparatus,  and  to  serve  the  oflice 
of  waste  pipes,  in  case  of  emergency.  Without  canvassing  this  sub- 
ject now,  we  may  assume  it  for  granted,  that  the  lymph  which  circulates 
in  the  lymphatic  vessels  is  as  identical  in  its  nature,  or  as  little  subject 
to  alteration,  as  the  chyle ;  and  that,  consequently,  whatever  may  be 
the  materials,  besides  the  liquor  sanguinis,  that  constitute  it,  an  action 
of  elaboration  and  selection  must  be  exerted  in  its  formation. 

It  has  been  conceived,  that  many  of  the  tissues  of  the  body,  the 
serous  membranes,  for  example,  do  not  receive  red  blood  ;  and  must, 
consequently,  be  nourished  by  white  blood.  The  13'mphatics,  in  such 
cases,  have  been  considered  to  be  to  the  white  arteries  what  the  veins 
are  to  the  red.  Such  has  been  presumed  to  be  one  of  their  offices,  but 
it  will  be  seen,  hereafter,  that  all  the  tissues  supplied  with  vessels  receive 
red  blood  ;  and  hence  it  is  unnecessary  to  suppose,  that  the  lymphatics 
execute  any  venous  function. 

'  Op.  citat.,  ii.  192.  ^  Journal  de  Physiologie,  viii.  26G. 

3  Kirkes  and  Paget,  Manual  of  Physiology,  2d  Amer.  edit.,  p.  210,  Philad.,  1853. 


LYMPHOSIS. 


249 


Fig.  74. 


Assuming,  for  the  present,  that  lymph  is  wholly  obtained  from 
materials  already  deposited  in  the  body  ;  the  next  inquiry  is, — the 
mode  in  which  its  formation  and  simultaneous  absorption  are  effected. 
On  this  topic,  we  have  no  arguments  to  employ  in  addition  to  those 
adduced  regarding  the  function  of  the  chyliferous  radicles.  In  every 
respect,  they  are  situate  identically,  and  to  the  history  of  the  latter  we 
must  refer  for  an  exposition  of  the  little  we  know  of  this  part  of  lym- 
phosis. 

The  causes  of  the  progression  of  the  lymph  in  the  vessels  are  the 
same  as  those  that  influence  the  chyle.  In  addition,  however,  to  those 
mentioned  under  chyliferous  ahorpiion,  there  is  one  that  applies  equall_f 
to  the  chyliferous  and  Ijmiphatic  vessels:  this  is  the  mode  in  which  the 
thoracic  duct  enters  the  subclavian  vein.  It  has  been  already  observed 
that  it  occurs  at  the 
point  of  junction^  be- 
tween the  jugular 
and  subclavian,  as  at 
D,  Fig.  74,  where  J 
represents  the  jugu- 
lar, and  y  S  the  sub- 
clavian, in  which  the 
blood  flows  from  V 
towards  S,  the  car- 
diac extremity. 

Now,  it  is  a  phy- 
sical fact,  that  when 
a  small  tube  is  in- 
serted perpendicu- 
larly into  the  lower 
side  of  a  horizontal 
conical  pipe,  in 
which  water  is  flow- 
ing from  the  nar- 
rower to  the  wider 

portion ;  and  if  the  small  vertical  tube  be  made  to  dip  into  a  vessel  of 
water,  not  only  will  the  water  of  the  larger  pipe  not  descend  into  the 
vessel ;  but  it  will  draw  up  the  water  through  the  small  tube  so  as  to 
empty  the  vessel.^  Instead  of  supposing  the  canals,  in  Fig.  74,  to  be 
veins  and  the  thoracic  duct;  let  us  presume  that  they  are  rigid  me- 
chanical tubes;  and  that  the  extremity  of  the  tube  D,  which  represents 
the  thoracic  duct,  dips  into  the  vessel  13.  As  the  fluid,  proceeding  from 
J  to  S  and  V  to  S,  is  passing  from  the  narrower  portions  of  conical 
tubes  to  wider,  it  follows,  that  the  fluid  will  be  drawn  out  of  the  ves- 
sel B,  simply  by  traction,  or,  by  what  Venturi^  terms  the  lateral  com- 
munication of  fluids.  This  would  happen  in  whatever  part  of  the  ves- 
sel the  tube  B  D  terminated.  But  its  insertion  at  D  has  another  advan- 
tage. By  the  mode  in  which  the  current  from  J  towards  S  unites  with 
that  from  V  towards  S,  a  certain  degree  of  diminished  pressure  must 


Termination  of  Thoracic  Duct. 


'  Sir  C.  Bell,  in  Animal  Mechanics,  p.  41,  Library  of  Useful  Knowledge,  Lond.,  1829. 
^  Sur  la  Communication  Lat^rale  du  Mouvement  dans  les  Fluides,  Paris,  1798. 


250  ABSORPTION. 

exist  at  D ;  so  tliat  tlie  atmosplieric  pressure,  on  the  surface  of  the 
water  in  the  vessel  B,  will  be  exerted  in  propelling  it  forwards.  In 
the  progress,  then,  of  the  chyle  and  lymph  along  the  thoracic  duct,  not 
only  may  the  traction  of  the  more  forcible  stream  along  the  veins  draw 
the  fluid  in  the  thoracic  duct  along  with  it,  but,  owing  to  the  dimin- 
ished pressure  at  the  mouth  of  the  duct,  atmospheric  pressure  may  have 
some — although  probably  but  little — influence,  in  forcing  the  chyle 
and  lymph  from  the  chyliferous  and  lymphatic  radicles  onwards.  The 
lymphatic  glands  have  been  looked  upon  as  small  hearts  for  the  pro- 
pulsion of  lymph ;  and  Malpighi  accounts  for  the  greater  number  in 
the  groin  in  this  way ; — the  lymph  having  to  ascend  to  the  thoracic  duct 
against  gravity :  and  this  appears  to  have  been  somewhat  the  opinion 
of  Bichat.  There  seems,  however,  to  be  nothing  in  their  structure  that 
ought  to  lead  to  this  belief;  and,  if  it  be  not  muscular  or  contractile, 
it  is  manifest,  that  their  number  must  have  the  effect  of  retarding  rather 
than  accelerating  the  flow.  The  most  prevalent  sentiment  is,  that  they 
are  somehow  concerned  in  the  elaboration  of  the  lymph ;  but  their  exact 
functions  we  know  nothing  definite.  What  has  been  already  said  of 
the  mesenteric  ganglions,  and  of  their  probable  agency  in  the  forma- 
tion of  chyle  corpuscles  is  equally  applicable  to  them  and  their  agency 
in  the  formation  of  lymph  corpuscles. 

On  the  subject  of  the  moving  powers  of  the  lymph,  M.  Adelon'  has 
remarked,  that  if  we  admit  it  to  be  the  serous  portion  of  the  blood ; 
and  that  the  lymphatics  are  vessels  of  return,  as  the  veins  are,  the 
heart  might  be  considered  to  have  the  same  influence  over  lymphatic, 
that  it  has  been  presumed  to  have  over  venous,  circulation ;  and  whether 
we  admit  this  or  not,  as  the  thoracic  duct  opens  into  the  subclavian 
vein,  the  influence  of  the  suction  power  of  the  organ  on  the  venous 
blood  may  affect  the  progression  of  the  chyle  also.  It  cannot,  how- 
ever, as  Miiller^  remarks,  be  the  primary  cause  of  the  motion  of  the 
chyle,  for  Autenrieth,  Tiedemann,  and  Carus  observed,  when  a  ligature 
was  applied  to  the  thoracic  duct,  that  the  part  of  the  duct  below  the 
ligature  became  distended  even  to  bursting.  We  shall  see  hereafter, 
that  during  inspiration,  absorption,  it  is  imagined,  may  be  facilitated 
by  the  dilatation  of  the  chest,  and  the  necessary  diminution  of  pi'essure 
on  the  heart  and  great  vessels. 

Professor  M tiller^  discovered,  that  the  frog,  and  several  other  am- 
phibious animals,  are  provided  with  large  receptacles  for  lymph,  situate 
immediately  under  the  skin,  and,  like  the  heart,  exhibiting  distinct  and 
regular  pulsations.  The  use  of  these  lymph  hearts  appears  to  be  to  pro- 
pel the  lymph  along  the  lymphatics.  In  the  frog,  four  of  them  have 
been  found;  two  posterior,  behind  the  joint  of  the  hip;  and  two 
anterior,  on  each  side  of  the  transverse  process  of  the  third  vertebra, 
and  under  the  posterior  extremity  of  the  scapula.  The  pulsations  of 
these  lymphatic  hearts  do  not  correspond  with  those  of  the  sanguifer- 
ous heart;  nor  do  those  of  the  right  and  left  sides  occur  synchronously. 

*  Art.  Absorption,  in  Diet,  de  Medecine,  2de  edit.,  i.  239,  Paris,  1832  ;  and  Plijsio- 
logie  de  rHomme,  edit.  cit.  iii.  92. 

2  Handbuch,  u.  s.  w. ;  and  Baly's  translation,  p.  284,  Lond.,  1838. 

3  Philos.  Transact,  for  1833  ;  and  op.  cit.  See,  also,  bis  Observations  on  tbe  Lym- 
phatic Hearts  of  Tortoises,  in  Miiller's  Arcbiv.,  Heft  1,  1840. 


LYMPHOSIS. 


251 


Fig.  75. 


Lymph  Heart  of  Pj-thon  Bivit- 
tatus,  Heart  9  lines  long ;  4 
broad. 

4.  External  areolar  coat.  5. 
Thick  muscular  coat  ;  four  mus- 
cular eolumns  cross  the  cavity, 
which  communicates  with  three 
lymphatics — only  one,  1,  seen 
here,  and  two  veins,  2,  2.  6. 
Smooth  lining  membrane  of  the 
cavity.  7.  An  appendix  or  auri- 
cle, tlie  cavity  of  which  commu- 
nicates with,  the  other. 


Tliej  often  alternate  irregularly.  Prof.  E.  H.  Weber  has  described 
tliem  in  a  larger  species  of  serpent — pytlion  hivittatus  ;'  and  Dr.  Joseph 
J.  Allison,  of  Philadelphia,^  a  young  and  zeal- 
ous observer,  who  was  cut  oiF  early  in  his  ca- 
reer, saw  them  in  the  tadpole,  the  frog,  the 
sauria,  ophidia,  and  chelonia.  His  researches 
led  him  to  conclude : — First.  That  the  pulsa- 
tions of  the  lymphatic  organs  vary  in  difierent 
specimens  (frogs  and  tadpoles)  from  60  or  less 
to  200  per  minute.  Secondly.  That  they  vary 
in  the  same  individual  so  as  sometimes  to  be- 
come double  in  frequency.  Thirdly.  That  the 
lymphatic  pulsations  bear  no  fixed  relation  to 
those  of  the  pulmonary  heart  or  to  respiration, 
the  lymphatic  hearts  beating  —on  an  average 
— with  greater  frequency. 

Professor  Stannius^  has  discovered  lymph- 
atic hearts  in  various  birds. 

Unlike  that  of  the  heart,  the  action  of  these 
lymph  hearts  appears  to  be  dependent  upon 
a  certain  limited  portion  of  the  spinal  cord ;  for 
Volkmann'' found,  that  by  dividing  the  anterior 
or  motor  roots  of  the  spinal  nerves  connected 
with  them,  the  pulsations  immediately  ceased. 

The  course  of  the  lymph  is  by  no  means  rapid.  If  a  lymphatic  be 
divided  on  a  living  individual,  the  lymph  oozes  slowly,  and  never  with 
a  jet.  Mr.  Cruikshank  estimated  its  velocity  along  the  vessels  to  be  four 
inches  per  second  or  twenty  feet  per  minute;  but  it  is  probably  much 
less.  M.  CoUard  de  Martigny'  obtained  nine  grains  of  lymph  in  ten 
minutes  from  the  thoracic  duct'  of  a  rabbit,  which  had  taken  no  food 
for  twenty -four  hours.  Having  pressed  out  the  lymph  from  the  prin- 
cipal lymphatic  trunk  of  the  neck,  in  a  dog,  the  vessel  filled  again  in 
seven  minutes :  in  a  second  experiment  it  filled  in  eight  minutes.  The 
data  for  any  correct  evaluation  of  this  matter  are  altogether  inadequate, 
the  deranging  influence  of  all  such  experiments  being  considerable. 

In  man  and  living  animals,  the  lymphatics  of  the  limbs,  head,  and 
neck  rarely  contain  lymph ;  their  inner  surface  appearing  to  be  merely 
lubricated  by  a  very  thin  fluid.  Occasionally,  however,  the  lymph  stops 
in  different  parts  of  the  vessels;  distends  them;  and  gives  them  an  ap- 
pearance very  like  that  of  varicose  veins,  except  as  to  colour.  Sciin- 
mering  states,  that  he  saw  several  in  this  condition  on  the  top  of  the 
foot  of  a  female;  and  M.  Magendie  one  around  the  corona  glandis  of  a 
male.  In  dogs,  cats,  and  other  living  animals,  lymphatics,  filled  with 
lymph,  are  frequently  seen  at  the  surface  of  the  liver,  gall-bladder,  vena 
cava,  vena  porta,  and  at  the  sides  of  the  spine.     Magendie  remarks, 

'  Muller,  op.  citat.,  p.  275. 

^  American  Journal  of  the  Medical  Sciences,  for  August,  1838. 

*  Miiller's  Archiv.,  1843,  Heft  5. 

"•  Ibid.,  419,  Berlin,  1844;  and  Valentin,  Lehrbucli  der  Physiologie  des  Mensclien,  ii. 
7G9,  Braunschweig,  1844. 

*  Journal  de  Physiologie,  torn.  viii. 


252  ABSORPTION. 

that  he  lias  never  met  with  the  thoracic  duct  empty,  even  when  the 
lymphatics  of  the  rest  of  the  body  were  entirely  so.'  It  must  be  recol- 
lected, however,  that  the  thoracic  duct  must  always  contain  the  product 
of  the  digestion  either  of  food  or  of  secretions  from  the  alimentary 
tube.  The  stagnation  of  lymph  in  particular  vessels  has  given  occasion 
to  the  belief,  that  it  flows  with  different  degrees  of  velocity  in  different 
parts  of  the  system;  and  this  notion  has  entered  into  the  pathological 
views  of  writers,  who  have  presumed,  that  something  like  determina- 
tions of  lymph  may  occur,  and  produce  lymphatic  swellings.  M.  Bor- 
den,^ indeed,  speaks  of  currents  of  lymph.  All  the  phenomena  of  the 
course  of  the  lymph  negative,  however,  this  presumption;  and  induce 
us  to  believe,  that  its  progress  is  pretty  uniform,  and  always  slow ;  and 
when  an  accumulation,  or  engorgement,  or  stagnation  occurs  in  any 
vessel,  it  is  more  probably  owing  to  increased  formation  by  the  lymph- 
atic radicles  that  communicate  with  the  vessel  in  question,  or  to  loss  of 
tone  in  the  parietes  of  the  engorged  lymphatics. 

The  lymph,  which  proceeds  by  the  thoracic  duct,  is  emptied,  along 
with  the  chyle,  into  the  subclavian  vein.  At  the  confluence,  a  valve 
is  placed,  which  does  not,  however,  appear  to  be  essential,  as  the  duct 
opens  so  favourably  between  the  two  currents  from  the  jugular  and 
subclavian,  that  there  is  little  or  no  tendency  in  the  blood  to  reflow 
into  it.  It  has  been  suggested,  that  its  use  may  be,  to  moderate  the 
instillation  of  the  fluid  from  the  thoracic  duct  into  the  venous  blood. 

With  regard  to  the  question,  whether  the  lymph  is  the  same  at  the 
radicles  of  the  lymphatics  as  in  the  thoracic  duct,  or  whether  it  does 
not  gradually  become  more  and  more  animalized  in  its  course  towards 
the  venous  system,  and  especially  in  its  progress  through  the  lymph- 
atic glands,  the  remarks  made  upon  this  subject,  as  respects  the  chyle, 
apply  with  equal  force  to  the  lymph.  , 

The  glands  of  the  mesentery,  and  lymphatics  in  general,  seem  to  be 
concerned  in  some  of  the  most  serious  diseases.  Swelling  of  the  lymph- 
atic glands  of  the  groin  may  indicate  the  existence  of  a  venereal  sore 
on  the  penis.  A  wound  on  the  foot  produces  tumefaction  of  the  ingui- 
nal glands;  one  on  the-hand  inflames  those  of  the  axilla.  Whenever, 
indeed,  a  lymphatic  gland  is  symptomatically  enlarged,  the  source  of 
irritation  will  be  found  at  a  greater  distance  from  the  vein  into  which 
the  great  lymphatic  trunks  pour  their  fluid  than  the  gland  is.  In  plague, 
one  of  the  essential  phenomena  is  swelling  of  the  lymphatic  glands  of 
the  groin  and  axilla ;  hence,  it  has  been  termed  adeno-adynarnic  fever 
(from  ahriv^  a  gland).  In  scrofula,  the  lymphatic  system  is  generally 
deranged;  and,  in  the  doctrine  of  Broussais,  a  very  active  sympathy  is 
affirmed  to  exist  between  the  glands  of  the  mesentery,  and  the  mucous 
surface  of  the  stomach  and  intestines.  This  discovery,  we  are  told, 
belongs  to  the  '■'■  x^husiological  dodrine,^^  which  has  shown,  that  all  gastro- 
enterites  are  accompanied  by  tumefaction  of  the  mesenteric  glands : 
although  chyle  may  be  loaded  with  acrid,  irritating,  or  even  poisonous 
matters,  it  traverses  the  glands  with  impunity,  provided  it  does  not 
inflame  the  gastro-enteric  mucous  surface.   "Our  attention,"  Broussais' 

'  Precii?,  &c.,  ii.  224.  2  CEavros  Completes,  par  Richerand,  Paris,  1818. 

3  Traite  do  Plivsiolotjie,  &c.,  and  Bell  and  La  Roche's  translation,  3d  Amer.  edit.,  p. 
362,  PMladelpliia,  1832. 


VENOUS.  253 

adds,  "has  been  for  a  long  time  directed  to  this  question,  and  we  have 
not  observed  any  instance  of  mesenteric  ganglionitis,  which  had  not 
been  preceded  by  well-evidenced  gastro-enteritis."  The  discovery  will 
not  immortalize  the  "doctrine."  We  should  as  naturally  look  for  tume- 
faction of  the  mesenteric  glands  or  ganglia,  in  cases  of  irritation  of  the 
intestine,  as  for  enlargement  of  the  glands  of  the  groin  in  irritation  of 
the  foot. 

Lastly;  the  lymph,  from  whatever  source  obtained — united  with 
the  chyle — is  discharged  into  the  venous  system.  Both,  therefore,  go 
to  the  composition  of  the  body.  They  are  entirely  analogous  in  pro- 
perties ;  but  differ  materially  in  quantity  ; — the  nutritious  fluid,  formed 
from  materials  obtained  from  without,  being  far  more  copious.  A  due 
supply  of  it  is  required  for  continued  existence ;  yet  the  body  can  live 
for  a  time,  when  the  supply  of  nutriment  is  entirely  cut  otY.  Under 
such  circumstances,  the  necessary  proportion  of  nutritive  fluid  must  be 
obtained  from  the  decomposition  of  the  tissues ;  but,  from  the  per- 
petual drain,  that  takes  place  through  the  various  excretions,  this  soon 
becomes  insufficient,  and  death  is  the  result.  In  a  note  to  a  recent 
edition  of  his  "  Principles  of  Human  Physiology,"^  Dr.  Carpenter  re- 
marks, that  at  the  time  of  the  publication  of  the  first  edition  of  his 
work  (1842)  he  was  under  the  impression,  that  the  view  maintained 
by  him,  "  that  the  special  function  of  the  lymphatics  like  that  of  the 
lacteals  is  nutritive  absorption,"  was  altogether  novel.  The  author 
attaches  little  value  to  originality  in  such  matters;  but  he  thinks  it 
well  to  state,  that  the  doctrine  in  the  text  is  that  adopted  by  him  in 
the  first  edition  of  this  work  (1832),  and  taught  by  him  ever  since  he 
has  been  a  teacher ;  yet  he  is  far  from  regarding  it  as  original  with 
him. 

We  have  seen,  then,  that  both  chyle  and  lymph  are  poured  into  the 
venous  blood ; — itself  a  compound  of  the  residue  of  arterial  blood,  and 
various  heterogeneous  absorptions.  As  an  additional  preliminary  to 
the  investigation  of  the  agents  of  internal  absorption,  let  us  inquire 
into  the  nature  and  course  of  the  fluid  contained  in  the  veins ;  but  so 
far  only  as  to  enable  us  to  understand  the  function  of  absorption;  the 
other  considerations  relating  to  the  blood  appertain  to  the  function  of 
circulation. 

III.   VENOUS  AB30KPTI0N. 

The  apparatus  of  venous  absorption  consists  of  myriads  of  vessels 
called  veins^  which  commence  in  the  very  tissues,  by  what  are  called 
capillary  vessels^  and  thence  pass  to  the  great  central  organ  of  the  cir- 
culation— the  heart;  receiving,  in  their  course,  the  products  of  the 
various  absorptions  effected  not  only  by  themselves,  but  by  the  chy- 
liferous  and  lymphatic  vessels.  The  anatomy  of  the  venous  system 
will  be  given  under  Circulation. 

'  Fourth  American  edition,  p.  506,  Philad.,  1850.  See  on  this  suhject,  Adelon,  Art. 
Absorjition,  in  Diet,  de  Medecine,  i.  117,  Paris,  1821 ;  and  Moultrie,  American 
Journal  of  the  Medical  Sciences  for  1827,  and  On  the  Organic  Functions  of  Animals, 
Charleston,  1844. 


254  ABSOEPTION. 


1.  PHYSIOLOGY  OF  TEXOCS  ABSORPTIOX. 

Whilst  tlie  opinion  prevailed  universally,  that  the  lymphatics  are 
the  sole  agents  of  absorption,  the  fluid,  circulating  in  the  veins,  was 
considered  to  consist  entirely  of  the  residue  of  arterial  blood,  after  it 
had  passed  through  the  capillary  system,  and  been  subjected  to  the 
different  nutritive  processes.  AVe  have  seen,  however,  that  drinks  are 
absorbed  by  the  mesenteric  veins ;  and  we  shall  hereafter  find,  that 
various  other  substances  enter  the  venous  system.  It  is  obvious, 
therefore,  that  venous  blood  cannot  be  simply  the  residue  of  arterial 
blood ;  and  we  can  thus  account  for  the  greater  capacity  of  the  venous 
than  of  the  arterial  system.  The  facts,  which  were  referred  to,  when 
considering  the  absorption  of  fluids  from  the  intestinal  canal,  may 
have  been  sufiicient  to  show,  that  veins  are  capable  of  absorbing ;  as 
odorous  and  colouring  properties  of  substances  were  distinctly  found 
in  the  mesenteric  veins.  A  question  arises,  whether  any  selection  or 
elaboration  is  exerted,  as  in  the  case  of  the  chyle,  or  whether  the 
fluid,  when  it  attains  the  interior  of  the  vessel,  is  the  same  as  without? 
M.  Adelon,^ — who,  with  many  of  the  German  physiologists,  believes 
in  both  venous  and  lymphatic  absorption,  and  venous  and  chyliferous 
absorption, — conceives,  tliat  a  vital  action  takes  place  at  the  very  ex- 
tremities of  the  venous  radicles,  precisely  similar  to  that  which  is  pre- 
sumed to  be  exerted  at  the  extremities  of  the  lymphatic  and  chyliferous 
radicles.  In  his  view,  consequently,  an  action  of  elaboration  is  exerted 
upon  the  fluid,  which  becomes,  in  all  cases,  converted  into  venous 
blood  at  the  very  moment  of  absorption.  On  the  other  hand,  MM. 
!Magendie,^  Fodera,^  and  others  maintain,  that  the  substance  when 
possessed  of  the  necessary  tenuity  soaks  through  the  vessel ;  and  that 
this  act  of  imbibition  is  purely  plwsical.  In  their  view,  consequently, 
the  fluid  within  the  vessel  must  be  the  same  as  without. 

In  favour  of  the  vital  action  of  the  veins  we  have  none  of  that  evi- 
dence, which  strikes  us  in  the  case  of  the  chyliferous  and  lymphatic 
vessels.  In  the  last  we  invariably  find  fluids,  identical — in  all  essen- 
tial respects — in  physical  characters ;  and  never  containing  extraneous 
matter, — if  we  make  abstraction  of  certain  salts,  that  have  been  occa- 
sionally met  with  in  the  thoracic  duct.  In  the  veins,  on  the  other 
hand,  the  sensible  properties  of  odorous  and  colouring  substances 
have  been  frequently  apparent.  It  may  be  argued,  however,  that  the 
fluid,  flowing  in  the  veins,  is  as  identical  in  composition  as  the  chyle 
or  the  lymph.  This  is  true;  but  it  must  be  recollected,  that  the 
greater  part  of  it  is  the  residue  of  arterial  blood;  and  that  its  hue  and 
other  sensible  properties  are  such  as  to  disguise  any  absorbed  fluid, 
not  itself  possessing  strong  characteristics.  The  fact, — now  indis- 
putable,— that  various  substances,  placed  outside  the  veins,  have  been 
detected  in  the  blood  Avithin,  is  not  only  a  proof  that  the  veins  absorb; 
but  that  no  action  of  elaboration  is  exerted  on  the  absorbed  fluid. 
Of  this  we  have  the  most  convincing  proof  in  certain  experiments  by 

'  Art.  Absorption,  in  Diet,  cle  Medecine,  2de  edit.,  i.  239,  Paris,  1832 ;  and  Physio- 
loijie  de  I'Homme,  2de  edit.,  iii.  113,  Paris,  1829. 
^^  Precis,  &c.,  2de  edit.,  ii.  271. 
^  Ileclierches  Experimentales  sur  I'Exhalation  et  I'Absorption,  Paris,  1823. 


VENOUS.  255 

M.  Magendie.^  In  exhibiting  to  his  class  the  mode  in  which  medi- 
cines act  upon  the  system,  he  showed,  on  a  living  animal,  the  eflfects 
of  introducing  a  quantity  of  water,  of  the  temperature  of  104"  Fah., 
into  the  veins.  In  performing  this  experiment,  it  occurred  to  him  to 
notice  what  would  be  the  effect  produced  by  artificial  plethora  on  the 
phenomena  of  absorption.  Having  injected  nearly  a  quart  of  water 
into  the  veins  of  a  dog  of  middle  size,  he  placed  in  the  cavity  of  the 
pleura  a  small  dose  of  a  substance  with  the  eflfects  of  which  he  was 
familiar,  and  was  struck  with  the  fact,  that  they  did  not  exhibit  them- 
selves for  several  minutes  after  the  ordinary  period.  He  immediately 
repeated  the  experiment,  and  with  a  like  result.  In  several  other  ex- 
periments, the  eflfects  appeared  at  the  ordinary  time,  but  were  mani- 
festly feebler  than  they  ought  to  have  been  from  the  dose  of  the 
substance  employed  ;  and  were  kept  up  much  longer  than  usual. 

In  another  experiment,  having  introduced  as  much  water  as  the  ani- 
mal could  bear  without  perishing, — which  was  about  two  quarts, — the 
effects  did  not  occur  at  all.  After  having  waited  nearly  half  an  hour 
for  their  developement,  which  generally  required  only  about  two  min- 
utes, he  inferred,  that  if  the  distension  of  the  bloodvessels  was  the  cause 
of  the  defect  of  absorption,  if  the  distension  were  removed,  absorption 
ought  to  take  place.  He  immediately  bled  the  animal  largely  in  the 
jugular;  and,  to  his  great  satisfaction,  found  the  effects  manifesting 
themselves  as  the  blood  flowed.  He  next  tried  whether,  if  the  quantity 
of  blood  were  diminished  at  the  commencement  of  the  experiment, 
absorption  would  be  more  rapid;  and  the  result  was  as  he  anticipated. 
An  animal  was  bled  to  the  extent  of  about  half  a  pound;  and  the 
effects,  which  did  not  ordinarily  occur  until  after  the  second  minute, 
appeared  before  the  thirtieth  second.  As  the  results  of  these  experi- 
ments seemed  to  show,  that  absorption  is  in  an  inverse  ratio  to  the 
degree  of  vascular  distension,  he  inferred,  that  it  is  effected  physically; 
is  dependent  upon  capillary  attraction ;  and  ought  to  take  place  as  well 
after  death  as  during  life.  To  prove  this,  he  instituted  the  following 
experiments. — He  took  a  portion  of  the  external  jugular  of  a  dog, 
about  an  inch  long  and  devoid  of  branches.  Eemoving  carefully  the 
surrounding  areolar  tissue,  he  attached  to  each  extremity  a  glass  tube, 
by  means  of  which  he  kept  up  a  current  of  warm  water  within  it.  He 
then  placed  the  vein  in  a  slightly  acid  liquor,  and  carefully  collected 
the  fluid  of  the  current.  During  the  first  few  minutes,  it  exhibited  no 
change;  but,  in  five  or  six  minutes,  became  sensibly  acid.  This  experi- 
ment was  repeated  on  veins  taken  from  the  human  subject  with  like 
results;  and  not  only  on  veins  but  on  arteries. 

Similar  experiments  were  next  made  on  living  animals.  He  took  a 
young  dog,  about  six  weeks  old,  whose  vessels  were  thin,  and,  conse- 
quently, better  adapted  for  the  success  of  the  experiment,  and  exposed 
one  of  its  jugular  veins.  From  this  he  dissected  entirely  the  surround- 
ing matter,  and  especially  the  areolar  tissue,  with  the  minute  vessels  that 
ramified  upon  it,  and  placed  it  upon  a  card,  in  order  that  there  might 
be  no  point  of  contact  between  it  and  the  surroimding  parts.  He  then 
let  fall  upon  its  surface,  and  opposite  the  middle  of  the  card,  a  thick 

'  Op.  citat.,  ii.  273. 


256  ABsoRPTioisr. 

watery  solution  of  iiux  vomica, — a  substance,  that  exerts  a  powerful 
action  on  dogs.  He  took  care,  that  no  particle  of  the  poison  touched 
any  thing  but  the  vein  and  card;  and  that  the  course  of  the  blood,  within 
the  vessel,  was  free.  Before  the  expiration  of  three  minutes,  the  effects 
he  expected  appeared, — at  first  feebly,  but  afterwards  with  so  much 
activity,  that  to  prevent  fatal  results  he  had  to  inflate  the  lungs.  The 
experiment  was  repeated  on  an  older  animal  with  the  same  results; 
except  that,  as  might  have  been  expected,  they  were  longer  in  exhibit- 
ing themselves,  owing  to  the  greater  thickness  of  the  parietes  of  the 
veins. 

Satisfied,  as  regarded  the  veins,  he  now  directed  his  attention  to  the 
arteries : — the  results  were  the  same.  They  were,  however,  slower  in 
appearing  than  in  the  case  of  the  veins,  owing  to  the  tissue  of  the  arte- 
ries being  less  spongy.  It  required  upwards  of  a  quarter  of  an  hour 
for  imbibition  to  be  accomplished.  In  one  of  the  rabbits,  which  died 
under  the  experiment,  they  had  an  opportunity  of  discovering,  that 
absorption  could  not  have  been  effected  by  any  small  veins,  that  had 
escaped  dissection.  One  of  the  carotids, — the  subject- vessel  of  the 
experiment, — was  taken  from  the  body ;  and  the  small  quantity  of 
blood,  adherent  to  its  inner  surface,  was  found  by  M.  Magendie,  and 
his  friends  who  assisted  at  the  experiment,  to  possess  the  extreme  bit- 
terness that  characterizes  nux  vomica.  These  experiments  were  suffi- 
cient to  prove  the  fact  of  imbibition  by  the  large  vessels,  both  in  the 
dead  and  in  the  living  state.  His  attention  was  now  directed  to  the 
smaller;  which  seemed,  a  priori^  favourable  to  the  action,  from  their 
delicacy  of  organization.  He  took  the  heart  of  a  dog,  that  had  died 
the  day  before,  and  injected  water,  of  the  temperature  of  86°  of  Fah,, 
into  one  of  the  coronary  arteries,  which  readily  returned  by  the  coro- 
nary vein  into  the  right  auricle,  whence  it  was  allowed  to  flow  into  a 
vessel.  Half  an  ounce  of  water,  slightly  acidulated,  was  now  placed 
in  the  pericardium.  At  first,  the  injected  fluid  did  not  exhibit  any 
signs  of  acidity ;  but,  in  five  or  six  minutes,  the  evidences  were  un- 
equivocal. 

From  these  facts,  M.  Magendie^  draws  the  too  broad  deduction, 
that  "all  bloodvessels,  arterial  and  venous,  dead  or  living,  large  or 
small,  possess  a  ph3'sical  property  capable  of  accounting  for  the  prin- 
cipal phenomena  of  absorption,"  AVe  shall  endeavour  to  show,  that 
it  explains  only  certain  varieties  of  absorption, — those  in  which  the 
vessel  receives  the  fluid  unmodified, — but  that  it  is  unable  to  account 
for  other  absorptions  in  which  an  action  of  selection  and  elaboration  is 
necessary. 

After  these  experiments  were  performed,  others  were  instituted  by 
MM.  Segalas^  and  Fodera,-'  from  which  the  latter  physiologist  attempts 
to  show,  that  exhalation  is  simply  a  transudation  of  substances  from  the 
interior  of  vessels  to  the  exterior ;  and  absorption  an  imlilition  or  pas- 
sage of  fluids  from  the  exterior  to  the  interior.  The  facts  adduced  by 
!M.  Fodcra  in  support  of  his  views  will  be  considered  under  the  head 
of  Secretion.     They  go  chiefly  to  show  the  facility  Avith  which  sub- 

'  Precis,  &c.,  ii.  283.  *  Magendle's  Journal  de  Physiol.,  ii.  217. 

3  Recherclies  ExiJeriment.  sur  I'Absorption,  &c.,  Paris,  1&24,  and  Magendie's  Journal, 
&c.,  iii.  35. 


VENOUS.  257 

stances  penetrate  the  parietes  of  vessels  and  other  tissues  of  the  body; 
an  action  which  he  found  to  be  singularly  accelerated  by  the  galvanic 
influence.  Prussiate  of  potassa  was  injected  into  the  cavity  of  the 
pleura;  and  sulphate  of  iron  introduced  into  that  of  the  peritoneum  in 
a  living  animal.  Under  ordinary  circumstances,  it  requires  five  or  six 
minutes  before  the  two  substances  meet  by  imbibition  through  the  dia- 
phragm; but  the  admixture  is  instantaneous  if  the  diaphragm  be  sub- 
jected to  a  slight  galvanic  current.  The  same  fact  is  observed,  if  one 
of  the  liquids  be  placed  in  the  urinary  bladder,  and  the  other  in  the 
abdomen ;  or  the  one  in  the  lung,  and  the  other  in  the  cavity  of  the 
pleura.  It  was  further  found,  that,  according  to  the  direction  of  the 
current,  the  union  took  place  in  the  one  or  the  other  cavity.  Dr.  Bos- 
tock,'  in  commenting  on  these  cases,  thinks  it  must  be  admitted,  that 
they  "go  very  far  to  prove  that  membranes,  perhaps  even  during  life, 
and  certainly  after  death,  before  their  texture  is  visibly  altered,  have 
the  power  of  permitting  the  transudation  of  certain  fluids."  That  such 
imbibition  occurs  during  life  is  indisputably  proved.  If  the  clear  and 
decisive  experiments  of  Magendie  and  Fodera  Iiad  been  insufficient  to 
establish  it,  the  additional  testimony, — aflbrded  hy  Lawrence,  Coates, 
and  Harlan  ;  by  Dutrochet,  Faust,  Mitchell,  Rogers,  Draper,  and  others, 
— would  be  ample. 

By  the  difterent  rates  of  penetrativeness  of  different  fluids,  and  of 
permeability  of  different  tissues,  we  can  explain  why  imbibition  may 
occur  in  one  set  of  vessels  and  not  in  another ;  and  the  constant  cur- 
rent, established  in  the  interior  of  the  vessel  is  a  sufficient  reply  to  the 
suggestion,  that  there  may  not  be  the  same  tendency  to  transude  after 
the  fluid  has  entered  it.  M.  Adelon^  is  of  opinion,  that  under  the  view 
of  imbibition  we  ought  to  find  substances  in  the  arteries  and  lymphatics 
also;  but  a  sufficient  objection  to  this  would  be, — the  comparative  tardi- 
ness, with  which  the  former  admit  the  action ;  and  the  selection,  and, 
consequently,  refusal,  exerted  by  the  latter;  but  even  here  evidences 
of  adventitious  imbibition  are  occasionally  met  with ;  as  in  the  case  of 
salts,  which — we  have  seen — have  been  detected  in  the  thoracic  duct, 
after  having  been  introduced  into  the  cavity  of  the  abdomen. 

The  two  following  experiments  by  Prof.  J.  K.  Mitchell,^  which  are 
analogous  to  numerous  others,  performed  in  the  investigation  of  this 
subject,  well  exhibit  endosmose  in  living  tissues.  A  quantity  of  a  solution 
of  acetate  of  lead  was  thrown  into  the  peritoneal  cavity  of  a  young  cat; 
sulphuretted  hydrogen  being  passed,  at  the  same  time,  into  the  rectum. 
In  four  minutes,  the  poisonous  gas  killed  the  animal.  Instantly  on  its 
death,  the  peritoneal  coat  of  the  intestines,  and  the  parietes  of  the 
cavity  in  contact  with  them,  were  found  lined  with  a  metallic  precipi- 
tate, which  adhered  to  the  surface,  and  was  removable  by  nitric  acid 
moderately  diluted.  It  was  the  characteristic  precipitate  of  sulphuretted 
hydrogen,  when  acting  on  lead.  In  another  experiment  on  a  cat,  a 
solution  of  acetate  of  lead  was  placed  in  the  thorax,  and  sulphuretted 
hydrogen  in  the  abdomen.  Almost  immediately  after  the  entrance  of 
the  sulphuretted  hydrogen  into  the  abdominal  cavity,  death  ensued. 

'  rhysiology,  edit,  cit.,  p.  629.  ^  Op.  cit. 

^  American  Journal  of  the  Medical  Sciences,  vii.  44,  Pliilada.,  1830. 
VOL.  I. — 17 


258  ABSORPTION. 

On  inspecting-  tlie  thoracic  side  of  the  diaphragm,  which  was  done  as 
quickly  as  possible,  the  tendinous  part  of  it  exhibited  the  leaden  appear- 
ance of  the  precipitate  thrown  down  by  sulphuretted  hydrogen.  The 
experiment  of  J.  Miiller,  referred  to  in  a  preceding  page,  establishes 
the  same  fact. 

It  may  be  concluded,  then,  that  all  living  tissues  imbibe  liquid  mat- 
ters which  come  in  contact  with  them ;  and  that  the  same  occurs  to 
solids,  provided  they  are  soluble  in  the  humours,  and  especially  in  the 
serum  of  the  blood.  But  although  imbibition  is  doubtless  effected  by 
living  tissues,  too  great  a  disposition  has  been  manifested  to  refer  all 
the  vital  phenomena  of  absorption  and  exhalation  to  it.  Even  dead 
animal  membrane  exerts  a  positive  agency  in  respect  to  bodies  placed 
on  either  side  of  it.  In  the  early  part  of  this  work'  the  phenomena  of 
imbibition  were  investigated,  and  it  was  there  explained  how  endos- 
mose  and  exosmose  are  affected  through  organic  membranes.  A  care- 
ful examination  of  those  phenomena  would  lead  to  the  belief,  that  in 
many  cases  the  membrane  exerts  no  agency  except  in  the  manner  last 
suggested  by  M.  Dutrochet.  This  is  signally  manifested  in  experi- 
ments with  porous,  inorganic  substances ;  and  it  has  been  ingeniously 
and  ably  confirmed  by  Dr,  Draper,^  of  New  York,  who  found,  that  the 
phenomena  were  elicited,  when,  instead  of  an  organic  tissue,  fissured 
glass  was  employed.  Still,  as  has  been  demonstrated,  the  nature  of  the 
septum  or  membrane  has  in  other  cases  a  marked  effect  on  endosmose. 

Sir  David  Barry,^ — in  different  memoirs  laid  before  the  Academie 
Royale  de  Medecine,  the  'Academie  Hoyale  des  Sciences  of  Paris,  and  the 
Medico- Ghirurgical  Society  of  London, — maintained,  that  the  whole 
function  of  external  absorption  is  a  physical  result  of  atmospheric  pres- 
sure ;  and  "  that  the  circulation  in  the  absorbing  vessels  and  in  the 
great  veins  depends  upon  this  same  cause  in  all  animals  possessing 
the  power  of  contracting  and  dilating  a  cavity  around  that  point  to 
which  the  centripetal  current  of  their  circulation  is  directed,"  In  other 
words,  it  is  his  opinion,  that,  at  the  time  of  inspiration,  a  tendency 
to  a  vacuum  is  produced  in  the  chest  by  its  expansion ;  and  as  the 
atmospheric  pressure  externally  thus  ceases  to  be  counterbalanced,  the 
pressure  without  occasions  the  flow  of  blood  towards  the  heart  along 
the  veins.  The  consideration  of  the  forces  that  propel  the  blood  will 
atTord  us  an  opportunity  of  saying  a  few  words  on  this  view;  at  present, 
we  may  only  observe,  that  Sir  David  ascribes  absorption, — which  he 
explicitly  states  to  be,  in  his  opinion,  extra  vital, — to  the  same  cause. 
In  proof  of  this,  he  instituted  numerous  experiments,  in  which  the 
absorption  of  poisons  from  wounds  appeared  to  take  place,  or  to  be 
suspended,  according  as  the  wounds  were,  as  he  conceived,  exposed  to 
atmospheric  pressure,  or  freed  from  its  influence  by  the  application  of 
a  cupping-glass.  The  same  quantity  of  poison,  which,  under  ordinary 
circumstances,  destroyed  an  animal  in  a  few  seconds,  was  rendered  com- 
pletely innocuous  by  the  exhausted  glass  ;  and  what  is  singular,  even 
when  the  symptoms  had  commenced,  the  application  of  the  cupping-glass 

'  See  p.  66. 

2  Amer.  Journ.  of  the  Mod.  Soiences,  for  Aug.  1836,  p.  276  ;  Nov.,  1837,  p.  122  ;  May, 
1838,  p.  23,  and  August,  1838 — more  especiallj  the  last  two. 

*  Experimental  Researches  on  the  Influence  of  Atmospheric  Pressure  upon  the  Circu- 
lation, &c.,  Lond.  1826. 


VENOUS.  -  259 

had  the  effect  of  speedily  and  completely  removing  them;  a  fact  of  es- 
sential importance  in  its  therapeutical  relations.  In  commenting  on  the 
conclusions  of  Sir  1).  Barry,  Messrs.  Addison  and  Morgan,' — who  main- 
tain the  doctrine,  that  all  poisonous  agents  produce  their  specific  eftects 
upon  the  brain,  and  general  system,  through  the  sentient  extremities  of 
nerves,  and  through  the  sentient  extremities  of  nerves  only  ;  and  that, 
when  such  agents  are  introduced  into  the  current  of  the  circulation  in  any 
way,  their  effects  result  from  the  impression  made  upon  the  sensible 
structure  of  the  bloodvessels,  and  not  from  their  direct  application  to 
the  brain  itself, — contend,  that  the  soft  parts  of  the  body,  when  covered 
by  an  exhausted  cupping-glass,  must  necessarily,  from  the  pressure  o^ 
the  edges  of  the  glass,  be  deprived  for  a*  time  of  all  connexion,  both 
nervous  and  vascular,  with  the  surrounding  parts; — that  the  nervts 
must  be  partially  or  altogether  paralysed  by  compression  of  their  trunks ; 
and  that,  from  the  same  cause,  all  circulation  through  the  veins  and 
arteries  within  the  area  of  the  glass  must  cease  ;  that  the  rarefaction 
of  the  air  within  the  glass  being  still  farther  increased  by  means  of 
the  small  pump  attached  to  it,  the  fluids,  in  the  divided  extremities  of 
the  vessels,  are  forced  into  the  vacuum,  and,' with  these  fluids,  either, a 
part  or  the  whole  of  the  poison,  which  had  been  introduced  ;  and  that, 
in  such  a  condition  of  parts,  tlie  compression,  on  the  one  hand,  and  the 
removal  of  the  poison  from  the  wound  on  the  other,  will  sufficientlv 
explain  the  result  of  the  experiment,  either  according  to  the  views  of 
those  who  conceive  the  impression  to  be  made  on  the  nerves  of  the 
bloodvessels,  or  of  those  who  think,  that  the  agent  must  be  carried 
along  with  the  fluid  of  the  circulation  to  the  pail  to  be  impressed. 

Thus  far  allusion  has  been  made  only  to  the  passage  of  tenuous  fluids 
into  the  veins.  It  has  been  already  seen,  that  many  albuminous  and 
saccharine  solutions  after  having  been  exposed  to  the  gastric  and  in- 
testinal juices  pass  into  the  radicles  of  the  portal  veins  to  be  con- 
veyed to  the  liver  to  undergo  assimilation. 

Insoluble  substances,  too,  have  been  detected  by  Professor  Oesterlen^ 
in  the  mesenteric  veins.  On  administering  levigated  charcoal  to  ani- 
mals for  five  or  six  days  in  succession,  the  blood  of  these  veins  exhi- 
bited distinctly  particles  of  charcoal  of  different  sizes,  some  of  them 
so  large,  that  it  was  a  matter  of  surprise  how  they  could  have  made 
their  way  into  the  blood  through  the  mucous  membrane  and  the  walls 
of  the  bloodvessels.  We  have  no  difficulty,  consequently,  in  compre- 
hending how  the  mild  chloride  and  other  insoluble  preparations  of 
mercury  might  be  able  to  enter  the  bloodvessels  in  this  manner. 

The  observations  of  Oesterlen  have  been  confirmed  by  Mensonides 
and  Donders''  not  only  with  charcoal,  but  with  sulphur,  and  with  starch, 
which  is  readily  detected  in  the  blood  by  the  iodine  test.  The  latter 
is  inclined  to  think  that  they  enter  the  lacteals  rather  than  the  veins, 
as  he  finds  them  deposited  in  the  lungs  more  than  the  liver.  It  is 
difficult  to  conceive  how  they  effect  their  passage.  The  extreme  velo- 
city of  the  blood  in  the  vessels  may  exert  a  degree  of  traction  on  them 

'  An  Essay  on  the  Operation  of  Poisonous  Agents  upon  tlie  Living  Body,  Lond.,  1S29. 
*  Heller's  Archiv.,  Bd.  iv.  Heft  1,  cited  in  Lond.  Med.  Gazette  for  July,  1^47. 
^  Canstatt's  Jahreshericht,  1851,  p.  122,  Wiirzburg,  1S52  ;  and  Ilenle  uud  Pfeufer's 
Zeitschrift,  1851,  Bd.  i.  s.  415-27. 


260  ABSORPTION. 

wliicli  may  account  for  tlieir  entrance,  when  it  could  not  be  effected 
through  dead  membrane. 

Such  would  seem  to  be  the  main  facts  regarding  the  absorbent  action 
of  the  veins,  which  rests  on  as  strong  evidence  as  we  possess  regarding 
any  of  the  functions  of  the  body ;  yet,  in  the  treatise  on  Animal  and 
Vegetable  Physiology  by  Dr.  Eoget,^  we  find  it  passed  by  without  a 
comment ! 

We  have  still  to  inquire  into  the  agents  of  internal  and  adventitious 
absorption. 

IV.   IXTERXAL  ABSOEPTIOX. 

On  this  point  but  few  remarks  will  be  necessary,  after  the  exposition 
of  the  different  vascular  actions  concerned  in  absorption.  The  term 
comprehends  intersiitial  absorjJtion,  and  the  absorption  of  recrementitial 
fluids.  l^hQ  first  comprises  the  agency  by  which  the  different  textures 
of  the  body  are  decomposed  and  conveyed  into  the  mass  of  blood.  It 
will  be  considered  more  at  length  under  the  head  of  Nutpjtion  ;  the 
second^  that  of  the  various  fluids  effused  into  cavities;  and  the  thirds 
that  which  is  effected  on  the  excretions  in  their  reservoirs  or  excretory 
ducts.  All  these  must  be  accomplished  by  one  of  the  two  sets  of  vessels 
previously  described;  lymphatics,  or  veins,  or  both.  Now,  we  have 
attempted  to  show,  that  an  action  of  selection  and  elaboration  is  exerted 
by  lymphatics;  whilst  we  have  no  evidence  of  such  action  in  the  case 
of  the  veins.  It  would  follow,  then,  that  all  the  varieties  of  internal 
absorption,  in  which  the  substance,  when  received  into  the  vessel,  pos- 
sesses different  characters  from  those  it  had  when  without,  must  be 
executed  by  lymphatics ;  whilst  those,  in  which  no  conversion  occurs, 
take  place  by  the  veins.  In  the  constant  absorption,  and  corresponding 
deposition,  incessantly  going  on  in  the  body,  the  solid  parts  must  be 
reduced  to  their  elements,  and  a  new  compound  be  formed;  inasmuch 
as  we  never  find  bone,  muscle,  cartilage,  membrane,  &c.,  existing  in 
these  states  in  any  of  the  absorbed  fluids ;  and  it  is  probable,  therefore, 
that,  at  the  radicles  of  the  Ij^mphatic  vessels,  they  are  converted  into 
the  same  fluid — the  lymph — in  like  manner  as  the  heterogeneous  sub- 
stances in  the  intestinal  canal  afford  to  the  lacteals  the  elements  of  a 
fluid  the  character  of  which  is  always  identical.  On  the  other  hand, 
when  the  recrementitial  fluid  consists  simply  of  the  serum  of  the  blood, 
more  or  less  diluted,  there  can  be  no  obstacle  to  the  passage  of  its 
aqueous  portion  immediately  through  the  coats  of  the  veins  by  imbi- 
bition, whilst  the  more  solid  part  is  taken  up  by  the  lymphatic  vessels. 
In  the  case  of  excrementitious  fluids,  there  is  reason  to  believe,  that 
absorption  simply  removes  some  of  their  aqueous  portions;  and  this,  it 
is  obvious,  can  be  effected  directly  by  the  veins,  through  imbibition. 
The  facts,  connected  with  the  absorption  of  substances  from  the  interior 
of  the  intestine,  have  clearly  shown,  that  the  chjdiferous  vessels  alone 
absorb  chyle,  and  that  the  drinks  and  adventitious  substances  pass  into 
the  mesenteric  veins.  These  apply,  however,  to  external  absorption 
only;  but  similar  experiments  and  arguments  have  been  brought  for- 
ward by  the  supporters  of  the  two  opinions,  in  regard  to  substances 

'  Bridgewater  Treatise,  Lond.,  1834;  Amer.  edit.,  Pliilad.,  1836. 


INTEKNAL.  261 

placed  on  the  peritoneal  surltice  of  the  intestine,  and  other  parts  of  the  . 
body.  Whilst  some  aflfinn,  that  they  have  entered  the  lymphatics ; 
others  have  only  been  able  to  discover  them  in  the  veins.  Mr.  Hunter, 
having  injected  water  coloured  with  indigo  into  the  peritoneal  cavity 
of  animals,  saw  the  lymphatics,  a  short  time  afterwards,  filled  with  a 
liquid  of  a  blue  colour.  In  animals,  that  had  died  of  pulmonary  or 
abdominal  hemorrhage,  Mascagni  found  the  lymphatics  of  the  lungs 
and  peritoneum  filled  with  blood;  and  he  asserts,  that,  having  kept  his 
feet  for  some  hours  in  water,  swelling  of  the  inguinal  glands  supervened, 
with  transudation  of  a  fluid  through  the  gland  ;  coryza,  &c.  M.  Des- 
genettes  observed  the  lymphatics  of  the  liver  containing  a  bitter,  and 
those  of  the  kidneys  a  urinous,  lymph.  Scimmering  detected  bile  in 
the  lymphatics  of  the  liver;  and  milk  in  those  of  the  axilla.  M.  Diipuy- 
treu  relates  a  case,  which  M.  Magendie  conceives  to  be  much  more 
favourable  to  the  doctrine  of  absorption  by  the  lymphatic  vessels  than 
any  of  the  others.  A  female,  who  had  an  enormous  fluctuating  tumour 
at  the  upper  and  inner  part  of  the  thigh,  died  at  the  IlOtel  Dieu,  of 
Paris,  in  1810.  A  few  days  before  her  death,  inflammation  occurred 
in  the  subcutaneous  areolar  tissue  at  the  inner  part  of  the  tumour. 
The  day  after  dissolution,  M.  Dupuytren  opened  the  body.  On  divid- 
ing the  integuments,  he  noticed  white  points  on  the  lips  of  the  incision. 
Surprised  at  the  appearance,  he  carefully  dissected  away  some  of  the 
skin,  and  observed  the  subcutaneous  areolar  tissue  overrun  by  whitish 
lines,  some  of  which  were  as  large  as  a  crow's  quill.  These  were  evi- 
dently lymphatics  filled  with  puriform  matter.  *The  glands  of  the  groin, 
with  which  these  lymphatics  communicated,  were  injected  with  the 
same  matter.  The  lymphatics  were  full  of  the  fluid,  as  far  as  the  lumbar 
glands ;  but  neither  the  glands  nor  the  thoracic  duct  presented  any  trace 
of  it.'  On  the  other  hand,  multiplied  experiments  have  been  instituted, 
by  throwing  coloured  and  odorous  substances  into  the  great  cavities  of 
the  body;  and  these  have  been  found  always  in  the  veins,  and  never 
in  the  lymphatics. 

To  the  experiments  of  Mr.  Hunter,  objections  have  been  urged, 
similar  to  those  brought  against  his  experiments  to  prove  the  absorp- 
tion of  milk  by  the  lacteals;  and  sources  of  fallacy  have  been  pointed 
out.  The  blue  colour,  which  the  lymphatics  seemed  to  him  to  possess, 
and  which  was  ascribed  to  the  absorption  of  indigo,  was  noticed  in 
the  experiments  of  Messrs,  Harlan,  Lawrence,  and  Coates;^  but  they 
discovered  that  this  was  an  optical  illusion.  What  they  saw  was  the 
faint  blue,  which  transparent  substances  assume,  when  placed  over 
dark  cavities.  Mr.  Mayo^  has  also  affirmed  that  the  chyliferous 
lymphatics  always  assume  a  bluish  tint  a  short  time  after  death,  even 
when  the  animal  has  not  taken  indigo.  The  cases  of  purulent  matter, 
&c.,  found  in  the  lymphatics,  may  be  accounted  for  by  the  morbid 
action  having  produced  disorganization  of  the  vessel,  so  that  the  fluid 
could  enter  the  lymphatics  directly ;  and,  if  once  within,  its  progres- 
sion could  be  readily  understood. 

M.  Magendie"  asserts,  that  M.  Dupuytren  and  he  performed  more 

'  Magendie,  Pi-rcis,  &c.,  2de  edit.,  ii.  195,  et  seq. ;  and  Adelon,  art.  Absorption,  Diet, 
de  Med^,  2de  edit.,  i,  239,  and  Physioloijie  de  rHomme,  2de  edit.,  iii.  65,  Paris,  1829. 
"  Harlan's  Physical  Researches,  p.  459,  Pliilad.,  1835. 
*  Outlines  of  Human  Physiology,  3d  edit.,  Lond.,  1833.  *  Op.  cit.,  ii.  211. 


262  ABSORPTION. 

.than  one  liundred  and  fifty  experiments,  in  wliich  they  submitted  to 
the  absorbent  action  of  serous  membranes  different  fluids,  and  never 
found  any  of  them  within  the  lymphatic  vessels.  These  fluids  pro- 
duced their  effects  more  promptly,  in  proportion  to  the  rapidity  with 
which  they  were  capable  of  being  absorbed.  Opium  exerted  its  nar- 
cotic influence;  wine  produced  intoxication,  &c.,  and  ]\[.  Magendie 
found,  from  numerous  experiments,  that  the  ligature  of  the  thoracic 
duct  in  no  respect  diminished  the  promptitude  with  which  these  effects 
supervened.  The  partisans  of  lymphatic  absorption,  however,  affirm 
that  even  if  these  substances  are  met  with  in  the  veins,  it  by  no  means 
follows,  that  absorption  has  been  effected  by  them;  for  the  lymphatics, 
they  assert,  have  frequent  communications  with  the  veins;  and,  con- 
sequently, they  may  still  absorb  and  convey  their  products  into  the 
venous  system.  In  reply  to  this,  it  may  be  urged,  that  all  the  vessels 
— arterial,  venous,  and  hnnphatic — appear  to  have  intercommunica- 
tion ;  but  there  is  no  reason  to  believe,  that  the  distinct  offices,  per- 
formed by  them,  are,  under  ordinary  circumstances,  interfered  with; 
and,  again,  where  would  be  the  necessity  for  these  intermediate  lymph- 
atic vessels,  seeing  that  imbibition  is  so  readily  effected  by  the  veins  ? 
The  axiom — quod  fieri  potest  per  pa^ca.,  non  debet  fieri  i^er  rnidta — is  here 
strikingly  appropriate.  The  lymphatics,  too,  as  we  have  endeavoured 
to  show,  exert  an  action  of  selection  and  elaboration  on  substances 
exposed  to  them;  but,  in  the  case  of  venous  absorption,  there  is  not 
the  slightest  evidence,  that  any  such  selection  exists, — odorous  and 
coloured  substances  retaining,  within  the  vessel,  the  properties  they 
had  without.  Lastly.  Where  would  be  the  use  of  organs  of  a  distinct 
lymiphatic  circulation  opening  into  the  thoracic  duct,  seeing  that  the 
absorbed  matters  might  enter  the  various  venous  trunks  directly 
through  these  supposititious  communicating  lymphatics;  and  ought 
we  not  occasionally  to  be  able  to  detect  in  the  lymphatic  trunks  some 
evidence  of  those  substances,  which  their  fellows  are  supposed  to  take 
up  and  convey  into  the  veins?  These  carrier  lymphatics  have  ob- 
viously been  devised  to  support  the  tottering  fabric  of  exclusive  lymph- 
atic absorption, — undermined,  as  it  has  been,  by  the  powerful  facts 
and  reasonings  that  have  been  adduced  in  favour  of  absorption  by 
veins. 

From  the  whole  of  the  preceding  history  of  absorption,  we  are  of 
opinion,  that  the  chyliferous  and  lymphatic  vessels  form  only  chyle 
and  lymph,  refusing  all  other  substances,  with  the  exception  of  saline 
and  other  matters,  that  enter  probablj^  by  imbibition, — that  the  veins 
admit  every  liquid,  which  possesses  the  necessary  tenuity ;  and  that 
whilst  all  the  absorptions,  which  require  the  substances  acted  upon  to 
be  decomposed  and  transformed,  are  effected  by  chyliferous  and  lymph- 
atic vessels ;  they  that  are  sufficiently  thin,  and  demand  no  alteration, 
are  accomplished  directly  through  the  coats  of  the  veins  by  imbibi- 
tion; and  we  shall  see  that  such  is  the  case  with  several  of  the  transu- 
dations or  exhalations. 

V.  ACCIDENTAL  ABSORPTION. 

The  experiments,  to  which  reference  has  been  made,  have  shown, 
that  many  substances,  adventitiously  introduced  into  various  cavities, 


CUTANEOUS.  263 

or  placed  iu  contact  with  different  tissues,  have  been  rapidly  absorljed 
into  the  blood,  without  experiencing  any  transformation.  Within 
certain  limits,  the  external  envelope  of  the  body  admits  of  this  func- 
tion ;  but  by  no  means  to  the  same  extent  as  its  prolongation,  which 
lines  the  different  excretory  ducts.  The  absorption  of  drinks  is  suffi- 
cient evidence  of  the  activity  of  the  function  as  regards  the  gastro- 
enteric mucous  membrane.  The  same  may  be  said  of  the  pulmonary 
mucous  membrane.  Through  it,  oxygen  and  nitrogen  pass  to  reach 
the  blood  in  the  lungs,  as  well  as  carbonic  acid  in  its  way  outwards. 
Aromatic  substances,  such  as  spirit  of  turpentine,  breathed  for  a  time, 
are  detected  in  the  urine;  proving  that  their  aroma  has  been  absorbed; 
and  it  is  by  absorption,  that  contagious  miasmata  probably  produce 
their  pestiferous  agency.  Dr.  Madden,^  however,  thinks  that  the  lungs 
do  not  absorb  watery  vapour  with  the  rapidity,  or  to  the  extent,  that 
has  been  imagined ;  whilst  Dr.  A.  Combe^  hazards  the  hypothesis,  that 
owing  apparently  to  the  extensive  absorption  of  aqueous  vapour  by 
the  lungs,  the  inhabitants  of  marshy  and  humid  districts,  as  the  Dutch, 
are  remarkable  for  the  predominance  of  the  lymphatic  system. 

Not  only  do  the  tissues,  as  we  have  seen,  suffer  imbibition  by  fluids, 
but  by  gases  also :  the  experiments  of  Chaussier  and  Mitchell  astonish 
us  by  the  rapidity  and  singularity  of  the  passage  of  the  latter  through 
the  various  tissues ; — the  rapidity  varying  according  to  the  permea- 
bility of  the  tissue,  and  the  penetrative  power  of  the  gas. 

a.   Cutaneous  Absorption. 

On  the  subject  of  cutaneous  ahsorjjtion^  much  difference  of  sentiment 
has  prevailed ; — some  asserting  it  to  be  possible  to  such  an  extent,  that 
life  may  be  preserved,  for  a  time,  by  nourishing  baths.  It  has  also 
been  repeatedly  affirmed,  that  rain  has  calmed  the  thirst  of  shipwrecked 
mariners  who  have  been,  for  some  time,  deprived  of  water.  It  is 
obvious,  from  what  we  know  of  absorption,  that,  in  the  first  of  these 
cases,  the  water  only  could  be  absorbed ;  and  even  the  possibility  of 
this  has  been  denied  by  many.  Under  ordinary  circumstances,  it  can 
happen  to  a  trifling  extent  only,  if  at  all;  but,  in  extraordinary  cases, 
where  the  system  has  been  long  devoid  of  its  usual  supplies  of  moist- 
ure, and  where  we  have  reason  to  believe,  that  the  energy  of  absorp- 
tion is  increased,  such  imbibition  may  be  possible.  Sanctorius,^  Von 
Gorter,"  Keill,*  Mascagni,^  Madden,'  E.  L.  Young,"  Dill,^  and  others 
believe,  that  this  kind  of  absorption  is  not  only  frequent  but  easy.  It 
has  been  affirmed,  that  after  bathing  the  weight  of  the  body  has  been 
manifestly  augmented;  and  the  last  of  these  individuals  has  adduced 
many  facts  and  arguments  to  support  the  position.  Strong  testimony 
has  been  brought  forward  in  favour  of  extensive  absorption  of  moist- 

'  Experimental  Inquiry  into  the  Physiology  of  Cutaneous  Absorption,  p.  G4,  Edinb., 
1838. 

2  Principles  of  Physiology  applied  to  the  Preservation  of  Health,  5th  edit.,  p.  72, 
Edin.,  1S3G. 

3  De  Static.  Medic,  Lugd.  Bat.,  1711. 

*  De  Persjiirat.  Insensib.,  Lugd.  Bat.,  1736. 

5  Teatamin.  Medico-Physic,  Lond.,  1718.        ^  Vas.  Lymphat.  Hist.,  Senis,  1783. 
'  Op.  cit.,  p.  58.  ®  De  Cutis  lulialatione,  Edinb.,  1813. 

^  Edinb.  Medico-Chir.  Transact.,  ii.  350. 


264:  ABS0RPTI03S'. 

ure  from  the  atmospliere.  Tliis  is  probably  effected  ratlier  tlirougb 
the  puhnouary  mucous  surface  than  the  skin,  A  case  of  ovarian 
dropsy  is  referred  to  by  Dr.  Madden/  in  which  the  patient,  during 
eighteen  days,  drank  692  ounces  of  fluid;  and  discharged  by  urine 
and  paracentesis  1298  ounces,  being  an  excess  of  606  ounces  of  fluid 
egesta  over  the  fluid  ingesta.  I3ishop  Watson,  in  his  Chemical 
Essays,  states,  that  a  lad  at  Newmarket,  having  been  almost  starved, 
in  order  that  he  might  be  reduced  to  the  proper  weight  for  riding  a 
match,  was  weighed  at  9,  and  again  at  10,  A.  M.,  when  he  was  found 
to  have  gained  nearly  30  ounces  in  weight  in  the  interval,  although 
he  had  only  taken  half  a  glass  of  wine.  Dr.  Carpenter^  gives  a 
parallel  case,  which  was  related  to  him  by  Sir  G.  Ilill,  Governor  of 
St.  A^incent.  A  jockey  had  been  for  some  time  in  training  for  a  race 
in  which  Sir  G.  Hill  was  much  interested,  and  had  been  reduced  to 
the  proper  weight.  On  the  morning  of  the  race,  suffering  much  from 
thirst,  he  took  "one  cup  of  tea,  and  shortly  afterwards  his  weight  was 
found  to  have  increased  six  pounds,  so  that  he  was  incapacitated  for 
riding.  These  cases  certainly  appear  difficult  of  belief:  yet  the  au- 
thority is  good.  Dr.  Carpenter  presumes,  that  nearly  the  whole  of 
the  increase  in  Bishop  Watson's  case,  and  at  least  three-fourths  of  it 
in  Sir  G.  Hill's  case,  must  be  attributed  to  cutaneous  absorption,  which 
was  probably  stimulated  by  the  wine  that  was  taken  in  the  one,  and 
by  the  tea  in  the  other.  Bichat  was  under  the  impression,  that,  in 
this  way  he  imbibed  the  tainted  air  of  the  dissecting  room,  in  which 
he  passed  a  large  portion  of  his  time.  To  avoid  an  objection,  that 
might  be  urged  against  this  idea, — that  the  miasmata  might  have  been 
absorbed  by  the  air-passages,  he  so  contrived  his  experiment,  as  by 
means  of  a  long  tube,  to  breathe  the  fresh  outer  air ;  when  he  found, 
that  the  evidence,  which  consisted  in  the  alvine  evacuations  having 
the  smell  of  the  miasmata  of  the  dissecting-room,  continued.  It  is 
obvious,  however,  that  such  an  experiment  would  hardly  admit  of 
satisfactory  execution,  and  it  is  even  doubtful,  whether  there  was  any 
actual  relation  between  the  assigned  effect  and  the  cause.  The  testi- 
mony of  MM.  Andral,  Boyer,  Dumcril,  Dupuytren,  Serres,  Lallemand, 
Ribes,  Lawrence,  Parent-Duchatelet,  and  that  afforded  by  the  author's 
own  observation,  are  by  no  means  favourable  to  the  great  unwhole- 
someness  of  cadaveric  exhalations.^ 

Dr.  J.  Bradner  Stuart"*  found,  after  bathing  in  infusions  of  madder, 
rhubarb,  and  turmeric,  that  the  urine  was  tinged  with  these  substances. 
A  garlic  plaster  affected  the  breath,  when  every  care  was  taken,  by 
breathing  through  a  tube  connected  with  the  exterior  of  the  apartment, 
that  the  odour  should  not  be  received  into  the  lungs.  Dr.  Thomas 
SewalP  found  the  urine  coloured,  after  bathing  the  feet  in  infusion  of 
madder,  and  the  hands  in  infusions  of  madder  and  rhubarb.  Dr. 
Mussey'*  proved,  that  if  the  body  be  immersed  in  a  decoction  of  mad- 

'  Op.  cit.,  p.  55. 

2  Principles  of  Human  Physiology,  Araer.  edit.,  p.  148,  Philacl.,  1855. 
^  Parent-Ducliatelet,  Hygiene  Publicjiie,  Paris,  183G  ;  and  the  remarks  of  the  author 
in  his  Human  Health,  p.  77,  Philad.,  1844. 

*  New  York  Med.  Repos.,  vols.  i.  and  iii.  1810-11. 

5  Med.  and  Physical  Journ.,  xxxi.  80,  Loud.,  1814. 

6  Philad.  Medical  and  Physical  Journal,  i.  288,  Philad.,  1808. 


ACCIDENTAL.  265 

der,  the  substance  may  be  detected  in  the  urine,  by  using  an  appro- 
priate test.  Dr.  Barton  found,  that  frogs,  confined  in  dry  glass  ves- 
sels, became  enfeebled,  diminished  in  size,  and  unable  to  leap;  but 
that,  on  the  introduction  of  a  small  quantity  of  water,  they  soon 
acquired  their  wonted  vigour,  became  plump,  and  as  lively  as  usual 
in  their  motions.^  M.  W.  F.  Edwards^  of  Paris,  is,  also,  in  fiivour  of 
absorption  being  carried  on  by  the  skin  to  a  considerable  extent. 

To  deny  cutaneous  absorption  altogether  is  impossible.  It  is  a  chan- 
nel, in  fact,  by  which  we  introduce  one  of  our  most  active  remedial 
agents  into  the  system; — and  it  has  not  unfrequently  happened,  where 
due  caution  has  been  omitted,  that  the  noxious  effects  of  different  mine- 
ral and  other  poisons  have  been  developed  by  their  application  to  the 
surface,  but  it  is  by  no  means  common  or  easy,  when  the  cuticle  is 
sound,  unless  the  substance  employed  possesses  unusually  penetrating 
properties.  M.  Chaussier  found,  that  to  kill  an  animal,  it  is  sufficient 
to  make  sulphuretted  hydrogen  gas  act  on  the  surface  of  the  body, 
taking  care  that  none  gets  into  the  air-passages:  the  researches  of  Prof. 
J.  K.  MitchelP  have  also  shown  that  this  gas  is  powerfully  penetrant. 
Unless,  however,  the  substances,  in  contact  with  the  epidermis,  are  of 
such  a  nature  as  to  attack  its  chemical  composition,  there  is  usually  no 
extensive  absorption. 

It  is  only  of  comparatively  late  years,  that  physiologists  have  ven- 
tured to  deny,  that  the  water  of  a  bath,  or  the  moisture  from  a  damp 
atmosphere,  is  taken  up  under  ordinary  circumstances;  and  if,  in  such 
cases,  the  body  appears  to  have  increased  in  weight,  it  is  affirmed,  and 
with  some  appeai'ance  of  truth,  that  this  may  be  owing  to  diminution 
of  the  cutaneous  transpiration.  It  is,  indeed,  probable,  that  one  great 
use  of  the  epidermis  is  to  prevent  the  inconveniences  to  which  we 
should  necessarily  be  liable,  were  such  absorption  easy.  This  is  con- 
firmed by  the  fact,  that  if  the  skin  be  deprived  of  the  epidermis,  and 
the  vessels  that  creep  on  the  outer  surface  of  the  true  skin  be  thus  ex- 
posed, absorption  occurs  as  rapidly  as  elsewhere.  J.  Miiller  afffrms, 
that  saline  solutions  applied  to  the  corium  penetrate  the  capillaries  in 
a  second  of  time.  To  insure  this  result  in  inoculation  and  vaccination, 
the  matter  is  always  placed  beneath  the  cuticle;  and,  indeed,  the  small 
vessels  are  generally  slightly  wounded,  so  that  the  virus  gets  imme- 
diately into  the  venous  blood.  Yet — it  is  proper  to  remark — the  lizard, 
whose  skin  is  scaly,  after  having  lost  weight  by  exposure  to  air,  reco- 
vers its  weight  and  plumpness  when  placed  in  contact  with  water;  and 
if  the  scaly  skin  of  the  lizard  permits  such  absorption,  M.  Edwards 
thinks  it  impossible  not  to  attribute  this  property  to  the  cuticle  of 
man.  When  the  epidermis  is  reujoved,  and  the  system  is  affected  by 
substances  placed  in  contact  with  the  true  skin,  we  have  the  endermio 
method  of  medication. 

M.  Scguin''  instituted  a  series  of  experiments  to  demonstrate  the  ab- 
sorbent or  non-absorbent  action  of  the  skin.    His  conclusion  was,  that 

'■  Klapp,  Inangnral  Essay  on  Cuticular  Absorption,  p.  30,  Philad.,  1805. 

*  Sur  rintluence  des  Agens  Physiques  ;  or  l)rs.  Hodgkin  and  Fisher's  translation, 
p.  61,  and  p.  187,  &c.,  Lond.,  1832. 

'  Anier.  Journal  of  the  Med.  Sciences,  vii.  44 ;  and  p.  68  of  this  work. 

*  Annales  de  Chimie,  xc.  185. 


266  ABSORPTION. 

water  is  not  absorbed,  and  that  the  epidermis  is  a  natural  obstacle  to 
the  action.  To  discover,  whether  this  was  the  case  as  regarded  other 
fluids,  he  experimented  on  individuals  labouring  under  venereal  afi'ec- 
tions,  who  immersed  their  feet  and  legs  in  a  bath,  composed  of  sixteen 
pints  of  water  and  three  drachms  of  corrosive  chloride  of  mercury,  for 
an  hour  or  two,  twice  a  day.  Thirteen,  subjected  to  the  treatment  for 
twenty-eight  days,  gave  no  signs  of  absorption;  the  fourteenth  was 
manifestly  affected,  but  he  had  itchy  excoriations  on  the  legs ;  and  the 
same  was  the  case  with  two  others.  As  a  general  rule,  absorption  ex- 
hibited itself  in  those  only  whose  epidermis  was  not  in  a  state  of  inte- 
grity. At  the  temperature  of  7-i°  Fahrenheit,  however,  the  sublimate 
was  occasionally  absorbed,  but  never  the  water.  From  other  experi- 
ments, it  appeared  evident,  that  the  most  irritating  substances,  and  those 
most  disposed  to  combine  with  the  epidermis,  were  partly  absorbed, 
whilst  others  were  apparently  not.  Having  weighed  a  drachm  (seventy- 
two  grains,  ^Jo/cZs  de  marc)  of  calomel,  and  the  same  quantity  of  camboge, 
scammony,  salt  of  alembroth,  and  tartar  emetic,  M.  Seguin  placed  an 
individual  on  his  back,  washed  the  skin  of  the  abdomen  carefully,  and 
applied  to  it  these  substances  at  some  distance  from  each  other,  covering 
each  with  a  watch-glass,  and  maintaining  the  whole  in  situ  by  a  linen 
roller.  The  heat  of  the  room  was  kept  at  65°.  M.  Seguin  remained 
with  the  patient,  in  order  that  the  substances  should  not  be  displaced : 
and  he  protracted  the  experiment  for  ten  hours  and  a  quarter.  The 
glasses  were  then  removed,  and  the  substances  carefully  collected  and 
weighed.  The  calomel  was  reduced  to  71|-  grains.  The  scammony 
weighed  71|;  the  camboge,  71;  the  salt  of  alembroth,  62  grains,^  and 
the  tartar  emetic  67  grains.^ 

It  requires,  then,  in  order  that  matters  shall  be  absorbed  b}^  the  skin, 
that  they  shall  be  kept  in  contact  with  it,  so  as  to  penetrate  its  pores, 
or  the  channels  by  which  the  cutaneous  transpiration  exudes;  or  else 
that  they  shall  be  forced  through  the  cuticle  by  friction, — the  iatraliptic 
mode.  In  this  way,  the  substance  comes  in  contact  with  the  cutaneous 
vessels,  and  enters  them  probably  by  imbibition.  Certain  it  is,  that 
mercury  has  been  detected  in  the  venous  blood  by  Colson,  Christison, 
Cantu,  Autenrieth,  Zeller,  Schubarth,  and  others.^ 

Not  long  after  the  period  that  M.  Seguin  was  engaged  in  his  experi- 
ments. Dr.  Eousseau,'*  of  Philadelphia,  contested  the  existence  of  ab- 
sorption through  the  epidermis,  and  attempted  to  show,  in  opposition 
to  the  experiments  we  have  detailed,  that  the  pulmonary  organs,  and 
not  tile  skin,  are  the  passages  by  which  certain  substances  enter  the 
system.  By  cutting  off  all  communication  with  the  lungs,  which  he 
effected  by  breathing  through  a  tube  communicating  with  the  atmo- 
sphere on  the  outside  of  the  chamber,  he  found,  that  although  the  sur- 
face of  the  body  was  bathed  with  the  juice  of  garlic,  or  the  spirit  of 
turpentine,  none  of  the  qualities  of  these  fluids  could  be  detected,  either 
in  the  urine,  or  the  serum  of  the  blood.   From  subsequent  experiments, 

'  Several  pimples  were  excited  on  the  part  to  which  it  was  applied. 

^  Magendie's  Precis,  &c.,  ii.  262. 

'  The  author's  General  Therapeutics  and  Materia  Medica,  5th  edit.,  i.  108,  Philad.,  1853. 

*  Experimental  Dissert,  on  Absorption,  Philad.,  1800. 


ACCIDENTAL.  267 

performed  by  Dr.  Rousseau,  assisted  by  Dr.  Samuel  B.  Smitb/and  many 
of  which  Professor  Chapman^  witnessed,  the  following  results  were  de- 
duced. First^  That  of  all  the  substances  employed,  madder  and  rhubarb 
were  those  only  that  affected  the  urine, — the  latter  of  the  two  more 
readily  entering  the  system;  and  secondly^  that  the  power  of  absorption 
is  limited  to  a  ver}^  small  portion  of  the  surface  of  the  body.  The  only 
parts,  indeed,  that  seemed  to  possess  it,  were  the  spaces  between  the 
middle  of  the  thigh  and  hip,  and  between  the  middle  of  the  arm  and 
shoulder.  Topical  bathing,  with  a  decoction  of  rhubarb  or  madder, 
and  poultices  of  these  substances  applied  to  the  back,  abdomen,  sides, 
or  shoulders,  produced  no  change  in  the  urine;  nor  did  immersion  of 
the  feet  and  hands  for  several  hours  in  a  bath  of  the  same  materials 
afford  the  slightest  proof  of  absorption. 

From  these  and  other  facts,  sufficiently  discrepant  it  is  true,  we  are 
justified  in  concluding,  that  cuticular  absorption,  under  ordinary  cir- 
cumstances, is  not  easy;  but  we  can  readily  conceive,  from  the  facility 
with  which  water  soaks  through  animal  tissues,  that  if  the  animal  body 
be  immersed  sufficiently  long  in  it,  and  especially  if  the  vessels  have 
been  previously  drained,  imbibition  may  take  place  to  a  considerable 
extent.  This,  however,  would  be  a  physical  absorption,  and  might  be 
effected  as  well  in  the  dead  as  in  the  living  body. 

b.  Other  Accidental  Absorptions. 

Amongst  the  adventitious  absorptions  have  been  classed  all  those 
that  are  exerted  upon  substances  retained  in  the  excretory  ducts,  or 
situate  in  parts  not  natural  to  them.  The  bile,  arrested  in  one  of  the 
biliary  ducts,  affords  us,  in  jaundice,  a  familiar  example  of  such  ab- 
sorption by  the  positive  existence  of  bile  in  the  bloodvessels;  although 
the  yellow  colour  has  been  gratuitously  supposed  to  be  caused  by  an 
altered  condition  of  the  red  globules,  and  not  by  the  presence  of  bile. 
This  condition  of  the  red  globules  would  account  for  some  of  the 
symptoms, — as  the  yellow  colour  of  the  skin,  and  urine, — but  it  does 
not  explain  the  clayey  appearance,  which  the  evacuations  present,  and 
which  has  been  properly  ascribed  to  the  absence  of  the  biliary  secre- 
tion. We  have,  moreover,  examples  of  this  kind  of  absorption,  where 
blood  is  effused  into  the  areolar  membrane,  as  in  the  case  of  a  common 
sprain,  or  in  those  accumulations  of  fluid  in  various  cavities,  that  are 
found  to  disappear  by  time ; — the  serous  portion  being  taken  up  at 
first  with  some  of  the  colouring  matter,  and,  ultimately,  the  fibrin.  In 
the  case  of  accumulation  of  the  serous  fluid  that  naturally  lubricates 
cavities,  it  is  of  such  a  character — the  aqueous  portion  at  least — as  to 
be  imbibed  with  facility,  and  probably  passes  into  the  veins,  in  this 
manner, — the  functions  of  exhalation  and  absorption  consisting  mainly, 
in  such  case,  of  transudation  and  imbibition. 

But  absorption  is  not  confined  to  these  fluids.  It  must,  of  course, 
be  exerted  on  all  morbid  deposits ;  and  it  is  to  excite  the  action  of  the 
absorbents,  that  our  remedial  agents  are  directed.  This  absorption — 
in  the  case  of  solids — is  of  the  interstitial  kind ;  and,  as  the  morbid 

'  Philad.  Med.  Museum,  i.  34,  Philad.,  1811. 

2  Elements  of  Therapeutics  and  Materia  Medica,  6th  edit.,  i.  65,  Philad.,  1831. 


268  RESPIRATION. 

formation  has  to  undergo  an  action  of  elaboration,  it  ouglit  to  be  refer- 
red to  lymphatic  agency. 

To  conclude  the  function  of  absorption : — All  the  products, — whether 
the  absorption  has  been  chyliferous,  lymphatic,  or  venous, — are  united 
in  the  venous  system,  and  form  part  of  venous  blood.  This  fluid  must, 
consequently,  be  variable  in  its  composition,  in  proportion  to  the  quan- 
tity of  heterogeneous  materials  taken  up  by  the  veins,  and  the  activity 
of  chyliferous  and  lymphatic  absorption.  It  is  also  clear,  that,  between 
the  parts  of  the  venous  system  into  which  the  supra-hepatic  veins, — 
loaded  with  the  products  of  intestinal  absorption  of  fluids, — enter,  and 
the  opening  of  the  thoracic  duct  into  the  subclavian,  the  blood  must 
differ  materially  from  that  which  flows  in  other  parts  of  the  system. 
All,  however,  undergo  admixture  in  their  passage  through  the  heart ; 
and  all  are  converted  into  arterial  blood  by  the  function,  that  Avill  next 
eno:a":e  us. 


CHAPTER  III. 

RESPIRATION. 

The  consideration  of  the  function  of  absorption  has  shown  how  the 
different  products  of  nutritive  absorption  reach  the  venous  blood.  By 
simple  admixture  with  this  fluid  they  do  not  become  converted  into  a 
substance,  capable  of  supplying  the  losses  sustained  by  the  frame  from 
xhe  different  excretions,  Nothing  is  better  established  than  the  fact, 
that  no  being,  and  no  part  of  any  being,  can  continue  its  functions  un 
less  supplied  with  blood,  that  has  become  arterial  by  exposure  to  air 
It  is  in  the  lungs,  that  the  absorbed  matters  undergo  their  final  conver 
sion  into  that  fluid, — by  a  function,  which  has  been  termed  hcematosis 
the  great  object  of  that  which  we  have  now  to  investigate — Respira- 
tion. This  conversion  is  occasioned  by  the  venous  blood  of  the  pul- 
monary vessels  coming  in  contact  with  air  in  the  air-cells  of  the  lungs, 
during  which  th'e  blood  gives  to  the  air  some  of  its  constituents,  and, 
in  return,  the  air  parts  with  its  elements  to  the  blood. 

To  comprehend  this  mysterious  process,  we  must  be  acquainted  with 
the  pulmonary  apparatus,  as  well  as  with  the  properties  of  atmospheric 
air,  and  the  mode  in  which  the  contact  between  it  and  the  blood  is 
effected. 

1.    ANATOMY  OF  TUE  KESPIRATORY  ORGANS. 

The  thorax  or  chest  contains  the  lungs, — the  great  agents  of  respira- 
tion. It  is  of  a  conical  shape,  the  apex  of  the  cone  being  formed  by 
the  neck,  and  the  base  by  a  muscle,  which  has  already  been  referred 
to  more  than  once, — the  diaphragm. 

The  osseous  framework.  Fig.  76,  is  formed,  posteriorly^  of  twelve 
dorsal  vertebrse;  anteriorly,^  of  the  sternum,  originally  composed  of 
eight  or  nine  pieces ;  and  laterally,,  of  twelve  ribs  on  each  side,  passing 
from  the  vertebraa  to,  or  towards,  the  sternum.  Of  these,  the  seven 
uppermost  extend  the  whole  distance  from  the  spine  to  the  breast-bone, 
and  are  called  true  or  sternal^  and  at  times,  vertebrosternal  ribs.     They 


EESPIEATOEY   ORGANS. 


269 


^^^li^ 


become  larger  as  they  descend,  and  are  situate  more  obliquely  in  re- 
gard to  the  spine.  The  other  five,  called  false  or  asternal^  do  not  pro- 
ceed as  fer  as  the  sternum ;  the  cartilages  of  three  of  them  join  that 
of  the  seventh  true  rib,  whilst  the  two  lowest  have  no  union  with  those 
above    them,    and    are,    therefore, 

called  floating  ribs.   These  false  ribs  Fig.  76. 

become  shorter  and  shorter  as  we 
descend ;  so  that  the  seventh  true 
rib  may  be  regarded  as  the  com- 
mon base  of  two  cones,  formed  by 
the  true  and  false  ribs  respectively. 

The  different  bones  constituting 
the  thorax  are  so  articulated  as  to 
admit  of  motion,  and  thus  of  dilata- 
tion and  contraction  of  the  cavity. 
The  motion  of  the  vertebrae  on 
each  other  is  described  under  an- 
other head.  It  is  not  materially 
concerned  in  the  respiratory  move- 
ments. The  articulation  of  the  ribs 
with  the  spine  and  sternum  de- 
mands attention.  They  are  articu- 
lated with  the  spine  in  two  places, 
— at  the  capitulum  or  head,  and  at 
the  tubercle.  In  the  former  of  these, 
the  extremity  of  the  ribs,  encrusted 
with  cartilage,  is  received  into  a 
depression,  similarly  encrusted,  at 
the  side  of  the  spine.  One  half  of 
this  depression  is  in  the  body  of  the 
upper  vertebra;  the  other  half  in 
the  one  beneath  it;  and,  conse- 
quently, partly  in  the  intervertebral  fibro-cartilage  between  the  two. 
The  joint  is  rendered  secure  by  various  ligaments;  but  it  can  move 
readily  up  and  down  on  the  spine.  In  the  first,  eleventh,  and  twelfth 
ribs,  the  articulations  are  with  single  vertebra3  respectively.  In  the 
second  articulation,  the  tubercle  of  the  rib,  also  encrusted  with  carti- 
lage, is  received  into  a  cavity  in  the  transverse  process  of  each  cor- 
responding vertebra ;  and  the  joint  is  rendered  strong  by  three  distinct 
ligaments.  In  the  eleventh  and  twelfth  ribs,  this  articulation  is  want- 
ing. The  articulation  of  the  ribs  with  the  sternum  is  effected  by  an 
intermediate  cartilage,  which  becomes  gradually  longer,  from  the  first 
to  the  tenth  ribs,  as  seen  in  Fig.  76.  The  end  of  the  cartilage  is  re- 
ceived into  a  cavity  at  the  side  of  the  sternum;  and  the  junction  is 
strengthened  by  an  anterior  and  a  posterior  ligament.  This  articula- 
tion does  not  admit  of  much  motion  ;  but  the  existence  of  a  synovial 
membrane  shows,  that  it  is  destined  for  some. 

The  cavity  of  the  thorax  is  completed  by  muscles.  In  the  intervals 
between  the  ribs  are  two  planes,  whose  fibres  pass  in  inverse  directions, 
and  cross  each  other.  These  are  the  iutercosials.  The  diaphragm 
forms  the  septum  between  the  thorax  and  abdomen.   Above,  the  cavity 


Anterior  View  of  Thorax. 

1.  Superior  piece  of  sternum.  2.  Middle  piece. 
3.  Inferior  piece,  or  ensiform  cartilage.  4.  First 
dorsal  vertebra.  5.  Last  dorsal  vertebra.  6. 
Fir.st  rib.  7.  Its  head.  8.  Its  neck,  resting  against 
transverse  process  of  first  dorsal  vertebra.  9.  Its 
tuberosity.  10.  Seventh  or  last  true  rib.  11. 
Costal  cartilages  of  true  ribs.  12.  Two  last  fal.se 
ribs — floating  ribs,  13.  Tlio  groove  along  lower 
border  of  rib  for  lodgment  of  intercostal  vessels  and 
nerve . 


270 


RESPIRATION. 


is  open ;  and  tlirougli  tlie  opening  numerous  vessels  and  nerves  enter. 
The  muscles,  concerned  in  the  respiratory  function,  are  numerous. 
The  most  important  of  them  is  the  diaphragm.  It  is  attached,  by  its 
circumference,  around  the  base  of  the  chest;  but  its  centre  rises  into 
the  thorax;  and,  during  its  state  of  relaxation,  forms  an  arch,  the 
middle  of  which  is  opposite  the  inferior  extremity  of  the  sternum.  It 
is  tendinous  in  its  centre,  and  is  attached  by  two  fasciculi,  called  jyillars, 

to  the  spine, — to   the 
Fig.  T7.  bodies  of  the  first  two 

lumbar  vertebrae.  It 
has  three  apertures ; 
one  before  for  the  pas- 
sage of  the  vena  cava 
inferior;  and  two  be- 
hind, between  the  pil- 
lars, for  the  passage  of 
the  oesophagus  and 
aorta.  The  other  great 
muscles  of  respiration 
are  the  serratns posticus 
inferior^  serratus  posti- 
cus superior^  levatores 
costarum^  intercostal 
muscles,  infra-costales, 
and  triangularis  sterni 
or  sterno-costalis ;  but, 
in  an  excited  condition 
of  respiration,  all  the 
muscles,  that  raise  and 
depress  the  ribs,  di- 
rectly or  indirectly, 
participate  —  as  the 
scalejii,  sterno-mastoidei, 
pectoralis,  (major  and 
minor,)  serratus  major 
anticus,  ahdominal mus- 
cles, &LQ,. 

In  the  structure  of 
the  lungs,  as  M.  Ma- 
gendie'  has  remarked, 
nature  has  resolved  a 


Anterior  View  of  the  Thoracic  Viscera  in  situ,  as  shown  by  the 
removal  of  the  Anterior  Parietes  of  the  Thorax. 


1.  Superior  lobe  of  right  lung.  2.  Its  middle  lobe.  3.  Its  inferior 
lobe.  4,  4.  Lobular  fissures.  5,  5.  luterual  layer  of  costal  pleura 
forming  the  right  side  of  the  anterior  mediastinum.  6,  6.  Right  dia- 
phragmatic portion  of  pleura  costalis.  7,  7.  Right  pleura  costalis  on 
the  ribs.  S.  Superior  lobe  of  left  lung.  9.  Its  inferior  lobe.  10,10. 
Interlobular  lissures.  11.  Portion  of  pleura  costalis  which  forms  the 
left  side  of  the  anterior  mediastinum.  12.  Left  diaphragmatic  portion 
of  pleura  costalis.     13.  Left  pleura  costalis.     14,  14.  The  middle  space     niCchanical  problem  of 

between  the  pleurse,  known  as  the  anterior  mediastinum.     15.  Pen-  .       i      .  

cardium.  16.  Fibrous  partition  over  which  the  plcur;c  are  reflected. 
17.  Trachea.  18.  Thyroid  gland.  19.  Anterior  portion  of  thyroid 
cartilage.  20.  Primitive  carotid  artery.  21.  Subclavian  vein.  22. 
Internal  jugular  vein.  23.  Brachio-cephalic  vein.  24.  Abdominal 
aorta.     25.  Xiphoid  cartilage. 


extreme  difficulty.  The 
problem  was, — to  es- 
tablish an  immense 
surface  of  contact  be- 
tween the  blood  and  air,  in  the  small  space  occupied  by  the  lungs. 
The  admirable  arrangement  adopted  consists  in  this, — that  each  of  the 
minute  vessels,  in  which  the  pulmonary  artery  terminates  and  the  pul- 


'  Precis,  &c.,  ii.  307. 


EESPIRATOEY   ORGANS. 


271 


monary  veins  originate,  is  surrounded  on  every  side  by  air.  The  lungs 
are  two  organs  of  considerable  size,  situate  iii  the  lateral  parts  of  the 
chest,  and  subdivided  into  lobes  and  lobules,  the  sliape  and  number 
of  which  cannot  be  readily  determined.  They  are  termed  right  and 
left^  respectively,  according  to  the  side  of  the  cavity  of  the  chest  which 
they      occupy.       The 

former  consists  of  three  Fig.  78. 

lobes;  the  latter  of  two. 
Each  of  these  exactly 
fills  the  corresponding 
cavity  of  the  pleura; 
and  they  are  separated 
from  each  other  by  a 
duplicature  of  the 
pleura  —  (the  serous 
membrane  that  lines 
the  chest,  and  is  re- 
flected over  the  lungs) 
— and  by  the  heart. 
The  colour  of  the  lungs 
is  generally  of  a  marble 
blue ;  and  the  exterior 
is  furrowed  by  figures 
of  hexagonal  shape. 
The  appearance  is  not, 
however,  the  same  at 
all  ages,  and  under  all 
circumstances.  In  in- 
fancy, they  are  of  a 
pale  red;  in  youth,  of 
a  darker  colour ;  and 
in  old  age,  of  a  livid 
blue. 

The  elements  that 
compose  them  are  ; — 
the  ramifications  of  the 
trachea ;  those  of  the 
pulmonary  artery  and 
pulmonary  veins,  be- 
sides the  organic  ele- 
ments, that  appertain 
to  every  living  struc- 
ture,— arteries,    veins. 


Posterior  View  of  the  Thoracic  Viscera,  showing  their  relative 
positions  by  the  removal  of  the  Posterior  Portion  of  the  Pa- 
rietes  of  the  Thorax. 

1,  2.  Upper  and  lower  lobes  of  right  lung.  3.  Interlobular  fis- 
sures. 4.  Internal  portion  of  pleura  custalis,  forming  one  of  the  sides 
of  posterior  mediastinum.  5.  Twelfth  rib  and  lesser  diaphragm. 
6.  Reflection  of  the  pleura  over  the  greater  muscle  of  the  diaphragm 
on  the  right  .side.  7,  7.  Right  pleura  costalis  adhering  to  the  ribs. 
8,  9.  The  two  lobes  of  the  left  lung.     10,  10.  Interlobular  fissures. 

11,  11.  Left  pleura,  forming  the  parietesof  the  posterior  mrdia.stinum. 

12,  1.3.  Its  reflections  over  the  diaphragm  on  this  side.  1-t,  1-1.  Left 
pleura  costalis  on  the  parietes  of  the  chest.  1.5.  Trachea.  IG.  Larynx. 
17.  Opening  of  the  larynx  and  the  epiglottic  cartilage  in  situ.  18. 
Root  and  top  of  the  tongue.  19,  19.  Right  and  left  bronchia.  20. 
The  heart  enclosed  in  pericardium.  21.  Upper  portion  of  diaphragm 
on  which  it  rests.  22.  Section  of  oesophagus.  2.3.  Section  of  aorta. 
21.  Arteria  innominata.     25.  Primitive  carotid  arteries.    26.  Subcla- 

1  ,        .  n     vian  arteries.     27.  Internal  jugular  veins.     28.  Second  cervical  ver- 

jymphatlCS,  nerves,  and.    tebra.    29.  Fourth  lumbar. 

areolar     tissue.      The 

ramifications  of  the  windpipe  form  the  cavity  of  the  organ  of  respira- 
tion. The  trachea  is  continuous  with  the  larynx,  from  which  it  re- 
ceives the  external  air  conveyed  to  it  by  the  mouth  and  nose.  It 
passes  down  to  the  thorax,  at  the  anterior  part  of  the  neck,  and  bifur- 
cates opposite  the  second  dorsal  vertebra,  forming  two  large  canals 
called  bronchi  or  bronchia.     One  of  these  goes  to  each  lung  ;  and,  after 


272 


RESPIRATION. 


numerous  subdivisions,  becomes  imperceptible  ;  lieuce,  tlie  multltiulin- 
ous  speculations  that  have  been  indulged  regarding  the  mode  in  which 
the  bronchial  ramifications  terminate.  Malpighi'  believed,  that  they 
form  vesicles,  at  the  inner  surface  of  which  the  pulmonary  artery  rami- 
fies. Reisseisen^  describes  the  vesicles  as  of  a  cjdindrical,  and  some- 
what rounded  figure ;  and  states,  that  they  do  not  communicate  with 
each  other.     Ilelvetius,^  on  the  other  hand,  affirmed,  that  they  end  in 

cells,  formed  by  the  dift'erent 
Fig-  79.  constituent  elements  of  the 

lung, — the  cells  having  no 
determinate  shape,  or  regular 
connexion  with  each  other; 
whilst  M.  Magendie''  asserts, 
that  the  minute  bronchial 
division,  which  arrives  at  a 
lobe,  does  not  enter  it,  but 
terminates  suddenly  as  soon 
as  it  has  reached  the  paren- 
chyma; and,  he  remarks, 
that  as  the  bronchus  does 
not  penetrate  the  spongy 
tissue  of  the  lung,  it  is  not 
probable,  that  the  surface 
of  the  cells,  with  which  the 
air  comes  in  contact,  is  lined 
by  a  prolongation  of  the 
mucous  coat,  which  forms 
the  inner  membrane  of  the 
air-passages.  Mr.  Hassall,^ 
however,  contrary  to  the 
opinion  of  most  observers, 
and — as  will  be  seen — to 
that  of  Mr.  Eainey,  one  of 
the  most  recent  of  them,  af- 
firms, that  in  sections  of  fresh  lungs  "it  is  a  very  easy  matter  not 
merely  to  determine  the  existence  of  epithelium  in  the  air-cells,  but 
also  the  fact  of  its  cylinder  and  ciliated  form  and  character,"  and  this 
"fact"  of  the  epithelium  extending  from  the  bronchial  tubes  into  them 
• — he  adds — would  seem  in  itself  to  imply  that  the  mucous  membrane 
also  lines  them. 

The  ramifications  of  the  pulmonary  artery  are  another  constituent 
element  of  the  lung.  This  vessel  arises  from  the  right  ventricle  of  the 
heart,  and,  at  a  short  distance  from  that  organ,  divides  into  two 
branches  ;  one  passing  to  each  lung.  Each  branch  accompanies  the 
corresponding  bronchus  in  all  its  divisions ;  and,  at  length,  becomes 
capillary  and  imperceptible.     Its  termination,  also,  has  given  rise  to 

'  Epist.  de  Pulmon.,  i.  133. 

2  Ueber  den  Bau  der  Lungen,  u.  s.  w.,  Berlin,  1822  ;  also,  in  Latin,  Berl.,  1822. 

3  Memoires  de  I'Academ.  pour  1718,  p.  18.  *  Precis,  &c.,  ii.  309. 

^  The  Microscopic  Anatomy  of  tlie  Human  Body  in  Health  and  Disease,  part  xii.  p. 
381,  London,  1848. 


A  shaded  Diagram,  representing  the  Heart  nnd  Groat 
Vessels,  injected  and  in  connexion  with  the  Luugsj 
the  Pericardium  is  removed. 

1.  Right  auricle.  2.  Vena  cava  superior.  3.  Vena  cava 
inferior.  4.  Kigiit  ventricle.  5.  Pulmonary  artery,  divid- 
ing into  two  branches  n,  a,  one  for  the  right,  the  other  for  the 
left  lung.  6.  Point  of  the  left  auricle.  7.  Part  of  left  ventri- 
cle. 8.  Aorta.  9,  10.  Two  lobes  of  the  left  lung.  11,12,13. 
Three  lobes  of  the  right  lung,  a,  a.  Right  and  left  pulmo- 
nary arteries.  6,  h.  Right  and  left  bronchi,  v,  v.  Right  and 
left  pulmonary  veins.  The  relative  position  of  these  three 
vessels  is  seen  to  ditfer  on  tlie  two  sides. 


RESPIRATORY   ORGAN'S. 


273 


Arrangement  of  the  Capillaries  of  the  Air-cells 
of  the  Human  Lung. 


conjecture.  Malpiglii  conceived  it  to  end  at  the  mucous  surface  of  the 
bronchi  in  an  extremely  delicate  network,  which  he  called  rete  onirabile ; 
and  this  was,  likewise,  the  opinion  of  Reisseisen.  Bichat^  admitted  at 
the  extremities  of  the  pulmonary 
artery,  and  between  that  artery 
and  the  veins  of  the  same  name, 
vessels  of  a  more  delicate  charac- 
ter, which  he  conceived  to  be  the 
agents  of  hgematosis,  and  called 
the  capillary  system  of  the  lungs. 
This,  however,  is  nothing  more 
than  the  fine  dense  capillary  net- 
work, formed  by  the  distribution 
of  the  artery  on  the  air-cells,  from 
which  the  pidmonaj-y  veins  arise. 
Their  radicles  communicate  freely 
with  those  of  the  pulmonary  ar- 
tery. When  we  observe  them  dis- 
tinctly, they  are  found  uniting  to 
constitute  larger  and  larger  veins, 
until  they  ultimately  end  in  four  great  trunks,  which  open  into  the 
left  auricle  of  the  heart.  The  pulmonary  arteries  do  not  anastomose 
in  their  course ;  and  according  to  Dr.  Cammann,^  the  capillaries  of  one 
lobule  do  not  communicate  with  those  of  another:  the  interstitial 
areolar  membrane  even  of  the  most  minute  lobules  was  seen  entirely 
free  from  colour  when  a  coloured  injection  was  thrown  into  the  vessels. 

In  addition  to  these  organic  constituents,  the  lung,  like  other  organs, 
receives  arteries,  veins,  lymphatics,  and  nerves.  It  is  not  nourished 
by  tlie  blood  of  the  pulmonary  artery,  which  is  not  adapted  for  the 
purpose,  seeing  that  it  is  venous.  The  hrondiial  arteries  are  its  nutritive 
vessels.     They  arise  from  the  aorta,  and  are  distributed  to  the  bronchi. 

Around  the  bronchi,  and  near  where  they  dip  into  the  tissue  of  the 
lung,  lymphatic  glands — bronchial  glands — exist,  the  colour  of  which  is 
almost  black,  and  with  which  the  few  lymphatic  vessels,  that  arise  from 
the  superficial  and  deep-seated  parts  of  the  lung,  communicate,  llal- 
ler^  has  traced  the  efferent  vessels  pf  these  glands  into  the  thoracic  duct. 

The  nerves,  distributed  to  the  lungs,  proceed  chiefly  from  the  eighth 
pair  or  pneumogastric.  A  few  filaments  of  the  great  sympathetic  are 
also  sent  to  them.  T'he  eighth  pair — after  having  given  off  the  superior 
laryngeal  nerves,  and  some  twigs  to  the  heart — interlaces  with  nume- 
rous branches  of  the  great  sympathetic,  and  forms  an  extensive  nervous 
network,  called  anterior  pulmonary  plexus.  After  this,  the  nerve  gives 
off  the  reourrents,  and  interlaces  a  second  time  with  branches  of  the 
great  sympathetic,  forming  another  network,  called  posterior  pulmonary 
plexus.  It  then  proceeds  to  the  stomach,  where  it  terminates.  (See 
Fig.  24.)  From  these  two  plexuses  the  nerves  proceed,  that  are  dis- 
tributed to  the  lungs.     These  accompany  the  bronchi,  and  are  spread 

'  Anatomie  Generale,  edit,  de  MM.  Beclard,  Blandin,  and  Magendie,  ii.  381-386, 
Paris,  1832. 

^  New  York  Journal  of  Medicine,  Jan.,  1848. 
*  Elem.  Physiologiae,  viii.  2,  §  15,  Lausann.  1764. 
VOL.  I. — 1« 


274  RESPIEATIOX. 

chiefly  on  tlie  mucous  membrane  of  the  air-tubes.  The  lung  likewise 
receives  some  nerves  directly  from  the  three  cervical  ganglions  of  the 
great  sympathetic,  and  from  the  first  thoracic  ganglion.  In  addition 
to  these,  a  distinct  system  of  nerves — the  respiratory  system,  described 
in  another  part  of  this  work — is  supposed  by  Sir  Charles  Bell  to  be 
distributed  to  the  multitude  of  muscles,  that  are  associated  in  the 
respiratory  function  in  a  voluntary  or  involuntary  manner.  This 
system  includes  one  of  the  nerves  just  referred  to — the  eighth  pair — 
and  the  phrenic  nerves,  which  are  distributed  to  the  diaphragm.  The 
various  nerves  composing  it  are  intimately  connected,  so  that,  in  forced 
or  hurried  respiration,  in  coughing,  sneezing,  &c.,  they  are  always  asso- 
ciated in  action.  It  will  be  seen,  however,  that  few  physiologists  now 
admit  the  respiratory  system  of  Sir  Charles. 

Lastly ;  the  lungs  are  constituted  also  of  areolar  tissue,  which  has 
been  termed  interlobular  tissue;  but  it  does  not  differ  from  areolar 
tissue  in  other  parts  of  the  body. 

Such  are  the  constituent  elements  of  the  pulmonary  tissue ;  but,  with 
regard  to  the  mode  in  which  they  are  combined  to  form  the  intimate 
texture  of  the  lung  we  are  not  wholly  instructed.  We  find,  that  the 
lobes  are  divided  into  lobules,  and  these,  again,  seem  to  be  subdivided 
almost  indefinitely,  forming  an  extremely  delicate  spongy  tissue,  the 
areolae  of  which — air-cells  or  lung-vesicles — can  only  be  seen  by  the  aid 
of  the  microscope.^  It  is  generally  thought,  that  the  areolae  commu- 
nicate with  each  other,  and  that  they  are  enveloped  by  the  areolar 
tissue  which  separates  the  lobules.  M.  Magendie^  inflated  a  portion  of 
lung,  dried  and  cut  it  in  slices,  in  order  that  he  might  examine  the 
deep-seated  cells.  These  appeared  to  him  to  be  irregular,  and  to  be 
formed  by  the  final  ramifications  of  the  pulmonary  artery,  and  the 
primary  ramifications  of  the  pulmonary  veins ;  the  cells  of  one  lobule 
communicating  with  each  other,  but  not  with  those  of  another  lobule. 
Professor  Horner,^  of  the  University  of  Pennsylvania,  has  attempted 
to  exhibit  that  this  communication  between  the  cells  is  lateral.  After 
filling  the  pulmonary  arteries  and  pulmonary  veins  with  minute  injec- 
tion, the  ramifications  of  the  bronchi,  with  the  air-cells,  were  distended 
to  their  natural  size  by  an  injection  of  melted  tallow.  The  latter, 
being  permitted  to  cool,  the  lung  was  cut  into  slices  and  dried.  The 
slices  were  subsequently  immersed  in  spirit  of  turpentine,  and  digested 
at  a  moderate  heat  for  several  days.  By  this  process,  all  the  tallow 
was  removed,  and  the  parts,  on  being  dried,  appeared  to  exhibit  the 
air-cells  empty,  and,  seemingly,  of  their  natural  size  and  shape.  Pre- 
parations, thus  made,  appear  to  show  the  air-cells  to  be  generally  about 
the  twelfth  of  a  line  in  diameter,  and  of  a  spherical  form,  the  cells  of 
each  lobule  communicating  freely,  like  the  cells  of  fine  sponge,  by 
lateral  apertures.  The  lobules,  however,  only  communicate  by  branches 
of  the  bronchi,  and  not  by  contiguous  cells.  This  would  seem  to 
negative  the  presumption  of  some  anatomists  and  physiologists. — as 
Reisseisen,  Blumenbach,  Cuvier,  &;c., — that  each  air-cell  is  insulated, 
communicating  only  with  the  minute  bronchus  that  opens  into  it; 
whilst  it  confirms  the  views  of  Haller,  Monro  (Secundus),  Boyer, 

'  Hassall,  op.  cit.  ^  Precis,  &c.,  ii.  309. 

'  American  Journal  of  the  Medical  Sciences  for  Feb.  1832,  p.  538,  and  op.  cit. 


BESPIRATORY   ORGANS.  275 

Sprengel,  Magendie,  Carpenter,  and  others; — but  it  is  not  easy  to  de- 
cide positively,  where  all  is  so  minute.  The  observations  of  Dr.  Addi- 
son^ led  him  to  maintain,  that  the  views  of  Eeisseisen  and  others  are 
certainly  true  as  regards  the  foetal  lung,  in  which  the  ultimate  subdi- 
visions of  the  bronchial  tubes  termiuate  in  closed  extremities.  But 
when  an  animal  has  respired,  the  terminations  are  said  to  experience 
a  great  change.  The  membrane  composing  them  ofters  but  slight  re- 
sistance to  the  pressure  of  the  air,  and  is  pushed  forwards,  and  dis- 
tended laterally  into  rounded  inflations,  forming  a  series  of  cells,  which 
are  moulded  by  mutual  pressure  into  various  angular  forms,  and  which 
communicate  freely  with  each  other  by  large  oval  apertures.  The 
passages,  thus  formed,  do  not  communicate  otherwise  than  by  their 
connexion  with  the  same  bronchial  tube,  and  the  bloodvessels  lie  be- 
tween the  contiguous  walls  of  each  two  of  them,  so  that  the  blood  in 
the  capillaries  is  exposed  to  air  on  both  sides.  It  would  appear,  also, 
from  the  researches  of  M.  Bourgery,^  that  the  developement  of  the 
air-cells, — and,  consequently,  the  capacity  for  forcible  inspiration, — 
continues  in  man  to  the  age  of  thirty,  at  which  time  the  capacity  is 
greatest.  Subsequently,  it  decreases,  especially  in  those  who  suffer 
from  cough, — the  violence  of  the  respiratory  eftbrt  often  causing  rup- 
ture of  the  air-cells,  and  thus  gradually  producing  the  emphysematous 
state  of  the  lungs  so  common  in  old  people.  After  thii-ty,  the  capa- 
city for  forcible  inspiration  diminishes  one-fifth  in  the  first  twenty 
years;  one-fifth  more  in  the  next  ten;  and  nearly  one-half  in  the  next 
twenty;  and  this  gradual  decrease  of  capacity  for  forcible  inspiration 
is  true  of  all  persons,  although  one  may  have  a  greater  general  capa- 
city of  respiration  than  another  of  the  same  age.  Hence  the  young 
person  possesses  a  greater  capacity  of  respiration,  as  it  were,  in  reserve. 
The  aged  have  little,  and  are,  therefore,  unfit  for  great  exertion. 

The  observations  of  Mr.  Eainey,^  which  have  been  adopted  by  many 
histologists,  lead  to  the  belief,  that  when  the  bronchi  have  attained  the 
diameter  of  from  g'^th  to   g'^th  of  an  inch,  they  gradually  lose  their 

cylindrical  form,  and  appear  more  like  ir- 
Fig-  81.  regular  passages — termed  by  Mr.  Kainey 

intercellular  or  lobular  ]:)assages — through 
the  substance  of  the  lung.  These  passages 
are  clustered  with  air-cells,  which  have 
the  appearance  of  polyhedral  alveolar  ca- 
vities separated  by  exceedingly  thin  septa, 
and  do  not  open  into  one  another  by  auas- 
Air-Ceiis  from  an  Emphysematous  tomosis  or  lateral  Communication,  but  com- 
1    .  ,  .""^!   ,  .,  ,    municate  freely  through  the  medium  of 

1.  A  group  of  air-cells  laid  open  anil  J  <->  i   •    i       i  i 

exhibiting  the  fact  that  there  is  no  late-  tllC  COmmOU  air-paSSagC  tO  whicll  they  bc- 
ral    iutercoinmunication.      2.  Two  air-     ,  rni  •        i     r-  /tti-         n-i\ 

cells;  the  one  to  the  left  exhibits  its    loug.      i he  margmal  figurc  [rig.  81)  re- 

bronchiolar  orifice.  3.  Another  group:  y^pp^jp^tc.  cpvprnl  frrollDS  of  air-Cplk  from 
to  the  left  are  represented  two  cells  freely     prCSCULS    SeVCJ  ai    glULipb    VI    dll-ceiib    liom 

communicating  from  the  partition  being  r^j^  emphvSematOUS  luilg,  draWU  the  sizC 
ruptured  by  over-distensiun ;    and   be-  I      J  •i-r-v/'-ii 

twoen  the  two  cells  to  the  right  are  ob-    of  uaturc  jrom  a  preparation  by  JDr.  (jrod- 

served  some  inflated  areola;  of  areolar      ^        i  mi  t  ^^•  oti  i     c).> 

tissue.  dard.      The  diagrams,  lugs.  o2   and  80, 

'  Proceedings  of  the  Royal  Society,  March  17,  1842;  and  Philos.  Transact,  for  1842. 
^  Gazette  Medieale,  16  Juillet,  1842,  and  Archives  Generales  de  Med.,  Mars.  1843. 
*  Medico-Chirurgical  Transactions,  vol.  xxviii.,  London,  1845.     Hee,  also,  Todd  and 
Bowman,  The  Physiological  Anat.  and  Physiology  of  Man,  Pt.  iv.,  p.  390,  Lond.  1852. 


276 


RESPIRATIOISr. 


are  given  by  Dr.  Leidy  to  facilitate  the  understanding  of  the  relative 
arrangement  of  the  air-cells  to  the  minute  bronchial  tubes^  in  this 
view  of  the  subject.  Mr.  Kainey  affirms,  as  the  result  of  actual  ob- 
servation, that  the  mucous  lining  of  the  bronchial  tube  is  not  conti- 
nued along  the  intercellular  passages  and  into  the  air-cells,  a  circum- 
stance, which,  as  he  suggests,  explains  the  different  effects  of  inflam- 
mation of  the  tubes  and  of  the  air-cells ; — the  latter,  which  are  lined 
by  fibro-areolar  tissue,  being  accompanied  by  the  exudation  of  fibrin 


Fig.  82. 


Fig.  83. 


Transverse  Section  of  a  portion  of  the  Pulmonary 
Parenchyma. 

1.  The  orifices  of  bronchioles.  2.  The  air-cells  arranged 
around  the  bronchioles,  and  opening  into  them,  but  not  com- 
municating laterally.  3.  Interspaces  filled  with  areolar  tis- 
sue, which,  when  inflated,  is  liable  to  be  mistaken  for  the 
true  air-cells. 


Longitudinal  Section  of  the  termina- 
tion of  a  Bronchus. 
1.  The  bronchiole,  in  which  are  seen 
the  orifices  (3)  of  the  air-cells  (2)  ar- 
ranged around  it  and  at  its  termina- 
tion. 


instead  of  mucus.  Anatomists,  consequently,  who,  by  the  term  "air- 
cell,"  meant  simply  the  ultimate  termination  of  a  bronchial  tube ;  and 
pathologists,  who  regarded  bronchitis  of  the  terminal  extremities  of 
those  tubes  and  pneumonia  as  essentially  alike,  were  nearer  the  truth 
than  was  generally  admitted.  The  researches  of  Mr.  Eainey  led  him 
to  conclude — in  opposition  to  Dr.  Addison, — that  the  fa^us,  prior  to 
the  act  of  respiration,  possesses  fully  formed  air-cells,  which  are  also 
surrounded  by  capillary  plexuses. 

M.  Rossignol,  who  has  elaborately  described  the  minute  structure 
of  the  lungs,  insists  on  the  ultimate  bronchial  ramifications  being 
shaped  like  an  inverted  funnel;  and  hence  he  calls  them  infundibula. 
The  cells  forming  a  honeycomb  on  their  interior  he  calls  alveoli.  Em- 
physema, according  to  him,  seems  to  consist  in  a  distension  of  the 
passages  and  cells,  and  a  breaking  down  and  obliteration  of  the  septa, 
first  between  the  cells  of  the  same  passages,  and  then  between  neigh- 
bouring passages,  and  even  between  contiguous  lobules,^ 

'  Qiiain's  Human  Anatomy,  by  Quain  and  Sharpey,  Amer.  edit,  by  Dr.  Leidy,  ii. 
119,  Philad.,  1849. 

^  The  Physiological  Anat.  and  PhysioL  of  Man,  Pt.  iv.  p.  391,  or  Amer.  edit., 
Philad.,  1853. 


RESPIRATORY  ORGAN'S. 


\ 

277 


Kcilliker^  admits  the  existence  of  two  layers  in  tlie  air-cells — a  fibrous 
membrane  and  an  epithelium.     The  former  is  manifestly  the  much 


Fig.  84. 


Thin  slice  from  the  Pleural  Surface  of  a  Cat's  Lung,  considerably  magnified. 

At  the  thin  edge,  6  e  d,  alveoli  are  seen.     In  the  centre  (as  a),  where  the  slice  is  thiclier,  alveoli  are  seen 
on  the  walls  of  infundCbula. 

attenuated  mucous  membrane  and  fibrous  tunic  of  the  bronchi  entirely 
deprived  of  the  smooth  muscles,  and  consisting  of  a  homogeneous  ma- 
trix of  connective  tissue  together  with  elastic  fibres  and  numerous 


Fig.  85. 


Bronchial  termination  in   the 
Lung  of  the  Bog. 


Fig.  86. 


a.  Tube  (lobular  passage) 
branching  towards  the  infuudi- 
bula.  6.  One  of  the  infundibula. 
c.  Septa  projecting  inwards  ou 
the  infundibular  wall  and  form- 
ing the  alveoli,  or  cells. 


iu*;-Xiat^' 


Air-oells  of  Human  Lung,  with  intervening  tissues. 

n.  Epithelium.     6.  Elastic  trabeculaj.     c.  Membranous 
wall,  with  fine  elastic  fibres. 


'  Mikroskopische  Anatomie,  ii.  315,  Leipz.,  1852,  or  Amer.  edit,  of  Sydenham  So- 
ciety'a  edition  of  KiJlliker's  Manual  of  Histology,  }).  579,  Pliilad.,  1854. 


278  EESPIRATIOX. 

vessels.  These  fibres  run  between  the  air-cells  in  the  form  of  trabeculre, 
and  coalesce  with  the  lining  membrane  so  as  to  strengthen  it.  The 
epithelial  la3^er  is  the  tesselated  form  constituted  of  minute  polygonal 
cells  without  cilia.  Dr.  Thomas  Williams,  "  who  has  devoted  many 
special  examinations  to  this  particular  point,  is  now  convinced,  that  a 
fine  pavement  epithelium  does  cover  these  parts,"  and  such  is  the 
opinion  of  Schroder  van  der  Kolk.^  The  position  is  contested,  how- 
ever, at  great  length  by  Mr.  Rainey.^ 

The  surface  afforded  by  the  air-cells  is  immense.  Hales'  supposed 
them  to  be  polyhedral,  and  about  one-hundredth  part  of  an  inch  in 
diameter.  The  surface  of  the  bronchi  he  estimated  at  1635  square 
inches ;  and  that  of  the  air-cells  at  40,000,  making  the  surface  of  the 
whole  lungs  41,635  square  inches  or  289  square  feet, — equal  to  19 
times  the  surface  of  the  bodj^,  which,  at  a  medium,  he  computes  to  be 
15  square  feet.  Keill*  estimated  the  number  of  cells  to  be  1,744,186,015; 
and  the  surface  21,906  square  inches ;  and  Lieberkiihn  has  valued  it 
at  the  enormous  amount  of  1500  square  feet.*  M.  Rochoux^  estimates 
the  number  of  cells  at  600,000,000,  and  that  there  are  about  17,790 
grouped  around  each  terminal  bronchus.  All  that  we  can  derive  from 
these  mathematical  conjectures  is,  that  the  extent  of  surface  is  surpris- 
ing, when  we  consider  the  small  size  of  the  lungs  themselves. 

The  diameter  of  the  lobular  passages  has  been  estimated  at  from  the 
yigth  to  200^^  of  an  inch,  and  that  of  the  cells  from  ^^^  to  -^\^  of 
an  inch  according  to  the  measurements  of  ]\[essrs.  Todd  and  Bowman. 
In  a  preparation  of  the  lung  given  them  by  Professor  Retzius,  they 
measured  gogth;  and  Dr.  Addison  makes  them  from  aao^^  ^^  soo^^ 
of  an  inch.'^  Weber  makes  their  diameter  from  the  200*^  ^^  ^^^  to*^ 
of  an  inch ;  and  Kolliker  and  Carpenter^  agree  with  him,  while  Mole- 
schott  estimates  them  at  much  less. 

Professor  Horner^  has  published  an  account  of  various  experiments, 
which  exhibit  the  ready  communication  between  the  pulmonary  air- 
vesicles  and  veins.  By  fixing  a  pipe  into  the  "human  trachea,  and  per- 
mitting a  column  of  water  to  pass  gently,  he  found  that  the  air-cells 
became  distended  with  water ;  and  that  the  left  side  of  the  heart  filled, 
and  the  aorta  discharged  water  freely  from  its  cut  branches.  This  ex- 
periment he  repeated  on  human  lungs  on  difl'erent  occasions,  and  with 
like  results.     A^ery  little  water  flowed  from  the  pulmonary  artery.     In 

'  Dr.  T.  Williams,  art.  Respiration,  Organs  of,  in  Cyclop,  of  Anat.  and  Physiol.,  Ft. 
45,  p.  271,  March,  1855. 

^  Brit,  and  For,  Med.-Chir.  Rev.,  Oct.,  1855,  p.  491. 

3  Statical  Essays,  i.  242. 

*  Tentam.  Med.  Phys.,  p.  80. 

5  Blumenbach,inEiliotson's  Physiology, p.  197,  Lond.,  1835.  Mr.  E.  Wilson  (Healthy 
Skin,  Amer.  edit.,  p.  52,  Pliilad.,  1S54)  observes:  "The  number  of  air-cf^ls  in  the  two 
lungs  has  been  estimated  at  1,7-14,000,000,  and  the  extent  of  the  skin  which  lines  the 
cells  and  tubes  together  at  1500  square  feet.  This  calculation  of  the  number  of  air- 
cells  and  the  extent  of  the  lining  membrane  rests,  I  believe,  on  the  authority  of  Dr. 
Addison,  of  Malvern." ! 

^  Gazette  Medicale,  4  Janv.,  1845. 

7  Todd  and  Bowman,  Op.  cit.,  p.  392. 

8  Principles  of  Human  Physiology,  p.  285,  Amer.  edit.,  Philad.,  1855. 

^  Amer.  Journ.  of  the  Medical  Sciences,  April,  1843,  p.  332;  and  Special  Anatomy 
and  Histology,  6th  edit.,  ii.  163. 


RESPIRATORY   ORGANS. 


279 


the  sheep  and  the  calf,  however,  when  the  experiment  was  practised 
upon  them  after  they  had  been  pretty  thoroughly  evacuated  of  blood, 
the  water  passed  freely  through  both  the  pulmonary  veins  and  the  pul- 
monary arteries.  Dr.  Horner  is  disposed  to  infer,  that  his  experiments 
exhibit  a  communication  of  the  pulmonary  air- vesicles  by  a  direct  route 
with  the  pulmonary  bloodvessels,  especially  the  veins ;  but  this  may 
well  be  questioned.  It  is  possible,  that  such  a  communication  may 
really  have  been  made  by  the  force  of  the  column  of  water  ;  and  if  not 
so,  the  passage  of  the  fluid  from  air-cells  to  bloodvessels  might  have 
been  effected  through  the  pores,  as  in  ordinary  imbibition,  which,  we 
have  elsewhere  seen,  is  readily  accomplished  in  the  lungs,  but  not  more 
readily  perhaps  than  in  the  case  of  serous  and  other  tissues  under 
favourable  circumstances.  Hemorrhage  by  transudation  occurs,  we 
know,  most  rapidly  at  times  through  the  coats  of  vessels,  whose  cohe- 
sion has,  however,  been  diminished  by  disease ;  and  a  thinner  fluid 
would  of  course  transude  more  easily.  It  can  scarcely  be  doubted, 
from  Dr.  Horner's  experiments,  that  a  certain  arrangement  exists  be- 
tweeen  the  air-vesicles  and  the  pulmonary  veins  in  man,  which  allows 
a  more  ready  imbibition  and 


transudation;  but  what  that 
arrangement  is  admits  of  ques- 
tion. 

Each  lung  is  covered  by  the 
pleura^  —  a  serous  membrane 
analogous  to  the  peritoneum, — 
and,  in  birds,  a  prolongation  of 
the  latter.  This  membrane  is 
reflected  from  the  adjacent  sur- 
face of  the  lung  to  the  pericar- 
dium which  covers  the  heart, 
and  is  then  spread  over  the  in- 
terior paries  of  tlie  half  of  the 
thorax  to  which  it  belongs ; 
lining  the  ribs  and  intercostal 
muscles,  and  covering  the  con- 
vex or  upper  surface  of  the 
diaphragm.  There  are,  conse- 
quently, two  pleura3,  each  of 
which  is  confined  to  its  own 
half  of  the  thorax,  lining  its 
cavity  and  covering  the  lung. 
Behind  the  sternum,  however, 
they  are  contiguous  to  each 
other,  and  form  the  partition 
called  mediastintim,  which  ex- 
tends between  the  sternum  and 
spine.  Fig.  87  exhibits  the 
boundaries  of  the  two  cavities 
of  the  pleura.  The  middle 
space  between  is  the  mediasti- 
num.   Within  this  septum,  the 


Fig.  87. 


Outline  of  a  Transverse  Section  of  the  Chest,  show- 
ing the  relative  position  of  the  Pleurse  to  the 
Thorax  and  its  Contents. 

1.  Skin  on  the  front  of  the  chest  drawn  up  by  a  hook. 
2.  Skin  on  the  sides  of  the  chest.  3.  Tliat  on  the  back. 
4.  Subcutaneous  fat  and  muscles  on  tlie  outside  of  the 
thorax.  5.  Section  of  the  muscles  in  the  vertebral 
glitter,  fi.  Section  of  fifth  dorsal  vertebra.  7.  Spinal 
canal.  8.  Spinous  process.  9,  9,  10,  10.  Sections  of 
ribs  and  intercostal  muscles.  11.  Their  cartilages.  12. 
Sternum.  13.  Division  of  the  pulmonary  artery.  1-t. 
Exterior  surface  of  lungs.  1.").  Posterior  face  of  lungs. 
Id.  Anterior  face  of  lungs.  17.  Inner  face  of  lungs.  18. 
Anterior  face  of  heart  covered  by  pericardium.  19.  Pul- 
monary artery.  20,  21.  Its  division  into  right  and  left 
branches.  22.  Portion  of  right  auricle.  2.3.  Descending 
cava  cut  off  at  right  auricle.  24.  Section  of  left  bron- 
chus. 2.").  Section  of  right  bronchus.  26.  Section  of 
ccsophagus.  27.  Section  of  thoracic  aorta.  The  space 
between  figures  12  and  IS  and  the  two  His  is  the  anterior 
mediastiuiim,  and  the  space  which  contains  26  and  27  is 
the  posterior  niedi.aslinum.  These  spaces  are  formed  by 
the  reflections  of  the  pleurte. 


280  RESPIRATION. 

heart,  enveloped  by  the  pericardium,  is  situate,  and  separates  the  pleurae 
considerably  from  each  other.  Anatomists  generally  subdivide  the 
mediastinum  into  two  regions ;  one  passing  from  the  front  of  the  peri- 
cardium to  the  sternum,  called  anterior  mediastinum ;  the  other,  from 
the  posterior  surface  of  the  pericardium  to  the  dorsal  vertebrae, — pos- 
terior mediastinum;  and,  by  some,  the  part  which  is  within  the  circuit 
of  the  first  ribs,  is  termed  superior  mediastinum.  The  second  of  these 
contains  the  most  important  organs, — the  lower  end  of  the  trachea, 
cesophagus.  aorta,  vena  azygos,  thoracic  duct,  and  pneumogastric 
nerves.  The  portion  of  the  pleura  covering  each  lung,  is  called  pleura 
pulmonalis  ;  that  which  lines  the  thorax,  pleura  costalis.  It  is  obvious 
that,  as  in  the  case  of  the  abdomen,  the  viscera  are  not  in  the  cavity  of 
the  pleura,  but  external  to  it ;  and  that  there  is  no  communication 
between  the  serous  sac  of  one  side  and  that  of  the  other. 

The  use  of  the  pleura  is  to  attach  the  lungs  by  their  roots  to  their 
respective  cavities,  and  to  facilitate  their  movements.  To  aid  this,  the 
membrane  is  always  lubricated  by  a  fluid,  exhaled  from  its  surface. 
The  other  surface  is  attached  to  the  lung  in  such  a  manner,  that  air 
cannot  get  between  it  and  the  parietes  of  the  thorax.  Dr.  Stokes' 
admits  a  proper  fibrous  tunic  of  the  lungs.  In  a  healthy  state,  this 
capsule,  although  possessing  great  strength,  is  transparent,  a  circum- 
stance in  which  it  difl:ers  from  the  fibrous  capsule  of  the  pericardium,' 
and  which,  Dr.  Stokes  thinks,  has  probably  led  to  its  being  overlooked. 
It  invests  the  whole  of  both  lungs ;  covers  a  portion  of  the  great  vessels ; 
and  the  pericardium  seems  to  be  but  its  continuation, — endowed,  in 
that  particular  situation,  with  a  greater  degree  of  strength,  for  purposes 
that  are  obvious.  It  covers  the  diaphragm  where  it  is  more  opaque : 
in  connection  with  the  pleura,  it  lines  the  ribs ;  and,  turning,  forms  the 
mediastina,  which  are  thus  shown  to  consist  of  four  layei's, — two  serous 
and  two  fibrous.  It  seems,  that  Dr.  Hart,  of  Dublin,  had,  for  years, 
demonstrated  this  tunic  to  his  class. 

It  was,  at  one  time,  the  prevalent  belief,  that  air  always  exists  in 
the  cavity  of  the  chest.  Galen  supported  the  opinion  by  the  fact, 
that,  having  applied  a  bladder,  filled  with  air,  to  a  wound,  which  had 
penetrated  the  chest,  the  air  was  drawn  out  of  the  bladder  at  the  time 
of  inspiration.  This  was  also  maintained  by  Hamberger,  Ilales,^  and 
numerous  others.  The  case,  alluded  to  by  Galen,  is  insufficient  to 
establish  the  position,  inasmuch  as  we  have  no  evidence,  that  the 
wound  did  not  also  implicate  the  pulmonary  tissue.  Since  the  time 
of  Haller,  who  opposed  the  prevalent  doctrine  by  observation  and 
reasoning,  the  fact  of  the  absence  of  air  in  the  cavity  of  the  pleura  has 
been  generally  considered  established.  It  is  obvious,  that  its  presence 
there  would  materially  interfere  with  the  dilatation  of  the  lungs,  and 
thus  be  productive  of  fatal  consequences;  besides,  anatomy  instructs 
us,  that  the  lungs  lie  in  pretty  close  contact  with  the  pleura  costalis. 
When  the  intercostal  muscles  are  dissected  off'  and  the  ])leura  costalis 
is  exposed,  the  surface  of  the  lungs  is  seen  in  contact  with  that  trans- 

'  On  Diseases  of  the  Chest,  Part  i.  p.  460,  Dublin,  1837;  or  Dunglison's  American 
Medical  Library  edition,  p.  301,  Philad.,  1837. 

2  Statical  Essays,  ii.  81.  , 


ATMOSPHEKIC   AIR.  281 

parent  membrane ;  and  when  the  pleura  is  punctured,  the  air  rushes 
in,  and  the  lungs  retire,  in  proportion  as  the  air  is  admitted.  This 
occurs  in  cases  of  injuries  inflicted  upon  the  chest  of  the  living  animal. 
Moreover,  if  a  dead  or  living  body  be  placed  under  water,  and  the 
pleura  be  punctured,  so  as  not  to  implicate  the  lungs,  it  has  been  found 
by  the  experiments  of  Brunn,  Sprogel,  Caldani,  Sir  John  Floyer,  Hal- 
ler,^  and  others,  that  not  a  bubble  of  air  escapes, — which  would  neces- 
sarily be  the  case,  if  air  were  in  the  cavity  of  the  pleura. 

2.    ATMOSPHEKIC  AIR. 

The  globe  is  surrounded  everywhere,  to  the  height  of  fifteen  or  six- 
teen leagues,  by  a  rare  and  transparent  fluid  called  air ;  the  total  mass 
of  which  constitutes  the  atvaospliere.  Atmospheric  air,  although  invi- 
sible, can  be  proved  to  j)ossess  the  ordinary  properties  of  matter ;  and, 
amongst  these,  weight.  It  also  partakes  of  the  character  of  a  fluid, 
adapting  itself  to  the  form  of  the  vessel  in  which  it  is  contained,  and 
pressing  equally  in  all  directions. 

As  air  is  possessed  of  weight,  it  results,  that  every  body  on  the 
earth's  surface  must  be  subjected  to  its  pressure ;  and  as  it  is  elastic  or 
capable  of  yielding  to  pressure,  thS  part  of  the  atmosphere  near  the 
surface  must  be  denser  than  that  above  it.  As  a  body,  therefore, 
ascends,  the  pressure  will  be  diminished;  and  this  accounts  for  the  dif- 
ferent feelings  experienced  by  those  who  ascend  lofty  mountains,  or 
voyage  in  balloons  into  the  higher  strata  of  the  atmosphere.  M.  Ed- 
wards^ ascribes  part,  at  least,  of  the  effect  produced  upon  the  breath- 
ing at  great  elevations,  to  the  increased  evaporation  which  takes  place 
from  the  skin  and  lungs ;  and  in  many  aerial  voyages  great  inconve- 
nience has  certainly  been  sustained  from  this  cause. 

The  pressure  of  the  atmosphere  at  the  level  of  the  sea  is  the  result 
of  the  whole  weight  of  the  atmosphere,  and  is  capable  of  sustaining  a 
column  of  water  thirty-four  feet  high,  or  one  of  mercury  of  the  height 
of  thirty  inches,  as  in  the  common  barometer.  This  is  equal  to  about 
fifteen  pounds  avoirdupois  on  every  square  inch  of  surface;  so  that  the 
body  of  a  man  of  ordinary  stature,  the  surface  of  which  Ilaller  esti- 
mates to  be  fifteen  square  feet,  sustains  a  pressure  of  32,400  pounds. 
Yet,  as  the  elasticity  of  the  air  witliin  the  body  exactly  balances  or 
counteracts  the  pressure  from  without,  he  is  not  sensible  of  it. 

The  experiments  of  Davy,  Dalton,  Gay  Lussac,  Humboldt,  Despretz, 
and  others,  have  shown,  that  pure  atmospheric  air  is  composed  essen- 
tially of  two  gases,  oxygen  and  nitrogen  or  azote^  which  exist  in  it  in 
the  proportion  of  21  of  the  former  to  79  of  the  latter:  according  to 
MM.  Dumas  and  Boussingault,^  20-81  of  the  former  to  79-19  of  the  lat- 
ter: Dr.  T.  Thomson  says  20  of  oxygen  to  80  of  nitrogen;  and  these 
proportions  have  generally  been  found  to  prevail  in  the  air  whence- 
soever  taken; — whether  from  the  summit  of  Mont  Blanc,  the  top  of 
Chimborazo,  the  sandy  plains  of  Egypt,  or  from  an  altitude  of  28,000 
feet  in  the  air."*     It  has  been  affirmed,  indeed,  that  the  proportion  of 

'  Element.  Physiol.,  viii.  2,  §  3,  Lausann.,  1764. 

2  De  rinflueiice  des  Agens  Physiques,  cScc,  p.  493,  Paris,  1824. 

3  Annales  de  Chimie  et  de  Pliysique,  iii.  257,  Paris,  1841. 

■»  Art.  Atmosphere,  (Physical  and  Chemical  History,)  by  Dr.  R.  M.  Patterson,  iu 
Amer.  Cyclopedia  of  Practical  Medicine  and  Surgery,  vol.  ii.  p.  526,  Philad.,  1836. 


282  RESPIEATIOX. 

the  gases  is  subject  to  a  variation  of  two  or  three  parts  in  the  thou- 
sand, in  situations  where  the  oxj'gen  is  much  exposed  to  absorption, 
as  over  the  sea,  when  there  is  no  wind.^  Chemical  analysis  has  not 
been  able  to  detect  the  presence  of  any  emanation  from  the  soil  of  the 
most  insalubrious  regions,  or  from  the  bodies  of  those  labouring  under 
the  most  contasrious  diseases, — malio;nant  and  'material  as  such  emana- 
tions  unquestionably  must  be.  Tlie  great  uniformity  in  the  propor- 
tion of  the  oxygen  to  the  nitrogen  in  the  atmosphere  has  led  to  the 
conclusion,  that  as  there  are  man}^  processes,  which  consume  the  oxygen, 
there  must  be  some  natural  agency,  by  which  a  quantity  of  oxygen  is 
produced  equal  to  that  consumed.  The  only  source,  however,  by  which 
oxygen  is  known  to  be  supplied,  is  the  process  of  vegetation.  A  healthy 
plant  absorbs  carbonic  acid  during  the  day;  appropriates  the  carbon 
to  its  own  necessities,  and  gives  off  the  oxygen  with  which  it  was  com- 
bined. This  is  a  nutritive  or  digestive  process;  but  at  the  same  time 
the  plant  is  respiring,  or  consuming  oxygen,  and  giving  off  carbonic 
acid.  In  bright  light,  however,  the  former  function  is  so  active  as  to 
preponderate  over,  and  mask  the  latter.  During  the  night  an  opposite 
effect  is  produced.  Digestion  is  almost  suspended;  and  respiration  is 
preponderant.  Oxygen  is  then  taken  from  the  air,  and  carbonic  acid 
given  off;  but  the  experiments  of  Davy  and  Priestley  show,  that  plants, 
during  the  twenty-four  hours,  yield  more  oxj^gen  than  they  consume. 
It  seems  impossible,  however,  to  look  to  this  as  the  great  cause  of  equi- 
librium between  the  oxygen  and  the  nitrogen.  Its  influence  can  ex- 
tend to  a  small  distance  only ;  yet  the  uniformity  has  been  found  to 
prevail,  as  we  have  seen,  in  the  most  elevated  regions,  and  in  coun- 
tries whose  arid  sands  never  admit  of  vegetation. 

In  addition  to  the  oxygen  and  nitrogen, — the  principal  constituents 
of  atmospheric  air, — another  gas  exists  in  very  small  proportion,  but 
is  always  present.  This  is  carbonic  acid.  It  was  found  by  De  Saus- 
sure  on  Mont  Blanc,  and  by  Von  Humboldt  in  air  brought  down  by 
Garnerin,  the  aeronaut,  from  the  height  of  several  thousand  feet.  The 
proportion  is  estimated  by  Dalton  not  to  exceed  the  y-f^'p^th  or  y^^fj^th 
of  its  bulk.  In  one  of  the  wards  of  La  Pitie,  in  Paris,  which  had 
been  kept  shut  during  the  night,  M.  Felix  Leblanc^  found  a  larger 
portion  of  carbonic  acid,  nearly  y  (fg^^hs;  and  in  a  dormitory  of  La 
Salpetri^re,  the  air  yielded  yo^^o^^^;  t^®  largest  proportion  found  by 
him  in  hospitals.  In  the  lecture  room  of  the  Sorbonne,  which  is 
capabable  of  containing  1000  cubic  inches  of  air,  after  a  lecture  an 
hour  and  a  half  long,  and  at  which  900  persons  were  present,  the 
oxygen  was  found  to  have  lost  1  in  every  hundred,  although  two 
doors  were  open ;  whilst  the  carbonic  acid  was  increased  in  rather  a 
greater  ratio.  In  a  ward  in  an  institution  for  children,  although  the 
door  was  half  open,  and  there  was  an  open  space  in  the  roof,  the  air 
■was  found  to  contain  y^^goths  of  carbonic  acid,  and  there  was  a  pro- 
portional diminution  of  oxj^gen.  Dr.  Dalton  analyzed  the  air  of  a 
room  in  which  50  candles  had  been  kept  burning,  and  500  people  had 

'  Lewy,  Comptes  Eendiis,  1842;  also,  Morren,  Annales  de  Cliimie  et  de  Physique,  xii. 
5,  Paris,  1844. 

2  Gazette  Med.  de  Paris,  11  Juin,  1842. 


ATMOSPHERIC   AIR.  283 

been  collected  for  two  hours,  and  found  it  to  contain  one  per  cent,  of 
carbonic  acid.^  M.  Boussingault^  has  made  142  analyses  of  large 
quantities  of  the  air  of  Paris,  whence  he  has  drawn  the  generally  ad- 
mitted conclusion,  that  the  quantity  of  carbonic  acid  contained  in  the 
air  of  large  towns  is  not  above  the  average.  The  average  quantity 
found  by  him  was  3*97  volumes  in  10,000.  Although  largely  pro- 
duced where  combustion  is  extensively  going  on,  and  where  numbers 
of  persons  are  congregated  together,  as  in  large  cities,  it  becomes  so 
speedily  diffused  in  the  atmosphere  as  not  to  excite  any  marked  dif- 
ference between  the  air  in  them  and  in  rural  districts.^ 

These,  then,  may  be  looked  upon  as  the  constituents  of  atmospheric 
air.  There  are  certain  substances,  however,  which  are  adventitiously 
present  in  variable  proportions;  and  which,  with  the  constitution  of 
the  atmosphere  as  to  density  and  temperature,  are  the  causes  of  gene- 
ral or  local  salubrity,  or  the  contrary.  Water  is  one  of  these.  The 
quantity,  according  to  M.  de  Saussure,  in  a  cubic  foot  of  air,  charged 
with  moisture,  at  65°  Fahr.,  is  11  grains.  Its  amount  in  the  atmo- 
sphere is  very  variable,  owing  to  the  continual  change  of  temperature 
to  which  the  air  is  subject,  and  even  when  the  temperature  is  the 
same,  the  quantity  of  vapour  is  found  to  vary,  as  the  air  is  rarely  in  a 
state  of  saturation.  The  varying  condition  as  to  moisture  is  indicated 
by  the  hyrjrometer.  From  a  comparison  of  numerous  observations, 
Gay  Lussac  affirms,  that  the  mean  hygrometric  state  of  the  atmosphere 
is  such,  that  the  air  holds  just  one-half  the  moisture  necessary  for  its 
saturation.  In  his  celebrated  aerial  voyage,  he  found  it  contain  but 
one-eighth.  This  is,  perhaps,  the  greatest  degree  of  dryness  ever 
noticed. 

It  has  been  presumed,  that  the  hygrometric  condition  of  the  air  has 
more  agency  in  the  production  of  disease  than  either  the  barometric  or 
thermometric.  It  is  not  easy  to  say,  which  exerts  the  greatest  influ- 
ence :  probably  all  are  concerned ;  and  when  we  have  a  union  of  par- 
ticular barometric,  thermometric,  hygrometric,  electric,  and  other 
conditions,  we  have  certain  epidemics  existing,  which  do  not  prevail 
under  any  other  combination.  When  the  air  is  dry,  we  feel  a  degree 
of  elasticity  and  buoyancy ;  whilst,  if  it  be  saturated  with  moisture — 
especially  during  the  heat  of  summer, — languor,  lassitude,  and  indis- 
position to  mental  or  corporeal  exertion  are  experienced. 

In  addition  to  aqueous  vapour,  numerous  emanations  from  animal 
and  vegetable  substances  are  generally  present,  especially  in  the  lower 
strata  of  the  atmosphere ;  by  which  the  salubrity  of  the  air  may  be 
more  or  less  affected.  All  living  bodies,  when  crowded  together,  de- 
teriorate the  air  so  much  as  to  render  it  unfit  for  the  maintenance  of 
the  healthy  functions.  If  animals  be  kept  crowded  together  in  ill- ven- 
tilated apartments,  they  speedily  sicken.  The  horse  becomes  attacked 
with  glanders;  fowls  with  pep,  and  sheep  with  a  disease  peculiar  to 
them  if  the}'"  be  too  closely  folded.  This  is  probably  a  principal  cause 
of  the  insalubrity  of  cities  compared  with  the  country.     In  them,  the 

'  London  and  Edinb,  Philos.  Magazine,  xii.  405,  1838. 

*  Annales  de  Chimie  et  de  Physique,  Mars,  1844.     See,  also,  M.  Lewy,  loc.  cit, 
^  See  Dr.  John  Reid,  article   Respiration,  in  Cyclopaedia  of  Anat.  and  Physiol.,  Pt. 
xxxii,  p.  326,  London,  April,  1848. 


284:  RESPIRATION. 

air  must  necessarily  be  deteriorated  by  the  impracticability  of  proper 
ventilation ;  and  this,  with  the  want  of  due  exercise,  is  a  fruitful  cause 
of  cachexia — and  of  tuberculous  cachexia;  hence,  also,  it  is,  that  in 
workhouses  and  manufactories,  diseases  dependent  on  this  condition 
of  constitution  are  prevalent.  One  of  the  greatest  evidences  we  pos- 
sess of  the  positive  insalubrity  of  towns  is  in  the  case  of  the  young. 
In  London,  the  proportion  of  those  that  die  annually  under  five  years 
of  age  to  the  whole  number  of  deaths  is  as  much  as  thirty-eight  per 
cent.,  and  under  two  years,  twenty-eight  per  cent. ;  in  Paris,  under  two 
years  of  age,  twenty-five  per  cent. ;  and  in  Philadelphia  and  Baltimore, 
.rather  less  than  a  third.  These  estimates  may  be  considered  approxi- 
mations; the  proportions  varying  somewhat,  according  to  the  precise 
year  in  which  they  have  been  taken.  Manifest,  however,  as  is  the 
existence  of  some  deleterious  principle,  in  these  cases,  it  has  always 
escaped  the  researches  of  the  chemist. 

Lastly.  Air  is  indispensable  to  organic  existence.  No  being — 
animal  or  vegetable — can  continue  to  live  without  a  due  supply  of 
it;  nor  can  any  other  gas  be  substituted  for  it.  This  is  proved  by  the 
fact,  that  all  organized  bodies  cease  to  exist,  if  placed  in  vacuo.  They 
require,  likewise,  renovation  of  the  air,  otherwise  they  die ;  and  if  the 
residual  air  be  examined,  it  is  found  diminished  in  quantity,  and  to 
have  received  a  gas,  which  is  totally  unfit  for  life, — carbonic  acid.  The 
experiments  of  Hales  prove  this  as  regards  vegetables ;  whilst  Spallan- 
zani  and  Vauquelin  have  confirmed  it  in  the  case  of  the  lower  animals. 
The  necessity  for  the  presence  of  air,  and  its  due  renewal, — as  regards 
man  and  the  upper  classes  of  animals, — is  sufficiently  obvious.  Not 
less  necessary  is  a  due  supply  of  it  to  aquatic  animals.  They  can  be 
readily  drowned,  when  the  air  in  the  water  is  consumed,  if  prevented 
from  coming  to  the  surface.  If  the  fluid  be  put  under  the  receiver  of 
an  air-pump,  and  the  air  be  withdrawn,  or  if  the  vessel  be  placed  so 
that  the  air  cannot  be  renewed,  the  same  changes  are  found  to  have 
been  produced  in  it.  Hence  the  necessity  for  making  holes  through 
the  ice,  where  small  fish-ponds  are  frozen  over,  if  we  are  desirous  of 
preserving  the  fish  alive.  The  necessity  for  the  renewal  of  air  is  not, 
however,  alike  imperative  in  all  animals.  Whilst  the  mammalia, 
birds,  fishes,  &c.,  speedily  expire,  when  placed  under  the  receiver  of 
an  air-pump,  if  the  receiver  be  exhausted ;  the  frog  is  but  slightly 
incommoded.  It  swells  up  almost  to  bursting,  but  retains  its  positiou, 
and  when  the  air  is  re-admitted  seems  to  have  sustained  no  injury.  The 
exception,  afforded  by  the  amphibious  animal  to  the  ordinary  effects 
of  destructive  agents,  we  have  already  had  occasion  to  refer  to  more 
than  once;  and  it  is  exemplified  in  the  fact,  now  indisputable,  that  the 
toad  has  been  found  alive  in  the  substance  of  trees  and  rocks,  where 
no  access  of  air  appeared  practicable. 

The  influence  of  air  on  mankind  is  interesting  and  important  in  its 
hygienic  relations,  and  has  accordingly  been  a  tojiic  of  study  since  the 
days  of  Hippocrates.  In  other  works,  it  has  been  investigated,  at 
considerable  length,  by  the  author.^ 

'  Human  Health,  Philad.,  1844;  and  American  Cyclopaedia  of  Practical  Medicine 
and  Surgery,  art.  Atmosphere,  p.  527,  Philad.,  183tJ. 


MECHANICAL   PHENOMENA — RESPIRATION.  285 

3.    PHYSIOLOGY  OF  RESPIRATION. 

a.  Mechanical  Phenomena  of  Respiration. — Within  certain  limits,  the 
function  of  respiration  is  under  the  influence  of  volition.  The  mus- 
cles, belonging  to  it,  have  consequently  been  termed  mixed,  as  we  can 
at  pleasure  increase  or  diminish  their  action,  but  cannot  arrest  it  alto- 
gether, or  for  any  great  length  of  time.  If,  by  a  forced  inspiration, 
we  take  air  into  the  chest  in  large  quantity,  we  find  it  impossible  to 
keep  the  chest  in  this  condition  beyond  a  certain  period.  Expiration 
irresistibly  succeeds,  and  the  chest  resumes  its  pristine  situation.  The 
same  occurs  if  we  expel  the  air  as  much  as  possible  from  the  lungs. 
The  expiratory  effort  cannot  be  prolonged  indefinitely,  and  the  chest 
expands  in  spite  of  the  effort  of  the  will.  The  most  expert  divers  do 
not  appear  capable  of  suspending  the  respiratory  movements  longer 
than  95  or  100  seconds,  or,  at  the  farthest,  two  minutes.  Dr.  Lefevre^ 
found  the  average  period  of  the  Turkish  divers  to  be  76  seconds  for 
each  man.  Yet  Dr.  Hutchinson^  states,  that  a  man  can  take  from  230 
to  300  cubic  inches  of  fresh  air  into  his  lungs,  and  live  upon  it  with- 
out inconvenience  for  two  minutes  without  breathing.  "It  is  better," 
he  says,  "to  inspire  and  expire  forcibly  five  or  six  times  and  then 
hold,"  with  the  view  of  removing  as  far  as  possible  the  old  air  from  the 
lungs  and  filling  the  chest  as  completely  as  possible.  "For  the  first 
fifteen  seconds,  a  giddiness  will  be  experienced ;  but  when  this  leaves 
us,  we  do  not  find  the  slightest  inconvenience  for  want  of  air." 

These  facts  have  given  rise  to  two  curious  and  deeply  interesting 
topics  of  inquiry ; — the  cause  of  the  first  inspiration  in  the  new-born 
infant ; — and  of  the  regular  alternation  of  inspiration  and  expiration 
during  the  remainder  of  existence  ?  The  first  of  these  will  fall  under 
consideration  when  we  investigate  the  physiology  of  infancy ;  the  lat- 
ter will  claim  some  attention  at  present.  Ilaller^  attempted  to  account 
for  the  phenomenon  by  the  passage  of  the  blood  through  the  lungs 
being  impeded  during  expiration, — a  reflux  of  blood  into  the  veins, 
and  a  degree  of  pressure  upon  the  brain,  being  thus  induced ;  hence  a 
painful  sensation  of  suffocation  in  consequence  of  which  the  muscles 
of  inspiration  are  called  into  action  by  the  will,  for  the  purpose  of 
enlarging  the  chest,  and,  in  this  way,  removing  the  impediment.  The 
same*lineasy  feelings,  however,  ensue  from  inspiration,  if  too  long  pro- 
tracted: the  muscles  cease  to  act,  and,  by  their  relaxation,  the  oppo- 
site state  of  the  chest  is  induced.  Whytf*  conceived,  that  the  passage 
of  the  blood  through  the  pulmonary  vessels  is  impeded  by  expiration, 
and  a  sense  of  anxiety  is  thus  produced.  The  unpleasant  sensation 
acts  as  a  stimulus  upon  the  nerves  of  the  lungs  and  the  parts  con- 
nected with  them,  which  arouses  the  energy  of  the  sentient  ])rinciple ; 
and  this,  by  acting  in  a  reflex  manner,  causes  contraction  of  the  dia- 
phragm, enlarges  the  chest,  and  removes  the  painful  feeling.  The 
muscles  then  cease  to  act,  in  consequence  of  the  stimulus  no  longer 

'  Loudon's  Magazine  of  Nat.  Hist.,  p.  617,  Dec,  1836  ;  and  Dunglison's  Amer.  Med. 
Intelligencer,  p.  30,  April  15,  1837. 

2  Art.  Thorax,  Cyclop,  of  Anat.  and  Physiol.,  iv.  1066,  London,  1852. 

3  Elementa  Physiologise,  viii.  4,  17,  Laiisann.,  1764. 

■*  An  Essay  on  the  Vital  and  other  Involuntary  Motions  of  Animals,  sect,  viii., 
Edinb.,  1751. 


286  EESPIRATION. 

existing.  These,  and  all  other  methods  of  accounting  for  the  pheno- 
mena, are,  however,  too  pathological.  From  the  first  moment  of 
respiration  the  process  appears  to  be  accomplished  without  the  slight- 
est difficulty,  and  to  be  as  much  a  part  of  the  instinctive  extra-uterine 
actions  of  the  frame,  as  circulation,  digestion,  or  absorption.  It  is 
obviously  an  internal  sensation,  after  respiration  has  been  once  esta- 
blished ;  and,  like  all  internal  sensations,  is  inexplicable  in  our  exist- 
ing state  of  knowledge.  The  part  which  developes  the  impression  is 
probably  the  lung,  through  its  ganglionic  nerves ;  and  the  pneumo- 
gastric  nerves  convey  the  impression  to  the  brain  or  spinal  marrow, 
which  calls  into  action  the  muscles  of  inspiration.  We  say,  that  the 
action  of  impression  arises  in  the  lungs,  and  this,  from  some  internal 
cause,  connected  with  the  office  to  be  filled  in  the  economy ;  but  in 
so  saying  we  sufficiently  exhibit  our  total  want  of  acqiiaintance  with 
its  nature. 

The  movements  of  inspiration  and  expiration,  which,  together,  consti- 
tute the  function  of  respiration,  are  entirely  accomplished  b}"  the  dilata- 
tion and  contraction  of  the  thorax.  Air  enters  the  chest  when  the  latter 
is  expanded;  and  is  driven  out  when  the  chest  is  restored  to  its  ordinary 
dimensions; — the  thorax  thus  seeming  to  act  like  an  ordinary  pair  of 
bellows  with  the  valve  stopped:  when  the  sides  are  separated,  the  air 
enters  at  the  nozzle,  and  when  they  are  brought  together,  it  is  forced 
out. 

(1.)    INSPIRATION. 

The  augmentation  of  the  capacity  of  the  thorax,  which  constitutes 
inspiration,  may  be  effected  to  a  greater  or  less  extent,  according  to  the 
number  of  muscles  that  are  thrown  into  action.  The  chest  may,  for 
example,  be  dilated  by  the  diaphragm  alone.  This  muscle,  as  we  have 
seen,  in  its  ordinary  relaxed  condition,  is  convex  towards  the  chest. 
When,  however,  it  contracts,  it  becomes  more  horizontal ;  in  this  man- 
ner augmenting  the  cavity  of  the  chest  in  a  vertical  direction.  The 
sides  or  lateral  portions  of  the  diaphragm,  which  are  fleshy  and  corre- 
spond to  the  lungs,  descend  more  in  this  movement  than  the  central 
tendinous  portion,  which  is  moreover  kept  immovable  by  its  attachment 
to  the  sternum,  and  its  union  with  the  pericardium.  In  the  gentlest  of 
all  breathing,  the  diaphragm  appears  to  be  the  sole  agent  of  inspiration; 
and  in  cases  of  inflammation  of  the  pleura  costalis,  or  of  fractured  rib, 
our  endeavours  are  directed  to  the  prevention  of  any  elevation  of  the 
ribs  by  which  the  diseased  part  might  be  put  upon  the  stretch.  Gene- 
rally, however,  as  the  diaphragm  descends,  the  viscera  of  the  abdomen 
are  compressed;  the  abdominal  muscles  relaxed;  the  abdomen  is  ren- 
dered more  prominent,  and  the  ribs  and  the  breast  bone  are  raised  so 
that  the  latter  is  protruded.  When  the  diaphragm  acts,  and,  in  addition,  , 
the  ribs  and  sternum  are  raised,  the  cavity  of  the  chest  is  still  farther 
augmented. 

In  young  children,  inspiration  is  effected  almost  wholly  by  the  dia- 
phragm ;  and  as  in  diaphragmatic  breathing  the  movement  of  the 
parietes  of  the  abdomen  is  more  marked  than  that  of  any  other  part, 
this  has  been  termed  the  ahdominal  mode  or  type  of  respiration. 

In  adult  men,  the  lower  part  of  the  chest  and  sternum  move  more 


I 


MECHANICAL   PHENOMENA — INSPIRATION. 


287 


largely  than  in  women;  who,  owing  to  greater  mobility  of  the  first  rib, 
have  a  more  extensive  movement  of  the  npper  than  of  the  lower  part 


Fig.  88. 


Fig.  89. 


The  Changes  of  the  Thoracic  and  Abdominal  Wails  of         The  Respiratory  Movements  in  the 
the  Male  during  Respiration.  Female. 

The  back  is  supposed  to  be  fixed  in  order  to  tlirow  forward  The  lines  indicate  the  same  changes  as 

the  respiratory  movement  as  much  as  possible.     The  outer        in  the  last  figure.     The  thickness  of  the 
black    continuous    line   in   front   represents    the   ordinary        continuous  line  over  the  sternum  shows 
breathing  movement :   the  anterior  margin  of  it  being  the        the  larger  extent  of  the  ordinary  breath- 
boundary  of  inspirfdion,  the  posterior  margin  the  limit  of        iug  movement  over  that  region  in  the  fe- 
expircdion.    The  line  is  thicker  over  the  abdomen,  since  the        male  than  in  the  male, 
ordinary  respiratory  movement  is  chiefly  abdominal:  thin 
over  the  chest,  for  there  is  less  movement  over  that  region. 
The  dotted  lino  indicate.s  the  movement  on  deep  inspiration, 
during  which  the  sternum  advances,  while  the  abdomen  re- 
cedes. 

of  the  chest, — an  arrangement  which,  it  has  been  suggested,  ma}'  have 
for  its  object  the  providing  of  sufficient  space  for  respiration  when  the 
lower  part  of  the  chest  is  encroached  upon  by  the  pregnant  uterus. 
The  former  is  called  by  MM.  Beau  and  Alaissiat  the  costo-inferior  or 
inferior  costal;  the  latter  the  costo-sn]jerior  or  siqjerior  costal  type  of 
respiration.' 

From  the  admeasurements  of  Mr.  Sibson^  it  appears,  that  in  health 
the  inspiratory  movement  of  the  walls  of  the  chest,  during  tranquil 
breathing,  is  only  from  two  to  six-hundredths  of  an  inch ;  whilst  that 
of  the  abdomen  is  about  three-tenths  of  an  inch.  During  a  deep  in- 
spiration, the  expansive  motion  of  the  walls  of  the  chest  is,  in  front, 
about  one  inch;  and.  at  the  sides  about  two-thirds  of  an  inch;  and  that 
of  the  abdomen  about  one  inch.  The  expansion  of  the  two  sides  of 
the  chest  is  nearly  equal;  the  left  side  does  not,  however,  expand  quite 
so  much  as  the  right  over  the  lower  two-thirds,  owing  to  the  position 
of  the  heart. 


'  Arcliives  Generales  de  Medecine,  iii.  263,  Paris,  1843 ;  also,  Kirkes  and  Paget.  Manual 
of  Physiology,  2d  Amer.  edit.,  p.  127,  Philad.,  1853. 

*  Provincial  Medical  and  Surgical  Journal,  Sept.  5,  1849. 


288  RESPIRATIOiSr. 

J 

The  mechanism,  by  which  the  ribs  are  elevated,  has  been  productive 
of  more  controversy  than  the  subject  merits.  Ilaller^  asserted,  that 
the  first  rib  is  immovable,  or  at  least  admits  of  but  trifling  motion 
when  compared  with  the  others;  and  he  denied  that  the  thorax,  as  a 
whole,  makes  any  movement  of  either  elevation  or  depression;  affirm- 
ing that  the  ribs  are  raised  successively  towards  the  top  of  the  cavity; 
and  this  to  a  greater  extent  as  they  are  more  distant  from  the  first. 
M.  Magendie,^  on  the  other  hand,  denies  that  they  are  elevated  in  this 
manner ;  and  endeavours  to  show  that  they  are  all  raised  at  the  same 
time;  that  the  first  rib,  instead  of  being  the  least  movable,  is  the  most 
so ;  and  that  the  disadvantage,  which  the  lower  ribs  possess  in  the 
movement,  by  their  admitting  of  less  motion  in  their  posterior  articu- 
lations, is  compensated  by  the  greater  length  of  those  ribs.  This  com- 
pensation he  considers  to  have  its  advantages;  for  as  the  true  ribs,  with 
their  cartilages  and  the  sternum,  usually  move  together,  and  the  motion 
of  one  of  these  parts  almost  always  induces  that  of  the  rest,  it  would 
follow,  that  if  the  lower  ribs  were  more  movable,  they  could  not  exe- 
cute a  more  extensive  movement  than  they  do ;  whilst  the  solidity  of 
the  thorax  would  be  diminished. 

By  the  elevation,  then,  of  the  ribs,  and  the  depression  of  the  dia- 
phragm, the  chest  is  augmented,  and  a  deeper  inspiration  effected  than, 
when  the  diaphragm  acts  singly.  In  this  elevation  of  the  ribs,  we  see 
the  advantage  of  their  obliquity  as  regards  the  spine.  Had  they  been 
horizontal,  or  inclined  obliquely  upwards,  any  elevation  would  neces- 
sarily have  contracted  the  thoracic  cavity,  and  thus  favoured  expiration 
instead  of  inspiration. 

The  muscles  chiefly  concerned  in  inspiration  are  the  intercostals,  and 
those  that  arise,  either  directly  or  indirectl}^  from  the  spine,  head,  or 
upper  extremities,  and  that  can,  in  any  manner,  elevate  the  thorax. 
Amongst  these  are  the  scaleni  antici  and  postici,  levatores  costarum, 
the  muscles  of  the  neck,  which  are  attached  to  the  sternum,  &c.  The 
elasticity  of  the  cartilages,  and  the  weight  of  the  osseous  portions  of 
the  parietes  of  the  chest,  must  afford  considerable  resistance  to  the 
action  of  the  inspiratory  muscles  in  dilating  it.  It  is  probable,  how- 
ever, that  the  estimates  of  Dr.  Hutchinson^  are  far  above  the  reality. 
He  calculates,  that  the  force  which  the  muscles  of  inspiration  have  to 
overcome  in  ordinary  breathing  from  these  sources  is  probably  at  least 
equal  to  about  100  lbs.;  and  in  deep  inspiration  to  about  300  lbs.;  and 
yet,  in  these  calculations,  the  additional  resistance  from  the  elasticity 
of  the  lungs  is  not  taken  into  the  account. 

As  no  air  exists  in  the  cavity  of  the  pleura,  it  necessarily  happens, 
that  when  the  capacity  of  the  chest  is  augmented,  the  residuary  air, 
contained  in  the  air-cells  of  the  lungs  after  expiration,  is  rarefied;  and, 
in  consequence,  the  denser  air  without  enters  the  larynx  by  the  mouth 
and  nose,  until  the  air  within  the  lungs  has  attained  the  density,  which 
the  residuary  air  had.  prior  to  inspiration, — not  that  of  the  external  air, 
as  has  been  affirmed.'*    At  the  time  of  inspiration,  the  glottis  opens  by 

'  Elementa  Physiologi3e,  viii.  4,  Lausann.,  1764. 

^  Precis,  &c.,  2de  edit.,  ii.  316. 

3  Medico-Chirurgical  Transactions,  xxix.  205,  London,  1846. 

*  Animal  Physiology,  Library  of  Useful  Knowledge,  p.  100,  London,  1829. 


MECHANICAL   PHENOMENA — INSPIRATION.  289 

the  relaxation  of  the  arjtenoidei  muscles,  as  M.  Legallois'  proved  by 
experiments  performed  at  the  Ecole  de  Medecine  of  Paris.  On  exposing 
the  glottis  of  a  living  animal,  the  aperture  is  found  to  dilate  distinctly 
at  each  inspiration,  and  contract  at  each  expiration.  If,  according  to 
M.  Magendie,  the  eighth  pair  of  nerves  be  divided  low  down  in  the 
neck,  and  the  dilator  muscles  of  the  glottis,  which  receive  their  nerves 
from  the  recurrents — branches  of  the  eighth  pair — be  thus  paralysed, 
the  aperture  is  no  longer  enlarged  during  inspiration,  whilst  the  con- 
strictors— the  arytenoidei  muscles,  which  receive  their  nerves  from  tlie 
superior  laryngeal, — given  off  above  the  point  of  section,  preserve  their 
action,  and  close  the  glottis  more  or  less  completely. 

When  air  is  inspired  through  the  mouth,  the  velum  is  raised,  so  as 
to  allow  it  to  pass  freely  to  the  glottis;  and,  in  forced  inspiration,  it  is 
so  horizontal  as  to  completely  expose  the  pharynx  to  view.  The  phy- 
sician takes  advantage  of  this  in  examining  morbid  affections  of  those 
I)arts,  and  can  often  succeed  much  better  in  this  way  than  by  pressing 
down  the  tongue.  On  the  other  hand,  when  inspiration  is  effected  en- 
tirely through  the  nose,  the  velum  palati  is  depressed  until  it  becomes 
vertical,  and  there  are  no  obstacles  to  the  free  entrance  of  the  air  into 
the  larynx.  In  such  case,  where  difficulty  of  breathing  exists,  the 
small  muscles  of  the  alas  nasi  are  frequently  thrown  into  violent  action, 
alternately  dilating  and  contracting  the  apertures  of  the  nostrils:  hence 
this  is  a  common  symptom  in  pulmonary  affections. 

Mayow^  conceived,  that  air  enters  the  lungs  in  inspiration  as  it  would 
a  bladder  put  into  a  pair  of  bellows,  and  communicating  with  the  ex- 
ternal air  by  the  pipe  of  the  instrument.  The  lungs,  however,  are  not 
probably  so  passive  as  this  view  would  indicate.  In  cases  of  pulmonary 
hernia,  the  extruded  portion  has  been  observed  to  dilate  and  contract 
in  inspiration  and  expiration.  Reisseisen  believed  this  to  be  owing  to 
muscular  fibres,  which  Meckel  and  himself  conceived  to  make  the  whole 
circuit  of  the  bronchial  ramifications.  Laennec^  affirms,  that  he  has 
endeavoured,  without  success,  to  verify  the  observations  of  Reisseisen; 
but  that  the  manifest  existence  of  circular  fibres  in  branches  of  a  mo- 
derate size,  and  the  phenomena  presented  l)y  many  kinds  of  asthma, 
induce  him  to  consider  the  temporary  constriction  and  occlusion  of  the 
minute  bronchial  ramifications  as  a  thing  established.  The  muscular 
action  of  the  lungs  may  be  demonstrated  by  galvanizing  them  shortly 
after  they  have  been  taken  from  the  body ;  when  they  contract  so  as 
to  lift  up  water  placed  in  a  tube  introduced  into  the  trachea;"*  and  it  is 
affirmed  by  M.  Longet^  and  by  Volkmann,^  that  they  may  be  made  to 
contract  by  stimulating  their  nerves.  The  latter  physiologist  tied  a 
glass  tube,  drawn  fine  at  one  end,  into  the  trachea  of  a  decapitated 
animal ;  and  when  the  small  end  was  turned  to  the  flame  of  a  candle, 

'  (Euvres,  p.  177,  Paris,  1824. 

2  Tractatus  Quinque,  p.  271,  Oxon.,  1674. 

*  On  the  Diseases  of  the  Chest,  &c.,  4th  edit.,  Lond.,  1834 ;  rc'iirinted  in  this  country, 
Philad.,  1835. 

*  C.  J.  B.  Williams,  Report  of  the  Meeting  of  the  British  Association,  in  Athena-um 
for  1840,  p.  802. 

*  Traite  de  Physiologic,  ii.  328,  Paris,  1850. 

®  Art.  Nervenphysiologie,  in  Wagner's  Handwortcrbucli  der  Physiologic,  lOte  Liefe- 
rung,  s.  58(j,  Braunschweig,  1845. 
VOL.  L— 19 


290  EESPIRATION. 

he  galvanized  the  trunk  of  the  pneumogastric  nerve.  On  each  ap- 
plication, tlie  flame  was  blown  upon ;  and  once  it 
was  extinguished. 

In  the  trachea,  an  obvious  muscular  structure 
exists  in  the  posterior  third,  where  the  cartilages 
are  wanting.  There  it  consists  of  a  thin  muscular 
plane, — the  trachealis  muscle, — the  fibres  of  which 
pass  transversely  between  the  interrupted  extremi- 
ties of  the  cartilaginous  rings  of  the  trachea  and 
bronchi,  to  which  a  layer  of  longitudinal  fibres 
may  at  times  be  seen  superadded.-^  The  use  of 
the  transverse  muscular  tissue,  as  suggested  by 
Small  Bronchial  Tube  j)p^  Physick,^  and  after  him  by  M.  Cruveilhier  and 
ai   ope"'  g^    Charles  BelP,  is  to   diminish  the  calibre  of 

Showing    the    transverse  .       '  .  . 

piexiform  arrangement  of  the  air-tubcs  lu  expectoratiou  I   SO  that  the  air 

the  muscular  hiver,  and  its     ,  .  ,  ,i  t        ji  ^  ^    j  j.- 

disposition  at  the  orifice  of  a  haviug  to  pass  through  the  contracted  portion 
flftT.-Masnified''2 Sam*''  with  greater  velocity,  its  momentum  may  remove 
the  secretions  that  are  adherent  to  the  mucous 
membrane.     The  explanation  is  ingenious  and  probably  just. 

In  the  larger  bronchi  the  muscles  have  the  form  of  circular  flattened 
fasciculi,  which,  except  in  old  people,  in  whom  interstices  of  diflerent 
sizes  are  observable,  constitute  a  completely  continuous  layer,  which 
are  still  perceptible  in  ramifications  of  from  y'^th  to  i\t]i  of  a  line  in 
diameter.'* 

M.  Magendie*  asserts,  that  the  lung  has  a  constant  tendency  to  return 
upon  itself,  and  to  occupy  a  smaller  space  than  it  fills ;  and  that  it  con- 
sequently exerts  a  degree  of  traction  on  every  part  of  the  parietes  of 
the  thorax.  This  traction  has  but  little  effect  upon  the  ribs,  which 
cannot  yield ;  but  upon  the  diaphragm  it  is  considerable.  It  is,  in  his 
opinion,  the  cause  why  that  muscle  is  always  tense,  and  drawn  so  as 
to  be  vaulted  upwards ;  when  the  muscle  is  depressed  during  contrac- 
tion, it  is  compelled  to  draw  down  the  lungs  towards  the  base  of  the 
chest,  so  that  they  are  stretched,  and  by  virtue  of  their  elasticity  have 
a  powerful  tendency  to  return  upon  themselves,  and  draw  the  dia- 
phragm upwards.  If  a  puncture  be  made  into  the  chest  in  one  of  the 
intercostal  spaces,  the  air  will  enter  the  chest  through  the  aperture,  and 
the  lung  will  shrink.  By  this  experiment,  the  atmospheric  pressure 
is  equalized  on  both  surfaces  of  the  lung,  and  the  organ  assumes  a  bulk 
determined  by  its  elasticity  and  weight.  Owing  to  this  resiliency  of 
the  lungs,  and  to  their  consequent  tendency  to  recede  from  the  pleura 
cosialis,  there  is  less  pressure  upon  all  the  parts  against  which  the  lungs 
are  applied;  and,  accordingly,  the  heart  is  not  exposed  to  the  same 
degree  of  pressure  as  the  parts  external  to  the  chest ;  and  the  degree  of 
pressure  is  still  farther  reduced,  when  the  chest  is  fully  dilated,  the 

'  Goddard,  in  Wilson'^  Anatomist's  Vade-Mecum,  Amer.  edit.,  p.  404,  note,  Philad., 
1843. 

^  Horner's  Lessons  in  Practical  Anat.,  p.  179,  Pliilad.,  1836. 
3  Philos.  Transact,  for  1832,  p.  301. 

*  KiJlliker,  Mikroskopische  Anat.,  ii.  313,  Leipz.,  1852  ;  or  Amer.  edit,  of  Sydenham 
Society's  translation  of  Kolliker's  Manual  of  Histology,  by  Dr.  Da  Costa,  p.  578,  Philad., 
1854. 

*  Precis,  &c.,  ii.  325. 


MECHANICAL   PHENOMENA — INSPIEATION. 


291 


lungs  farther  expanded,  and  their  elastic  resiliency  increased.  Dr. 
Carson^  states,  that  in  his  experiments  on  calves,  sheep,  and  large  dogs, 
the  resiliency  of  the  lungs  was  found  to  be  balanced  by  a  column  of 
water,  varying  in  height  from  a  foot  to  a  foot  and  a  half;  and  in  rabbits 
and  cats  by  a  column  varying  in  height  from  six  to  ten  inches. 

Many  physiologists  have  pointed  out  three  degrees  of  inspiration, 
but  it  is  manifest  that  there  may  be  innumerable  shades  between  them: 
— 1.  Ordinary  gentle  inspiration^  owing  simply  to  the  action  of  the  dia- 
phragm ;  or,  in  addition,  to  a  slight  elevation  of  the  chest.  2.  Deep 
inspiration,  when,  with  the  depression  or  contraction  of  the  diaphragm, 
there  is  evident  elevation  of  the  thorax;  and,  lastly, /orcecZ  inspiration, 
when  the  air  is  strongly  drawn  in  by  the  rapid  dilatation  produced  by 
the  action  of  all  the  respiratory  muscles  that  elevate  the  chest  directly 
or  indirectly. 

Trials  have  been  instituted  for  determining  the  quantity  of  air  taken 
into  the  lungs  at  an  inspiration;  and  considerable  diversity,  as  might 
be  expected,  exists  in  the  evaluations  of  different  experimenters.^  We 
have  just  remarked,  that,  in  the  same  individual,  the  inspiration  may 
be  gentle,  deep,  or  forced;  and,  in  each  case,  the  quantity  of  air  in- 
spired will  necessarily  differ.  There  is,  likewise,  considerable  diver- 
sity in  individuals;  so  that  an  approximation  can  alone  be  attained. 
The  following  table  sufficiently  exhibits  the  discordance  on  this  point. 
Many,  however,  of  the  estimates,  which  seem  so  discrepant,  may  pro- 
bably be  referred  to  imperfection  in  the  mode  of  conducting  the  expe- 
riment, as  well  as  to  the  causes  above  mentioned : — 


Cubic  inches 

Cubic  inches 

at  each 

at  each 

Inspiration. 

Inspiration. 

Reil, 

42  to  100 

Jeffreys, 

Herbst, 

26 

24  to  30 

Meuzies, 

Sauvages, 

Herholdt,       .... 

20  to  29 

Hales, 

Jurine  and  Coathupe, 

20 

Haller, 

Kite, 

17 

Ellis, 

Allen  and  Pepys,    .     . 

16^ 

Sprengel, 

T.  Thomson,       .     .     . 

16 

Sommering, 

40 

Hutchinson, 

16  to  20 

Chaptal 

J.  Borelli,      .... 

15  to  40 

Bell, 

Goodwin,       .... 

14 

Monro, 

Valentin,       .... 

14  to  92 

Blumenbacli, 

Sir  H.  Davy,      .     .     . 

13  to  17 

Thomson, 

Lavoisier  and  Seguin, 

13 

Bostock,                 J 

Abcrnethy  and  Mojou, 

12 

Jurin,        

35  to  38 
35 

Vierordt,        .... 
Keutsch, 

10  to  42 
6  to  12 

Fontana, 

Richerand  and  Cavallo, 

30  to  40 

Abildgaard,  .... 

3 

Dalton, 

30 

In  passing  through  the  mouth,  nasal  fossae,  pharynx,  larynx,  tra- 
chea, and  bronchi,  the  inspired  air  acquires  nearly  the  temperature  of 
the  body  ;  and,  if  it  be  cool,  the  same  quantity  by  weight  occupies  a 

■  Philosophical  Transactions,  for  1820,  p.  42. 

^  Dr.  Marshall  Hall  has  devised  a  pnenmatometer  for  this  purpose.  See  art.  Irrita- 
bility, in  Cyclop,  of  Auat.  and  Physiol.,  July,  1840. 


292  RESPIRATION. 

much  larger  space  in  the  lungs,  owing  to  its  rarefaction  in  those  organs. 
According  to  Valentin,  the  temperature  of  the  expired  air  is  y9°-5 
Fahr.,  when  breathing  an  atmosphere  of  moderate  temperature.  In  its 
passage,  too,  it  becomes  mixed  with  the  halitus,  that  is  constantl}'-  ex- 
haled from  the  mucous  membrane  of  the  air-passages  :  in  this  condi- 
tion, it  enters  the  air-cells,  and  becomes  mixed,  by  difiusion,  with  the 
residuary,  air. 

It  is  obvious,  that  if  we  knew  the  exact  capacity  of  the  lungs  in  an 
individual  in  health,  we  might  be  able  to  determine  the  extent  of  solidi- 
fication in  pulmonary  affections  by  the  diminution  in  their  capacity. 
Owing,  however,  to  our  want  of  this  requisite  preliminary  knowledge, 
the  test  is  not  of  much  avail. 

(2.)    EXPIRATION. 

A  brief  interval  elapses  after  the  accomplishment  of  inspiration, 
before  the  reverse  movements  of  expiration  succeeds ;  and  tlie  air  is 
expelled  from  the  chest.  The  great  cause  of  this  expulsion  is  the  re- 
storation of  the  chest  to  its  former  dimensions ;  and  the  elasticity  of 
the  yellow  tissue  composing  the  bronchial  ramifications,  which  has 
been  put  upon  the  stretch  by  the  air  rushing  into  them  during  in- 
spiration. The  restoration  of  the  chest  to  its  dimensions  may  be 
effected  simply  by  the  cessation  of  the  contraction  of  the  muscles,  that 
have  raised  it,  and  the  elasticity  of  the  cartilages,  that  connect  the 
bony  portions  of  the  ribs  with  the  sternum  or  breast-bone.  In  active 
expiration,  however,  the  ribs  are  depressed  by  the  contraction  of 
appropriate  muscles,  and  the  chest  is  still  farther  contracted.  The 
chief  expiratory  muscles  are  the  triangularis  sterni,  the  broad  muscles 
of  the  abdomen,  rectus  abdominis,  sacro-lumbalis,  longissimus  dorsi, 
serratus  posticus  inferior,  &c.  Haller'  conceived  that  the  ribs,  in  ex- 
piration, are  successively  depressed  towards  the  last  rib ;  which  is  first 
fixed  by  the  abdominal  muscles  and  quadratus  lumborum.  The  in- 
tercostal muscles  then  act,  and  draw  the  ribs  successively  downwards. 
M.  ]\[ao-endie^  contests  the  explanation  of  Haller  ;  and  the  truth  would 
seem  to  be,  that  the  muscles,  just  mentioned,  participate  with  the  inter- 
costals  in  every  expiratory  movement.  'By  this  action,  the  capacity  of 
the  chest  is  diminished  ;  the  lungs  are  correspondently  pressed  upon, 
and  the  air  issues  by  the  glottis.  It  has  been  already  remarked,  that, 
during  expiration,  the  arytenoidei  muscles  contract,  and  the  glottis 
appears  to  close.  Still,  space  sulTicient  is  left  to  permit  the  exit  of  the 
air. 

It  has  been  asked  : — Is  the  air  expired  precisely  that  which  has  been 
taken  in  by  the  previous  inspiration  ?  Certainly  not.  It  has  expe- 
rienced much  change.  A  portion  of  the  oxygen  has  disappeared  and 
carbonic  acid  has  taken  its  place.  The  amount  of  the  inspired  air 
does  not  differ  largely  from  that  which  is  expired;  and  the  quantity 
employed  in  an  ordinary  act  of  inspiration  bears — as  will  be  seen — 
but  a  small  proportion  to  the  residual  air.  There  must  be  some  mode 
consequently  in  which  the  residual  air  or  that  occupying  the  air-cells 
is  changed,  and  this  is  probably  effected  mainly  by  the  mutual  diffu- 

'  Element.  Physiol.,  viii.  4,  Lausaun.,  17G4.  *  Precis,  &c.,  ii.  324. 


MECHANICAL   PHENOMEKA — EXPIRATION.  293 

sion  of  gases ;  wliicli  mix  readily  with  each  other  when  either  of  dif- 
ferent densities  or  different  temperatures;  and  this  admixture  is  doubt- 
less greatly  favoured  by  the  respiratory  movement.  The  muscular 
fibres  and  the  minute  bronchial  tubes  may  have  an  agency  in  the  mat- 
ter, as  suggested  by  Prof.  Draper.'  Were  the  parietes  of  the  air-cells 
possessed  of  contractile  fibres,  they  might  be  greatly  concerned;  but 
this  is  not  admitted.^ 

Many  experiments  have  been  made  to  determine  the  change  of  bulk 
which  air  experiences  by  being  respired.  According  to  Sir  Humphry 
Dav}^,^  it  is  diminished,  by  a  single  inspiration,  from  ^'^th  to  yioth 
part  of  its  bulk.  Cuvier  makes  it  about  g'^th  ;  Allen  and  Pepys  a  little 
more  than  one-half  per  cent.  Berthollet  from  0"69  to  3'70  per  cent.;  and 
Bostock  s'oth, — as  the  average  diminution.  Assuming  this  last  estimate 
to  be  correct,  and  forty  cubic  inches  to  be  the  quantity  drawn  into  the 
lungs  at  each  inspiration,  it  would  follow,  that  half  a  cubic  inch  disap- 
pears each  time  we  respire.  This,  in  a  day,  would  amount  to  14:,-i()0 
cubic  inches,  or  to  rather  more  than  eight  cubic  feet.  The  experiments 
of  M]\.[.  Dulong  and  Despretz  make  the  diminution  considerable.  The 
latter  gentleman  placed  six  small  rabbits  in  forty-nine  quarts  of  air  for 
two  hours,  at  the  expiration  of  which  time  the  air  had  diminished  one 
quart.     A  portion  of  the  inspired  air  must,  consequently,  be  absorbed. 

In  the  ordinary  respiration  of  men  from  seventeen  to  thirty-three 
years  old,  Valentin'*  has  calculated,  from  the  watery  vapour  contained 
in  the  saturated  expired  air,  that  the  average  quantity  of  air  expired 
in  a  minute  is  400  cubic  inches, — the  extremes  under  varying  circum- 
stances being  234:  and  GS^S  cubic  inches,  and  the  average  quantity  of 
one  ordinary  expiration  31*1  cubic  inches;  the  extremes  in  very  tran- 
quil and  somewhat  hurried  respiration  114  and  74  cubic  inches.  Mr. 
Paget,^  however,  thinks  that  Mr.  Coathupe's*^  estimate  of  20  to  25  cubic 
inches  is  probably  better,  inasmuch  as  it  was  drawn  from  the  results 
of  respiration  continued  during  a  longer  period  and  with  less  restraint 
than  in  the  experiments  of  Valentin. 

It  has  long  been  an  inquiry  of  interest,  especially  for  the  apprecia- 
tion of  encroachments  of  pulmonary  disease,  to  determine  the  amount 
of  air  expelled  from  the  chest ;  and  different  instruments  have  been 
devised  for  the  purpose  by  Kentish,  Phcibus,  and  others.''  Pulmo- 
metry  is  consequently  not  new ;  but  it  had  never  been  carefully  inves- 
tigated before  the  interesting  experiments  made  by  Dr.  Hutchinson^ 
with  the  instrument  somewhat  unhappily  termed  by  him  a  spirometer, 
by  which  he  measures  the  quantity  of  air  expired  in  a  full  and  forci- 
ble expiration,  and  which  he  esteems  an  index  of  the  vital  capacity,  as 
it  expresses  the  power  which  a  person  has  of  breathing  in  the  exigen- 

'  Anier.  Journ.  of  the  Med.  Sciences,  April,  1852. 

2  Kulliker,  Mikroskopische  Anatoinie,  and  Amer.  edit,  of  his  JLanual  of  Human  His- 
tology, by  Dr.  Da  Costa,  p.  579,  Philad.,  1854. 

'  Researches,  Clieinical  and  Philosophical,  p.  431,  Lond.,  1800. 

*  Lehrbuch  der  Physiologie  des  Menschen,  i.  542,  Braunschweig,  1844. 

s  Kirkes  and  Paget,  Manual  of  Physiology,  2d  Amer.  edit.,  p.  128,  Philad.,  1853. 

^  Philos.  Magazine,  June,  1839. 

'  Pabius  [et  Buys-Ballot]  De  Spirometro.     Diss,  inang.,  Amsterdam,  1853. 

^  Meilico-Chirurgical  Transactions,  xxix.  p.  237,  Lond.,  184();  and  art.  Thorax,  in 
Cycl.  of  Anat.  and  Physiol.,  iv.  10tJ8,  Loud.,  1852;  also.  Dr.  John  Ileid,  Ibid.,  p.  339. 


294 


RESPIRATION. 


cies  of  active  exercise,  violence,  and  disease.  From  the  results  of  1923 
observations  made  on  males,  he  has  inferred,  that  for  every  inch  of 
height — from  five  feet  to  six — eight  additional  cubic  inches  of  air  at 
60°  Fahr.  are  given  out  by  a  forced  expiration  ;  so  that,  he  believes, 
from  the  height  alone  of  an  adult  male,  he  can  pronounce  what  quan- 
tity of  air  he  should  breathe  when  healthy.  This  is  a  singular  result,  as 
it  is  not  easy  to  see  what  relation  there  can  be  between  the  height  of  a 
person,  which  is  greatly  regulated  by  the  length  of  his  legs  ;  and  the 
quantity  of  air  he  is  capable  of  respiring.  Much  must  obviously  de- 
pend upon  the  degree  of  nervous  power  or  of  muscular  activity,^  but 
the  diftcrence  cannot  be  altogether  accounted  for  in  this  way ;  as  cases 
are  not  uncommon  in  which  men  of  great  muscular  powers  are  below 
the  standard ;  whilst  others,  by  no  means  remarkable  for  such  power, 
greatly  exceed  it.^ 

Di\  Hutchinson  gives  the  following  table  of  the  quantity  of  air, 
expelled  by  the  strongest  expiration  after  the  deepest  inspiration,  for 
every  inch  of  height  between  five  and  six  feet,  as  ascertained  by  actual 
observation  with  the  spirometer,  and  as  calculated  by  the  rule  of  pro- 
"Tession  referred  to  above. 


Height. 

From  Observation. 

Eegular  Progression 

Ft.  in.    Ft.  in.                                            Cub.  in.                                          Cub.  in. 

5     0  to  5     1        .        .        .         .         174        .        .        .        .         174 

5     1  "  5     2 

177 

182 

5     2  "  5     3 

189 

190 

5     3  "  5     4 

193 

198 

5     4  "  5     5 

201 

206 

5     5  "  5     6 

214 

214 

.5     (i  "  5     7 

229 

222 

5     7  "  5     8 

228 

230 

5     8  "  5     9 

237 

238 

5     9  "  5  10 

246 

24(5 

5  10  "  5  11 

247 

254 

5  11  "  6     0 

259 

262 

Dr.  Hutchinson  found,  that  two  other  conditions  influence  the  quan- 
tity of  air  that  passes  to  and  from  the  lungs  in  forced  voluntary  respi- 
ration,— weight,  and  age.  The  former  does  not  affect  the  respiratory 
power  of  an  individual  of  any  height  between  five  feet  one  inch  and 
five  feet  eleven  inches,  until  it  has  increased  seven  per  cent,  above  the 
average  weight  of  the  body  in  persons  of  that  height;  but,  beyond 
this,  it  diminishes  in  the  ratio  of  one  cubic  inch  per  pound  for  the 
next  35  pounds, — the  limit  of  his  calculations.  In  males  of  the  same 
height  the  respiratory  power  is  increased  from  15  to  35  years  of  age ; 
but  from  35  to  65  years  it  decreases  nearly  1|  cubic  inch  for  each 
year;'''  and  the  results  of  the  examinations  are  so  nearly  uniform,  that 
it  has  been  inferred,  disease  may  be  suspected  in  any  man  who  cannot 
blow  out  nearly  as  many  cubic  inches  as  the  average  of  those  of  the 
same  height,  even  when  by  external  measurement  his  chest  appears  to 
be  of  full  size.  The  size  of  the  chest  is,  indeed,  stated  to  afford  no 
good  indication  of  the  capacity  of  expiration.     The  only  exceptions 

'  Prof.  S.  .Jackson,  in  Med,  Examiner,  .Jan.,  1851,  p.  51. 

2  Dr.  C.  Radclytfe  HaU,  in  Transact,  of  Prov.  Med.  and  Surg.  Assoc,  1851. 

3  For  the  quantity  of  air  inspired  and  expired  in  forced  respiration,  see  Hales,  Stati- 
cal Essays,  i.  242,  and  Bostock,  System  of  Pliysiology,  p.  316,  Lond.,  1836. 


I 


MECHANICAL   PHENOMENA — EXPIRATION.  295 

among  tlie  "healtliy  to  the  general  rule  of  the  direct  proportion  between 
the  height  of  the  body  and  the  capacity  of  expiration,  are  in  the  cases 
of  fat  persons,  whose  capacity  is  always  low.  It  was  the  observation 
— made  by  M.  Bourgery' — that  thin  men  have  the  greatest  capacity  of 
respiration,  which  first  led  Dr.  Hutchinson  to  the  experiments,  that 
furnished  the  law  given  above.  He  found,  that  the  full  expiratory 
force  of  a  healthy  man  is  commonly  about  one-third  greater  than  his 
inspiratory  force;  and  he  states,  that  whenever  the  expiratory  are  not 
stronger  than  the  inspiratory  muscles,  some  disease  is  present.  In 
examining  the  results  of  all  his  experiments — 1500  in  number — he 
found  the  power  of  the  inspiratory  muscles  was  greatest  in  men  of  five 
feet  nine  inches  in  height, — their  inspiratory  powers  being  equal,  on 
an  average,  to  a  column  of  2*75;  and  their  expiratory  power  to  one  of 
8*97  inches  of  mercury;  whilst  in  four  of  the  classes,  composed  gene- 
rally of  active,  efficient  and  healthy  individuals,  namely  Firemen, 
Metropolitan  Police,  Thames  Police,  and  Royal  Horse  Guards,  the 
inspiratory  power  of  the  men  of  five  feet  seven  inches  was  the  greatest, 
being  equal  to  3"07  inches  of  mercury;  and  those  of  five  feet  eight 
inches  to  2*96,  or  nearly  three  inches.  The  average  power  of  the  five 
feet  seven  inches  and  five  feet  eight  inches  men  of  all  classes  examined 
was  only  2*65  inches  of  mercury.  He  infers,  from  all  his  experiments, 
that  a  healthy  man  of  the  height  of  five  feet  seven  inches  or  five  feet 
eight  inches  ought  to  elevate  by  inspiration  a  column  of  mercury  of 
three  inches. 

The  experiments  of  Valentin'  and  Mendelssohn,^  as  far  as  they  go, 
confirm  those  of  Dr.  Hutchinson. 

Attempts  have  been  made  to  estimate  the  quantity  of  air  remaining 
in  the  lungs  after  respiration ;  but  the  sources  of  discrepancy  are  here 
as  numerous  as  in  the  cases  of  inspiration  or  expiration.  Groodwyn'* 
estimated  it  at  109  cubic  inches:  Menzies^  at  179;  Jurin^  at  220;  Fon- 
tana^  at  40;  and  Cuvier,  after  a  forced  inspiration,  at  from  100  to  60. 
Davy^  concluded,  that  his  lungs,  after  a  forced  expiration,  still  retained 
41  cubic  inches  of  air;  and  after  a  natural  expiration  118  cubic  inches; 
after  a  natural  inspiration,  135;  and  after  a  forced  inspiration,  254. 
Vierordt^  supposes  that  the  residual  air  after  the  deepest  expiration  is 
about  8(3.600  cubic  inches.  By  a  full  forced  expiration  after  a  forced 
inspiration,  he  expelled  190  cubic  inches;  after  a  natural  inspiration, 
78*5 ;  and  after  a  natural  expiration,  67*5.  Mr.  Julius  Jeflreys^°  divides 
the  air  of  respiration  into  four  quantities — First,  the  residual  air,  or 
that  which  cannot  be  expelled  from  the  lungs,  but  remains  after  a  full 
and  forcible  expiration;  which  he  estimates  at  120  cubic  inches — 
Secondly,   the  supplementary  air, — reserve  air  of  Dr.   Hutchinson — or 

'  Arcliiv.  Generales  de  Medecine,  Mars,  1843. 

^  Lelirbiich  der  Physiologie  des  Menscheii,  i.  524,  Braunschweig,  1844. 
'  Der  Mechanismus  der  Respiration  und  Circulation,  Berlin,  1845  ;  cited  by  Dr.  John 
Reid,  op.  cit.,  p.  336. 

*  Op.  citat.,  p.  36.  ^  Op.  cit.,  p.  31. 

^  Philosoph.  Trans.,  vol.  xxx.  p.  758.  ''  Philosoph.  Trans,  for  1799,  p.  355. 

*  Op.  citat.,  p.  411. 

^  Art.  Respiration,  in  Wagner's  Handworterbuch  der  Physiologie,  \\.  s.  w.  12te  Lie- 
ferung,  Braunschweig,  1845. 
'"  Views  upon  the  Statics  of  the  Human  Chest,  &c.,  London,  1843. 


296  RESPIRATION. 

that  wliicli  can  be  expelled  by  a  forcible  expiration,  after  an  ordinary 
outbreatbing,  valued  at  130  cubic  inches — Thirdly^  the  breath,  or  tidal 
air, — hreathiug  air  of  Dr.  Hutchinson — valued  at  26  cubic  inches;  and 
Fourthhj,  the  complementary  or  complemental  air,  or  that  which  can  be 
inhaled  after  an  ordinary  inspiration,  which  amounts  to  100  cubic 
inches.  This  estimate  gives  250  cubic  inches  as  the  average  volume 
which  the  chest  contains  after  an  ordinary  expiration. 

It  is  impossible,  from  such  variable  data  as  the  above,  to  deduce  any 
thing  like  a  satisfactory  conclusion;  but  if  we  assume  with  Dr.  Bostock, 
and  Dr.  Thomson'  is  disposed  to  adopt  the  estimate,  170  cubic  inches 
as  the  quantity  that  may  be  forcibly  expelled,  and  that  120  cubic  inches 
will  be  left  in  the  lungs,  we  shall  have  290  cubic  inches  as  the  measure 
of  the  lungs  in  their  natural  or  quiescent  state ;  to  this  quantity  40  cubic 
inches  are  added  by  each  ordinary  inspiration,  giving  330  cubic  inches 
as  the  measure  of  the  lungs  in  their  distended  state.  Hence  it  would 
seem,  that  about  one-eighth  of  the  whole  contents  of  the  lungs  is  changed 
by  each  respiration ;  and  that  rather  more  than  two-thirds  can  be  ex- 
pelled by  a  forcible  expiration.  Supposing  that  each  act  of  respiration 
occupies  three  seconds,  or  that  we  respire  twenty  times  in  a  minute,  a 
quantity  of  air,  rather  more  than  2|  times  the  whole  contents  of  the 
lungs,  will  be  ex]:)elled  in  a  minute,  or  about  four  thousand  times  their 
bulk  in  twenty-four  hours.  The  quantity  of  air  respired  during  this 
period  will  be  1,152,000  cubic  inches,  about  'o'o'dh  cubic  feet.  Such  is 
Dr.  Bostock's  estimate. 

It  is  the  residuary  air,  that  gives  to  the  lungs  the  property  of  float- 
ing on  the  surface  of  water,  after  they  have  once  received  the  breath 
of  life;  and  no  pressure  can  force  out  the  air,  so  as  to  make  them  sink. 
Hence,  the  chief  proofs,  whether  a  child  has  been  born  alive  or  dead, 
are  deduced  from  the  lungs.  These  constitute  docimasia  jJulmonum, 
Lungenprobe  or  Athemprobe  ("Lung-proof  or  Eespiration-proof") 
of  the  Germans. 

Expiration,  like  inspiration,  has  been  divided  into  three  grades;  ordi- 
7iary,  free,  and  forced;  but  it  must  necessarily  admit  of  multitudinous 
shades  of  dift'ereuce.  In  ordinary  passive  respiration,  expiration  is 
effected  solely  by  the  relaxation  of  the  diaphragm.  In  free  active 
respiration,  the  muscles  that  raise  the  ribs  are  likewise  relaxed,  and 
there  is  a  slight  action  of  the  direct  expiratory  muscles.  In  forced 
expiration,  all  the  respiratory  muscles  are  thrown  into  action.  In  this 
manner,  the  air  makes  its  way  along  the  air-passages  through  the 
mouth  or  nostrils,  or  both ;  carr3dug  with  it  a  fresh  portion  of  the 
halitus  from  the  mucous  membrane.  This  it  deposits  when  the  atmo- 
sphere is  colder  than  the  temperature  acquired  by  the  respired  air,  and 
if  the  atmosphere  be  sufficiently  cold,  as  in  winter,  the  vapour  becomes 
condensed  as  it  passes  out,  and  renders  expiration  visible. 

Dr.  Hutchinson'-^  measured  the  costal  movement  during  ordinary 
respiration  in  healthy  males,  and  found  it  not  to  exceed  from  two  to 
four-tenths  of  a  line.     He  states,  that  the  difference  between  the  cir- 

'  System  of  Chemistry,  vol.  iv. 

2  iieclico-Chiiurgical  Transactions,  xxix.  187,  Loud.,  1846;  and  art.  Thorax,  in  Cy- 
clop, of  Anat.  and  Physiol.,  iv.  1080,  Loud.,  1852. 


MECHANICAL   PHENOMENA — EXPIEATION.  297 

cumference  of  an  ordinary  man's  cbest  measni'ecl  over  the  nipples  in 
the  two  states  of  a  deep  inspiration  and  a  deep  expiration  amounts  to 
three  inches;  and  Valentin/  under  the  same  circumstances,  found  the 
average  difference  in  the  circumference  of  the  chest,  measured  over  the 
scrobiculus  cordis,  in  seven  individuals  of  the  male  sex  between  IT^- 
and  80  years  of  age,  to  be  as  1  :  8'29  of  the  whole  circumference. 

In  the  majority  of  cases,  perhaps,  the  times  occupied  by  the  murmurs 
of  inspiration  and  of  expiration  will  be  nearly  in  the  ratio  of  three  to 
one.  Thus,  if  a  healthy  person  breathes  fifteen  times  in  a  minute,  or 
once  in  four  seconds,  the  time  occupied  by  the  periods  of  inspiration, 
expiration,  and  repose  will  be  nearly  one  and  a  half,  a  half,  and  two 
seconds,  respectively.  Differences  will  exist  in  healthy  individuals; 
but  the  above  may  perhaps  be  esteemed  the  expression  of  the  general 
truth.  It  is  important  to  bear  these  facts  in  mind,  inasmuch  as,  in  dis- 
ease, the  expiratory  murmur  is  apt  to  become  prolonged,  first  of  all  at 
the  expense  of  the  period  of  repose,  and  afterwards  of  that  of  inspira- 
tion;^— a  circumstance  to  which  attention  was  first  forcibly  directed  by 
Dr.  James  Jackson,  Jun.,  of  Boston.  Budge^  does  not  admit,  that  the 
length  of  inspiration  is  as  great  when  compared  with  that  of  expira- 
tion as  is  given  above;  and  he  considers  the  pause  or  period  of  repose 
to  be  more  apparent  than  real. 

The  number  of  respirations  in  a  given  time  differs  considerably  in 
different  individuals.  Dr.  Hales,''  Dr.  Dalton,^  Mr.  Coathupe,®  and  Dr. 
Bostock^  reckon  them  at  twenty.  Laennec  from  twelve  to  fifteen.  A 
man,  on  whom  Menzies  made  experiments,  breathed  only  fourteen  times 
in  a  minute.  Sir  Humphry  Davy^  made  between  twenty-six  and  twenty- 
seven  in  a  minute.  Dr.  Thomson,^  and  Allen  and  Pepys,  about  nine- 
teen; and  Magendie,^°  fifteen.  In  171-i  adults  of  the  male  sex  considered 
to  be  in  a  state  of  health.  Dr.  Hutchinson''  found,  that  the  majority,  in 
the  sitting  posture,  breathed  betAveen  16  and  24  in  the  minute;  and  of 
these  a  great  number  20  per  minute.  Yierordt'^  found  the  number  in 
his  own  person  to  be,  on  an  average,  ll-j'^gths  when  sitting  and  the  mind 
disengaged ;  whilst  the  maximum  was  15,  and  the  minimum  9.  Our 
own  average  is  about  sixteen;  and  this  is  the  average,  in  the  adult, 
assumed  by  Giinther'^  and  Berthold.'"'  That,  deduced  from  the  few  ob- 
servers, who  have  recorded  their  observations, — twenty  per  minute, — 

'  Lfthrbucli  der  Pliysiologie  des  Menschen,  i.  541,  Braunschweig,  1844. 

*  Lectures  on  the  Physical  Diagnosis  of  the  Diseases  of  the  Lungs  and  Heart,  by 
Herbert  Davies,  M.D.,  p.  69,  London,  1851. 

'  Memoranda  der  speciellen  Physiologic  des  Menschen,  5te  Auflasre,  S.  60,  Weimar, 
1853. 

"  Statical  Essays,  3d  edit.,  i.  243. 

^  Memoirs  of  the  Literary  and  Philosophical  Society  of  Manchester,  2d  series,  ii.  26, 
Manchester,  1813. 

**  Lond.  and  Edinb.  Philos.  Magaz.,  xiv.  401,  1839. 

'  System  of  Physiology,  p.  321,  Lond.,  1836. 

^  Researches  chiefly  concerning  Nitrous  Oxide,  p.  434,  Lond.,  1800. 

®  System  of  Chemistry,  iv.  604.  Glasgow,  1820. 

'"  Precis  de  Physiologie,  2de  edit.,  Paris,  1825.  "  Op.  cit.,  p.  226. 

'^  Wagner's  Handworterbuch  der  Physiologie,  art.  Respiration,  ii.  834,  Braunschweig, 
1845. 

'^  Lehrbuch  der  Physiologie  des  Menschen,  2ter  Band,  Iste  Abtheil.,  S.  217,  Leipzig, 
1848. 

»  Lehrbuch  der  Physiologie,  3te  Aullago,  2tcr  Theil,  S.  227,  Gutting.,  1848. 


298  KESPIRATIO^S". 

has  geDerally  been  taken;  but  we  are  satisfied  it  is  above  the  truth ; 
eighteen  would  be  nearer  the  general  average,  and  it  has  accordingly 
been  admitted  by  many.  Eighteen  in  a  minute  give  twenty-five  thou- 
sand nine  hundred  and  twenty  in  the  twenty-four  hours.  The  number 
is  influenced,  however,  by  various  circumstances.  The  child  and  the 
female,  and  perhaps  also  the  aged,  breathe  more  rapidly  than  the  adult 
male.  A£M.  Hourmann  and  Dechambre'  examined  two  hundred  and 
fifty-five  women  between  the  ages  of  sixty  and  ninety-six,  the  average 
number  of  whose  respirations  was  21'79  per  minute.  According  to  ISi. 
Quetelet,^  a  child  breathes  in  the  minute,  on  the  average, — 


44  times. 

26      » 

20      " 

lS-7  " 

16-0  " 

18.1  " 

At  birth 

At  5  years      ....... 

From  15  to  20  years       ..... 

"      20  to  25     " 

"     25  to  30     " 

"      30  to  50     " 

AYe  find  as  much  variety  in  the  respiration  of  men  as  we  do  in  tliat 
of  horses:  whilst  some  are  short,  others  are  long-winded;  and  this  last 
condition  may  be  improved  by  appropriate  training,  to  which  the  pe- 
destrian and  the  prize-fighter,  equally  with  the  horse,  are  subjected  for 
some  time  before  they  are  called  upon  to  test  their  powers.  In  sleep, 
the  respiration  is  generally  deeper,  less  frequent,  and  appears  to  be  per- 
formed greatly  by  the  intercostals  and  diaphragm.^  Motion  has  also  a 
sensible  efiect  in  hurrj'ing  the  respiration,  as  well  as  distension  of  the 
stomach  by  food,  certain  mental  emotions,  &c. :  it  is  less  in  the  hori- 
zontal than  in  the  sitting  posture;  and  less  in  the  sitting  than  in  the 
erect.  Its  condition  during  disease  becomes  a  subject  of  interesting 
study  to  the  physician,  and  one  that  has  been  much  facilitated  by  the 
acoustic  method  introduced  by  Laennec.  To  his  instrument — the  stetho- 
scope— allusion  has  already  been  made.  By  it,  or  by  the  ear  applied  to 
the  chest,  we  are  able  to  hear  distinctly  the  respiratory  murmur  and  its 
modifications;  and  thus  to  judge  of  the  nature  of  pulmonary  affections. 
But  this  is  a  topic  that  appertains  more  especially  to  pathology. 

(3.)    EESPIKATOKY  PHEXOMENA  COXCERXED  IX  CEKTAIX  FUXCTIOXS. 

There  are  certain  respiratory  movements,  concerned  in  effecting  other 
functions,  that  require  consideration.  Some  of  these  have  already  been 
discussed.  M.  Adelon"  has  classed  them  into:  First.  Those  employed 
in  the  sense  of  smell,  either  for  the  purpose  of  conveying  the  odorous 
molecules  into  the  nasal  fossse  ;  or  to  repel  them  and  prevent  their  in- 
gress. Secondly.  The  inspiratory  actions  employed  in  the  digestive  func- 
tion, as  in  snclcijig.  Thirdhj.  Those  connected  with  muscular  motion 
when  forcibly  exerted  ;  and  particularly  with  straining  or  the  employ- 
ment of  violent  effort.  Fourthly.  Those  concerned  in  the  various  ex- 
cretions, either  voluntary, — as  in  defecation  and  spitting ;  or  involuntary, 
— as  in  coughing,  sneezing,  vomiting,  accouchement,  &c. ;  and  lastly,  those 
that  constitute  phenomena  of  expression, — as  sighing,  yawning,  laughing, 

■  Arcliiv.  Gener.  de  Metiecine,  Nor.  1835. 

2  A  Treatise  on  Man,  Chambers's  Edinb.  translation,  p.  71,  Edinb.,  1842;  and  Vier- 
ordt,  art.  Respiration,  iu  Wagner's  HandwiJrterbuch  der  Physiologie,  ii.  834,  Braun- 
schweig, 1844. 

*  Adelou,  Physiologie  de  rHomme,  iii.  185.  ■•  Op.  cit.,  p.  188. 


MECHANICAL   PHENOMENA — SNEEZING.  299 

crying^  soiling,  kc.  Some  of  these,  that  have  already  engaged  attention, 
do  not  demand  comment;  others  are  topics  of  considerable  interest,  and 
require  investigation. 

1.  Straining. — The  state  of  respiration  is  much  affected  during  the 
more  active  voluntary  movements.  Muscular  exertion  of  whatever 
kind,  when  considerable,  is  preceded  by  a  long  and  deep  inspiration ; 
the  glottis  is  closed;  the  diaphragm  and  respiratory  muscles  of  the  chest 
are  contracted,  as  well  as  the  abdominal  muscles  which  press  upon  the 
contents  of  the  abdomen  in  all  directions.  AVhilst  the  proper  respira- 
tory muscles  are  exerted,  tliose  of  the  face  participate,  owing  to  their 
association  through  the  medium  of  particular  nerves.  By  this  series  of 
actions,  the  chest  is  rendered  capacious;  and  the  force  that  can  be  de- 
veloped is  augmented,  in  consequence  of  the  trunk  being  rendered 
immovable  as  regards  its  individual  parts, — thus  serving  as  a  fixed  point 
for  the  muscles  that  arise  from  it,  so  that  they  are  enabled  to  employ 
their  full  effort.^  The  physiological  state  of  muscular  action,  as  con- 
nected with  the  mechanical  function  of  respiration,  is  happily  described 
by  Shakspeare,  when  he  makes  the  fifth  Harry  encourage  his  soldiers 
at  the  siege  of  Harfleur, 

"  Stiflfen  the  sinews,  summon  up  the  blood ; 
Now  set  the  teeth,  and  stretch  the  nostrils  wide ; 
Hold  hard  the  breath  and  bend  up  every  spirit 
To  its  full  height."  King  Henry  V.  iii.  1. 

In  the  effort  required  for  effecting  the  various  excretions,  a  similar 
action  of  the  respiratory  muscles  takes  place.  The  organs,  from  wliich 
these  excretions  have  to  be  removed,  are  either  in  the  thorax  or  abdo- 
men ;  and  in  all  cases  have  to  be  compressed  by  the  parietes  of  those 
cavities.  A  full  inspiration  is  first  made ;  the  expiratory  muscles,  with 
those  that  close  the  glottis,  are  then  forcibly  and  simultaneously  con- 
tracted, and  by  this  means  the  thoracic  and  abdominal  viscera  are 
compressed.  Some  difference,  however,  exists,  according  as  the  viscus 
to  be  emptied  is  seated  in  the  al^domen  or  thorax.  In  the  evacuation 
of  the  faeces,  the  lungs  are  first  filled  with  air ;  and  whilst  the  muscles 
of  the  larynx  contract  to  close  the  glottis,  those  of  the  abdomen  con- 
tract also;  and  as  the  lung,  in  consequence  of  the  included  air,  resists 
the  ascent  of  the  diaphragm,  the  compression  bears  upon  the  large  in- 
testine. The  same  happens  in  the  excretion  of  the  urine,  and  in  ac- 
couchement. 

2.  Coughing  and  Sneezing. — AVhen  the  organs  that  have  to  be  cleared 
are  the  air-passages, — as  in  coughing  to  remove  mucus  from  them, — 
the  same  action  of  the  muscles  of  the  abdomen  is  invoked;  but  the 
glottis  is  open  to  allow  the  exit  of  the  mucus.  In  this  case,  the  expi- 
ratory muscles  contract  convulsively  and  forcibly,  so  that  the  air  is 
driven  violently  from  the  lungs ;  and,  in  its  passage,  sweeps  off'  the 
irritating  matter,  and  conveys  it  out  of  the  body.  To  aid  this,  the 
muscular  fibres,  at  the  posterior  part  of  the  trachea  and  larger  bron- 
chial tubes,  contract,  so  as  to  diminish  the  calibre  of  these  canals ;  and 
in  this  way  expectoration  is  facilitated.  The  action  differs,  however, 
according  as  the  expired  air  is  sent  through  the  nose  or  mouth;  in  the 

'  Op.  cit.,  p.  190;  and  art.  Effort,  in  Diet,  de  Med.,  2de  edit.,  xi.  197,  Paris,  1835. 


300  RESPIRATION. 

former  case,  constituting  sneezing;  in  the  latter,  coughing.  The  former 
is  more  violent  than  the  latter,  and  is  involuntary;  whilst  the  latter  is 
not  necessarily  so.  In  both  cases  the  movement  is  excited  by  some 
external  irritant,  applied  directly  to  the  mucous  membrane  of  the  wind- 
pipe or  nose;  or  by  some  modified  action  in  the  very  tissue  of  the  part, 
which  acts  as  an  irritating  cause.  In  both  cases  the  air  is  driven  forci- 
bly forwards ;  and  both  are  accompanied  by  sounds  that  cannot  be 
mistaken.  In  these  actions,  we  have  striking  exemplifications  of  the 
extensive  association  of  muscles,  through  the  medium  of  nerves,  to 
which  we  have  so  often  alluded.  The  pathologist,  too,  has  repeated 
opportunities  for  observing  the  extensive  sympathy  between  distant 
parts  of  the  frame,  as  indicated  by  the  actions  of  sneezing  and  cough- 
ing, especially  of  the  former.  If  a  person  be  exposed  for  a  short  period 
to  the  partial  and  irregular  application  of  cold,  so  that  the  organic  ac- 
tions of  a  part  of  the  body  are  modified,  as  where  we  get  the  feet  wet, 
or  sit  in  a  draught  of  air,  a  few  minutes  is  frequently  sufficient  to  ex- 
hibit sympathetic  irritation  in  the  Schneiderian  membrane  of  the  nose, 
and  sneezing.  Nor  is  it  necessary,  that  the  organic  actions  of  a  distant 
part  shall  be  modified  by  the  application  of  cold.  We  have  had  the 
most  positive  evidence,  that  if  they  be  irregularly  accomplished,  even 
by  the  application  of  heat,  whilst  the  rest  of  the  body  is  receiving  none, 
inflammation  of  the  mucous  membrane  of  the  nasal  fossas  and  fauces 
may  supervene  with  no  less  certain tj^. 

3.  Blowing  the  Xose. — The  substance  that  has  to  be  excreted  by  this 
operation  is  composed  of  the  nasal  mucus,  the  tears  sent  down  the 
ductus  ad  nasum,  and  the  particles  deposited  on  the  membrane  by  the 
air  in  its  passage  through  the  nasal  fossas.  Commoidy,  these  secretions 
are  only  present  in  quantity  sufficient  to  keep  the  membrane  moist,  the 
remainder  being  evaporated  or  absorbed.  Frequentl}^,  however,  they 
exist  in  such  quantity  as  to  fall  by  their  own  gravity  into  the  pharynx, 
where  they  are  sent  down  into  the  stomach  by  deglutition,  are  thrown 
out  at  the  mouth,  or  make  their  exit  at  the  anterior  nares.  To  prevent 
this  last  effect  more  especially,  we  have  recourse  to  blowing  the  nose. 
This  is  accomplished  by  taking  in  air,  and  driving  it  out  suddenly  and 
forcibly,  closing  the  mouth  at  the  same  time,  so  that  the  air  may  issue 
by  the  nasal  fossee  and  clear  them;  the  nose  being  compressed  so  as  to 
make  the  velocity  of  the  air  greater,  as  well  as  to  express  all  the  mucus 
that  may  be  forced  forwards. 

•i.  Si'itting  differs  somewhat  according  to  the  part  in  which  the 
mucus  or  matter  to  be  ejected  is  seated.  At  times,  it  is  exclusively  in 
the  mouth ;  at  others,  in  the  back  part  of  the  nose,  pharjmx,  or  larjmx. 
When  the  mucus  or  saliva  of  the  mouth  has  to  be  excreted,  the  muscu- 
lar parietes  of  the  cavity,  as  well  as  the  tongue,  contract  so  as  to  eject 
it  from  the  mouth ;  the  lips  being  at  times  approximated,  so  as  to  ren- 
der the  passage  narrow,  and  impel  the  sputa  more  strongly  forward.  The 
air  of  expiration  may  be,  at  the  same  time,  driven  forcibly  through  the 
mouth,  so  as  to  send  the  matter  to  a  considerable  distance.  The  prac- 
tised spitter  sometimes  astonishes  us  with  the  accuracy  and  power  of 
propulsion  of  which  he  is  capable.  When  the  matter  to  be  evacuated 
is  in  the  nose,  pharynx,  or  larynx,  it  requires  to  be  brought,  first  of  all, 
into  the  mouth.    If  in  the  posterior  nares,  the  mouth  is  closed,  and  the 


MECHANICAL   PHENOMENA — YAWNING.  801 

air  is  drawn  in  forcibly  throngli  the  nose,  the  pharynx  being  at  the 
same  time  constricted  so  as  to  prevent  the  substances  from  passing 
down  into  the  oesophagus.  The  pharynx  now  contracts  from  below  to 
above,  in  an  inverse  direction  to  that  required  in  deglutition ;  and 
the  farther  excretion  from  the  mouth  is  effected  in  the  manner  just 
described. 

Where  the  matters  are  situate  in  the  air-passages,  the  action  may 
consist  in  coughing  ;  or,  if  higher  up,  simply  in  hawking.  A  forcible 
expiration,  unaccompanied  by  cough,  is,  indeed,  in  many  cases,  suffi- 
cient to  detach  the  superfluous  mucous  secretion  from  even  the 
bronchial  tubes.  In  hawking,  the  expired  air  is  sent  forcibly  forwards, 
and  the  parts  about  the  fauces  are  suddenly  contracted  so  as  to  diminish 
the  capacity  of  the  tube,  and  propel  the  matter  onwards.  The  noise 
is  produced  by  their  discordant  vibrations.  Both  these  modes  bear 
the  general  name  of  expectoration. 

AVhen  these  secretions  are  swallowed,  they  are  subjected  to  the 
digestive  process  ;  a  part  is  taken  up,  and  the  remainder  rejected  ;  so 
that  they  belong  to  the  division  of  recremento-eaxrementitial  fluids  of 
some  physiologists. 

(4.)    RESPIKATORY  PHENOMENA  CONNECTED  WITH  EXPKESSION. 

It  remains  to  speak  of  the  expiratory  phenomena  that  strictly  form 
part  of  the  function  of  expression,  and  depict  the  moral  feeling  of  the 
individual  who  gives  them  utterance. 

1.  Sighing  consists  of  a  deep  inspiration,  by  which  a  large  quantity 
of  air  is  received  slowly  and  gradually  into  the  lungs,  to  compensate 
for  the  deficiency  in  the  due  aeration  of  the  blood  which  precedes  it. 
The  most  common  cause  of  sighing  is  mental  uneasiness:  it  also  occurs 
during  languor,  at  the  approach  of  sleep,  or  immediately  after  waking. 
In  all  these  cases,  the  respiratory  efforts  are  executed  more  imperfectly 
than  under  ordinary  circumstances;  the  blood,  consequently,  does  not 
circulate  through  the  lungs  in  due  quantity,  but  accumulates  more  or 
less  in  these  organs,  and  in  the  right  side  of  the  heart ;  and  it  is  to 
restore  the  due  balance,  that  a  deep  inspiration  is  now  and  then 
established. 

2.  Yaicning^  oscitancy^  oscitation  or  gaping^  is  a  full,  deep,  and 
protracted  inspiration,  accompanied  by  a  wide  separation  of  the  jaws, 
and  followed  by  a  prolonged  and  sometimes  sonorous  expiration.  It  is 
excited  by  many  of  the  same  causes  as  sighing.  It  is  not,  however, 
the  expression  of  a  depressing  passion,  but  is  occasioned  by  any  cir- 
cumstance that  impedes  the  necessary  aeration  of  the  blood ;  whether 
it  be  retardation  of  the  action  of  the  respiratory  muscles,  or  the  air 
being  less  rich  in  oxygen.  Hence  we  yawn  at  the  approach  of  sleep, 
and  immediately  after  waking.  The  inspiratory  muscles,  fatigued  from 
any  cause,  experience  some  difficulty  in  dilating  the  chest;  the  lungs 
are,  consequently,  not  properl}^  traversed  by  the  blood  from  the  right 
side  of  the  heart ;  oxygenation  is,  therefore,  not  dul}'-  effected,  and  an 
uneasy  sensation  is  induced ;  this  is  put  an  end  to  by  the  action  of 
yawning,  which  allows  the  admission  of  a  considerable  quantity  of  air. 
We  yawn  at  the  approach  of  sleep,  because  the  agents  of  respiration, 
becoming  gradually  more  debilitated,  require  to  be  now  and  then  ex- 


302  EESPIRATION. 

cited  to  fresli  activity,  and  the  blood  needs  the  requisite  aeration. 
Yawning  on  waking  seems  to  be  partly  for  the  purpose  of  arousing  the 
respiratory  muscles  to  greater  activity,  the  respiration  being  always 
slower  and  deeper  during  sleep.  It  is,  of  course,  impossible  to  explain 
why  the  respiratory  nerves  should  be  chiefly  concerned  in  these  respi- 
ratory movements  of  an  expressive  character.  The  fact,  however,  is 
certain  ;  and  it  is  remarkably  proved  by  the  circumstance,  that  yawn- 
ing can  be  excited  by  even  looking  at  another  affected  in  this  manner; 
nay,  by  simply  looking  at  a  sketch,  and  even  thinking  of  the  action. 
The  same  also  applies  to  sighing  and  laughing,  and  especially  to  the 
latter. 

3.  Pandiculation  or  stretching  is  a  frequent  concomitant  of  yawning, 
and  appears  to  be  established  instinctively  to  arouse  the  extensor  mus- 
cles to  a  balance  of  power,  when  the  action  of  the  flexors  has  been 
predominant.  In  sleep,  the  flexor  muscles  exercise  that  preponderance 
which,  in  the  waking  state,  is  exerted  by  the  extensors.  This,  in  time, 
is  productive  of  some  uneasiness ;  and  hence,  occasionally  during 
sleep,  but  still  more  at  the  moment  of  waking,  the  extensor  muscles 
are  roused  to  action  to  restore  the  equipoise  :  or,  perhaps,  as  the  mus- 
cles of  the  upper  extremities,  and  those  engaged  directly  or  indirectly 
in  respiration,  are  chiefly  concerned  in  the  action,  it  is  exerted  for  the 
purpose  of  exciting  the  respiratory  muscles  to  increased  activity. 

ByDr.  Good,^  yawning  and  stretching  have  been  regarded  as  morbid 
affections  and  amongst  the  signs  of  debility  and  lassitude : — "  Every 
one,"  he  remarks,  "  who  resigns  himself  ingloriously  to  a  life  of  lassi- 
tude and  indolence,  will  be  sure  to  catch  these  motions  as  a  part  of 
that  general  idleness  which  he  covets  ;  and,  in  this  manner,  a  natural 
and  useful  action  is  converted  into  a  morbid  habit ;  and  there  are 
loungers  to  be  found  in  the  world,  who,  though  in  the  prime  of  life, 
spend  their  days  as  well  as  their  nights  in  a  perpetual  routine  of  these 
convulsive  movements,  over  which  they  have  no  power  ;  who  cannot 
rise  from  the  sofa  without  stretching  their  limbs,  nor  open  their  mouths 
to  answer  a  plain  question  without  gaping  in  one's  face.  The  disease 
is  here  idiopathic  and  chronic  ;  it  may  perhaps  be  cured  by  a  perma- 
nent exertion  of  the  will,  and  ridicule  or  hard  labour  will  generally 
be  found  the  best  remedies  for  calling  the  will  into  action." 

4.  Laughing  is  a  convulsive  action  of  the  muscles  of  respiration  and 
voice,  accompanied  by  a  facial  expression,  which  has  been  explained 
elsewhere.  It  consists  of  a  succession  of  short,  sonorous  expirations. 
Air  is  first  inspired  so  as  to  fill  the  lungs.  To  this  succeed  short, 
interrupted  expirations,  with  simultaneous  contractions  of  the  muscles 
of  the  glottis,  so  that  the  aperture  is  slightly  contracted,  and  the  lips 
assume  the  tension  necessary  for  the  production  of  sound.  The  inter- 
rupted character  of  the  expirations  is  caused  by  convulsive  contrac- 
tions of  the  diaphragm,  which  constitute  the  greater  part  of  the  action. 
In  very  violent  laughter,  the  respiratory  muscles  are  thrown  into  such 
forcible  contractions,  that  the  hands  are  applied  to  the  sides  to  support 
them.  The  convulsive  action  of  the  thorax  likewise  interferes  with 
the  circulation  through  the  lungs;  the  blood,  consequently,  stagnates 

'  Study  of  Medicine,  class  4,  ord.  3,  gen.  2,  sp.  6. 


WEEPING — SOBBING.  803 

in  the  upper  part  of  the  body ;  the  face  becomes  flushed ;  the  sweat 
trickles  down  the  forehead,  and  the  eyes  are  sufiused  with  tears ;  but 
this  is  apparently  owing  in  part  to  mechanical  causes ;  not  to  the 
lachrymal  gland  being  excited  to  unusual  action,  as  in  weeping.  At 
times,  however,  we  find  the  latter  cause  in  operation,  also. 

5.  Wee2yi7ig.  The  action  of  weeping  is  very  similar  to  that  of  laugh- 
ing; although  the  causes  are  so  dissimilar.  It  consists  in  an  inspira- 
tion, followed  by  a  succession  of  short,  sonorous  expirations.  The 
facial  expression,  so  diametrically  opposite  to  that  of  laughter,  has 
been  depicted  in  another  place. 

Laughter  and  weeping  appear  to  be  characteristic  of  humanity. 
Animals  shed  tears,  but  the  act  does  not  seem  to  be  accompanied  by 
the  mental  emotion  that  characterizes  crying  in  the  sense  in  which  we 
employ  the  term.  It  has,  indeed,  been  affirmed  by  Steller,^  that  the 
])hoca  ursina  or  ursine  seal;  by  Pallas,^  that  the  camel;  and  by  Yon 
Humboldt,^  that  a  small  American  monkey,  shed  tears  when  labour- 
ing under  distressing  emotions.  The  last  scientific  traveller  states, 
that  "the  countenance  of  the  titi  of  the  Orinoco, — simia  sciurea  of 
Linnasus, — is  that  of  a  child  ;  the  same  expression  of  innocence ;  the 
same  smile;  the  same  rapidity  in  the  transition  from  joy  to  sorrow. 
The  Indians  affirm,  that  it  weeps  like  man,  when  it  experiences  cha- 
grin; and  the  remark  is  accurate.  The  large  eyes  of  the  ape  are  suf- 
fused with  tears,  when  it  experiences  fear  or  any  acute  suffering." 
Shakspeare's  description  of  the  weeping  of  the  stag, — 

"  Tkat  from  the  hunter's  aim  had  ta'en  a  hurt," 

is  doubtless  familiar  to  most  of  our  readers. 

"  The  wretched  animal  heaved  forth  such  groans, 
That  their  discliarge  did  stretch  his  leathern  coat 
Almost  to  bursting  ;  and  the  big,  round  tears 
Coursed  one  another  down  his  innocent  nose* 
In  piteous  chase  ;  and  thus  the  hairy  fool, 
Much  marked  of  the  melancholy  Jaques, 
Stood  on  th'  extremest  verge  of  the  swift  brook, 
Augmenting  it  witli  tears." 

As  You  Like  It,  11. 1. 

We  have  less  evidence  in  favour  of  the  laughter  of  animals.  Le  Cat,^ 
indeed,  asserts,  that  he  saw  the  chimpanzee  both  laugh  and  weep.  The 
orang,  carried  to  Great  Britain  from  Batavia  by  Dr.  Clarke  Abel, 
never  laughed ;  but  he  was  seen  occasionally  to  weep.^ 

6.  /Sobbing  still  more  resembles  laughing,  except  that,  like  weeping, 
it  is  usually  indicative  of  the  depressing  passions ;  and  generally  ac- 

'  Nov.  Comm.  Academ.  Scient.  Petropol.,  ii.  353. 

*  Sammlungen  Historisch.  Nachricht.  iiber  die  Mongolischen  Volkerschaften,  Th. 
i.  177. 

^  Recueil  d'Observations  de  Zoologie,  &c.,  i.  333. 

*  "  The  alleged  '  big  round  tears,'  which  '  course  one  another  down  the  innocent 
nose'  of  the  deer,  the  hare,  and  other  animals,  when  hotly  pursued,  are  in  fact  only 
sebaceous  matter,  which,  under  these  circumstances,  flows  in  profusion  from  a  collec- 
tion of  follicles  in  the  hollow  of  the  cheek." — Fletcher's  Rudiments  of  Physiology,  part 
ii.  b.  p.  50,  Edinb.,  183G. 

^  Traite  de  I'Existence  du  Fluide  des  Nerfs,  p.  35. 

^  Lawrence,  Lectures  on  Physiology,  Zoology,  and  the  Natural  History  of  Man,  p. 
236,  Lond,,  1814. 


304  KESPIEATIOlSr. 

companies  weeping.  It  consists  of  a  convnlsive  action  of  the  dia- 
phragm; wliich  is  alternately  raised  and  depressed,  but  to  a  greater 
extent  than  in  laughing,  and  with  less  rapidity.  It  is  susceptible  of 
various  degrees,  and  has  the  same  physical  effects  upon  the  circulation 
as  weeping.  Dr.  Wardrop^  considers  laughter,  crying,  weeping,  sob- 
bing, sighing,  &c.,  as  efforts  made  with  a  view  to  effect  certain  altera- 
tions in  the  quantity  of  blood  in  the  lungs  and  heart,  when  the  circu- 
lation has  been  disturbed  by  mental  emotions. 

7.  Panting  or  anhelation  consists  in  a  succession  of  alternate,  quick, 
and  short  inspirations  and  expirations.  Its  physiology,  however,  does 
not  differ  from  that  of  ordinary  respiration.  The  object  is,  to  produce 
a  frequent  renewal  of  air  in  the  lungs,  in  cases  where  the  circulation 
is  unusually  rapid ;  or  where,  owing  to  disease  of  the  thoracic  viscera, 
a  more  than  ordinary  supply  of  fresh  air  is  demanded.  We  can, 
hence,  undei'stand  why  dyspnoea  should  be  one  of  the  concomitants  of 
most  of  the  severe  diseases  of  the  chest;  and  why  it  should  occur 
whenever  the  air  we  breathe  does  not  contain  a  sufficient  quantity  of 
oxygen.  The  panting,  produced  by  running,  is  owing  to  the  necessity 
for  keeping  the  chest  as  immovable  as  possible,  that  the  whole  effort 
may  be  exerted  on  the  muscles  of  locomotion ;  and  thus  suspending, 
for  a  time,  the  respiration,  or  admitting  onl}^  of  its  imperfect  accom- 
plishment. This  induces  an  accumulation  of  blood  in  the  lungs  and 
right  side  of  the  heart ;  and  panting  is  the  consequence  of  the  aug- 
mented action  necessary  for  transmitting  it  through  the  vessels. 

b.   Chemical  Phenomena  of  Pespiration. 

Having  studied  the  mode  in  which  air  is  received  into,  and  expelled 
from,  the  lungs,  we  have  now  to  inquire  into  the  changes  produced  on 
the  venous  blood — containing  the  products  of  the  various  absorptions 
■ — in  the  lungs;  as  well  as  on  the  air  itself.  These  changes  are  effected 
by  the  function  o^  sanguification,  hcematosis,  respiration  in  the  restricted 
sense  in  which  it  is  employed  by  some,  arterialization,  decarbonization, 
aeration,  atmospherization,  &c.,  of  the  blood.  With  the  ancients  this 
process  was  but  little  understood.  It  was  generally  believed  to  be  the 
means  of  cooling  the  body;  and,  in  modern  times,  Ilelvetius  revived 
the  notion,  attributing  to  it  the  office  of  refrigerating  the  blood, — 
heated  by  its  passage  through  the  long  and  narrow  channels  of  the 
circulation, — by  the  cool  air  constantly  received  into  the  lungs.  The 
reasons,  which  led  to  this  opinion,  were: — that  the  air,  which  enters 
the  lungs  in  a  cool  state,  issues  warm;  and  that  the  pulmonary  veins, 
which  convey  the  blood  from  the  lungs,  are  of  less  dimension  than  the 
pulmonary  arterj^,  which  conveys  it  to  them.  Froih  this  it  was  con- 
cluded, that  the  blood,  during  its  progress  through  the  lungs,  must 
lose  somewhat  of  its  volume,  or  be  condensed  by  refrigeration.  The 
warmth  of  the  expired  air  can,  however,  be  readily  accounted  for; 
and  it  is  not  true  that  the  pulmonar}'-  veins  are  smaller  than  the  pul- 
monary artery.  The  reverse  is  the  fact ;  and  it  is  obvious,  that  the 
doctrine  of  Ilelvetius  does  not  explain  how  we  can  exist  in  a  tempera- 

'  On  the  Nature  and  Treatment  of  Diseases  of  the  Heart,  part  i.  p.  62,  Lond.,  1837. 


H^MATOSIS.  805 

lure  superior  to  our  own;  wliicli,  in  his  liypothesis,  ought  to  be  im- 
practicable.' 

Another  theory,  which  prevailed  for  some  time,  was; — that  during 
inspiration  the  vessels  of  the  lungs  are  deployed  or  unfolded,  as  it 
were,  and  that  thus  the  passage  of  the  blood  from  the  right  side  of  the 
heart  to  the  left,  through  the  lungs,  is  facilitated.  Its  progress  was, 
indeed,  conceived  to  be  impossible  during  expiration,  in  consequence 
of  the  considerable  flexures  of  the  pulmonary  vessels.  The  discovery 
of  the  circulation  of  the  blood  gave  rise  to  this  theory;  and  Haller^ 
attaches  importance  to  it,  when  taken  in  connexion  with  the  chauges 
effected  upon  the  blood  in  the  vessels.  It  is  incorrect,  however,  to 
suppose,  that  the  circulation  of  the  blood  througli  the  lungs  is  mecha- 
nically interrupted,  when  respiration  is  arrested.  The  experiments  of 
Drs.  Williams^  and  Kay**  would  seem  to  show,  that  the  interruption  is 
mainly  ascribable  to  the  non-conversion  of  venous  into  arterial  blood, 
and  to  the  non-adaptation  of  the  radicles  of  the  pulmonary  veins  for 
any  thing  but  arterial  blood,  owing  to  which  causes  stagnation  of  blood 
supervenes  in  the  pulmonary  radicles.  Numerous  other  objections 
might  be  made  to  this  view.  In  the  first  place,  it  supposes,  that  the 
lungs  are  emptied  at  each  expiration;  and,  again,  if  a  simple  deploying 
or  unfolding  of  the  vessels  were  all  that  is  required,  any  gas  ought  to 
be  sufficient  for  respiration, — which  is  not  the  fact. 

In  these  different  theories,  the  principal  object  of  respiration  is  over- 
looked-— the  conversion  of  the  venous  blood,  conveyed  to  the  lungs  by 
the  pulmonary  artery,  into  arterial  blood.  This  is  effected  by  the 
contact  of  the  inspired  air  with  the  venous  blood  ;  in  which  they  both 
lose  certain  elements,  and  gain  others.  Most  physiologists  have  con- 
sidered that  the  whole  function  of  h^matosis  is  effected  in  the  luno;s. 
M.  Chaussier,*  however,  has  presumed,  that  some  kind  of  elaboration 
is  effected  on  the  air,  in  passing  through  the  cavities  of  the  nose  and 
mouth,  and  the  different  bronchial  ramifications,  by  being  agitated 
with  the  bronchial  mucus ;  similar  to  what  he  conceives  is  effected  by 
the  mucus  on  the  aliment  in  its  passage  from  the  mouth  to  the  sto- 
mach; but  his  view  is  conjectural  in  both  one  case  and  the  other,  M. 
Legallois,^  again,  thought,  that  hasmatosis  commences  at  the  part, 
where  the  chyle  and  lymph  are  mixed  with  the  venous  blood,  or  in 
the  subclavian  vein.  This  admixture,  he  conceives,  occurs  more  or 
less  immediately ;  is  aided  in  the  heart,  and  the  conversion  is  com- 
pleted in  the  lungs.  To  this  belief  he  was  led  by  the  circumstance, 
that  when  the  blood  quits  the  lungs  it  is  manifestly  arterial;  and  he 
thought,  that  what  the  products  of  absorption  lose  or  gain  in  the 
lungs  is  too  inconsiderable  to  account  for  the  important  and  extensive 
change;  and  that  therefore  it  must  have  commenced  previously. 
Facts,  however,  are  not  exactly  in  accordance  with  the  view  of  Legal- 
lois.     They  seem  to  show,  that  the  blood  of  the  pulmonary  artery  is 

'  Adelon,  Physiologie  de  I'llomme,  edit,  cit.,  iii.  201. 
^  Element.  Physiol.,  lib.  viii.  sect,  iv.,  Lausanu.,  17(56. 
^  Edinburgh  Medical  and  Surgical  Journal,  vol.  Ixxvii.,  1823. 

*  Edinburgh  Med.  and  Surg.  Journal,  vol.  xxix.  ;  and  Physiology  and  Pathology, 
&c.,  of  Asphyxia,  Lond.,  1834. 

^  Adelon,  Physiologie  de  rHomme,  iii.  205.  ®  Annales  de  Chimie,  iv.  115. 

VOL.  I. — 20 


306  RESPIRATION. 

analogous  to  tliat  of  the  subclavian  vein;  and  hence  it  is  probable, 
that  there  is  no  other  action  exerted  upon  the  fluid  in  this  part  of  the 
venous  system,  than  a  more  intimate  admixture  of  the  venous  blood 
with  the  chyle  and  lymph  in  their  passage  through  the  heart. 

The  changes,  wrought  on  the  air  by  respiration,  are  considerable. 
It  is  immediately  deprived  of  a  portion  of  both  of  its  main  consti- 
tuents— oxygen  and  nitrogen ;  and  it  always  contains,  when  expired, 
a  quantity  of  carbonic  acid  greater  than  it  had  when  received  into  the 
lungs,  along  with  an  aqueous  and  albuminous  exhalation  to  a  consi- 
derable amount. 

Oxygen  is  consumed  in  the  respiration  of  all  animals,  from  the 
largest  quadruped  to  the  most  insignificant  insect;  and  if  we  examine 
the  expired  air,  the  deficiency  is  manifest.  Many  attempts  have  been 
made  to  estimate  the  precise  quantity  consumed  during  respiration; 
but  the  results  vary  essentially  from  each  other;  partly  owing  to  the 
fact,  that  the  amount  consumed  by  the  same  animal  differs  in  different 
circumstances.  Menzies'  was  probably  the  first  that  attempted  to 
ascertain  the  quantity  consumed  by  man  in  a  day.  According  to  him, 
86  cubic  inches  are  expended  in  a  minute;  consequently,  61,840  in 
the  twenty-four  hours,  equal  to  17,496  grains.  Lavoisier^  makes  it 
46,048  cubic  inches,  or  15,541  grains.  This  was  the  result  of  his  ear- 
lier experiments,  and,  in  his  last,  which  he  was  executing  at  the  time 
when  he  fell  a  victim  to  the  tyranny  of  Robespierre,  he  made  it  15592*5 
grains ;  corresponding  greatly  with  the  results  of  his  earlier  observa- 
tions. The  experiments  of  Sir  Humphry  Davy^  coincide  greatly 
with  those  of  Lavoisier.  He  found  the  quantity  consumed  in  a  mi- 
nute to  be  31*6  cubic  inches;  making  45,504  cubic  inches,  or  15,337 
grains  in  twenty-four  hours.  The  results  obtained  by  Messrs.  Allen 
and  Pepys^  make  it  much  less.  They  consider  the  average  consump- 
tion to  be,  in  the  twenty-four  hours,  under  ordinary  circumstances, 
39,534  cubic  inches,  equal  to  13,343  grains. 

If  we  regard  the  experiments  of  Lavoisier  and  Davy,  between  which 
there  is  the  greatest  coincidence,  to  be  an  approximation  to  the  truth, 
it  will  follow,  that,  in  a  day,  a  man  consumes  rather  more  than  25  cubic 
feet  of  oxygen ;  and  as  the  oxygen  amounts  to  only  about  one-fifth  of 
the  respired  air,  he  must  render  125  cubic  feet  of  air  unfit  for  support- 
ing combustion  and  respiration. 

The  experiments  of  Crawford,  Jurine,  Lavoisier  and  Seguin,  Prout, 
Fyfe,  and  Edwards,^  have  proved,  that  the  quantity  of  oxygen  con- 
sumed varies  according  to  the  condition  of  the  functions  and  the  system 
generally.  Seguin^  found,  that  muscular  exertion  increases  it  nearly 
fourfold.  Dr.  Prout,^  who  gave  much  attention  to  the  subject,  was 
induced  to  conclude,  from  his  experiments,  that  moderate  exercise 
increases  it;  but  if  the  exercise  be  continued  so  as  to  induce  fatigue,  a 

'  Dissertation  on  Respiration,  p.  21,  Edin.,  170G. 
*  Memoir,  de  I'Academ.  des  Sciences,  1789,  1790. 

'  Researclies,  &c.,  p.  431.  «  Philos.  Transact,  for  1808. 

^  De  riufluence  des  Agens  Phvsiques  3ur  la  Vie,  p.  410,  Paris,  1824 ;  or  Hodglcin  and 
Fisher's  translation. 

^  Mem.  de  PAcadem.  des  Sciences,  1789  and  1790. 
'  Annals  of  Philos.,  ii.  330,  iv.  331,  and  xiii    2(39. 


H^MATOSIS.  307 

diminished  consumption  takes  place.  The  exhilarating  passions  ap- 
peared to  increase  the  quantity;  whilst  the  depressing  passions  and 
sleep,  the  use  of  alcohol  and  tea,  diminished  it.  He  discovered,  that 
the  quantity  of  oxygen  consumed  is  not  uniformly  the  same  during  the 
twenty-four  hours.  Its  maximum  occurred  between  10  a.  m.  and  2  P.  M., 
or  generally  between  11  A.M.  and  1  P.M.:  its  minimum  commenced 
about  8|  P.  M.,  and  it  continued  nearly  uniform  till  about  3 J  A.M.  Dr. 
Fyfe'  found,  that  the  quantity  was  diminished  by  a  course  of  nitric 
acid,  by  a  vegetable  diet,  and  by  affecting  the  system  with  mercury. 
Temperature  has  an  influence.  Dr.  Crawford^  found,  that  a  Guinea-pig, 
confined  in  air  at  the  temperature  of  55°,  consumed  double  the  quantity 
which  it  did  in  air  at  104°.  He  also  observed,  in  such  cases,  that  venous 
blood,  when  the  body  was  exposed  to  a  high  temperature,  had  not  its 
usual  dark  colour ;  but^  by  its  florid  hue,  indicated  that  the  full  change 
had  not  taken  place  in  its  constitution  in  the  course  of  circulation. 
The  same  fact  is  mentioned  by  a  recent  observer,  who  affirms,  that  if, 
when  an  animal  is  near  dying  from  the  effect  of  heat,  an  artery  be 
opened,  its  blood  is  as  black  as  that  of  a  vein,  and  does  not  become 
bright  by  exposure. 

We  may  thus  understand  the  great  lassitude  and  yawning,  induced 
by  the  hot  weather  of  summer;  and  the  languor  and  listlessness  which 
are  so  characteristic  of  those  who  have  long  resided  in  torrid  climes. 
Dr.  Prout  conceives,  that  the  presence  or  absence  of  the  sun  alone  regu- 
lates the  variation  in  the  consumption  of  oxygen  which  he  has  described ; 
but  the  deduction  of  Dr.  Fleming^  appears  to  be  more  legitimate, — 
that  it  keeps  pace  with  the  degree  of  muscular  action,  and  is  dependent 
upon  it.  Consequently,  a  state  of  increased  consumption  is  always  fol- 
lowed b}''  an  equally  great  decrease,  in  the  same  manner  as  activity  is 
followed  by  fatigue. 

The  disagreement  of  experimenters,  as  respects  the  removal  of  nitro- 
gen or  azote  from  the  air,  during  respiration,  is  still  greater  than  in  the 
case  of  oxygen.  Priestley,  Davy,  Von  Humboldt,  Henderson,  Cuvier, 
and  Pfaff,  found  a  less  quantity  exhaled  than  was  inspired.  Spallanzani, 
Lavoisier  and  Seguin,  Vauquelin,  Allen  and  Pep3^s,  Ellis,  Thomson, 
Valentin  and  Brunner,  and  Dalton,  inferred  that  neither  absorption  nor 
exhalation  takes  place, — the  quantity  of  that  gas,  in  their  opinion, 
undergoing  no  change  during  its  passage  through  the  air-cells  of  the 
lungs;  whilst  Jurine,  Nysten,  Berthollet,  and  Dulong  and  Despretz,  on 
the  contrary,  found  an  increase  in  the  bullv  of  the  nitrogen.  In  this 
uncertainty,  most  physiologists  have  been  of  opinion  that  the  nitrogen 
is  entirely  passive  in  the  function.  The  facts,  ascertained  by  M.  W. 
F.  Edwards,*  of  Paris,  shed  considerable  light  on  the  causes  of  this  dis- 
crepancy amongst  observers.  He  has  satisfactorily  shown  that,  in  the 
respiration  of  the  same  animal,  the  quantity  of  nitrogen  may  be,  at  one 
time,  augmented;  at  another,  diminished;  and,  at  a  third,  wholl}'  un- 
changed. These  phenomena  he  has  traced  to  the  influence  of  the  sea- 
sons, and  he  suspects  that  other  causes  have  a  share  in  their  produc- 
tion.    In  nearly  all  the  lower  animals  that  were  the  subjects  of  expe- 

'  Annals  of  Philos.,  iv.  334,  and  Bostock'b  Physiol.,  i.  350.  2  Op_  ^it,,  p.  387, 

5  Philosophy  of  Zoology,  i.  355,  Edinburgh,  1S22.  «  Op.  cit.,  p.  402, 


308  RESPIRATION. 

riment,  an  augmentation  of  nitrogen  was  observable  during  summer. 
Sometimes,  it  was  so  slight  that  it  might  be  disregarded ;  but,  in 
numerous  instances,  it  was  so  great  as  to  place  the  fact  beyond  the 
possibility  of  doubt ;  and,  on  some  occasions,  it  almost  equalled  the 
whole  bulk  of  the  animal.  Such  were  the  results  of  his  observations 
until  the  close  of  October,  when  he  noticed  a  sensible  diminution  in  the 
nitrogen  of  the  inspired  air,  and  the  same  continued  throughout  the 
whole  of  winter  and  beginning  of  spring.  M.  Edwards  considers  it 
probable,  that,  in  all  cases,  both  exhalation  and  absorption  of  nitrogen 
are  going  on;  that  they  are  frequently  accurately  balanced,  so  as  to 
exhibit  neither  excess  nor  deficiency  of  nitrogen  in  the  expired  air; 
whilst,  in  other  cases,  depending,  as  it  would  appear,  chiefly  upon  tem- 
perature, either  the  absorption  or  the  exhalation  is  in  excess,  producing 
a  corresponding  effect  upon  the  composition  of  the  air  of  expiration. 
MM.  Regnault  and  Reiset,'  in  their  experiments  on  animals,  always 
observed  an  exhalation  of  nitrogen ;  the  proportion  of  which  varied — as 
in  the  case  of  carbonic  acid  formed — with  the  nature  of  the  food. 

Whilst  the  respired  air  has  lost  its  oxygenous  portion,  it  has  received, 
as  we  have  remarked,  an  accession  of  carbonic  acid,  and,  likewise,  a 
quantity  of  watery  vapour.  If  we  breathe  through  a  tube,  one  end  of 
which  is  inserted  into  a  vessel  of  lime-water,  the  fluid  soon  becomes 
milky,  owing  to  the  formation  of  carbonate  of  lime,  which  is  insoluble 
in  water.  Carbonic  acid  must,  consequently,  have  been  given  off"  from 
the  lungs.  In  the  case  of  this  gas,  again,  it  has  been  attempted  to  com- 
pute the  quantity  formed  in  the  day.  Jurine  conceived,  that  the  amount, 
in  air  once  respired  in  natural  respiration,  is  in  the  large  proportion  of 
-j'^th  or  y'.^th ;  Menzies,  that  it  is  o'(jth ;  and,  from  his  estimate  of  the 
total  quantity  of  air  respired  in  the  twenty-four  hours,  he  deduced  the 
amount  of  carbonic  acid  formed  to  be  61840  cubic  inches,  equal  to 
24i05"6  grains.  MM.  Lavoisier  and  St'guin,*in  their  first  experiments, 
valued  it  at  17720"89  grains;  but  in  the  next  year  they  reduced  their 
estimate  more  than  one-lialf; — to  8450.20  grains;  and,  in  Lavoisier's 
last  experiment,  it  was  farther  reduced  to  7550*4  grains.  Sir  Hum- 
phry Davy's  estimate  nearly  corresponds  with  that  of  the  first  experi- 
ment of  MM.  Lavoisier  and  Seguin, — i7811"3()  grains;  and  Messrs. 
Allen  and  Fepys  accord  pretty  nearly  with  him.  Thcvsc  gentlemen 
found,  that  air,  when  inspired,  issued,  on  the  succeeding  expiration, 
charged  with  from  8  to  6  per  cent,  of  carbonic  acid ;  but  this  estimate 
greatly  exceeds  that  of  Dr.  Apjohn,^  of  Dublin,  who,  in  his  experiments, 
found  the  expired  air  to  contain  only  3"6  per  cent.  The  experiments 
and  observations  of  Messrs.  Crawford,  Prout,  Edwards,  and  others,  to 
which  we  have  referred — as  regards  the  consumption  of  oxygen,  under 
various  circumstances — apply  equally  to  the  quantity  of  carbonic  acid 
formed,  which  always  bears  a  pretty  close  proportion  to  the  oxygen 
consumed.  These  experiments  also  account,  in  some  degree,  for  the 
discrepancy  in  the  statements  of  individuals  on  this  subject. 

The  observations  of  Vierordt,''  at  various  temperatures  between  38° 

'  Comptes  Rendus,  Paris,  1848. 

2  Memoir,  de  I'Academ.  des  Sciences,  p.  609,  Paris,  1790. 

3  Edinb.  Med.  and  Surg.  Journal,  Jan.,  1831. 

*  Lelirbuch  der  Physiologisclien  Chemie,  iii.  386',  Leipzig,  1852 ;  or  Amer.  edit,  of 
Dr.  Day's  translation,  by  Dr.  Robert  E.  Rogers,  ii.  443,  Pliilad.,  1855. 


H^MATOSIS.  809 

and  75°  Fahr.,  showed,  that  a  rise  equal  to  10°  caused  a  diminution  of 
about  two  cubic  inches  in  the  quantity  of  carbonic  acid  exhaled  per 
minute.  Letellier/  too,  found,  by  experiments  on  animals  at  much 
higher  and  lower  temperatures  than  those,  that  the  higher  the  tempera- 
ture, as  far  as  10-i°,  the  less  was  the  amount  of  carbonic  acid  exhaled, 
whilst  the  nearer  it  approached  zero  the  greater  was  the  amount  of  car- 
bonic acid  given  of. 

The  experiments  of  Mr.  Coathupe,^  which  were  carefully  conducted, 
make  the  amount  of  carbonic  acid,  generated  in  the  24  hours,  about 
17856  cubic  inches,  that  is  2'616  grains  or  5|  ounces  of  solid  carbon. 
Liebig  found  the  proportion  of  carbon  expired  by  himself  to  be  8^ 
ounces  daily;  by  a  soldier,  13|  ounces;  by  prisoners  in  close  confine- 
ment, 7  ounces;  and  by  a  boy  who  took  considerable  exercise,  9  ounces.^ 
Subsequently,  farther  experiments  Avere  made  on  the  subject  by  com- 
petent observers.  Professor  Scharling,*  of  Copenhagen,  found,  that, 
at  the  age  of  85,  he  exhaled  7"7  ounces  avoirdupois  of  carbon  in  the 
twenty-four  hours — seven  of  which  were  passed  in  sleep.  A  soldier, 
28  years  of  age,  exhaled  8"15  ounces;  a  lad  of  16,  7*9  ounces;  a  young 
woman,  aged  19,  5*88  ounces;  a  boy,  9|  years  old,  8'069  ounces;  and 
a  girl,  10  years  old,  4*42  ounces.  In  the  last  two,  the  time  ^spent  in 
sleep  was  9  hours.  These  amounts,  however,  were  exhaled  both  from 
the  luno-s  and  cutaneous  surface.  He  constructed  an  air-tight  chamber, 
of  dimensions  sufficient  to  permit  him  to  remain  in  it  for  some  time 
without  inconvenience.  This  was  connected  with  an  apparatus  by 
which  the  air  was  constantly  renewed,  and  the  air  removed  was  care- 
fully analyzed,  in  order  to  determine  the  quantity  of  carbonic  acid 
contained  in  it.  Of  the  7'7  ounces  exhaled  by  himself  in  the  twenty- 
four  hours,  we  may  perhaps  estimate  the  amount  from  the  lungs  at  5'5 
ounces.  He  infers,  from  all  his  experiments,  that  males  exhale  more 
carbonic  acid  than  females;  and  children  comparatively  more  than 
adults.  . 

MM.  Andral  and  Gavarret  undertook  a  series  of  interesting  experi- 
ments on  the  subject.  Their  fii-st  object  was  to  ascertain  the  modifying 
influence  of  age,  sex,  and  constitution  on  the  quantity  of  carbonic  acid 
exhaled  from  the  lungs.  To  determine  this,  their  observations  were 
made  under  circumstances  as  uniform  as  possible;  and  each  experi- 
ment was  repeated  several  times  on  the  same  subject.  The  apparatus 
employed  was  so  devised  as  to  enable  the  respirations  to  be  freely  per- 
formed; no  portion  of  the  expired  air  was  again  inspired;  and  the 
greatest  care  was  taken  to  analyze  the  expired  air  with  accuracy.  The 
general  results  obtained  by  tliese  observers  were  as  follows: — 1.  The 
quantity  of  carbonic  acid  exhaled  by  the  lungs  in  a  given  time  varies 
according  to  age,  sex,  and  constitution.  2.  In  both  male  and  female, 
the  quantity  undergoes  modification,  according  to  the  agds  of  the  indi- 
viduals experimented  upon,  quite  independently  of  their  weights.  3. 
In  all  periods  of  life,  there  is  a  difierence  between  the  male  and  female 

'  Annales  de  Cliimie  et  de  Physique,  1845. 
^  Philosophical  Magazine,  Juno,  1839. 

^  Graham's  Elements  of  Chemistry,  Amer.  edit.,  p.  G8G,  Philad.,  1843. 
"  Annalt'S  des  Sciences  Naturelles,  Fevrier,  1843 ;  cited  in  Brit,  and  For.  Med.  Rev. 
for  July,  1843,  p.  285. 


310 


RESPIRATION. 


in  the  amount  of  carbonic  acid  exhaled  in  a  given  time:  cceteris  paribus, 
man  exhales  a  much  larger  quantity  than  woman.  Between  the  ages 
of  16  and  40,  the  former  exhales  nearly  twice  as  much  as  the  latter. 
4.  In  man,  the  quantity  exhaled  goes  on  regularly  increasing  from  8 
to  30  years  of  age ;  and  a  remarkable  augmentation  takes  place  at 
puberty.  After  80,  it  begins  to  decrease ;  and  the  decrease  continues 
becoming  more  and  more  marked  as  the  individual  approaches  nearer 
and  nearer  extreme  old  age ;  so  that,  at  this  last  period,  it  returns  to 
the  standard  at  which  it  was  about  the  age  of  ten.  5.  In  woman  the 
exhalation  augments  up  to  the  period  of  puberty,  according  to  the 
same  law  as  in  man;  the  increase  then  suddenly  ceases,  and  the  quan- 
tity continues  at  this  low  standard,  with  little  variation  so  long  as  the 
catamenia  appear  regularly;  but  as  soon  as  they  cease,  the  exhalation 
of  carbonic  acid  from  the  lungs  undergoes  a  considerable  augmenta- 
tion, after  which  it  decreases  as  in  man,  according  to  the  advance  of  age. 
6.  During  pregnancy,  the  amount  of  carbonic  acid  exhaled  is  raised 
temporarily  to  the  standard  which  it  attains  after  the  cessation  of  the 
catamenia.  7.  In  both  sexes,  and  at  all  ages,  the  quantity  of  carbonic 
acid  exhaled  by  the  lungs  is  greater  in  proportion  to  the  strength  of 
the  constitution,  and  the  developement  of  the  muscular  system. 

The  following  table  exhibits  the  amount  of  solid  carbon  calculated 
to  be  exhaled  in  one  hour  at  dift'erent  ages ; — the  gramme  is  equal  to 
about  15|  grains. 


Male. 

Female. 

8  years.          5  grammes. 

8  years.           5 

grammes. 

The  same  standard  con- 

15  8-7 

1*2-38     .     . 

.     6-4 

tinues  in  women  during  the 

16   . 

10-8 

38-50     .     . 

.     8-4 

whole  of  the  menstrual  pe- 

18-20 

11-4 

50-60     .     . 

.     7-3 

riod:  but  if  the  catamenia 

20-30 

12-2 

60-80    .     . 

.     6-8 

be  temporarily  suppressed, 

30^0 

12-2 

82          .     . 

.     6-0 

or  pregnancy  occur,  it  rises 

40-60 

•    10-1 

to  the  standard   it  attains 

60-80 

9-2 

after  their  entire  cessation, 

102 

5-9 

namely,  8-4  grammes. 

These  numbers  express  the  averages, — the  maximum  amount  being 
often  considerably  greater.  In  a  young  man  of  athletic  system,  and 
sound  constitution,  the  quantity  of  carbonic  acid  exhaled  in  an  hour 
was  li"!  grammes;  in  a  man  of  60,  equally  vigorous  for  his  age,  13*6 
grammes;  and  in  one  of  63,  124  grammes.  An  old  man,  of  92,  of  a 
remarkable  degree  of  energy,  and  who  had  possessed  unusual  vigour 
in  his  youth,  was  found  to  exhale  8"8  grammes  per  hour;  whilst  the 
same  amount  appeared  to  be  the  ordinary  standard  in  a  man  of  45; 
who,  unlike  the  last,  had  a  feeble  system,  although  in  equally  good 
health.  How  far  these  variations  were  connected  with  differences  in 
the  capacity  of  the  chest,  and  with  the  number  of  the  respiratory 
movements,  MM,  Andral  and  Gavarret  proposed  to  investigate  subse- 
quently.    This  they  have  not  done. 

The  following  table,  by  Dr,  John  Reid,'  of  the  quantity  of  carbonic 


'  Art,  Respiration,  Cyclopfedia  of  Anat,  and  Physiol.,  Pt,  xxxii,  p,  345,  Lond,,  Aug. 

1848. 


HiEMATOSIS. 


311 


acid  gas  in  100  parts  of  the  expired  air  estimated  by  volume  gives  tlie 
result  obtained  bj  recent  experimenters. 


Difference  between 

Average. 

Maximum. 

Minimum. 

Maximum  and  Minimum. 

Prout 

3-45 

4-10 

3-30 

.80 

Coathupe    . 

4-02 

7-98 

1-91 

6-07 

Brunner  and  Valentin 

4-380 

5-495 

3-299 

2-196 

Vierordt 

4-334 

6-220 

3-358 

2-86 

Thomson     . 

4-ltJ 

7-16 

1-71 

5-45 

It  has  been  a  question  amongst  physiologists,  whether  the  quantity 
of  carbonic  acid  given  out  is  equal  in  bulk  to  the  oxygen  taken  in. 
In  Dr.  Priestley's  experiments/  the  latter  had  the  preponderance. 
Menzies  and  Crawford  found  them  to  be  equal,  MM.  Lavoisier  and 
Seguin  supposed  the  oxygen,  consumed  in  the  twenty-four  hours,  to  be 
15661"66  grains;  whilst  the  oxygen,  required  for  the  formation  of  the 
carbonic  acid  given  out,  was  no  more  than  1292-i  grains;  and  Sir 
Humphry  Davy  found  the  oxygen  consumed  in  the  same  time  to  be 
15337  grains,  whilst  the  carbonic  acid  produced  was  17811"36  grains; 
which  would  contain  1282-±"18  grains  of  oxygen.  The  experiments  of 
Messrs.  Allen  and  Pepys  seem,  however,  to  show  that  the  oxygen 
which  disappears  is  replaced  by  an  equal  volume  of  carbonic  acid; 
and  hence  it  was  supposed  that  the  whole  of  it  must  have  been  em- 
ployed in  the  formation  of  this  acid.  They,  consequently,  accord  with 
Menzies  and  Crawford;  and  the  view  is  embraced  by  Dalton,  Prout, 
Ellis,  Henry,  and  other  distinguished  individuals.  On  the  other  hand, 
the  view  of  those,  who  consider  that  the  quantity  of  carbonic  acid 
produced  is  less  than  that  of  the  oxygen  which  has  disappeared,  is 
embraced  by  Dr.  Thomson,  and  by  MM.  Dulong  and  Despretz.  In 
the  carnivorous  animal,  tliey  found  the  difference  as  much  as  one- 
third  ;  in  the  herbivorous,  on  the  average,  only  one-tenth.  The  expe- 
riments of  M.  Edwards  have  shown,  that  here,  also,  the  discordance 
has  not  depended  so  much  upon  the  different  methods  and  skill  of  the 
operators,  as  upon  a  variation  in  the  results  arising  from  other  causes; 
and  he  concludes,  that  the  proportion  of  oxygen  consumed  to  that 
employed  in  the  production  of  carbonic  acid  varies  from  more  than 
one-third  of  the  volume  of  carbonic  acid  to  almost  nothing;  that  the 
variation  depends  upon  the  particular  animal  species  subjected  to  ex- 
periment, its  age,  or  some  peculiarity  of  constitution,  and  that  it  differs 
considerably  in  the  same  individual  at  different  times. 

According  to  the  law  of  diffusion  of  gases,  the  carbonic  acid  given 
off"  from  the  blood  will,  of  itself,  independently  of  the  movements  of 
respiration,  have  a  tendency  to  quit  the  lungs  by  diffusing  itself  in 
the  external  air  in  which  it  is  in  less  proportion ;  and  the  oxygen  of 
the  bronchial  tubes  and  external  air  will  have  a  tendency  to  pass  to- 
wards the  air-cells  in  which  its  proportion  is  less  than  in  the  air  of  the 
tubes  and  the  external  air.  Were  this  not  the  case,  the  air  in  the  air- 
cells  would  be  highly  charged  with  carbonic  acid,  and  could  not  fail 

'  Experiments,  &c.,  on  Different  Kinds  of  Air,  vol.  iii.,  3d  edit.,  Lond.,  1781. 


312  RESPIRATION". 

to  act  injuriously,  inasmucli  as  the  respiratory  movements,  even  when 
aided  by  the  resiliency  of  the  pulmonary  tissue,  can  never  empty  the 
air-cells;  and  hence  there  is  always — as  has  been  shown — a  quantity 
of  reserve  and  residual  air  in  the  cells/ 

Interesting  experiments  by  Valentin^  and  Brunner,  made  on  a  large 
scale,  seemed  to  demonstrate,  that  the  chemical  changes  in  respiration 
are  a  good  deal  owing  to  the  simple  diffusion  of  gases  taking  place 
between  those  of  the  atmosphere  and  of  the  blood.  The  volumes  of 
oxygen  absorbed  and  of  carbonic  acid  exhaled  from  the  blood  may  be, 
according  to  them,  determined  by  the  established  laws  of  the  diffusion 
of  gases,  so  that,  for  one  volume  of  carbonic  acid  exhaled,  1"17421 
volume  of  oxygen  is  absorbed, — these  numbers  representing  the  pro- 
portionate diffusion-volumes  of  the  two  gases,  calculated  according  to 
the  law  that  they  are  inversely  as  the  square  roots  of  their  specific 
gravities, — or,  according  to  weight,  one  part  of  carbonic  acid  to  0'85163 
of  oxygen.  One  part  by  weight  of  carbonic  acid  contains  0'72727  of 
oxygen;  consequently  for  each  part  of  carbonic  acid  discharged  in 
respiration,  there  is  an  excess  of  0*12436  of  oxygen,  which  is  disposed 
of  otherwise  than  in  forming  the  carbonic  acid  thrown  off'  from  the 
lungs, — or,  by  volumes,  for  each  one  of  carbonic  acid  there  is  an  excess 
of  0'17421  of  oxygen.  Hence  if  it  be  known  how  much  carbonic  acid 
has  been  exhaled  from  the  lungs  in  a  given  time,  we  can  calculate  the 
amount  of  oxygen  absorbed  in  the  same  time.  Valentin  and  Brunner 
satisfied  themselves,  that  in  a  medium  temperature  and  atmospheric 
pressure,  each  of  them,  on  an  average  of  six  experiments,  breathed 
562'929  litres  of  air  in  the  hour,  and,  in  the  same  time,  expired 
635'8565  grains  of  carbonic  acid,  containing  173'414:  grains  of  carbon. 
From  this  and  their  respective  diffusion-volumes,  the  hourly  consump- 
tion of  oxygen  was  calculated  at  541"5  grains; — the  results  obtained 
by  these  gentlemen  according  greatly  with  those  of  MM.  Andral  and 
Gavarret. 

A  series  of  apparently  carefully  conducted  experiments  in  regard 
to  the  changes  produced  in  tlie  air  by  respiration  was  performed  by 
MM.  Regnault  and  Keiset.^  The  following  are  the  results  of  one  on  a 
young  dog,  which  was  confined  in  an  appropriate  apparatus  for  twenty- 
four  hours  and  a  half. 

Oxygen  consumed,  .......  182*288  grammes. 

Carbonic  acid  produced,   ......  185'961         " 

Oxygen  contained  in  the  carbonic  acid,    .         .         .  135 "244         " 

Nitrogen  given  off, 0-1820       " 

Eepresenting  the  quantity  of  oxygen  consumed  at  100,  the  results 
would  be  as  follows : — ■ 


en  consumed,   .......  100 

Oxygen  in  the  carbonic  acid,    .....       74'191 

Oxygen  otherwise  disposed  of,  ....       25*809 

Nitrogen  disengaged,         ......         0*0549 

Average  quantity  of  oxygen  consumed  in  an  hour,  .         7*44 


'  Kirkes  and  Paget,  Manual  of  Physiology,  2d  Amer.  edit.,  p.  131,  Philad.  1853. 
2  LeiirhuLli  der  Physiologic  des  Menschen,  i.  547. 
'  Comptes  Reudus,  Paris,  1848. 


HuEMATOSIS.  813 

These  experiments  are  not  confirmatory,  however,  of  the  views  of 
Valentin  and  Brunner,  in  regard  to  the  exchanged  oxygen  and  car- 
bonic acid  in  respiration,  being  in  the  proportion  to  each  other  as  their 
diffusion-volumes.  Fresh  observations  are,  indeed,  needed  on  this 
subject.  In  the  meantime  it  has  been  well  remarked  by  Messrs. 
Kirkes  and  Paget,^  that  the  conditions  of  the  gases,  engaged  in  respi- 
ration, are  not  those  in  which  the  law  of  diffusion  would  exactly  hold. 
The  law  requires,  that  both  gases  should  be  free  and  under  equal 
pressure ;  whilst  in  the  actual  case,  the  gas  in  the  blood  is  dissolved 
under  pressure,  and  separated  by  a  membrane  from  that  with  which 
it  has  to  be  diffused. 

In  their  experiments  on  animals,  MM.  Eegnault  and  Reiset  found 
that  the  nature  of  the  diet  influences  the  relative  amount  of  oxygen 
absorbed,  and  of  carbonic  acid  given  out.  "When  animals  were  fed  on 
flesh,  they  absorbed  much  more  oxygen  in  proportion.  In  the  case  of 
a  dog,  confined  exclusively  to  this  kind  of  aliment,  the  proportion  of 
oxygen  absorbed  to  100  parts  of  carbonic  acid  exhaled  was  lo-l:"8, 
much  more  than  that  which  the  law  of  diffusion  of  gases  would  indi- 
cate; whilst  in  that  of  a  rabbit,  fed  wholly  on  vegetable  food,  the  pro- 
portion was  as  100  to  109-31:,  or  less.  The  difference  between  the 
relative  proportions  of  surplus  oxygen  in  the  same  animal,  under  these 
different  circumstances,  was  as  high  as  62  to  104.  The  same  experi- 
menters found  that,  when  an  animal  was  kept  fasting,  the  relation  be- 
tween the  quantity  of  oxygen  absorbed,  and  of  carbonic  acid  exhaled, 
is  nearly  the  same  as  when  it  is  fed  on  flesh ; — "  the  reason  evidently 
being,"  observes  a  recent  writer,^  "  that  in  the  former  case  the  animal's 
respiration  is  kept  up  at  the  expense  of  the  constituents  of  its  own 
body,  which  correspond  with  animal  food  in  their  composition."  It 
must  be  borne  in  mind,  however,  that  in  such  circumstances  the  fat 
would  probably  be  most  largely  taken  up ;  and  it  corresponds  in  com- 
position with  vegetable  food. 

It  would  appear,  then,  that  the  whole  of  the  oxygen,  which  respira- 
tion abstracts  from  the  air,  is  by  no  means  accounted  for  by  the  quan- 
tity of  carbonic  acid  formed ;  and  that,  consequently,  a  portion  of  it 
disappears  altogether.  It  has  been  supposed  by  some,  that  a  part  of 
the  watery  vapour,  given  off'  during  expiration  is  occasioned  by  the 
union  of  a  portion  of  the  oxygen  of  the  air  with  hydrogen  from  the 
blood  in  the  lungs ;  but  the  view  is  conjectural.  This  subject,  with 
the  quantity  of  vapour  combined  with  the  expired  air,  will  be  a  matter 
of  inquiry  under  the  head  of  Secretion.^ 

The  air  likewise  loses,  during  inspiration,  certain  foreign  matters 
diffused  in  it.  In  this  way,  it  has  been  attempted  to  convey  medicines 
into  the  system.  If  air,  charged  with  odorous  particles, — as  with  those 
of  turpentine, — be  breathed  for  a  short  time,  their  presence  in  the 
urine  can  be  detected ;  and  it  is  probably  in  this  manner,  that  miasmata 

'  Op.  cit.,  p.  137. 

'  Carpenter's  Principles  of  Physiology,  4tli  Amer.  edit.,  p.  304,  Pliilad.,  1855. 

^  See  on  the  whole  of  this  subject,  Br.  John  Reid,  art.  Respiration,  Cyclop,  of  Anat. 
and  Physiol.,  pt.  xxxii.  p.  34(j,  Lond.,  Aug.,  1848  ;  and  Vierordt,  art.  Respiration, 
Wagner's  Handworterbucli  der  Physiologie,  12te  Lieferung,  s.  828,  Braunschweig, 
1845. 


314  RESPIRATION. 

produce  tlieir  effects  on  the  frnme,  AnjEstbetic  agents  act  in  the 
same  way ;  and  all  pass  immediately  through  the  coats  of  the  pulmo- 
nary veins  by  imbibition,  and  thus,  speedily  affect  the  system.  The 
changes,  produced  in  the  air  during  respiration,  are  easily  shown,  by 
placing  an  animal  under  a  bell-glass,  until  it  dies.  On  examining  the 
air,  it  will  be  found  to  have  lost  a  portion  of  its  oxygen  and  nitrogen, 
and  to  contain  carbonic  acid  and  aqueous  vapour.  The  expired  air 
has  alwa3's,  even  in  greatly  varying  temperatures  of  the  atmosphere,  a 
temperature  of  from  97°"25  to  99°*5  Fahr., — most  commonly  the  latter. 

It  may  now  be  inquired,  whether  the  changes  produced  in  the 
respired  air  are  connected  with  those  effected  on  the  blood  in  the  lungs. 
In  its  progress  through  the  lungs,  this  fluid  has  been  changed  from 
venous  into  arterial.  It  has  become  of  a  florid  red  colour ;  of  a  strons^er 
odour;  of  a  higher  temperature  by  from  one  to  four  degrees,  accord- 
ing to  some,^  but  others  have  perceived  no  difference,  whilst  others, 
again,  have  found  it  of  lower  temperature;^ — Prof.  Bernard  has,  indeed, 
established  this  unanswerably.'^  It  is  of  less  specific  gravity,  in  the 
ratio  of  1053  to  1050  on  the  average,  according  to  Dr.  John  Davy  ;* 
and  it  coagulates  more  speedily,  according  to  most  observers;  but  Mr. 
Thackrah'  observed  the  contrarv.  That  this  conversion  is  owins^  to 
the  contact  of  air  in  the  lungs  we  have  many  proofs.  Lower®  was  one 
of  the  first,  who  clearly  pointed  out,  that  the  change  of  colour  occurs 
in  the  capillaries  of  the  lungs.  Prior  to  his  time,  the  most  confused 
notions  had  prevailed  on  the  subject,  and  the  most  visionary  hypo- 
theses been  indulged.  On  opening  the  thorax  of  a  living  animal,  he 
observed  the  precise  point  of  the  circulation  at  which  the  change  of 
colour  takes  place ;  and  showed,  that  it  is  not  in  the  heart,  since  the 
blood,  when  it  leaves  the  right  ventricle,  continues  to  be  purple.  He 
then  kept  the  lungs  artificially  distended,  first  with  a  regular  supply 
of  fresh  air,  and  afterwards  with  the  same  portion  of  air  without  re- 
newing it.  In  the  former  case,  the  blood  experienced  the  usual  change 
of  colour.  In  the  latter,  it  was  returned  to  the  left  side  of  the  heart 
unaltered. 

Experiments,  more  or  less  resembling  those  of  Lower,  have  been 
performed  by  Goodwyn,^  Cigna,  Bichat,*  Wilson  Philip,  and  numerous 
others, — and  with  similar  results. 

The  direct  experiments  of  Dr.  Priestley^  more  clearly  showed,  that 

*  Magendie,  Precis  de  Physiologie,  ii.  343 ;  Dr.  J.  Davy,  in  Philos.  Transact,  for 
1814;  Metcalfe  on  Caloric,  ii.  548,  Loud.,  1843  ;  and  Becquerel  and  Brescliet,  Annales 
des  Sciences  Naturelles,  2de  serie,  vii.  94,  Paris,  1837. 

*  Wagner's  Elements  of  Physiology,  by  R.  Willis,  §  180,  Lond.,  1842 ;  and  Simon's 
Animal  Chemistry,  vol.  i.  p.  193,  Lond.,  184.5. 

3  Notes  of  M.  Bernard's  Lectures  on  the  Blood:  by  Walter  F.  Atlee,  M.  D.,  p.  140, 
Philad.,  1854;  and  Gavarret,  De  la  Chaleur  Produite  par  les  Etres  Vivants,  p.  110, 
Paris,  1855. 

*  Physiological  and  Anatomical  Researches,  American  Med.  Library  edit.,  p.  16, 
PhiladI,  1840. 

*  Inquiry  into  the  Nature  and  Properties  of  the  Blood,  p.  42,  Lond.,  1819. 
^  Tractatus  de  Corde,  &c.,  c.  iii.,  Amstelod.,  1761. 

^  The  Connection  of  Life  with  Resi^iration,  &c.,  Lond.,  1788. 

8  Recherches  Physiol,  sur  la  Vie  et  la  Mort,  Semeedit.,  p.  238,  Paris,  1805. 

*  Experiments,  &c.,  on  Dillerent  Kinds  of  Air,  &c.,  Loud.,  1781. 


H^MATOSIS. 


815 


the  change  effected  on  the  blood  was  to  be  ascribed  to  the  air.  He 
found,  that  a  clot  of  venous  blood,  confined  in  a  small  quantity  of  air, 
assumed  a  scarlet  colour,  and  that  the  air  experienced  the  same  change 
as  from  respiration.  He  afterwards  examined  the  effects  produced  on 
the  blood  bj  the  gaseous  elements  of  the  atmosphere  separately,  as 
well  as  by  the  other  gaseous  fluids  that  had  been  discovered  in  his 
time.  The  clot  was  reddened  more  rapidly  by  oxygen  than  by  the  air 
of  the  atmosphere,  whilst  it  was  reduced  to  a  dark  purple  by  nitrogen, 
hydrogen,  and  carbonic  acid. 

Since  Dr.  Priestley's  time,  the  effect  of  different  gases  on  the  colour 
of  venous  blood  has  been  investigated  by  numerous  observers.  The 
following  is  the  result  of  their  observations,  as  given  by  M.  Thenard.^ 
It  must  be  remarked,  however,  that  all  the  experiments  were  made  on 
blood  out  of  the  body ;  and  it  by  no  means  follows,  that  precisely  the 
same  changes  would  be  accomplished  if  it  were  circulating  in  the 
vessels. 


Gas. 

Colour. 

Remarks. 

Oxygen    .... 

Rose  red. 

The  blood  employed  had 

Atmospheric  air        .         . 

Do. 

been  beaten,  and,  conse- 

Ammonia 

Cherry  red. 

quently,   deprived   of  its 

Gaseous  oxide  of  carbon  • 

Slightly  violet  red. 

fibrin. 

Deutoxide  of  azote  . 

Do. 

Carburetted  hydrogen 

Do. 

Azote        .... 

Brown  red. 

Carbonic  acid  . 

Do. 

Hydrogen 

Do.2 

Protoxide  of  azote     . 

Do. 

Arseniuretted  hydrogen  . 
Sulphuretted  hydrogen     . 

("Deep   violet,  passing 
■|    gradually  to  a  green- 
ly   ish  brown. 

Chlorohydric  acid  gas 

Maroon  brown. 

Sulphurous  acid  gas 

Black  brown. 

These  three  gases  coa- 

f Blackish  brown,  pass-  - 

gulated  the   blood  at  the 

Chlorine  .... 

<    ing  by  degress  to  a 

same  time. 

t   yellowish  white. 

It  is  sufficiently  manifest,  then,  from  the  disappearance  of  a  part  of 
the  oxygen  from  the  inspired  air,  and  from  the  effects  of  that  gas  on 
venous  blood  out  of  the  body,  that  it  plays  an  essential  part  in  the 
function  of  sanguification.  But  Ave  have  seen,  that  the  expired  air 
contains  an  unusual  proportion  of  carbonic  acid.  Hence  carbon,  either 
in  its  simple  state  or  united  with  oxygen,  must  have  been  given  off 
from  the  blood  in  the  vessels  of  the  lungs. 

To  account  for  these  changes  on  chemical  principles  has  been  a  great 
object  with  chemical  physiologists  at  all  times.  At  an  early  period, 
the  conversion  of  venous  into  arterial  blood  was  supposed  to  be  a  kind 
of  combustion ;  and,  according  to  the  Stahlian  notion  of  combustion 
then  prevalent,  it  was  presumed  to  consist  in  the  disengagement  of 
phlogiston ;  in  other  words,  the  abstraction  or  addition  of  a  portion  of 
phlogiston  made  the  blood,  it  was  conceived,  arterial  or  venous ;  and 

'  Traite  de  Chimie,  &c.,  5e  edit.,  Paris,  1827. 

^  Miiller  says  he  agitated  blood  with  hydrogen,  but  could  perceive  no  change  of  colour. 
Handbuch,  u.  s.  w.,  Baly's  translation,  p.  322,  Lond.,  1838. 


316  EESPIRATION. 

its  removal  was  looked  upon  as  the  principal  use  of  respiration.  This 
hypothesis  was  modified  by  M.  Lavoisier,  who  proposed  one  of  the 
chemical  views  to  be  now  mentioned. 

Two  chief  chemical  theories  have  been  framed  to  explain  the  mode 
in  which  carbon  is  given  off.  The  first  is  that  of  Black/  Priestley,* 
Lavoisier,^  Crawford  ;•*  and  others  ;* — that  the  oxygen  of  the  inspired 
air  attracts  carbon  from  venous  blood,  and  the  carbonic  acid  is  gene- 
rated by  their  union.  The  second,  which  has  been  supported  by  La 
Grange,*  Ilassenfratz,^  Edwards,®  Miiller,^  Bischoft",  Magnus,  and  others, 
— that  the  carbonic  acid  is  generated  in  the  course  of  the  circulation, 
and  is  given  off"  from  the  venous  blood  in  the  lungs,  whilst  oxygen 
gas  is  absorbed.  The  former  of  these  views  is  still  maintained  by 
many  chemical  physiologists.  It  is  conceived,  that  the  oxygen,  derived 
from  the  air  unites  with  certain  parts  of  the  venous  blood, — the  carbon 
and  hj^drogen, — owing  to  which  union,  carbonic  acid  and  water  are 
found  in  the  expired  air ;  the  venous  blood,  thus  depurated  of  its  car- 
bon and  hydrogen,  becomes  arterialized  ;  and,  in  consequence  of  these 
various  combinations,  heat  enough  is  disengaged  to  keep  the  body 
always  at  the  due  temperature.  According  to  this  theory,  respiration 
is  assimilated  to  combustion.  The  resemblance,  indeed,  between  the 
two  processes  is  striking.  The  presence  of  air  is  absolutely  necessary 
for  respiration  ;  in  every  variety  the  air  is  robbed  of  a  portion  of  its 
oxygen  ;  hence  a  fresh  supply  is  continually  needed  ;  and  respiration 
is  always  arrested  before  the  whole  of  the  oxygen  of  the  air  is  ex- 
hausted; and  this  partly  on  account  of  the  residuary  nitrogen  and  car- 
bonic acid  gas  given  oft"  during  expiration.  Lastly,  it  can  be  continued 
much  longer  when  an  animal  is  confined  in  pure  ox3^gen  than  in  atmo- 
spheric air.  All  these  circumstances  likewise  occur  in  combustion. 
Every  kind  requires  the  presence  of  air.  A  part  of  the  oxygen  is 
consumed ;  and,  unless  the  air  is  renewed,  combustion  is  impossible. 
It  is  arrested,  too,  before  the  whole  of  the  oxygen  is  consumed,  owing 
to  the  residuary  nitrogen,  and  carbonic  acid  formed ;  and  it  can  be 
longer  maintained  in  pure  oxygen  than  in  atmospheric  air.  Moreover, 
when  air  has  been  respired,  it  becomes  unfit  for  combustion.  Again, 
the  oxygen  of  the  air,  in  which  combustion  is  taking  place,  combines 
with  the  carbon  and  hydrogen  of  the  burning  body;  hence  the  forma- 
tion of  carbonic  acid  and  water ;  and,  as  in  this  combination,  the  oxy- 
gen passes  from  the  state  of  a  rare  gas,  or  one  containing  a  consider- 
able quantity  of  caloric  between  its  molecules,  to  that  of  a  much  denser, 
and  even  of  a  liquid,  the  whole  of  the  caloric,  which  the  oxygen  con- 
tained in  its  former  state,  can  no  longer  be  held  in  the  latter,  and  is 
accordingly  disengaged ;  hence  the  increased  temperature.  In  like 
manner,  in  respiration,  the  oxygen  of  the  inspired  air,  it  is  conceived, 
combines  with  the  carbon  and  hydrogen  of  the  venous  blood,  giving 

'  Lectures  on  the  Elements  of  Chemistry,  by  Robison,  ii.  87,  Edinb.,  1803. 
2  Philosoph.  Transact,  for  1776,  p.  147. 
^  Mem.  de  I'Acad.  des  Sciences,  pour  1777,  p.  185. 

*  On  Animal  Heat,  2d  edit.,  Lond.,  17SS.  ^  Metcalfe,  op.  cit. 

6  Annales  de  Chimie,  ix.  2(39.  '  Ibid.,  ix.  2(J5. 

8  De  rinfluence  des  Agens  Physiques,  &c.,  p.  411,  Paris,  1823  ;  or  Hodgkin  and 
Fisher's  translation.  "  Physiology,  by  Baly,  p.  537. 


HiEMATOSTS.  317 

rise  to  the  formation  of  carbonic  acid  and  water  ;  and,  as  in  these  com- 
binations, the  oxygen  passes  from  the  state  of  a  rare  to  that  of  a  denser 
gas,  or  of  a  liquid,  there  is  a  considerable  disengagement  of  caloric, 
which  becomes  the  source  of  the  high  temperature  maintained  by  the 
human  body,  M.  Thenard'  admits  a  modification  of  this  view, — san- 
guification being  owing,  he  conceives,  to  the  combustion  of  the  carbon- 
aceous parts  of  the  venous  blood,  and  probably  of  its  colouring  matter, 
by  the  oxj^gen  of  the  air. 

This  chemical  theory,  which  originated  chiefly  with  Lavoisier,  and 
La  Place  and  Scguin,  was  adopted  by  many  physiologists  with  but 
little  modification.  Mr.  Ellis,  indeed,  imagined,  that  the  carbon  is 
separated  from  the  venous  blood  by  a  secretory  process ;  'and  that  then, 
coming  into  direct  contact  with  oxygen,  it  is  converted  into  carbonic 
acid.  The  circumstance  that  led  him  to  this  opinion  was  his  disbelief 
ill  the  possibility  of  oxygen  being  able  to  act  upon  the  blood  through 
the  animal  membrane  or  coat  of  the  vessel  in  which  it  is  confined. 
It  is  obvious,  however,  that  to  reach  the  blood  circulating  in  the  lungs, 
the  oxygen  must,  in  all  cases,  pass  through  the  coats  of  the  pulmonary 
vessels.  These  coats,  indeed,  offer  little  or  no  obstacle,  and,  conse- 
quently, there  is  no  necessity  for  the  vital  or  secretory  action  suggested 
by  Mr.  Ellis.  Besides,  Priestley  and  Hassenfratz  exposed  venous 
blood  to  atmospheric  air  and  oxj^gen  in  a  bladder,  and  in  all  cases, 
the  parts  of  the  blood,  in  contact  with  the  gases,  became  of  a  florid 
colour.  The  experiments  of  Drs.  Faust,  Mitchell,  and  others  (p.  68), 
are,  in  this  respect,  pregnant  with  interest.  They  prove  the  great 
facility  with  which  the  tissues  are  penetrated  by  gases,  and  confirm 
the  facts  developed  by  the  experiments  of  Priestley,  Hassenfratz,  and 
others. 

The  second  theory, — that  the  carbonic  acid  is  generated  in  the 
course  of  the  circulation, — was  proposed  by  M.  La  Grange,  in  conse- 
quence of  the  objection  he  saw  to  the  former  hypothesis — that  the  lung 
ought  to  be  consumed  by  the  perpetual  disengagement  of  caloric  within 
^  it;  or,  if  not  so,  that  its  temperature  ought  to  be  much  superior  to  that 
of  other  parts.  He  accordingly  suggested,  that,  in  the  lungs,  the  oxy- 
gen is  simply  absorbed,  passes  into  the  venous  blood,  circulates  with  it, 
and  unites,  in  its  course,  with  the  carbon  and  hydrogen,  so  as  to  form 
carbonic  acid  and  water,  which  circulate  with  the  blood,  and  are  finally 
exhaled  from  the  lungs. 

The  ingenious  and  apparently  accurate  experiments  of  M.  Edwards' 
proved  convincingl}'',  not  only  that  0x3' gen  is  absorbed  by  the  pulmo- 
nary vessels,  but  that  carbonic  acid  is  exhaled  from  them.  When 
he  confined  a  small  animal  in  a  large  quantity  of  air,  and  continued 
the  experiment  sufficiently  long,  he  found,  that  the  rate  of  absorption 
was  greater  at  the  commencement  than  towards  the  termination  of  the 
experiment;  and  that,  at  the  former  period,  there  was  an  excess  of 
oxygen,  and  at  the  latter  an  excess  of  carbonic  acid.  This  proved  to 
him,  that  the  diminution  was  dependent  upon  the  absorption  of  oxy- 
gen, not  of  carbonic  acid.     His  experiments  in  proof  of  the  exhalation 

'  Traite  de  Chimie,  edit,  citat. 

^  Op.  citat.,  p.  437,  and  Messrs.' Allen  and  Pepys,  in  Philos.  Transactions  for  1829. 


318  RESPIRATION. 

of  carbonic  acid,  ready  formed,  by  tbe  lungs,  are  decisive.  Spallanzani 
had  asserted,  that  when  certain  of  the  lower  animals  are  confined  in 
gases  containing  no  oxygen,  the  production  of  carbonic  acid  is  unin- 
terrupted. Upon  the  strength  of  this  assertion,  M.  Edwards  confined 
frogs  in  pure  hydrogen  for  a  length  of  time.  The  result  indicated,  that 
carbonic  acid  was  produced,  and  in  such  quantity,  that  it  could  not 
have  been  derived  from  the  residuary  air  in  the  lungs;  as  in  some 
cases  it  was  equal  to  the  bulk  of  the  animal.  The  same  results,  although 
to  a  less  degree,  were  obtained  with  fishes  and  snails, — the  animals  on 
which  Spallanzani's  observations  were  made.  The  experiments  of 
Edwards  were  extended  to  the  mammalia.  Kittens,  two  or  three  days 
old,  were  immersed  in  hydrogen:  they  remained  in  this  situation  for 
nearly  twenty  minutes  without  dying,  and  on  examining  the  air  of  the 
vessel  after  death,  it  was  found,  that  they  had  given  ofi"  a  quantity  of 
carbonic  acid  greater  than  could  possibly  have  been  contained  in  their 
luno-s  at  the  commencement  of  the  experiment.  The  conclusion  of  Dr. 
Edwards,  from  his  various  experiments,  is,  "that  the  carbonic  acid  ex- 
pired is  an  exhalation  proceeding  wholly  or  in  part  from  the  carbonic 
acid  contained  in  the  mass  of  blood."  Several  experiments  were  sub- 
sequently made  by  M.  Collard  de  Martigny,^  who  substituted  nitrogen 
for  hydrogen;  and,  in  all  cases,  carbonic  acid  gas  was  given  out  in 
considerable  quantity.  These  and  other  experiments  would  seem,  then, 
to  show,  that  in  the  lungs,  carbonic  acid  is  exhaled,  and  oxygen  and 
nitrogen  are  absorbed.  They  would  also  seem  to  prove  the  existence 
of  carbonic  acid  in  venous  blood,  respecting  which  so  much  dissidence 
has  existed  amongst  chemists,  but  which  ought  to  be  put  at  rest  by  the 
decisive  observations  of  Magnus,^  which  show,  that  both  venous  and 
arterial  blood  contain  oxygen,  nitrogen  and  carbonic  acid,  which  they 
give  up  when  the  blood  is  placed  in  vacuo;  and  farther,  that  from  10 
to  12J^  per  cent,  of  oxygen,  by  volume,  exists  in  arterial  blood ;  whilst 
in  venous  blood,  there  is  only  one-half  that  amount ;  and  on  the  other 
hand,  that  there  is  about  25  per  cent.,  by  volume,  of  carbonic  acid  in 
venous  blood,  to  only  20  in  arterial. 

Allusion  has  already  been  made  to  the  fact,  that  gelatin  is  not  met 
with  in  the  blood,  and  to  the  idea  of  Dr.  Prout,^  that  its  formation  from 
albumen  must  be  a  reducing  process.  This  process  he  considers  to  be 
one  great  source  of  the  carbonic  acid  that  exists  in  venous  blood. 
Gelatin  contains  three  or  four  per  cent,  less  carbon  than  albumen;  it 
enters  into  the  structure  of  every  part  of  the  animal  frame,  and  espe- 
cially of  the  skin;  the  skin,  indeed,  contains  little  else  than  it.  He 
considers  it,  therefore,  most  probable,  that  a  large  part  of  the  carbonic 
acid  of  venous  blood  is  formed  in  the  skin,  and  analogous  textures. 
"Indeed,"  he  adds,  "we  know  that  the  skin  of  many  animals  gives  oflf 
carbonic  acid,  and  absorbs  oxygen ; — in  other  words,  performs  all  the 
offices  of  the  lungs; — a  function  of  the  skin  perfectly  intelligible,  on 
the  supposition,  that  near  the  surface  of  the  body  the  albuminous  por- 
tions of  the  blood  are  always  converted  into  gelatin."     Gmelin  and 

'  Journal  de  Physiologic,  x.  111. 

2  Annal.  der  Physik  und  Chemie,  Ixvi.  177,  Philosophical  Mag.,  Dec.  1845,  and 
Annales  de  Chemie  et  de  Physique,  Nov.  1837. 

3  Bridgewater  Treatise,  Aiuer.  edit,,  p.  280,  Philad.,  1834. 


H^MATOSIS.  319 

Tieclemann,  Mitsclierlich/  and  Stromeyer,^  affirm,  on  the  strengtli  of 
experiments,  that  the  blood  does  not  contain  free  carbonic  acid,  but  that 
it  holds  a  certain  quantity  in  a  state  of  combination,  which  is  set  free 
in  the  lungs,  and  commingles  with  the  expired  air.  The  views  of 
Gmelin  and  Tiedemann,  and  Mitscherlich  on  this  subject  are  as  follows. 
It  may  be  laid  down  as  a  truth,  that  the  greater  part,  if  not  all,  of  the 
properties  of  secreted  fluids  are  not  dependent  upon  any  act  of  the  se- 
creting organs,  but  are  derived  from  the  blood,  which  again,  must 
either  owe  them  to  the  food,  or  to  changes  effected  on  it  within  the 
body.  These  changes  are  probably  accomplished,  in  part,  during  the 
process  of  digestion,  but  are  doubtless  mainly  effected  in  the  lungs  by 
the  contact  of  the  blood  with  the  air.  Now,  most  of  the  animal  fluids, 
when  exposed  to  the  air,  generate,  by  the  absorption  of  oxygen,  acetic 
or  lactic  acid,  and  this  is  aided  by  an  elevated  temperature,  like  that 
of  the  lungs.  In  their  theory  of  respiration,  the  nitrogen  of  the  inspired 
air  is  but  sparingly  absorbed, — by  far  the  greater  proportion  remaining 
in  the  air-cells.  The  oxygen,  on  the  other  hand,  penetrates  the  mem- 
branes freely ;  mingles  with  the  blood ;  combines  partly  with  the  carbon 
and  hydrogen  of  that  fluid,  and  generates  carbonic  acid  and  water,  which 
are  thrown  off  with  the  expired  air;  the  remainder  combines  with  the 
organic  particles  of  the  blood,  forming  new  compounds,  of  which  the 
acetic  and  lactic  acids  are  two;  these  unite  with  the  carbonated  alkaline 
salts  of  the  blood,  and  set  free  the  carbonic  acid,  so  that  it  can  be  thrown 
off  by  the  lungs.  The  acetate  of  soda — thus  formed  during  the  passage 
of  the  blood  through  the  lungs — is  deprived  of  its  acetic  acid  by  the 
several  secretions,  especially  by  those  of  the  skin  and  kidneys,  and  the 
soda  again  combines  with  the  carbonic  acid,  formed  during  the  circula- 
tion of  the  blood  through  the  body,  by  the  decomposition  of  its  organic 
elements.  Carbonate  of  soda  is  thus  regenerated,  and  conveyed  to  the 
lungs,  to  be  again  decomposed  by  the  fresh  formation  of  acids  in  those 
organs.  Almost  the  same  view  is  entertained  by  MM.  Dumas  and 
Boussingault,  and  it  is  esteemed  by  Professor  Graham^  to  be  highly 
probable. 

Another  view,  in  many  respects  similar,  is  held  by  Professor  Arnold.* 
As  it  is  more  than  probable,  he  remarks,  that  the  carbonic  acid  occurs 
in  the  venous  blood,  united  with  some  substance  from  which  it  is  sepa- 
rated with  greater  or  less  rapidity  by  the  contact  of  atmospheric  air ; 
and  as,  further,  the  carbonate  of  protoxide  of  iron  greedily  withdraws 
oxygen  from  the  atmosphere,  at  the  same  time  parting  with  its  car- 
bonic acid  and  becoming  changed  into  a  peroxide,  it  may  be  reason- 
ably supposed,  that  the  carbonic  acid  of  venous  blood  is  united  with  the 
iron  of  the  red  colouring  matter,  and  is  set  free  during  the  act  of  re- 
spiration, by  the  ^-eciprocal  action  of  the  blood  and  air.  The  protoxide, 
by  absorption  of  oxygen,  becomes  a  peroxide,  which,  during  the  circu- 
lation of  the  blood  through  the  capillaries,  again  parts  with  its  oxygen. 
Carbon  is  at  the  same  time  eliminated  from  the  blood,  and  unites  with 
the  liberated  oxygen  to  form  carbonic  acid,  which  is  thrown  out  by  the 

'  Tiedemann  und  Treviranus,  Zeitsehrift  fiir  Physiol.,  B.  v.  H.  i. 

^  Schweigger's  Journal  fiir  Chimie,  u.  s.  w.,  Ixiv.  105. 

'  Elements  of  Chemistry,  Amer.  edit.,  by  Dr.  Bridges,  p.  687,  Philad.,  1843. 

*  Lehrbuch  der  Phvsiologie  des  Meuschen,  Ziirich,  1836-7. 


820  RESPIRATION. 

luiifis,  whilst  oxvgen  is  again  absorbed.  Tliis  is  the  view  embraced  by 
Liebig/  who  has  affirmed,  that  the  amount  of  iron  present  in  the  bhood, 
if  in  the  state  of  protoxide,  is  sufficient  to  furnish  the  means  of  trans- 
porting twice  as  much  carbonic  acid  as  can  possibly  be  formed  by  the 
oxygen  absorbed  in  the  lungs. 

MM.  Chaussier  and  Adelon,'*  again,  regard  the  whole  process  of 
hsematosis  to  be  essentially  organic  and  vital.  They  are  of  opinion, 
that  an  action  of  selection  and  elaboration  is  exerted  both  as  regards 
the  reception  of  ox^-gen  and  the  elimination  of  carbonic  acid.  But 
their  arguments  on  this  point  are  unsatisfactor}^,  and  are  negatived  by 
the  facilit}^  with  which  ox}' gen  can  be  imbibed,  and  carbonic  acid  trans- 
udes through  animal  membranes.  In  their  view,  the  whole  process  is 
effected  in  the  lungs,  as  soon  as  the  air  comes  in  contact  with  the  vessels 
containing  venous  blood.  Imbibition  of  oxygen  they  look  upon  as  a 
case  of  ordinary  absorption;  transudation  of  carbonic  acid  as  one  of 
exhalation;  both  of  which  they  conceive  to  be,  in  all  cases,  tito  factions, 
and  not  to  be  likened  to  any  phj^sical  or  chemical  process. 

Admitting  that  oxygen  and  a  portion  of  nitrogen  absolutely  enter 
the  pulmonary  vessels,  of  which  we  have  direct  proof,  are  they,  it  has 
been  asked,  separated  from  the  air  in  the  air-cells,  and  then  absorbed ; 
or  does  the  air  enter  undecomposed  into  the  vessels,  and  then  furnish 
the  proportion  of  each  of  its  constituents  needed  by  the  wants  of  the 
svstem, — the  excess  being  rejected  ?  Could  it  be  shown,  that  such  a 
decomposition  is  actually  effected  at  the  point  of  contact  between  the 
pulmonary  vessels  and  the  air  in  the  lungs,  it  would  seem,  at  first,  to 
prove  the  notion  of  Mr.  Ellis,^  and  of  Chaussier  and  Adelon,  that  a  vital 
action  of  selection  is  exerted;  but  the  knowledge  we  have  attained 
concerning  the  transmission  of  gases  through  animal  membranes  would 
suggest  another  explanation.  The  rate  of  transmission  of  carbonic 
acid  is  greater  than  that  of  0x3^ gen;  of  oxygen  greater  than  that  of 
nitrogen  (see  p.  69).  We  can  hence  understand,  that  more  oxygen  than 
nitrogen  may  pass  through  the  coats  of  the  pulmonary  bloodvessels, 
and  can  comprehend  the  facility  with  which  the  carbonic  acid,  formed 
in  the  course  of  the  circulation,  may  permeate  the  same  vessels,  and 
mix  with  the  air  in  the  lungs.  Sir  Humphry  Davy  is  of  opinion,  that 
the  whole  of  the  air  is  absorbed,  and  that  the  surplus  quantitj^  of  each 
of  the  constituents  is  subsequently  discharged.  In  favour  of  this  view, 
he  remarks  that  air  has  the  power  of  acting  upon  the  blood  through  a 
stratum  of  serum,  and  he  thinks  that  the  undecomposed  air  must  be 
absorbed  before  it  can  arrive  at  the  blood  in  the  vessels.  It  is  proba- 
ittle,  however,  from  the  ditYerent  penetrating  powers  of  the  gases — oxy- 
gen and  nitrogen, — that  the  proportion  of  those  constituents  cannot  be 
the  same  in  the  interior  as  at  the  exterior  of  the  pulmonary  vessels. 
Professor  Miiller,"  however,  accords  with  Sir  Humphry,  and  supposes 
that  the  air,  on  entering  the  lungs,  is  decomposed  in  consequence  of 
the  affinity  of  oxygen  for  the  red  particles  of  the  blood ;  carbonic  acid 

'  Animal  Chemistry,  Webster's  Amer.  edit.,  p.  2G1,  Cambridge,  1S43. 
^  Pliysiologie  de  rHomrae,  edit,  cit.,  iii.  25-1. 

'  An  Enquiry  into  the  Changes  induced  on  Atmospheric  Air,  &c.,  Ediub.,  1807;  and 
Further  Enquiries,  Edinb.,  181(3. 

*  Ilandbuch,  u.  s.  w.,  Baly's  translation,  p.  334,  Loud.,  1838. 


H^MATOSIS.  321 

being  formed,  whicli  is  exhaled  in  the  gaseous  form,  along  with  tlie 
greater  part  of  the  nitrogen.^ 

It  has  been  remarked,  that  when  oxygen  is  applied  to  venous  blood 
out  of  the  bod}^,  the  latter  assumes  a  florid  colour.  On  what  part  of 
the  blood,  then,  does  the  oxygen  act?  Doubtless,  upon  the  red  cor- 
puscles. Facts,  hereafter  stated  in  the  description  of  venous  blood, 
have  appeared  to  some  to  show  that  these  corpuscles  are  devoid  of 
colour,  whilst  they  exist  in  chyle  and  lymph ;  and  that  in  the  lungs, 
the  contact  of  air  changes  them  to  a  florid  red.  The  coloration  of  the 
blood  is,  consequently,  eflected  in  the  lungs ;  but  whether  this  change 
be  of  any  importance  in  heematosis  is  doubtful.  In  many  animals,  the 
red  colour  does  not  exist ;  and,  in  all,  it  can  perhaps  only  be  esteemed 
an  evidence,  that  the  other  important  changes  have  been  accomplished 
in  those  organs.  Of  late,  the  opinion  has  been  revived,  that  the  oxy- 
gen of  the  air  acts  upon  the  iron,  which  Engelhart  and  Rose^  had 
detected  in  the  colouring  matter, — but  how  we  are  not  instructed.  It 
has  been  asserted,  that  if  the  iron  be  separated,  the  rest  of  the  colour- 
ing matter,  which  is  of  a  venous  red  colour,  loses  the  property  of 
becoming  scarlet  by  the  contact  of  oxygen ;  but  this,  again,  has  been 
denied. 

Another  view  of  arterialization  has  been  advanced  by  Dr.  Stevens.^ 
According  to  him,  the  colouring  matter  is  naturally  very  dark;  is 
rendered  still  darker  by  acids,  and  acquires  a  florid  hue  from  the  addi- 
tion of  chloride  of  sodium,  and  from  the  neutral  salts  of  the  alkalies 
generally.  The  colour  of  ai'terial  blood  is  ascribed  by  him  to  hema- 
tm  reddened  by  the  salts  contained  in  the  serum;  the  characters  of 
venous  blood  to  the  presumed  presence  of  carbonic  acid,  which,  like 
other  acids,  darkens  hematin;  and  the  conversion  of  venous  into 
arterial  blood  to  the  influence  of  the  saline  matter  in  the  serum  being 
restored  by  the  separation  of  carbonic  acid.  If  we  take  a  firm  clot  of 
venous  blood,  cut  oft"  a  thin  slice,  and  soak  it  for  an  hour  or  two  in 
repeatedly  renewed  portions  of  distilled  water;  in  proportion  as  the 
serum  is  washed  away,  the  colour  of  the  clot  deepens;  and,  when 
scarcely  any  serum  remains,  the  colour,  by  reflected  light,  is  quite 
black.  In  this  state,  it  may  be  exposed  to  the  atmosphere,  or  a  cur- 
rent of  air  may  be  blown  upon  it,  without  any  change  of  tint  what- 
ever; whence  it  would  follow,  that  when  a  clot  of  venous  blood, 
moistened  with  serum,  is  made  florid  by  the  air,  the  presence  of  serum 
is  essential  to  the  phenomenon.  The  serum  is  believed,  by  Dr.  Ste- 
vens, to  contribute  to  this  change  by  means  of  its  saline  matter;  for 
when  a  dark  clot  of  blood,  which  oxygen  fails  to  redden,  is  immersed 
in  a  pure  solution  of  salt,  it  quickly  acquires  the  crimson  tint  of  arte- 
rial blood ;  and  loses  it  again  when  the  salt  is  abstracted  by  soaking 
in  distilled  water.     The  facts,  detailed  by  Dr.  Stevens,  were  confirmed 

'  See,  on  this  subject,  I>r.  John  Reid,  art.  Respiration,  Cyclop,  of  Auat.  and  Physiol., 
Ft.  xxxii.  p.  3t)5,  Lond.,  Aug.,  1848. 

^  Edinb.  Med.  and  Surg.  Journal  for  Jan.,  1827. 

'  Observations  on  the  Healthy  and  Diseased  Properties  of  the  Blood,  Lond.,  1832 ; 
and  Proceedings  of  the  Royal  Society  for  183-J-5,  p.  334. 
VOL.  I. — 21 


322  RESPIRATION. 

by  Mr.  Prater,'  and  by  Dr.  Turner,^  of  the  London  University.  The 
latter  gentleman,  assisted  by  Professor  Quain,  of  the  same  institution, 
performed  the  following  satisfactory  experiment.  He  collected  some 
pei'fectly  florid  blood  from  the  femoral  artery  of  a  dog ;  and  on  the 
following  day,  when  a  firm  coagulum  had  formed,  several  thin  slices 
were  cut  from  the  clot  with  a  sharp  penknife,  and  the  serum  was 
removed  from  them  by  distilled  water,  which  had  just  before  been 
briskly  boiled,  and  allowed  to  cool  in  a  well-corked  bottle.  The  water 
was  gently  poured  on  these  slices,  so  that  while  the  serum  was  dis- 
solving, as  little  as  possible  of  the  colouring  matter  should  be  lost. 
After  the  water  had  been  poured  off",  and  renewed  four  or  five  times, 
occupying  in  all  about  an  hour,  the  moist  slices  were  placed  in  a 
saucer  at  the  side  of  the  original  clot,  and  both  portions  were  shown 
to  several  medical  friends,  all  of  whom  unhesitatingly  pronounced  the 
unwashed  clot  to  have  the  perfect  appearance  of  arterial  blood,  and  the 
washed  slices  to  be  as  perfectly  venous.  On  restoring  one  of  the  slices 
to  the  serum  it  shortly  recovered  its  florid  colour ;  and  another  slice, 
placed  in  a  solution  of  bicarbonate  of  soda,  instantly  acquired  a  similar 
hue  ; — yet,  as  we  have  seen,  carbonate  of  soda  is  considered  by  Messrs. 
Gmelin,  Tiedemann,  and  Mitscherlich,  to  exist  in  venous  or  black 
blood! 

In  brightening,  in  this  way,  a  dark  clot  by  a  solution  of  salt  or  a 
bicarbonate.  Dr.  Turner  found  the  colour  to  be  often  still  more  florid 
than  that  of  arterial  blood ;  but  the  colours  were  exactly  alike  when 
the  salt  was  duly  diluted.  Dr.  Turner  remarks,  that  he  is  at  a  loss  to 
draw  any  other  inference  from  this  experiment,  than  that  the  florid 
colour  of  arterial  blood  is  not  due  to  oxygen  ;  but,  as  Dr.  Stevens  sug- 
gests, to  the  saline  matter  of  the  serum.  The  arterial  blood,  which 
was  used,  had  been  duly  oxygenized  within  the  body  of  the  animal, 
and  should  not  in  that  state  have  lost  its  tint  hy.  the  mere  removal  of 
its  serum;  and  he  adds, — the  change  from  venous  to  arterial  blood 
appears,  contrary  to  the  received  doctrine,  to  consist  of  two  parts 
essentially  distinct;  one  a  chemical  change,  essential  to  life,  accom- 
panied by  absorption  of  oxygen,  and  evolution  of  carbonic  acid;  the 
other  dependent  on  the  saline  matter  of  the  blood,  which  gives  a  florid 
tint  to  the  colouring  matter  after  it  has  been  modified  by  the  action  of 
oxygen.  "Such,"  says  Dr.  Turner,  "appears  to  be  a  fair  inference 
from  the  facts  above  stated;  but  being  drawn  from  very  limited  ob- 
servation, it  is  ottered  with  diffidence,  and  requires  to  be  confirmed  or 
modified  by  future  researches."  But  we  are  perhaps  scarcely  justified 
in  inferring,  from  the  experiments  of  Stevens,  Turner,  and  others, 
more  than  the  fact,  that  a  florid  hue  is  communicated  to  blood  by  sea- 
salt,  and  by  the  neutral  salts  of  the  alkalies  in  general,  and  indeed  by 
admixture  with  sugars ;  whilst  acids  render  it  still  darker.  The  pre- 
cise changes  that  occur  during  the  arterialization  of  the  blood  in  the 
lungs  are  still  unknown. 

Since  Dr.  Stevens  first  published  his  views,  fhe  subject  has  been 
farther  investigated  by  Dr.  William  Gregory,  and  Mr.  Irvine.     They 

'  Experim.  Inquiries  in  Chemical  Physiology,  Part  i.,  on  the  Blood,  Lond.,  1832. 
*  Elements  of  Chemistry,  5th  edit.,  by  Dr.  Bache,  p.  609,  Pliilad.,  1835. 


H^MATOSIS.  323 

introduced  portions  of  clot,  freed  b}''  ■washing  from  serum,  into  vessels 
containing  pure  hydrogen,  nitrogen,  and  carbonic  acid,  placed  over 
mercury.  As  soon  as  the  strong  saline  solution  came  in  contact  with 
them,  the  colour  of  the  clot,  in  all  the  gases,  changed  from  black  to 
bright  red ;  and  the  same  change  was  found  to  take  place  in  the  Tor- 
ricellian vacuum.  On  repeating  these  experiments  with  the  serum  of 
blood,  and  a  solution  of  salt  in  water  of  equal  strength  with  the  serum, 
no  change  took  place  until  atmospheric  air,  or  oxygen  gas,  was  ad- 
mitted. Whence  it  appears — as  properly  inferred  by  the  late  Mr. 
Egerton  A.  Jennings,  who  published  an  interesting  "  Report  on  the 
Chemistry  of  the  Blood  as  Illustrative  of  Pathology,'" — that  though 
saline  matter  may  be  necessary  to  effect  the  change  of  colour  of  venous 
to  that  of  arterial  blood,  with  so  dilute  a  saline  solution  as  that  which 
exists  in  serum,  the  presence  of  oxygen  is  likewise  necessary.  Dr. 
Davy^  dissents,  however,  from  these  conclusions,  and  is  disposed  to 
infer,  from  all  the  facts  with  which  he  is  acquainted,  that  the  colour  of 
the  blood,  whether  venous  or  arterial, — that  is,  dark  or  florid, — is  inde- 
pendent of  the  saline  matter  in  the  serum,  considered  in  relation  to 
agency;  and  that,  according  to  the  commonly  received  view,  oxygen 
is  the  cause  of  the  bright  hue  of  the  arterial  fluid,  and  its  consump- 
tion and  conversion  into  carbonic  acid  the  cause  of  the  dark  hue  of 
the  venous, — the  saline  matter  being  negative  in  regard  to  colour;  and 
its  chief  use,  in  his  opinion,  being  "  to  preserve  the  red  globules  from 
injury,  prevent  the  solution  of  their  colouring  matter,  retain  their 
forms  unchanged,  and  to  bear  them  in  their  course  through  the  circu- 
lation. 

In  the  difficulty  of  the  subject,  an  idea  has  been  entertained,  that 
the  change  from  arterial  to  venous  blood,  and  conversely,  as  regards 
colour,  is  dependent  in  a  great  measure  on  a  difference  in  the  shape  of 
the  blood  corpuscles ;  and  is  therefore  owing  rather  to  physical  than 
to  chemical  changes  in  them.  Such  is  the  opinion  of  Kaltenbrunner, 
Schultz,  Renter,  Gulliver,  Ilarless,  Kirkes  and  Paget,^  Nasse,  Mulder, 
Funke,  and  others.  It  is  of  course  opposed  to  that  of  Liebig,  already 
stated.  Mulder'*  explains  the  difference  between  the  colour  of  arterial 
and  venous  blood  as  follows.  Two  oxides  of  protein  are  formed  in 
the  act  of  respiration,  which  have  a  strong  plastic  tendency,  and  soli- 
dify around  each  corpuscle,  making  the  capsule  thicker,  and  better 
qualified  to  reflect  light.  Each  corpuscle  of  arterialized  blood  is  then, 
in  reality,  invested  with  a  complete  envelope  of  buffy  coat,  which  gra- 
dually contracts,  and  speedily  forms  cupped  or  bi-concave  surfaces, 
which  are  favourable  to  the  reflection  of  light.  On  reaching  the  capil- 
laries, the  coating  of  the  oxides  of  protein  is  removed,  and  the  cor- 
puscles, losing  their  opaque  investment,  and  cupped  form,  no  longer 

'  Transactions  of  the  Provincial  Medical  and  Surgical  Association,  vol.  iii.,  Worces- 
ter and  London,  1835. 

^  Researches,  Physiological  and  Anatomical,  Dunglison's  Amer.  Med.  Lib.  edit.,  p. 
96,  Philad.,  1840. 

^  Manual  of  Physiology,  2d  Amer.  edit.,  p.  59,  Philad.,  1853. 

■■  Versuch  einer  Allgemeinen  Physiologischen  Chemie,  cited  by  Dr.  Day  in  Simon, 
Animal  Chemistry,  Sydenham  edit.,  p.  193,  Lond.,  1845;  and  Chemistry  of  Vegetable 
and  Animal  Pliysiology,  translated  by  Fromberg,  p.  342,  Lond.  and  Ediiib.,  1849. 


32-i  RESPIRATION. 

reflect  light,  and  tlie  blood  assumes  the  venous  tint.  Dr.  G.  0.  Rees/ 
however,  considers  this  explanation  to  be  entirely  hypothetical  and 
erroneous.  He  rejects  the  idea  of  a  layer  of  plastic  oxy-protein  being 
deposited  on  the  blood  corpuscles  during  respiration;  and  instead  of 
considering  the  hematin  as  undergoing  no  change,  and  maintaining 
the  same  condition  in  arterial  and  venous  blood,  he  looks  upon  it  as 
the  cause  of  the  change  of  colour  in  the  blood  by  virtue  of  some  che- 
mical alteration,  which  takes  place  in  it,  but  whose  nature — if  there 
be  anv  such  alteration — remains  a  mystery.  He  has  himself  advanced 
the  following  ingenious  theory.^  He  found  by  analysis,  that  the  cor- 
puscles of  venous  blood  contain  fatty  matter  in  combination  with 
phosphorus.  This  does  not  exist  in  arterial  blood,  or,  at  most,  is  met 
with  in  it  in  very  small  quantity.  During  respiration  the  oxygen  of 
the  inspired  air  unites  with  the  phosphorus  and  fatt}^  matter,  and  com- 
bustion takes  place;  of  which  the  products  are  water  and  carbonic  acid 
from  the  union  of  the  oxygen  with  the  elements  of  the  fatty  matter ; 
and  phosphoric  acid  from  the  union  of  the  oxygen  with  the  phosphorus. 
The  carbonic  acid  and  water  are  exhaled,  and  appear  in  the  expired 
air ;  the  phosphoric  acid  attracts  the  soda  of  the  liquor  sanguinis  from 
its  combination  with  albumen  and  lactic  acid,  and  forms  a  tribasic 
phosphate  of  soda, — a  salt,  which  possesses  in  a  marked  degree  the 
property  of  communicating  a  bright  colour  to  hematin. 

It  is  proper  to  add,  thatBurdach,  MuUer,  Bruch,  Marchand,  Scherer, 
and  others,  have  failed  to  detect  by  the  microscope  any  difterence  in 
the  external  form  of  the  corpuscles  in  arterial  and  in  venous  blood. 
Still,  Dr.  John  Reid^  is  disposed  to  conclude,  that  the  change  in  the 
blood  from  the  venous  to  the  arterial  hue  in  the  lungs  is  a  physical 
and  not  a  chemical  action;  and  "that  though  there  is  pretty  strong 
evidence  in  favour  of  the  opinion,  that  this  physical  change  consists 
in  an  alteration  of  the  form  of  the  red  corpuscles,  yet  it  is  not  free 
from  doubt."  The  author  has,  indeed,  always  had  great  doubts  on  the 
matter;  and  must  continue  to  have  them,  until  such  a  change  as  is 
supposed  to  be  produced  in  the  shape  of  the  corpuscles  is  demon- 
strated. It  remains  to  be  proved,  that  the  blood — as  Dr.  Carpenter^ 
now  maintains — "is  darkened  by  whatever  tends  to  distend  the  corpus- 
cles, so  as  to  render  them  flat,  or  biconvex,  whilst  it  is  brightened  by 
whatever  tends  to  empty  them,  so  as  to  render  them  more  deeply  bi- 
concave than  usual.  And  observation  of  the  effects  of  oxygen  and 
carbonic  acid,  respectively,  upon  the  form  of  the  corpuscles,  confirms 
the  idea,  that  this  is  the  mode  in  which  these  agents  affect  their  colour, 
for  the  former  causes  their  contraction,  and  renders  their  cell  walls 
thick  and  granular  so  as  to  increase  their  power  of  reflecting  light; 
whilst  the  latter,  producing  a  dilatation  of  the  corpuscles,  thins  their 
cell  walls,  and  enables  them  to  transmit  light  more  readil3\"     Recently, 

»  Lond.  Med.  Gazette,  1844-5,  p.  840.     See,  also,  Mulder,  op.  cit.,  p.  341. 

2  Proceedings  of  the  Royal  Society,  June  3,  1847,  and  Lond.,  Edinb.,  and  Dublin 
Philos.  Magazine  for  July,  1848. 

3  Art.  Respiration,  Cyclop,  of  Anat.  and  Physiology,  Pt.  xxxii.  p.  361,  Loudon, 
August,  1848. 

*  Principles  of  Human  Physiology,  Amer.  edit.,  p.  195,  Philad.  1855. 


H^MATOSIS.  325 

Moleschott^  and  Brucli  have  instituted  a  fresh  set  of  observations  to 
show,  that  the  colour  of  the  blood  is  independent  of  the  shape  of  the 
corpuscles.  The  former  affirms,  that  neither  oxygen,  nor  carbonic 
acid,  which  are  concerned  in  the  coloration  of  that  fluid,  change  per- 
ceptibly the  shape  or  size  of  the  blood-corpuscles  in  man,  the  mam- 
malia, fowls,  or  frogs;  and  he  affirms,  that  very  dilute  solutions  of 
chloride  of  sodium  or  of  sulphate  of  soda,  which  produce  no  change 
in  the  shape  of  the  corpuscles  sensibly  redden  the  blood.  Messrs. 
Todd  and  Bowman^  carefully  examined  two  portions  of  the  same  blood 
after  they  had  been  agitated  in  oxygen  and  carljonic  acid  gas,  and  thus 
been  rendered  respectively  scarlet  and  purple,  and  failed  to  detect  any 
well-marked  difference  in  shape  between  the  corpuscles  of  the  two 
specimens.  Bruch^  has  also  given  additional  reasons  for  the  belief, 
that  the  colour  of  the  blood  is  independent  of  the  shape  of  the 
corpuscles.  He  is  of  opinion,  that  the  natural  colour  is  probabl}'^  that 
of  venous  blood;  and  that  the  vermilion  hue  is  communicated  to 
arterial  blood  by  the  combination  of  the  hematin  with  oxygen ."• 

The  author  has  always  been  of  opinion,  that  the  question  will  have 
to  be  settled  by  tlie  chemist  rather  than  by  the  physicist ;  and  that  the 
change  of  colour  is  owing  to  the  different  effects  of  agents — of  which 
oxygen  is  the  chief — on  the  hematin ;  but  as  to  the  precise  mode  in 
which  the  phenomena  are  accomplished  we  are  in  want  of  information. 

The  slight  diminution,  if  it  exist,  in  the  specific  gravity  of  arterial 
blood  has  been  considered,  but  we  know  not  on  what  grounds,  to  de- 
pend on  the  transpiration,  which  takes  place  into  the  air-cells,  and  was 
formerly  thought  to  be  owing  to  the  combustion  of  oxygen  and  hydro- 
gen. This  will  engage  us  in  another  place ; — as  well  as  the  changes 
produced  in  its  capacity  for  heat,  on  which  several  ingenious  specula- 
tions have  been  founded  to  account  for  animal  temperature.  The 
other  changes  are  at  present  inexplicable;  and  can  only  be  understood 
by  minute  chemical  analysis,  and  by  an  accurate  comparison  of  the 
two  kinds  of  blood, — venous  and  arterial.  This  has  been  carefully 
done  by  Simon,  who  infers,  from  his  analyses,  that  arterial  blood  gene- 
rally contains  less  solid  residue  than  venous  blood;  and  less  fat,  albu- 
men, hematin,  extractive  matter,  and  salts ;  but  further  experiments 
are  demanded. 

The  blood  corpuscles  of  arterial  blood  contain  less  colouring  matter 
than  those  of  venous  blood.^ 

It  is  manifest,  from  the  preceding  detail,  that  our  knowledge  regard- 
ing the  precise  changes  effected  on  the  air  and  the  blood  by  respiration 
is  by  no  means  definite.  We  may,  however,  consider  the  following 
points  established.  In  the  first  place: — the  air  loses  a  part  of  its  oxy- 
gen and  nitrogen;  but  this  loss  varies  according  to  numerous  circum- 

'  Ziir  Lelire  von  der  Blutfarbe,  in  Milnchn.  Illustr.  Med.  Zeit.,  Mars,  1853;  and 
Canstatt's  Jahresb.,  1853,  i.  101,  Wilrzburg,  1854. 

^  Physiological  Anatomy  and  Physiology  of  Man,  Pt.  iv.,  p.  298,  Lond.,  1852;  or 
Amer.  edit.,  Philad.,  1853. 

'^  Ueber  die  Blutfarbe,  in  Siebold  und  Kcilliker's  Zeitschr.  ;  and  Canstatt,  loc.  cit. 

*  J.  Beclard,  Traite  Klementaire  de  Physiologie,  p.  295,  Paris,  1855. 

*  For  various  analyses  of  the  two  kinds  of  blood,  see  Simon,  op.  cit.,  p.  194. 


826  RESPIRATION. 

Stances,  2(lly.  It  is  found  to  have  acquired  carbonic  acid,  the  quan- 
tity of  which  is  also  variable.  3dly.  The  bulk  of  the  air  is  diminished; 
but  the  extent  of  this  likewise  differs.  4thly.  The  blood,  when  it 
attains  the  left  side  of  the  heart,  has  a  more  florid  colour,  othly. 
This  change  appears  to  be  caused  by  the  contact  of  oxygen.  6thly. 
The  blood  in  the  lungs  gets  rid  of  a  quantity  of  carbonic  acid.  Tthly. 
The  oxygen  taken  in  is  more  than  necessary  for  the  carbonic  acid 
formed.  8thly.  The  constituents  of  the  air  pass  directly  through  the 
coats  of  the  pulmonary  vessels,  and  certain  portions  of  each  are  dis- 
charged or  retained,  according  to  circumstances.  9thly.  A  quantity 
of  aqueous  vapour  is  discharged  from  the  lungs ;  the  expired  air  is 
indeed  saturated  with  it.  lOthly.  The  expired  air  has  always  a  tem- 
perature at  or  near  99°;  and,  lastly,  it  would  appear,  from  the  facts 
stated  elsewhere,  that  the  red  corpuscles  are  not  the  only  constituent 
of  the  blood  that  undergoes  a  change  in  the  respiratory  process ;  and 
that  the  fibrin  of  venous  blood  most  nearly  resembles  albumen,  whilst 
that  of  arterial  blood  contains  more  oxygen. 

c.   Cutaneous  Bespii-ation,  d-c. 

A  question  has  arisen,  whether  absorption  and  exhalation  of  air, 
and  conversion  of  blood  from  venous  to  arterial,  take  place  in  any 
other  part  of  the  body  than  the  lungs.  The  reasons,  urged  in  favour 
of  the  affirmative  of  this  question,  are; — that,  in  the  lower  classes  of 
animals,  the  skin  is  manifestly  the  organ  for  the  reception  of  air;  that 
the  mucous  membrane  of  the  lungs  evidently  absorbs  air,  and  is  simply 
a  prolongation  of  the  skin,  resembling  it  in  texture;  and,  lastly,  that 
when  a  limited  quantity  of  air  has  been  placed  in  contact  with  the  skin 
of  a  living  animal,  it  has  been  absorbed,  and  found  to  have  experienced 
the  same  changes  as  are  effected  in  the  luno-s.  Mr.  Cruikshank'  and 
Mr.  Abernethy-^  analyzed  air  in  which  the  hand  or  foot  had  been  con- 
fined for  a  time ;  and  detected  in  it  a  considerable  quantity  of  carbonic 
acid.  Jurine,  having  placed  his  arm  in  a  cylinder  hermetically  closed, 
found,  after  it  had  remained  there  two  hours,  that  oxygen  had  disap- 
peared, and  0.08  of  carbonic  acid  had  been  formed.  These  results 
were  confirmed  by  Gattoni;^  and  from  experiments  by  Professor 
Scharling,  referred  to  before,  the  amount  of  carbon  exhaled  by  the 
skin  in  the  twenty-four  hours,  has  been  estimated  at  two  ounces ;  but 
this  is  probably  beyond  the  real  amount.  On  the  other  hand,  Drs. 
Priestley,"*  Klapp,*  and  Gordon®  could  never  perceive  the  least  change 
in  the  air  under  such  circumstances.  Perhaps  in  these,  as  in  all  cases 
where  the  respectability  of  testimony  is  equal,  the  positive  ought  to  be 
adopted  rather  than  the  negative.  It  is  probable,  however,  that  ab- 
sorption is  effected  with  difficulty;  and  that  the  cuticle,  as  we  have 
elsewhere  shown,  is  placed  on  the  outer  surface  to  obviate  the  bad 

'  Experiments  on  the  Insensible  Perspiration,  &c.,  Lond.,  1795. 
^  Surgical  and  Physiological  Essays,  Part  ii.  p.  115,  Lend.,  1793. 
3  Diet,  des  Sciences  Medicales,  art.  Peau. 

*  Experiments  and  Observations  on  Difl'erent  Kinds  of  Air,  ii.  193,  and  v.  100,  Lend., 
1774. 

*  Inaugural  Essay  on  Cutieular  Absorption,  p.  24,  Philirl,,  1S05. 

^  Ellis's  Imjuiry  into  the  Changes  of  Atmospheric  Air,  &c.,  p.  355,  Edinb.,  1837. 


EFFECTS   OF   DIVIDING   CERTAIN   NERVES.  327 

effects  that  would  be  induced  by  heterogeneous  gaseous,  miasmatic,  or 
other  absorption.  We  have  seen  that  some  of  the  deleterious  gases, 
as  sulphuretted  hydrogen,  are  most  powerfully  penetrant,  and,  if  they 
could  enter  the  surface  of  the  body  with  readiness,  unfortunate  re- 
sults might  supervene.  In  those  parts  where  the  cuticle  is  extremely 
delicate,  as  in  the  lips,  some  conversion  of  venous  into  arterial  blood 
may  be  effected,  and  this  may  be  a  great  cause  of  their  florid  colour. 

According  to  this  view,  the  arterialization  of  the  blood  occurs  in  the 
lungs  chiefly,  owing  to  their  formation  being  so  admirably  adapted  to 
the  purpose;  and  it  is  not  effected  in  other  parts,  because  their  arrange- 
ment is  unfavourable  for  such  a  result. 

d.  Effects  of  the  Section  of  certain  Nerves  on  Respiration. 

It  remains  to  inquire  into  the  effect  produced  on  the  lungs  by  the 
cerebro-spinal  and  spuial  nerves  distributed  to  them, — or  rather,  into 
what  is  the  effect  of  depriving  the  respiratory  organs  of  their  nervous 
influence  from  the  brain  and  spinal  marrow.  The  only  encephalic 
nerves,  distributed  to  them,  are  the  pneamogastric  or  eighth  pair  of 
Willis,  which,  we  have  seen,  are  sent,  as  their  name  imports,  to  both 
the  lungs  and  stomach.  The  section  of  these  nerves  early  suggested 
itself  to  physiologists,  but  it  is  only  in  recent  times  that  the  pheno- 
mena resulting  from  it  have  been  clearly  comprehended.  The  opera- 
tion appears  to  have  been  performed  as  long  ago  as  the  time  of  Eufus 
of  Ephesus,  and  was  afterwards  repeated  by  Chirac,  Bohn,  Duverney, 
Vieussens,  Schrader,  Valsalva,  Morgagni,  Haller,  and  numerous  other 
distinguished  physiologists.  It  is  chiefly,  however,  in  recent  times, 
and  especially  from  the  labours  of  Dupuytren,  Dumas,  De  Blainville, 
Provengal,  Legallois,  Magendie,  Breschet,  Hastings,  Broughton,  Sir 
Benjamin  Brodie,  Wilson  Philip,  Longet,  John  Reid,  and  others,  that 
the  precise  effects  upon  the  respiratory  and  digestive  functions  have 
been  appreciated. 

When  these  nerves  are  divided  in  a  living  animal,  on  both  sides  at 
once,  the  animal  dies  more  or  less  promptly ;  at  times  immediately 
after  their  division,  but  it  sometimes  lives  for  a  few  days; — M.  Magen- 
die says  never  beyond  three  or  four.  The  eftects  produced  upon  the 
voice,  by  their  division  above  the  origin  of  the  recurrents,  will  be 
referred  to  under  another  head.  Such  division,  however,  does  not 
simply  implicate  the  larynx;  it  necessarily  aftects  the  lungs,  as  well 
as  the  stomach.  As  regards  the  larynx,  the  same  results,  according 
to  M.  Magendie,^  are  produced  by  dividing  the  trunk  of  the  pneu- 
mogastric  above  the  origin  of  the  recurrents  as  by  the  division  of 
the  recurrents  themselves ;  the  muscles,  whose  function  it  is  to  dilate 
the  glottis,  are  paralyzed  ;  and  consequently,  during  inspiration,  no 
dilatation  takes  place;  Avhilst  the  constrictors,  which  receive  their 
nerves  from  the  superior  laryngeal,  preserve  all  their  action,  and  close 
the  glottis,  at  times  so  completely,  that  the  animal  dies  at  once  from 
suffocation.  But  if  the  division  of  those  nerves  should  not  induce  in- 
stant death  in  this  manner, phenomena  f-)llow,  considerably  alike  in  all 
cases,  which  go  on  until  the  death  of  the  animal.     These  are  the  fol- 

'  Precis,  &c.,  2de  edit.,  ii.  355. 


328  RESPIRATION. 

lo\ying: — respiration  is,  at  first,  difficult;  the  inspiratory  movements 
are  more  extensive  and  rapid,  and  the  animal's  attention  appears  to 
be  particularlv  directed  to  them;  the  locomotive  movements  are  less 
frequent,  and  evidently  fatigue;  frequently,  the  animal  remains  en- 
tirely at  rest ;  the  formation  of  arterial  blood  is  not  prevented  at  first, 
but  soon,  on  the  second  day  for  instance,  the  difficulty  of  breatliing 
augments,  and  the  inspiratory  efforts  become  gradually  greater.  The 
arterial  blood  has  now  no  longer  the  vermilion  hue  proper  to  it.  It  is 
darker  than  it  ought  to  be:  its  temperature  falls;  respiration  requires 
the  exertion  of  all  the  respiratory  powers;  the  body  gradually  becomes 
cold,  and  the  animal  dies.  On  opening  the  chest,  the  air-cells,  bronchi, 
and  frequently  the  trachea,  are  found  filled  by  a  frothy  fluid,  which  is 
sometimes  bloody;  the  substance  of  the  lung  is  tumid ;  the  divisions  and 
even  the  trunk  of  the  pulmonary  artery  are  greatly  distended  with  dark, 
almost  black,  blood ;  and  extensive  effusions  of  serum  and  even  of  blood 
are  found  in  the  parenchyma  of  the  lungs.  Experiments  have,  like- 
wise, shown  that,  in  proportion  as  these  phenomena  appeared,  the  ani- 
mal consumed  less  and  less  oxygen,  and  gave  off  a  progressively  dimin- 
ishing amount  of  carbonic  acid. 

From  the  phenomena  that  occur  after  the  section  of  the  nerves  on 
both  sides,  it  would  seem  to  follow,  that  the  first  effect  is  exerted  upon 
the  tissues  of  the  lungs,  which,  being  deprived  of  nervous  influence, 
are  no  longer  capable  of  exerting  their  ordinary  tonicity  and  muscu- 
larity. Eespiration,  consequently,  becomes  difficult ;  the  blood  no 
longer  circulates  freely  through  the  capillary  vessels  of  the  lungs ; 
the  consequence  is,  that  transudation  of  its  serous  portions,  and  occa- 
sionally effusion  of  blood,  owing  to  rupture  of  small  vessels,  takes 
place,  filling  the  air-cells  more  or  less ;  until,  ultimately,  all  com- 
munication is  prevented  between  the  inspired  air  and  the  bloodves- 
sels, and  the  conversion  of  venous  into  arterial  blood  is  completely 
precluded.  Death  is  then  the  inevitable  and  immediate  consequence. 
The  division  of  the  nerve  on  one  side  affects  merely  the  lung  of  the 
corresponding  side.  Life  can  be  continued  by  the  action  of  one  lung 
only :  it  is,  indeed,  a  matter  of  astonishment  how  long  some  indi- 
viduals have  lived  when  the  lungs  have  been  almost  wholly  obstructed. 
Every  morbid  anatomist  has  had  repeated  opportunities  of  observing, 
that  for  a  length  of  time  prior  to  dissolution,  in  cases  of  pulmonary 
consumption,  the  process  of  respiration  must  have  been  carried  on  by 
a  very  small  portion  of  lung. 

From  his  experiments  on  this  subject.  Sir  Astley  Cooper  infers,  that 
the  pneumogastric  nerve  is  most  important ; — 1st,  in  assisting  in  the 
maintenance  of  the  function  of  the  lungs,  by  contributing  to  the  change 
of  venous  into  arterial  blood;  2dly,  in  being  necessary  to  the  act  of 
swallowing  ;  and  3dly,  in  being  essential  to  the  digestive  process.  Dr. 
John  Reid  is  of  opinion,  that  the  pulmonary  branches  seem  to  be 
nerves  concerned  chiefly  in  transmitting  to  the  medulla  oblongata  the 
impressions  that  excite  respiratory  movements,  and  are  thus  princi- 
pally afferent  nerves ;  but  it  is  possible,  he  thinks,  that  they  contain- 
motor  filaments  also.' 

'  Edinb.  Med.  and  Surg.  Joum.,  April,  1839  ;  and  art.  Par  Vagum  in  Cyclop,  of 
Anat.  and  Physiol.,  Part  sxvii.  p.  896,  March,  1846. 


OF   ANIMALS.  329 

The  experiments  of  Dr.  Wilson  Philip'  and  others  show,  moreover, — 
what  has  been  more  than  once  inculcated, — the  great  similarity  between 
the  nervous  and  galvanic  fluids.  The  state  of  dyspnoea  induced  by  the 
division  of  the  pneumogastric  nerves  was,  in  numerous  cases,  entirely 
removed  by  the  galvanic  current  passed  from  one  divided  extremity  to 
the  other.  The  results  of  these  experiments  induced  him  to  try  gal- 
vanism in  cases  of  asthma.  By  transmitting  its  influence  from  the 
nape  of  the  neck  to  the  pit  of  the  stomach,  he  gave  decided  relief  in 
every  one  of  twenty-two  cases ;  four  of  which  occurred  in  private  prac- 
tice, and  eighteen  in  the  Worcester  Infirmary. 

Sir  A.  Cooper^  instituted  similar  experiments  on  the  phrenic  nerves. 
As  soon  as  they  were  tied,  the  most  determined  asthma  was  produced; 
breathing  went  on  by  means  of  the  intercostal  muscles ;  the  chest  was 
elevated  to  the  utmost  by  them ;  and  in  expiration  the  chest  was  as 
remarkably  drawn  in.  The  animals  did  not  live  an  hour ;  but  they 
did  not  die  suddenly,  as  they  do  from  pressure  on  the  carotid  and 
vertebral  arteries.  The  lungs  appeared  healthy,  but  the  chest  con- 
tained more  than  its  natural  exhalation.  He  also  tied  the  great  sym- 
pathetic; which  produced  little  effect;  the  heart  appeared  to  beat  more 
quickly  and  feebly  than  usual.  The  animal  was  kept  seven  days, 
when  one  nerve  was  found  ulcerated  through ;  the  other  nearly  so  at 
the  situation  of  the  ligatures.  On  examination,  no  particular  altera- 
tion of  any  organ  was  observed.  Lastly,  Sir  Astley  tied  all  three 
nerves  on  each  side,  the  pneumogastric,  phrenic,  and  great  sympa- 
thetic: the  animal  lived  little  more  than  a  quarter  of  an  hour,  and 
died  of  dyspnoea.  From  these  experiments,  he  infers,  that  the  sudden 
deatli,  which  he  found  to  follow  pressure  on  the  sides  of  the  neck, 
cannot  be  attributed  to  any  injury  of  the  nerves,  but  to  an  impediment 
to  the  due  supply  of  blood  to  the  great  centres  of  nervous  influence. 

The  nervous  centre  of  the  respiratory  movements  is  the  vesicular 
neurine  in  the  upper  part  of  the  medulla  oblongata.  Into  it  the  pneu- 
mogastric nerves,  which  appear  to  be  the  chief  excitors  of  respiration, 
may  be  traced;  and  from  it  the  different  motor  or  efferent  nerves  pro- 
ceed either  directly  or  indirectly.  Of  these,  the  most  important  is  the 
phrenic.  The  vesicular  neurine  of  the  medulla  receives  the  impression 
of  the  besoin  de  respirer  or  necessity  of  breathing;  and  thence  it  is 
reflected  along  the  appropriate  nerves  to  the  muscles  concerned  in 
inspiration.^ 

e.  Respiration  of  Animals. 

In  concluding  the  subject  of  respiration,  we  may  briefly  advert  to 
the  different  modes  in  which  the  process  is  effected  in  the  classes  of 
animals,  and  especially  in  birds, — the  respiratory  organs  of  which  con- 
stitute one  of  the  most  singular  structures  of  the  animal  economy. 
The  lungs  themselves  are  comparatively  small,  and  adherent  to  the 
chest, — where  they  seem  to  be  placed  in  the  intervals  of  the  ribs. 

'  Experimental  Inquiry  into  the  Laws  of  the  Vital  Functions,  &c.,  2d  edit.,  p.  223, 
Lend.,  1818;  also,  Journal  of  Science  and  Arts,  viii.  72. 
^  Op.  cit.,  p.  475. 
^  See,  on  all  this  subject,  Louget,  Traite  de  Physiologie,  ii.  328,  Paris,  1850. 


330  CIRCULATION". 

They  are  covered  by  the  pleura  on  their  under  surface  only,  so  that 
they  are,  in  fact,  on  the  outside  of  the  cavity  of  the  chest.  A  great 
part  of  the  thorax,  as  well  as  of  the  abdomen,  is  occupied  by  mem- 
branous air-cells,  into  which  the  lungs  open  by  considerable  apertures. 
Besides  these  cells,  a  considerable  portion  of  the  skeleton  in  many 
birds  forms  receptacles  for  air,  and  if  we  break  a  long  bone  of  a  bird 
of  flight,  and  blow  into  it  when  the  body  of  the  animal  is  immersed 
in  water,  bubbles  of  air  will  escape  from  the  bill.  The  object,  of 
course,  of  all  this  arrangement  is  to  render  the  body  light,  and  thus 
to  facilitate  its  motions.  Hence,  the  largest  and  most  numerous  bony 
cells  are  found  in  such  birds  as  have  the  highest  and  most  rapid  flight, 
as  the  eagle.  The  barrels  of  the  quills  are  likewise  hollow,  and  can 
be  filled  with  air,  or  emptied  at  pleasure.  In  addition  to  the  uses  just 
mentioned,  these  air  receptacles  diminish  the  necessity  for  breathing 
so  frequently  in  the  rapid  and  long-continued  motions  of  certain  birds, 
and  in  the  great  vocal  exertions  of  those  that  sing. 

In  fishes,  in  the  place  of  lungs  we  find  branchice  or  gills,  which  are 
placed  behind  the  head  on  each  side,  and  have  a  movable  gill-cover. 
By  the  throat,  which  is  connected  with  the  gills,  the  water  is  conveyed 
to,  and  distributed  through  them:  in  this  way,  the  air,  contained  in 
the  water,  which,  according  to  Biot,  Von  Humboldt^  and  Provengal, 
Configliachi,  and  Thomson,"^  is  richer  in  oxygen  than  that  of  the  atmo- 
sphere, having  from  29  to  32  parts  in  the  100,  instead  of  20  or  21, 
comes  in  contact  with  the  blood  circulating  through  the  gills.  The 
water  is  afterwards  discharged  through  the  branchial  openings, — ajjer- 
iurce  branchiales, — and,  consequently,  they  do  not  expire  along  the 
same  channel  as  they  inspire. 

Lastly,  in  the  insect  tribe, — in  the  white-blooded  animal, — we  find 
the  function  of  respiration  effected  altogether  by  the  surface  of  the 
body;  at  least,  so  far  as  regards  the  reception  of  air,  which  enters 
through  apertures  termed  stigmata,  the  external  terminations  of  ira- 
chece  or  air  tubes,  whose  office  it  is  to  convey  air  to  different  parts  of 
the  sj^stem. 

In  all  these  cases,  we  find  precisely  the  same  changes  effected  upon 
the  inspired  air; — and  especially,  that  oxygen  has  disappeared;  and 
that  carbonic  acid  of  a  bulk  nearly  equal  to  that  of  the  organ  is  met 
with  in  the  residuary  air.^ 


CHAPTEK  IV. 

CIRCULATION". 

The  next  function  to  be  considered  is  that  by  which  the  products  of 
the  various  absorptions,  converted  into  arterial  blood  in  the  lungs,  are 

'  Memoires  de  la  Societe  d'Arcueil  i.  252,  and  ii.  400. 

2  Dr.  Thomson  found  that  100  cubic  inches  of  the  water  of  the  river  Clyde  con- 
tained 3-1 13  inches  of  air  ;  and  that  tlie  air  contained  29  per  cent,  of  oxygen.  Edinb. 
New  Philosoph.  Journal,  xxi.  370,  Edinb.,  1836. 

3  See  Carpenter's  Principles  of  Comparative  Physiology,  Amer.  edit.,  Philad.  1854. 


CIRCULATORY   APPARATUS. 


331 


Heart  of  the  Duf 


D. 


Right  auricle.  E.  Right  ventricle. 
K.  Left  auricle.  L.  Left  ventricle.  F. 
Pulmonary  artery.     A.  Aorta. 


distributed  to  every  part  of  the  body, — a  Fig-  SI* 

function  most  important  to  the  physiolo- 
gist and  the  pathologist,  and  without  a 
knowledge  of  which  it  is  impossible  for 
the  latter  to  comprehend  the  doctrine  of 
disease. 

Assuming  the  heart  to  be  the  great 
organ  of  the  function,  the  circulatory 
fluid  must  set  out  from  it,  be  distributed 
through  the  lungs,  undergo  aeration  there, 
be  sent  to  the  opposite  side  of  the  heart, 
whence  it  is  distributed  to  every  part  of 
the  system  by  efferent  vessels,  and  be  re- 
turned by  veins  or  afferent  vessels  to  the 
right  side,  from  which  it  set  out, — thus 
performing  a  complete  circuit. 

The  lower  classes  of  animals  differ  es- 
sentially, as  we  shall  find  hereafter,  in  their 

organs  of  circulation  :  whilst  in  some,  the  apparatus  appears  to  be 
confounded  with  the  digestive;  in  others,  the  blood  is  propelled  with- 
out any  great  central  organ ;  and  in  others,  again,  the  heart  is  biit  a 
siligle  organ.  In  man,  and  in  the  upper  classes  of  animals,  the  heart 
is  double; — consisting  of  two  sides,  or  really  two  hearts,  separated  from 
each  other  by  a  septum.  In  the  dugong,  the  two  ventricles  are  almost 
entirely  detached  from  each  other. 

As  all  the  blood  of  the  body  has  to  be 
emptied  into  this  central  organ,  and  to  be 
subsequently  sent  from  it ;  and  as  its  flow  is 
continuous,  two  cavities  are  required  in  each 
heart, — the  one  to  receive  the  blood,  the  other 
to  propel  it.  The  latter  distinctly  contracts 
and  dilates  alternately.  The  cavity  or  cham- 
ber of  each  heart,  that  receives  the  blood,  is 
called  auricle^  and  the  vessels  that  transport 
it  thither  are  veins;  the  cavity  by  which  the 
blood  is  projected  forwards  is  called  ventricle^ 
and  the  vessels,  along  which  the  blood  is  sent, 
are  arteries.  One  of  these  hearts  is  entirely  ap- 
propriated to  the  circulation  of  venous  blood, 
and  hence  has  been  called  venous  hearty — also 
right  or  anterior  heart,  from  its  situation, — and 
pulmonary^  from  the  pulmonary  artery  arising 
from  it.  The  other  is  for  the  circulation  of 
arterial  blood,  and  is  hence  called  arterial  heart, 
also  left  or  posterior,  from  its  situation, — aortic 
heart,  because  the  aorta  arises  from  it ;  and 
systeynic,  because  the  blood  is  sent  from  it  to 
the  general  system. 

The  whole  of  the  vessels  communicating 

■j-l,     xl  •     T  J     1  ,  ,     •  TIT         sysiomic  capiii 

Wltn    the    right    heart    contain    venous    blood  ;     collected  by  the  veins,  and  earned 

those  of  the  left  side  arterial  blood.  \lf^X  "'"  ^'"'^  '^'""'"'  '^'  ^'''* 


Diagram  of  the  Circulating  Ap- 
paratus in  MamniaU  and  Birds. 

a.  The  heart,  containing  four  cavi- 
ties. !>.  Vena  cava,  delivering  ve- 
nous blood  into  e,  the  right  auricle. 
d.  The  right  ventricle,  propelling 
venous  blood  through  e,  the  pulmo- 
nary artery,  to  /,  the  capillaries  of 
the  lungs,  g.  The  left  auricle,  re- 
ceiving the  aerated  blood  from  the 
pulmonary  vein,  and  delivering  it 
to  the  left  ventricle,  h,  which  pro- 
pels it  through  the  aorta,  i,  to  the 
systemic  capillaries,  y,  ivhence  it  Is 


332 


CIRCULATIOISr. 


If  we  consider  the  heart  to  be  the  centre,  two  circulations  must  be 
accomplished,  before  the  blood,  setting  out  from  one  side  of  the  heart, 
performs  the  whole  circuit.  One  of  these  consists  in  the  transmission 
of  the  blood  from  the  right  side  of  the  heart,  through  the  lungs,  to  the 
left;  the  other,  in  its  transmission  from  the  left  side,  along  the  arteries, 
and  by  means  of  the  veins,  back  to  the  right.  The  former  is  called  the 
lesser  or  pulmonic,  the  latter  the  grexiter  or  systemic  circulation.  The 
organs,  by  which  these  are  effected,  will  require  a  more  detailed  exa- 
mination. 

1.    AXATOMT  OF  THE  CIRCULATORY  ORGANS. 

The  circulatory  apparatus  is  composed  of  organs  by  which  the  blood 
is  put  in  motion,  and  along  which  it  passes  during  its  circuit. 

a.  Heart. 

To  simplify  the  consideration  of  the  subject  we  shall  consider  the 

heart  double ;  and  that 


Fig.  93. 


Heart  placed  with  its  Anterior  Surfnce  upward?,  and  its  Apex 
turned  to  the  right  hand  of  the  spectator.  The  Right  Auricle 
and  Right  Ventricle  are  both  opened. 

Parts  in  right  auricle: — h.  Eutrance  of  vena  cava  superior,  which 
is  itself  markeil  d.  Inferior  cava,  mai'ked  r,  has  a  prohe  passed 
through  it  into  the  auricle,  rn.  The  smooth  part  of  the  auricle,  o. 
Musculi  pectiuati,  seen  in  the  auricular  appendix  which  is  cut  open. 
n.  Eustachian  valve  placed  over  the  mouth  of  the  inferior  cava.  i. 
Fossa  ovalis,  or  vestige  of  the  foramen  ovale,  s.  Annulus  ovalis. 
The  probe  leading  from  s  into  the  right  ventricle  passes  through  the 
auriculo-veutricular  opening,  v.  Mouth  of  the  coronary  vein.  Parts 
in  the  right  ventricle,  in  which  the  other  end  of  the  probe,  from  s, 
appears: — a.  Cavity  of  couus  arteriosu.s,  leading  to  the  pulmonary 
artery,  Jr.  I.  Convex  septum  between  the  ventricles,  c.  Anterior 
segment  of  the  tricuspid  valve,  connected  by  slender  cords,  the 
chordae  tendiuea,  to  the  musculi  papillares,  e.    /.  The  aorta. 


each  system  of  circu- 
lation is  composed  of 
a  heart;  of  arteries, 
through  which  the 
blood  is  sent  from  tRe 
heart;  and  of  veins,  by 
which  the  blood  is  re- 
turned to  it.  At  the 
minute  termination  of 
each  of  these  is  a  capil- 
lary system.  We  shall 
first  describe  the  cen- 
tral oi'gan  as  forming 
two  distinct  hearts;  and 
afterwards  the  two  uni- 
ted. 

The  pulmonic,  right, 
or  anterior  heart,  called 
also  heart  of  hlach  hlood, 
is  composed  of  an  auri- 
cle and  a  ventricle.  The 
auricle,  so  termed  from 
some  resemblance  to  a 
small  ear,  is  situate  at 
the  base  of  the  organ, 
and  receives  the  whole 
of  the  blood  returned 
from  various  parts  of 
the  body  by  three 
veins; — the  two  vense 
cav^e,  and  the  coronary. 
The  vena  cava  descend- 
ens  terminates  in  the 
auricle  in  the  direction 


CIRCULATORY  APPARATUS. 


833 


situate  in  the  anterior 
Fig.  94. 


of  the  aperture  by  which  the  auricle  communicates  with  the  ventricle. 
The  vena  cava  ascendens,  the  termination  of  which  is  directed  more  back- 
wards, has  the  remains  of  a  valve  which  is  much  larger  in  the  foetus, 
called  valve  of  Eustachius.  The  third  vein  is  the  cardiac  or  coronary  ; 
it  returns  the  blood  from  the  heart  which  has  been  carried  thither  by 
the  coronary  artery.  In  the  septum  between  the  right  and  left  auricle, 
there  is  a  superficial  depression,  about  the  size  of  the  point  of  the 
finger,  which  is  the  vestige  of  the  tbramen  ovale, — an  important  part  of 
the  circulatory  apparatus  of  the  foetus.  The  opening  through  which 
the  auricle  projects  its  blood  into  the  ventricle,  is  situate  downwards 
and  forwards,  as  seen  in  Fig.  93.  The  inner  surface  of  the  ^J^'oper 
auricle^  or  that  which  more  particularly  resembles  the  ear  of  a  quadru- 
ped,— the  remainder  being  sometimes  called  siniis  venosus  or  sinus  vena- 
rum  cavariim, — is  distinguished  by  having  a  number  of  fleshy  pillars 
in  it,  which,  from  their  supposed  resemblance  to  the  teeth  of  a  comb, 
are  called  musculi  'pectinati.  They  are  mere  varieties,  however,  of  the 
columnce  carneoi  of  the  ventricles. 

The  right  ventricle  or  pulmonary  ventricle  is 
part  of  the  heart;  the  base  and  apex  corre- 
sponding to  those  of  the  heart.  Its  cavity  is 
generally  greater  than  that  of  the  left  side,  and 
its  parietes  not  so  thick,  owing  to  its  having 
merely  to  force  the  blood  through  the  lungs. 
It  communicates  with  the  auricle  by  the  auri- 
culo-veyiti-icular  opening — ostium  venosum;  and 
the  only  other  opening  into  it  is  that  which 
communicates  with  the  interior  of  the  pul- 
monary artery.  The  opening  between  the 
auricle  and  ventricle  is  furnished  with  a  tri- 
partite valve,  called  tricuspid  or  trigloddn;  and 
the  pulmonary  artery  has  three  others,  the  sigmoid  or  semilunar.  From 
the  edge  of  the  tricuspid  valve,  next  the  apex  of  the  heart,  small,  round, 
tendinous  cords^  called  chordae  tendineoe^  are  sent  oft',  which  are  fixed,  as 
represented  in  Fig.  93,  to  the  extremities  of  a  few  strong  columnar  car- 
nece, — called  musculi  papillares.  These  tendinous  cords  are  of  such  a 
length  as  to  allow  the  valve 
to  be  laid  against  the  sides  of 
the  ventricle,  in  the  dilated 
state  of  that  organ;  and  to  ad- 
mit of  its  being  pushed  back 
by  the  blood,  until  a  nearly 
complete  septum  is  formed 
durino;  the  contraction  of  the 
ventricle.  The  semilunar  or 
sigmoid  valves  are  three  in 
number,  situate  around  the 
artery.  When  these  fall  to- 
gether, there  must  necessarily     c.  orifices  of  the  coronary  arteries. 

be  a  space  left  between  them. 

To  obviate  the  inconvenience  that  would  result  from  the  existence  of 

such  a  free  space,  a  small  granular  body  is  attached  to  the  middle  of 


Semilunar  Valves  closed. 


Diagram  of  the  Semilunar  Valves  of  the  Aorta. 
!.  Corpus  Arantil  on  the  free  border.    6.  Attached  border. 


334 


CIRCULATION. 


tlie  margin  of  each  valve;  and  these,  coming  together,  as  at  A,  Fig.  94, 
when  the  valves  are  shut  down,  complete  the  diaphragm,  and  prevent 
any  blood  from  passing  back  to  the  heart.  These  small  bodies  are 
termed,  from  their  reputed  discoverer,  corjmscida  Arantii,  and  also  cor- 
puscula  Morgagnii;  or,  from  their  resemblance  to  the  seed  of  the  sesamum, 
corpuscula  sesamoidea.  The  valves,  when  shut,  are  concave  towards  the 
lungs,  and  convex  towards  the  ventricle.  Immediatel}'-  above  thern  the 
artery  bulges  out,  forming  three  sacculi  or  sinuses,  called  sinuses  of  Val- 
salva. These  are  often  said  to  be  partly  formed  by  the  pressure  of  the 
blood  upon  the  sides  of  the  vessel.  The  structure  is  doubtless  ordained, 
and  is  admirably  adapted  for  a  specific  purpose, — namely,  to  allow  the 
free  edges  of  the  valves  to  be  readily  caught  by  the  refluent  blood,  and 
thus  facilitate  their  closure.    Within  the  right  ventricle,  and  especially 

Fig.  96. 


Sections  of  Aorta,  to  show  the  action  of  the  Semilunar  Valves. 

A.  The  valves,  represented  by  the  dotted  lines,  in  contact  with  the  arterial  walls,  represented  by  the 
continuous  outer  line.  b.  The  arterial  wall  distended  into  three  pouches  (a),  and  drawn  away  from  the 
valves,  which  are  straightened  into  the  form  of  an  equilateral  triangle,  as  represented  by  tlie  dotted  lines. 
r.  The  margins  of  the  valves  when  in  action: — a.  Tlie  pouches  between  the  valves  and  the  arterial  wall. 
h.  The  apposed  edges,  c.  The  apposed  surfaces  of  the  valves,  d.  Mouths  of  coronary  arteries,  e.  Cut 
edge  of  aorta. 

towards  the  apex  of  the  heart,  many  strong  eminences  are  seen,  columnce 
carnece  (Fig.  93),  These  run  in  different  directions,  but  the  strongest 
of  them  longitudinally  with  respect  to  the  ventricle.  They  are  of  va- 
rious sizes,  and  form  a  beautifully  reticulated  texture.  Their  chief  use 
probably  is,  to  strengthen  the  ventricle,  and  prevent  it  from  being 
over-distended;  in  addition  to  which  they  may  tend  to  mix  the  differ- 
ent products  of  absorption. 

The  corporeal^  left,  aortic,  or  systemic  heart, — called  also  heart  of  red 
hhod, — has  likewise  an  auricle  and  a  ventricle.  The  hft  auricle  is  con- 
siderably thicker  and  stronger  but  smaller  than  the  right;  and  it  is 
likewise  divided  into  simts  (sinus  arteriosus)  and  2:)roper  auricle,  which 
form  a  common  cavity.  The  columns  in  the  latter  are  like  those  of 
the  right,  but  less  distinct.  From  the  under  part  of  the  auricle,  a  cir- 
cular passage,  termed  ostium  arteriosum  or  "auricular  orifice,"  leads  to 
the  posterior  part  of  the  base  of  the  cavity  of  the  left  ventricle.  The 
left  auricle  receives  the  blood  from  the  pulmonary  veins.  The  left  or 
aortic  ventricle  is  situate  at  the  posterior  and  left  part  of  the  heart.  Its 
sides  are  three  times  thicker  and  stronger  than  those  of  the  right  ven- 
tricle, to  adapt  it  for  the  much  greater  force  it  has  to  exert;  for,  whilst 
the  right  ventricle  merely  sends  its  blood  to  the  lungs,  the  left  ventricle 
transmits  it  to  every  part  of  the  body.     Its  muscular  force  has  been 


CIECULATORY   APPARATUS. 


835 


Fig.  97. 


estimated  at  twice  tliat  of  tlie  right.'  It  is  narrower  and  rounder,  but 
considerably  longer,  than  the  right  ventricle,  and  forms  the  apex  of 
the  heart.  The  internal  surface  of  this  ventricle  has  the  same  general 
appearance  as  the  other;  but  differs 
from  it  in  having  larger,  more  nu- 
merous, firmer,  and  stronger  columnse 
carneoe.  In  the  aperture  of  communi- 
cation with  the  corresponding  auri- 
cle, there  is  here,  as  in  the  opposite 
side  of  the  heart,  a  ring  or  zone,  from 
which  a  valve,  essentially  like  the 
tricuspid,  goes  off".  It  is  stronger, 
however,  and  divided  into  two  prin- 
cipal portions  only;  the  chordae  tend- 
ine«  and  musculi  jmjnUares,  are  also 
stronger  and  more  numerous.  This 
valve  has  been  termed  mitral,  from 
some  supposed  resemblance  to  a 
bishop's  mitre,  and  bicuspid.  At  the 
fore  and  right  side  of  the  valve,  and 
behind  the  commencement  of  the 
pulmonary  artery,  a  round  opening 
exists,  which  is  the  mouth  of  the 
aorta.  Here  are  three  semilunar 
valves,  with  their  coiyuscula  Arantii; 
like  those  of  the  pulmonary  artery, 
but  a  little  stronger;  and,  on  the 
outer  side  of  the  semilunar  valves. 


Heart  seen  from  behind,  and  having  the  Left 
Auricle  and  Ventricle  opened. 

Parts  in  left  auricle: — a.  Smooth  wall  of  ati- 
ricular  septum,  c,  c,  c.  Opeaiugs  of  the  four 
pulmonary  veins,  d.  Left  auricular  appendage. 
e.  Slight  depression  in  the  septum,  corresponding 
to  the  fossa  ovalis  on  the  right  side.  A  probe 
is  seelll,  which  passes  down  into  the  ventricle 
through  the  auriculo-ventricular  orifice.  Parts 
in  left  ventricle: — i.  Posterior  segment  of  the 
,  .  -      -  Ti.T         mitral  valve,  behind  which  is  the  probe  passed 

are    the    sinuses    of      Vatsatva,    a    little     tVom  the  left  auricle.    ■».,  w.  The  two  groups  of 
„  •  i.    J.1   „        il      „„     ,-P    j-"U^      musculi  papillares.    o.  Section  of  the  thick  walls 

more     prominent    than    those     Ot    the     ^f  this  ventricle,  which  may  be  comparod  with 
■nnlmnnov'sr  nrtar-ir  that  of  the  walls  of  the  right  ventricle,  Fig.  93. 

puimoil.liy   aiLCiy.  _         r.  Entrance  of  inferior  cava. 

The  structure  of  the  two  hearts  is 
the  same.    A  serous  membrane  covers  both.    It  is  an  extension  of  the 
inner  membrane  of  the  pericardium. 

The  substance  of  the  heart  is  essentially  muscular.  The  fibres  run 
in  different  directions,  longitudinally  and  transversely,  but  most  of 
them  obliquely.  Many  pass  over  the  point,  from  one  heart  to  the 
other,  and  all  are  so  involved  as  to  render  it  difficult  to  unravel  them. 
The  cavities  are  lined  by  a  thin  membrane,  endocardium,,  which  differs 
somewhat  in  the  two  hearts; — being  in  one  a  prolongation  of  the 'inner 
coat  of  the  aorta,  and  in  the  other  of  the  venae  cavae.  On  this  account, 
the  inner  coat  of  the  left  heart  is  but  slightly  extensible,  more  easily 
ruptured,  and  considerably  disposed  to  ossify;  that  of  the  right  heart, 
on  the  other  hand,  is  very  extensible,  not  readily  ruptured,  and  but 
little  liable  to  ossify.  The  endocardium  invests  all  the  elevations  and 
depressions  of  the*^  heart,  as  well  as  the  papillary  muscles  and  their 
tendons,  and  the  valves.  It  consists  of  three  layers;  an  epithelium,  an 
elastic  layer  on  which  the  varying  thickness  of  the  endocardium  in  dif- 

'  Valentin,  Lehrbucli  der  Physiologic  des  Menschen,  i.  415,  Braunscliweig,  1844. 


536 


CIECULATION. 


ferent  situations  depends,  and  a  thin  laj-er  of  connective  tissue.^  M. 
Deschamps^  Las  described  a  membrane,  which  is  situate  between  the 
endocardium  and  the  areolar  tissue  that  lines  the  muscular  structure  at 
its  inner  surface,  and  belongs  essentially  to  the  elastic  fibrous  tissue. 

The  tissue  of  the  heart  is  supplied  with  blood  by  the  cardiac  or  coro- 
nary arteries — the  first  division  of  the  aorta ;  and  their  blood  is  con- 
veyed back  to  the  right  auricle  by  the  coronary  veins.  The  nerves, 
which  follow  the  ramifications  of  the  coronary  arteries,  proceed  chiefly 
from  a  plexus,  formed  by  the  spinal  nerves  and  great  sympathetic. 
Besides  the  large  ganglia  on  the  cardiac  plexuses  at  the  base  of  the 
organ,  the  nerves  present  minute  ganglia  along  their  course  in  its  sub- 
stance ;^  and  Dr.  Eobert  Lee^  has  affirmed,  that  it  can  be  clearly  de- 
monstrated, that  every  artery  distributed  throughout  the  walls  of  the 
heart,  and  every  muscular  fasciculus  of  tlie  organ,  is  supplied  with 
nerves  upon  which  ganglia  are  formed.  The  results  of  Dr.  Lee's  ob- 
servations, are  not,  however,  considered  by  all  to  be  established.* 

In  both  hearts,  the  auricles  are  much  thinner  and  more  capacious 
than  the  ventricles ;  but  they  are  themselves  much  alike  in  structure 


Fig.  98. 


Fig.  99. 


Anterior  View  of  External  Musoulnr  Lnj'er 
of  the  Heart  after  removal  of  its  Serous  Coat, 

1.  Right  anricle.  2.  Descending  vena  cava.  3. 
Eiglit  anterior  pulmonary  vein.  4.  Horizontal  band 
of  flbre.s  passing  across  the  base  of  the  auricles  D. 
Left  anterior  pulmonary  vein.  6.  Muscular  fibres 
between  auricles.  7.  Fringed  or  ring-shaped  bauds 
of  tibres  at  the  extremity  of  left  auricle.  S.  Muscu- 
lar fibres  at  the  base  of  right  auricle.  !).  Section  of 
pulmonary  artery,  showing  semilunar  valves.  10, 
11.  Anterior  bis-ventricular  muscular  fibres.  12,  13. 
Their  continuation  on  to  left  ventricle. 


Posterior  View  of  the  same. 

1.  Right  auricle.  2.  Descending  vena  cava. 
3.  Right  posterior  pulmonary  vein.  4.  Muscu- 
lar fibres  of  left  auricle.  5.  Left  posterior  pul- 
monary vein.  6,  7.  Arrangement  of  muscular 
fibres  at  the  end  of  left  auricle.  8.  Orifice  of 
great  coronary  vein.  9.  Band  of  fibres  between 
the  two  venje  cavse.  10.  Orifice  of  the  ascend- 
ing vena  cava ;  Eustachian  valve  is  at  the  end 
of  the  line.  11,  12.  Muscular  fibres  at  the  base 
of  auricle.  13,  14.  Muscular  fibres  in  the  ven- 
tricles. 


and  size.  The  observation,  that  the  right  ventricle  is  larger  than  the 
left,  is  as  old  as  Hippocrates,  and  has  been  attempted  to  be  accounted 
for  in  various  ways.     Some  have  ascribed  it  to  original  conformation ; 


'  KoUiker,  Mikroskopische  Anatomic,  2ter  Band,  s.  492,  Leipzig,  1854;  and  Amer. 
edit,  of  his  Manual  of  Human  Histology,  by  Dr.  Da  Costa,  p.  669,  Philad.,  1854. 

^  Gazette  Medicale  de  Paris,  No.  10,  and  Encyclograpliie  des  Sciences  Medicales,  Avril, 
1840,  p.  281. 

3  Remak,  Kcilliker,  op.  cit. 

*  Philcsophical  Transactions,  Part  i.  for  1849. 

*  British  and  Foreign  Medico-Chirurgical  Review,  p.  550,  Oct.  1849. 


CIRCULATOEY  APPAEATUS.  337 

others  to  the  bh:)od  being  cooled  in  its  passage  through  the  lurig,  and 
therefore  occupying  a  smaller  space  when  it  reaches  the  left  side  of  the 
heart.  Ilaller^  and  MeckeP  assert,  that  it  is  dependent  upon  the  kind 
of  death ;  that  if  the  right  ventricle  be  usually  more  capacious,  it  is 
owing  to  the  lung  being  one  of  the  organs  that  yields  first,  thus  occa- 
sioning accumulation  of  blood  in  the  right  cavities  of  the  heart ;  and 
they  state  that  they  succeeded,  in  their  experiments,  in  rendering  either 
one  or  the  other  of  the  ventricles  more  capacious,  according  as  the 
cause  of  death  arrested  first  the  circulation  in  the  lung  or  in  the  aorta; 
but  the  experiments  of  Legallois^  and  Seiler,"*  especially  of  the  former, 
upon  dogs,  cats,  Gruinea  pigs,  rabbits,  the  adult,  the  child,  and  the 
stillborn  foetus,  with  mercury  poured  into  the  cavities,  have  shown 
that,  except  in  the  foetus,  the  right  ventricle  is  more  capacious,  whether 
death  has  been  produced  by  suffocation,  in  which  the  blood  is  accu- 
mulated in  the  right  side  of  the  heart,  or  by  hemorrhage;  and  Legal- 
lois'  thinks,  that  the  difference  is  owing  to  the  left  ventricle  being 
more  muscular,  and,  therefore,  returning  more  upon  itself.  The  capa- 
city of  each  of  the  ventricles  in  the  full-sized  heart  has  been  estimated 
at  about  two  fluid  ounces  f  but  by  Valentin^  at  more  than  double,  and 
by  Volkmann  more  than  treble  that  amount. 

The  two  hearts,  united  together  by  a  median  septum,  form,  then, 
one  organ,  which  is  situate  in  the  middle  of  the  chest,  (see  Fig.  79,) 
between  the  lungs,  and,  consequently,  in  the  most  fixed  part  of  the 
thorax.  Figure  100  is  modified  from  one  carefully  made  from  nature 
by  Dr.  Penuock.^  It  represents  the  normal  position  of  the  heai-t  and 
great  vessels. 

According  to  Carus,^  the  weight  of  the  heart  compared  with  that  of 
the  body  is  as  1  to  160.  M.  J.  Weber^°  found  the  proportion,  in  one 
case,  to  be  1  to  150  ;  Dr.  Clendinning"  that  of  the  male  to  be  1  to  160; 
that  of  the  female  1  to  150;  and  Lae'nnec  considered  the  organ  to  be 
of  a  healthy  size  when  equal  to  the  fist  of  the  individual.  M.  Cru- 
veilhier  estimates  the  mean  weight  at  six  or  seven  ounces.  M.  Bouil- 
laud^^  weighed  the  hearts  of  thirteen  subjects,  in  whom,  from  the  gene- 
ral habit,  previous  state  of  health,  and  mode  of  death,  there  was  every 
reason  to  believe  that  they  were  in  the  natural  state.  The  mean  was 
eight  ounces  and  three  drachms.  From  all  his  data  he  is  led  to  fix 
the  averan^e  weis-ht  of  the  heart,  in  the  adult,  from  the  25th  to  the  60th 
year,  at  from  8  to  9  ounces.  Dr.  Clendinning  carefully  examined 
nearly  four  hundred  hearts  of  persons  of  both  sexes,  and  of  all  ages 

'  Element.  PliysioL,  iv.  3,  3. 

^  Ilandbucli  der  Menschlichen  Anatomie,  Halle,  1817,  s.   46  ;    or  the  translation 
from  the  French  version,  by  Dr.  Doane,  Philad.,  1832. 
'■^  Diet,  des  Sciences  Medicales,  v.  440. 

*  Art.  Ilerz.  in  Pierer's  Anat.  Physiol.  Real  Worterh.,  iv.  32,  Leix>z.,  1821. 
5  (Euvres,  Paris,  1824. 

^  Quain  and  Sharpey's  edit,  of  Quain's  Human  Anatomy,  Amer.  edit.,  by  Leidy,  ii. 
487,  Philad.,  1849.  ■"  Lehrbuch  der  Physiologie  des  Menschen,  i.  415. 

*  Medical  Examiner,  April  4,  1840. 

^  Introduction  to  Comp.  Anat.,  translated  by  R.  T.  Gore,  Lond.,  1827. 
'"  Hildebrandt's   llandbuch  der  Anatomie,  von  E.  H.  Weber,  Braunschweig,  1831, 
Band.  iii.  s.  125. 
"  Journal  of  the  Statistical  Society  of  London,  July,  1838. 
'^  Traite  Clinique  des  Maladies  du  Coeur,  &c.,  Paris,  1835. 
VOL.  I. — 22 


338  CIECULATION. 

above  puberty.     The  average  weight  was  about  nine  ounces  avoirdu- 
pois,— much  less  than  that  observed  by  Dr.  John  Eeid,^  who  found 

Fiff.  ]00. 


View  of  the  Heart  in  situ. 

S.  Outline  of  sternum.  C,  C.  Clavicles.  1,  2,  3,  4,  5,  6,  &c.  Kib.s.  1',  2',  3',  4',  5',  6',  &e.  Cartilages  of 
ribs.  4'.  Right  and  left  nipples,  a.  Right  ventricle,  h.  Left  ventricle,  c.  Septum  between  ventricles. 
d.  Right  auricle,  e.  Left  auricle.  /.  Aorta.  /'.  Xeedle  passing  through  aortic  valves,  g.  Pulmonary 
artery,  g'.  Xeedle  passing  through  valves  of  pulmonary  artery,  h.  Vena  cava  descendens.  i.  Line  of 
direction  of  mitral  valve ;  dotted  portion  posterior  to  the  right  ventricle,  i.  !Xeedle  passed  into  mitral 
valve  at  its  extreme  left.    k.  Line  of  tricuspid  valve,     o.  Trachea. 

the  average  weight  of  the  male  heart — of  89  weighed — to  be  11  oz. 
and  1  dr. :  and  of  the  female  heart — of  53  weighed — to  be  9  oz.  and  J 
dr.  The  weight  and  dimensions  of  the  organ,  according  to  Lobstein 
and  Bouillaud,  are  as  follows: — Weight,  9  to  10  ounces;  length  from 
base  to  apex,  5  inches  6  lines;  breadth  at  the  base,  3  inches;  thickness 
of  walls  of  left  ventricle,  7  lines ;  do.  at  a  finger's  breadth  above  the 
apex,  4  lines ;  thickness  of  walls  of  right  ventricle,  2;^  lines ;  do.  at 
apex,  \  a  line;  thickness  of  right  auricle,  1  line;  do.  of  left  auricle,  J 
a  line.  M.  Bizot^  has  given  the  following  measurements,  taking  the 
average  of  males  from  16  to  89  years. 

Base.  Middle.        Apex. 

Left  ventricle 4^  lines         5^  3| 

Right  ventricle l{f  If  l^g 

'  Lond.  and  Edinb.  Monthly  Journal  of  Med.  Science,  April,  1843,  p.  322. 

2  For  the  results  of  M.  Bizet's  researches,  to  ascertain  the  dimensions  of  the  heart 
and  arteries,  see  Memoires  de  la  Socit  te  M  dicale  d"Ol)servation,  Paris,  1837  ;  and  Hope 
on  the  Diseases  of  the  Heart,  Amer.  edit.,  by  Dr.  Pennock,  p.  234,  Philad.,  1842. 


CIRCULATORY  APPARATUS.  839 

In  the  female,  the  average  thickness  is  something  less.  Dr.  Ranking^ 
has  published  the  results  of  measurements,  evidently  made  with  accu- 
rac}^,  of  upwards  of  100  hearts, — care  being  taken  to  exclude  all  those 
that  exhibited  any  trace  of  organic  change.  The  following  are  the 
mean  admeasurements.  Of  15  male  hearts,  the  mean  circumference 
was  9||ths  inches;  of  17  female  hearts,  8i|ths  inches.  The  mean 
length  of  the  male  heart  was  4i|ths  inches;  of  the  female,  4||ths. 
The  mean  thickness  of  the  left  ventricle,  in  the  male,  was  f  gths  of  an 
inch;  in  the  female,  ffths;  of  the  right  ventricle,  in  the  male,  4^gths  ; 
in  the  female,  /gths.  The  septum  ventriculorum  has,  in  the  male,  a 
mean  thickness  of  ffths  of  an  inch;  in  the  female,  ^gths.  The  aortic 
orifice,  in  the  male,  had  a  mean  circumference  of  2||ths  inches;  the 
right  auriculo- ventricular  orifice,  4|fths  inches;  the  left  auriculo- ven- 
tricular orifice,  3||ths  inches.  The  corresponding  parts  of  the  female 
were  relatively  less.  Dr.  Ranking  infei's,  that  the  heart  of  the  male  is 
larger  than  that  of  the  female, — that  the  length  of  the  healthy  heart 
is  to  its  circumference  rather  less  than  1  to  2, — that  the  thickness  of 
the  parietes  of  the  right  ventricle  to  the  left  is  as  1  to  3  nearly: — that 
the  pulmonary  artery  is  slightly  wider  than  the  aorta;  and,  lastly,  that 
the  right  auriculo- ventricular  opening  is  considerably  larger  than  the 
left. 

It  need  scarcely  be  said,  that  the  weight  and  dimensions  of  the  organ 
must  vary  according  to  the  age,  sex,  &c.,  of  the  individual.  M.  Bizot^ 
found,  that  the  influence  of  stature  on  its  size  was  slight;  and  not  such 
as  might  have  been  expected  a  pj-iori ;  for,  in  individuals  of  the  male 
sex  above  sixty  inches,  and  in  females  above  fifty-five  inches,  in  height, 
the  mean  dimensions  of  the  organ,  especially  its  breadth,  were  less 
than  in  persons  of  a  lower  stature.  He  found  the  width  of  the  shoulders 
furnish  a  better  proportionate  standard  of  its  measurement, — the  dis- 
tance between  the  acromial  point  of  the  clavicles,  and  the  length  and 
breadth  of  the  heart  increasing  in  a  tolerably  regular  ratio.  Numerous 
measurements  of  the  organ  have  been  made  on  children  by  MM.  Rilliet 
and  Barthez;^  whence  it  results:  First.  That  its  circumference  does  not 
augment  in  proportion  to  age.  It  is  nearly  the  same  from  15  months 
to  five  years  and  a  half;  and  from  the  latter  age  it  goes  on  increasing 
irregularly  until  puberty.  Secondhj.  The  distance  from  the  base  to  the 
apex  is  nearly  one-half  the  total  circumference  at  the  base  of  the  ven- 
tricles. Thirdly.  The  maximum  thickness  of  the  parietes  of  the  right 
ventricle  varies  but  little  according  to  age.  It  is  generally  0'078  Eng. 
inch  to  the  age  of  six  years;  and  after  this  from  O'llS  to  0"157. 
Fourthly.  The  maximum  thickness  of  the  left  ventricle  remains  below 
0'3yo  Eng.  inch,  until  six  years  of  age.  Later,  it  is  habitually  0-893, 
or  a  little  more.  Fiftldy.  The  proportion  between  the  thickness  of  the 
two  ventricles  is  generally,  as  stated  by  ]\[.  Guersant,  as  3  to  1,  or  4  tol, 
rather  more  than  less.  Sixthly.  The  maximum  thickness  of  the  septum 
is  nearly  the  same  as  that  of  the  left  ventricle,  a  little  more  rather  than 
less.     Seventhly.  The  seat  of  the  maximum  thickness  of  the  right  ven- 

'  London  Medical  Gazette,  No.  xxir.,  1842. 

*  Miuioires  de  la  Societe  Medicale  d'Observation  de  Paris,  torn,  lere,  Paris,  1S36. 

'  Traite  Cliniqiie  et  Pratique  des  Maladies  des  Eufauts,  iii.  GG2,  Paris,  lb43. 


840  CIRCULATION. 

tricle  is  at  the  base,  and  near  the  auriculo-ventricular  orifice ;  that  of 
the  left  ventricle  one  or  two  centimetres  (in.  O'SyS  or  0'796)  from  the 
base;  and  that  of  the  septum  from  two  to  three  centimetres  (in.  0.796 
to  1"171).  Eighihlij.  The  size  of  the  right  auriculo-ventricular  orifice 
remains  nearly  the  same  until  the  age  of  5  years  ;  it  scarcely  increases 
in  size  up  to  tlie  age  of  10 ;  but  then  augments  more  manifestly. 
Ninthly.  The  left  auriculo-ventricular  orifice,  which  is  always  smaller 
than  the  right,  increases  a  little  more  regularly  than  it  with  age,  and 
frequently  has  the  same  dimensions  as  the  distance  from  the  base  of  the 
heart  to  its  apex.  Tenthhj.  The  aortic  orifice  presents  but  a  slight 
augmentation  from  15  months  to  13  j^ears  of  age.  Eleventhly.  The 
pulmonary  artery,  on  the  other  hand,  increases  notably  from  the  age  of 
six  years  to  eight,  so  that  although  before  this  period  it  is  equal  to  or 
scarcely  greater  than  the  aortic  orifice,  afterwards  it  is  commonly  much 
larger.  They  did  not  find  any  marked  difl:ereuce  between  the  male  and 
female  heart  in  children. 

The  heart  is  surrounded  by  its  proper  capsule,  called  pericardhim. — 
a  fibro-serous  membrane,  composed  of  two  layers.  The  outermost  of 
these  is  fibrous,  semi-transparent,  and  inelastic;  strongly  resembling 
the  dura  mater  in  its  texture.  Its  thickness  is  greater  at  the  sides  than 
below,  where  it  rests  upon  the  diaphragm ;  or  than  above,  w^here  it 
passes  along  the  great  vessels  which  communicate  with  the  heart.  The 
inner  layer  is  of  a  serous  character,  and  lines  the  outer,  giving  the 
polish  to  its  cardiac  surface ;  it  is  then  reflected  over  the  heart,  and 
adheres  to  it  by  areolar  substance.  Like  other  serous  membranes,  it 
secretes  a  fluid,  termed  liquor  pericardii^  to  lubricate  the  surface  of  the 
heart.  This  fluid  is  always  found  in  greater  or  less  quantity  after 
death;  and  a  question  has  arisen  as  to  the  amount  that  should  be  con- 
sidered morbid.  This  must  obviously  vary  according  to  circumstances. 
In  the  healthy  condition,  it  is  seldom  above  a  tea-spoonful.  When  its 
quantity  is  augmented,  the  disease  hydropericardium  exists.  Its  great 
use  probably  is  to  keep  the  heart  constantly  moist  by  the  exhalation 
effected  from  it;  and,  also,  to  restrain  the  movements  of  the  organ, 
which,  under  the  influence  of  the  emotions,  sometimes  leaps  inordi- 
nately. If  the  pericardium  be  divided  in  a  living  animal,  the  heart  is 
found  to  bound,  as  it  were,  from  its  ordinary  position;  and  hence  the 
expression, — "  leaping  of  the  heart," — during  emotion,  is  physiologi- 
cally accurate. 

b.  Arteries. 

Arteries  are  solid,  elastic  tubes,  which  arise,  by  a  single  trunk,  from 
the  ventricle  of  each  heart,  and  gradually  divide  and  subdivide,  until 
they  are  lost  in  the  capillary  system.  The  large  artery,  which  arises 
from  the  left  ventricle,  and  conducts  the  blood  to  every  part  of  the 
bodjif, — even  to  the  lungs,  so  far  as  regards  their  nutrition, — is  the 
aorta;  and  that,  which  arises  from  the  right  ventricle  and  conveys 
venous  blood  to  the  lungs  for  aeration,  is  the  pulmonary  artery.  Nei- 
ther the  one  nor  the  other  is  the  continuation  of  the  proper  tissue  of 
the  ventricles ;  the  inner  membrane  is  alone  continuous — the  muscu- 
lar structure  of  the  heart  being  united  to  the  fibrous  coat  of  the  arte- 
ries by  means  of  an  intermediate  fibrous  tissue.     The  aorta^  as  soon 


CIRCULATORY   APPARATUS.  341 

as  it  quits  tlie  left  ventricle,  passes  beneath  the  pulmonary  artery,  is 
entirely  concealed  by  it,  and  ascends  to  form  a  curvature  with  the  con- 
vexity upwards,  the  summit  of  which  rises  to  within  three  quarters  of 
an  inch  or  an  inch  of  the  superior  edge  of  the  sternum.  This  great 
curvature  is  called  the  cross  or  arch  of  the  aorta.  The  vessel  then 
passes  downwards,  from  the  top  of  the  thorax  to  nearly  as  far  as  the 
sacrum,  Avhere  it  divides  into  two  trunks,  one  of  which  proceeds  to 
each  lower  extremity.  In  the  whole  of  this  course,  it  lies  close  to  the 
spine,  and  gives  off  the  various  branches  that  convey  arterial  blood  to 
the  different  parts  of  the  body.  Of  the  immense  multitude  of  these 
ramifications  an  idea  may  be  formed,  when  we  reflect,  that  the  finest 
pointed  needle  cannot  be  run  into  any  part  of  the  surface  of  the  body, 
without  blood — probably  both  arterial  and  venous — flowing.  The 
larger  arteries  are  situate  deeply;  and  are  thus  remote  from  external 
injury.  They  communicate  freely  with  each  other,  and  their  anasto- 
moses are  more  frequent  as  the  arteries  become  smaller  and  forther 
from  the  heart.  At  their  final  terminations,  they  communicate  with 
the  veins  and  lymphatics. 

It  has  been  a  common,  but  questionable  belief,  that  the  branches  of 
the  aorta,  when  taken  collectively,  are  of  much  greater  capacity  than 
the  parent  trunk,  and  that  this  excess  goes  on  augmenting ;  so  that 
the  ultimate  divisions  of  an  artery  are  of  much  greater  capacity  than 
the  parent  trunk.  Hence,  the  arterial  system  has  been  considered  to 
represent,  in  the  aggregate,  a  cone,  whose  apex  is  at  the  heart,  and 
base  in  the  organs;  but  as  all  the  minute  arterial  ramifications  are  not 
visible,  it  is  obviously  impracticable  to  discover  the  ratio  between  their 
united  capacity  and  that  of  the  aorta  at  its  origin :  yet  the  problem 
has  been  attempted.  Keill,  by  experiments  made  on  an  injected  sub- 
ject, considered  it  to  be  as  44:,607  to  1 : — J.  C.  A.  Helvetius  and  Sylva 
as  500  to  1.  Senac  estimated,  not  their  capacities  but  their  diameters, 
and  conceived  the  ratio  of  these  to  be  as  118,490  to  90,000 ;  and  George 
Martine  affirmed,  that  the  calibre  of  a  parent  arterial  trunk  is  equal  to 
the  cube  root  of  the  united  diameters  of  the  branches.^  It  will  be 
shown,  however,  hereafter,  from  the  observations  of  M.  Poiseuille  and 
Mr.  Ferneley,  that  the  notion  of  the  much  greater  capacity  of  the 
branches  than  of  the  parent  trunk  is  a  fallacy.  The  whole  subject 
will  be  referred  to  in  another  place. 

The  pulmonary  artery  strongly  resembles  the  aorta.  Its  distribution 
has  been  already  described  as  a  part  of  the  respiratory  organs. 

The  arteries  are  composed  of  different  coats  in  superposition,  respect- 
ing the  number  of  which  anatomists  have  not  been  entirely  of  accord. 
Some  have  admitted  six ;  others  five;  others  four;  but  at  the  present 
day,  three  only  are  perhaps  generally  received ; — first,  an  external., 
areolar  or  cellular.,  called  also  nervous^  and  cartilaginous  by  Yesalius, 
and  tendinous  by  Ileister,  which  is  formed  of  condensed  areolar  sub- 
stance, and  has  considerable  strength  and  elasticity,  so  that  if  a  ligature 
be  applied  tightly  round  the  vessel,  the  middle  and  internal  coats  may 
be  com|iletely  cut  through,  whilst  the  outer  coat  may  remain  entire. 
Scarpa  is  not  disposed  to  admit  this  as  one  of  the  coats.     He  considers 

'  Haller,  Element.  Pliysiolog.,  lib.  ii.,  sect.  1,  g  18,  Lausan.,  1757. 


34:2  CIKCULATION. 

it  only  an  exterior  envelope,  to  retain  the  vessel  in  siiu.  The  next 
coat  is  the  mitklle^  muscular  or  'proi:)er  coat,  the  character  of  which  has 
been  the  subject  of  much  discussion.  It  was,  at  one  time,  almost 
universally  believed  to  be  muscular.  Such  was  the  opinion  of  Mr. 
Hunter.^  Henle^  advances  the  opinion,  that  its  structure  is  interme- 
diate between  areolar  and  muscular  tissue;  its  microscopic  elements 
being  broad  and  very  flat,  slightly  granulated  fibres  or  bands,  which 
lie  in  rings  around  the  internal  membrane,  and  are  about  0"003  lines 
in  diameter.  These  with  a  system  or  network  of  dark  streaks  consti- 
tute the  middle  coat.  In  the  large  arteries,  as  the  aorta  and  its  main 
branches,  nearly  the  whole  thickness  of  this  coat  is  composed  of  yel- 
low elastic  tissue — the  tissu  jaune  of  the  French  anatomists:  few  mus- 
cular fibres  are  perceptible ;  but  in  the  smaller  arteries  the  proportion- 
ate thickness  of  the  elastic  coat  gradually  diminishes;  whilst,  as  a 
general  rule,  the  muscular  fibres  increase  in  number,  and  form  a  layer 
within  the  elastic  coat.  Kolliker,^  indeed,  affirms,  that  the  middle 
tunic  of  the  small  arteries  is  purely  muscular,  without  the  slightest 
admixture  of  connective  tissue  and  elastic  elements.  The  muscular 
fibres  resemble  those  of  the  intestinal  tube,  being  of  the  nonstriped 
or  nonstriated  variety.  They  are  arranged  areolarly ;  are  pale  and 
flat,  and  mingled  with  filaments  of  fine  elastic  tissue, 

Nysten,*  Magendie,*  and  Mliller"  applied  the  galvanic  stimulus  to 
the  middle  coat,  which  is  the  most  sensible  test  of  irritability,  but 
without  effect.  It  is  proper,  however,  to  remark,  that  the  heart 
seems  equally  unsusceptible  of  the  galvanic  stimulus ;  or  at  least  is 
not  affected  by  it  like  the  voluntary  muscles.  In  the  cases  of  two  exe- 
cuted criminals,  which  the  author  had  an  opportunity  of  observing, 
although  all  degi^ees  of  galvanism  were  applied  half  an  hour  after  the 
drop  fell,  no  motion  whatever  was  perceptible ;  yet  the  voluntary  mus- 
cles contracted,  and  continued  to  do  so  for  an  hour  and  a  half  after 
execution.  The  same  fact  is  recorded  in  the  galvanic  experiments  of 
Dr.  Ure,  detailed  in  another  part  of  this  work,  and  is  attested  by 
Bichat,  Treviranus  and  others.  Humboldt,  Pfaft",  J,  F,  Meckel, 
Wedemeyer,  and  J,  Miiller,  however,  affirm  the  contrary.  The  last 
observer  states,^  that  with  a  single  pair  of  plates  he  excited  con- 
tractions not  only  in  a  frog's  heart,  which  had  ceased  to  beat,  but  also 
in  that  of  a  dog,  under  similar  circumstances.  Into  the  subject  of  the 
cause  of  the  heart's  action,  we  shall,  however,  inquire  presently. 
Miiller^  suggests,  that  in  the  capability  to  contract  under  the  influence 
of  cold,  as  exhibited  in  the  experiments  of  Schwann,  referred  to  here- 
after, the  contractile  tissue  of  the  arteries  resembles  that  of  the  dartos, 

■  On  the  Blood,  luflammatiou  and  Gunshot  "Wounds;  by  Palmer,  Amer.  edit.,  p. 
156,  Philad.,  1840. 

2  Casper's  Wochenschrift,  May  23,  1840,  cited  in  Brit,  and  For.  Med.  Rev.,  Oct. 
1840,  p.  551. 

*  Mikroskopische  Anatomic,  2ter  Bd.  s.  507,  Leipz.,  1854;  or  his  Manual  of  Histo- 
logy, Sydenham  Society  edit.,  Lond.,  1854;  or  Da  Costa's  Amer.  edit,  of  the  same,  p. 
679,  Philad. ,1854. 

^  Recherches  de  Physiologie,  &c.,  p.  325,  Paris,  1811. 

5  Precis.  2de  edit.,  ii.  387^  Paris,  1825. 

^  Handbach  der  Physiologie,  Baly's  translation,  p.  205,  Lond.,  1838. 

^  Loc.  cit.  *  Archiv.  fur  l8od,  in  Lond.  Med.  Gaz.,  May,  1837. 


CIRCULATORY  APPARATUS.  343 

and  that  found  in  many  parts  of  tlie  skin,  as  about  the  nipple  and 
follicles,  althougli  the  physical  characters  of  the  latter  are  so  different 
from  elastic  tissue.  The  third  or  inner  coat  is  smooth  and  polished, 
and  a  continuation  of  the  membrane  that  lines  the  ventricles.  It  has 
an  epithelial  lining,  resembles  the  serous  membranes,  and  is  lubricated 
by  a  form  of  serous  exhalation.' 

The  arteries  receive  the  constituents  that  belong  to  every  living  part, 
— arteries,  veins,  lymphatics,  and  nerves.  These  arteries  do  not  pro- 
ceed from  the  vessels  they  nourish,  but  from  adjacent  trunks,  as  we 
have  remarked  of  the  vasa  vasorum^  to  which  class  they  really  belong. 
The  nerves  proceed  from  the  great  sympathetic;  form  plexuses  around 
the  vessels,  and  accompany  them  through  all  their  ramifications.  By 
some  anatomists,  the  arteries  of  the  head,  neck,  thorax,  and  abdomen, 
are  conceived  to  be  supplied  from  the  great  sympathetic,  whilst  those 
of  the  extremities  are  supplied  from  the  nerves  of  the  spinal  marrow. 
It  is  probable,  however,  that  more  accurate  discrimination  might  trace 
the  dispersion  of  twigs  of  the  nerves  of  involuntary  motion  on  all  these 
vessels.  The  organization  of  the  arteries  renders  them  tousrh  and  ex- 
tremely  elastic,  both  of  which  qualities  are  necessary  to  enable  them  to 
withstand  the  impulse  of  the  blood  sent  from  the  heart,  and  to  react 
upon  the  fluid  so  as  to  influence  its  course.  It  is  by  virtue  of  this 
structure,  that  the  parietes  retain  their  form  in  the  dead  body, — one  of 
the  points  that  distinguish  them  from  the  veins. 

The  vitality  of  the  arteries  is  inconsiderable.  Hence  their  diseases 
are  by  no  means  numerous  or  frequent, — an  important  fact,  seeing  that 
their  functions  are  essential,  and  their  activity  incessant. 

c.  Intermediate^  Peripheral  or  Cajdllary  System.. 

The  capillary  or  intermediate  vessels  are  of  extreme  minuteness,  and 
are  by  some  considered  to  be  formed  by  the  terminations  of  arteries 
and  the  commencement  of  veins;  by  others  to  be  a  distinct  set  of  ves- 
sels. This  system  forms  a  plexus  which  is  distributed  over  every  part 
of  the  body,  and  constitutes,  in  the  aggregate,  what  is  meant  by  the 
capillary  system.  It  admits  of  two  great  divisions,  one  situate  at  the 
termination  of  the  branches  given  off  from  the  aorta,  and  called  the 
general  capillary  system  ;  the  other  at  the  termination  of  the  branches 
of  the  pulmonary  artery, — the  2^^'^^'>nonic  capillary  system.  Although 
the  capillary  system  of  man  does  not  admit  of  detection  by  the  unaided 
sight, its  existence  is  evidenced  by  the  microscope;  by  injections,  which 
develope  it  artificially  in  almost  every  organ ;  by  the  application  of 
excitants,  and  by  inflammation.  The  parietes  frequently  cannot  be 
distinguished  from  the  substance  of  the  tissues ;— -the  colour  of  the 
blood,  or  the  matter  of  the  injection  alone  indicating  their  course.  In 
some  parts,  as  in  the  white  textures,  these  vessels  do  not  seem  to  admit 
the  red  particles  of  the  blood,  whilst  others  admit  them  always.  This 
diversity  gave  rise  to  a  distinction  of  the  capillaries  into  red  and  ivkite; 
but  there  are  probably  none  of  the  latter.     It  is  difficult,  indeed,  to 

'  For  some  speculations  as  to  the  a£;ency  of  this  secretion  in  the  production  of  the 
buffy  state  of  the  blood,  &c.,  see  M.  Kouiain  Gcrardin,  in  Journal  des  Counaissances 
Mcdico-Chirurgicales,  Mars,  183(3. 


BU 


CIRCULATION. 


conceive  how  the  red  particles  could  be  arrested  at  tlie  mouths  of  the 
white  arteries — if  such  existed — without  their  preventing  altogether  the 
entrance  of  blood  into  them.  The  true  cause  of  the  whiteness  appears 
to  be  the  small  quantity  of  blood  they  receive;  and  it  is  only  when  the 
network  is  very  close,  and  the  quantity  of  blood  passing  through  them 
great,  that  a  perceptible  colour  is  produced.  If  a  plate  of  red  glass  be 
reduced  to  a  very  thin  pellicle,  and  be  placed  between  the  eye  and 
light,  its  colour  will  be  scarcely  sensible.  To  perceive  it,  several  of 
these  pellicles  must  be  placed  over  each  other,  and  they  must  be  ex- 
amined not  by  their  transparency,  but  by  causing  the  light  to  fall  on 
their  surface,  or  by  reflection. 

There  are  certain  textures,  again,  which  receive  no  bloodvessels, — 
the  corneous  and  epidermic,  for  example.  They  are  probably  nou- 
rished by  transudation  of  nutritive  matter  from  the  vessels  of  the  sur- 
rounding tissue. 

The  ancients  were  of  opinion,  that  arteries  and  veins  are  separated 
by  an  intermediate  substance,  consisting  of  a  fluid  effused  from  the 
blood,  which  they  called,  in  consequence,  parenchyma.^  The  notion  is, 
indeed,  still  entertained ;  and  is  considered  to  be  supported  by  micro- 
scopical observations.  In  the  examination  of  delicate  and  transparent 
tissues,  currents  of  moving  globules  are  seen  witli  many  spaces  of  ap- 
parently solid  substances,  resembling  small  islets,  surrounded  by  an 
agitated  fluid.     If  the  tissue  be  irritated  by  thrusting  a  fine  needle  into 


Fig,  101. 


Circulation  in  the  Web  of  the  Frog's  Foot. 
1,  1.  Veins.     2,  2.  Arteries. 


it,  the  motion  of  the  globules  becomes  more  rapid;  new  currents  arise 
where  none  wei^e  previously  perceptible,  and  the  whole  becomes  a  mass 
of  moving  particles,  the  general  direction  of  which  tends  towards  the 
points  of  irritation.     But  although  a  part  of  the  apparatus  of  inter- 


'  Galen.  Administrat.  Anatom,,  vi.  2. 


CIRCULATORY  APPARATUS, 


345 


mediate  circulation  may  be  arranged,  in 
this  manner,  there  are  reasons  for  the 
belief,  that  a  more  direct  communication 
between  the  arteries  and  veins  exists  also. 
The  substance  of  an  injection  passes  from 
one  set  of  vessels  into  the  other,  without 
any  evidence  of  intermediate  extravasa- 
tion. The  blood  has  been  seen,  too,  pass- 
ing in  living  animals,  directly  from  the 
arteries  into  the  veins.  Leeuenhoek^  and 
Malpighi,^  on  examining  the  swim-blad- 
ders, gills,  and  tails  of  fishes,  the  mesen- 
tery of  frogs,  &c. — which  are  transpa- 
rent,— observed  this  distinctly ;  and  the 

fact  has  been  proved  by  the  observations     Portion  of  the  Web  of  the  Frog's  Foot. 

of  Cowper,  Cheselden,    Hales,    Spallan-    ^^{.^  ^Z^^ :i^;7:i^;X^ 

Zani,  TllOmSOn,  Cuvier,  Configliachi,  RUS-     communicate,      c,  c.  The  angular  unnu- 

coni,  Dcillinger,  Cams,  and  others. 

Fig.  103. 


cleated  cells  of  the  pai'enchyma. 


Circulation  in  the  Under  Surface  of  the  Tongue  of  the  Frog. 
sc,  X.  Venous  branches  uniting  to  form  a  principal  vein,  y.    z,  z.  Folliclos  into  which  a  small  artery- 
enters,  whicli  becomes  convoluted  before  issuing  from  them.     A  beautiful   capillary  rete,   and  some 
muscular  fibres  are  also  seen. 

The  artery  and  vein  terminate  in  tAvo  different  ways; — at  times,  after 
the  former  has  become  extremely  minute,  by  sending  off  numerous 

'  Select  Works,  containing  his  Microscopical  Discoveries,  by  Samuel  Hooke,  p.  90, 
Lend.,  1778. 

2  Epist.  do  Pulmonibus,  1661,  and  Haller,  Element.  Physiol.,  lib.  iii.  sect.  3,  §  20, 
Lausann.,  1757. 


346 


CIRCULATION. 


lateral  branches,  as  Haller  states  lie  noticed  in  the  swim  bladders  of 
fislies;  at  others,  by  proceeding  parallel  to  each  other,  and  communi- 
cating by  a  multitude  of  transverse  branches.  Fig.  101  exhibits  a 
microscopic  view  of  the  membrane  between  two  of  the  toes  of  the 
hind  foot  of  the  frog,  Rana  esculenta,  magnified  three  diameters. 

Fig.  102  shows  a  portion  of  the  web  of  a  frog's  foot  magnified  45 
diameters.  The  superficial  network  of  capillaries  is  seen  admitting 
but  a  single  series  of  blood  particles.  All  the  vessels,  here  figured, 
are,  according  to  Wagner,'  furnished  with  distinct  parietes. 

Fig.  103  is  a  beautiful  representation  of  the  circulation  in  the  under 
surface  of  the  tongue.  Along  the  larger  vessels  the  blood  can  be  seen 
rushing  with  excessive  velocity.  It  is  proper,  however,  to  state  that 
the  more  the  parts  are  magnified,  the  greater  will  be  the  apparent 
velocity.  The  mean  real  velocity,  Valentin^  thinks,  is  one-eighth  less 
in  the  capillaries  than  in  the  veins  and  arteries.-'  These  larger  vessels 
have  distinct  coats ;  but  single  files  of  globules  are  seen  proceeding 
slowly  through  channels  to  which  the  author  has  not  been  able  to 
satisfy  himself  that  there  were  distinct  parietes.  The  tongue  of  the 
frog  offers  by  far  the  most  satisfactory  opportunity  for  distinctly  wit- 
nessing the  circulation ;  a  fact  for  the  knowledge  of  which  the  author 
is  indebted  to  M.  Donne.'* 


Fia.  104. 


Fiff.  105. 


Capillary  Network  of  Nervous  Centres. 


Capillar}'  Network  of  Fungiform  Pa- 
pilla of  the  Tongue. 


The  capillary  vessels  have  been  esteemed  b}^  some  to  belong  chiefly 
to  the  arteries,  the  venous  radicles  not  arising  almost  imperceptibly 
from  the  capillary  system,  as  the  arteries  terminate  in  it,  but  having  a 
marked  size  at  the  part  where  they  quit  this  system,  which  strikingly 
contrasts  with  the  excessive  tenuity  of  the  capillary  arterial  vessels ; 
whilst  between  the  capillary  system  and  the  arteries  there  is  no  distinct 
line  of  demarcation.  The  opinion  of  Bichat^  was,  that  this  s^'stem  is 
entirely  independent  of  both  arteries  and  veins;  and  Autenrieth* 
imagined,  that  the  minute  arteries  unite  to  form  trunks,  which  again 
divide  before  communicating  with  the  veins,  so  as  to  represent  a  system 
analogous  to  that  of  the  vena  porta.    The  experiments  of  Dr.  Marshall 

*  Elements  of  Physiology,  by  R.  Willis,  Lond.,  1842. 

*  Lehrbuch  der  Fhysiologie  des  Menschen,  i.  467,  Braunschweig,  1844. 
3  See  also  Lebert,  Fhysiologie  Fathologique,  i.  7,  Faris,  1845. 

*  Cours  de  Microscopie,  p.  109,  Faris,  1844  ;  and  Atlas,  planche  vi.,  Faris,  1845. 

6  Anatomic  Generale,  &c.,  edit,  de  MM.  Blandiu  et  Mageudie,  ii.  299,  Faris,  1832. 
8  Physiologic,  ii.  13S. 


CIECULATORY   APPARATUS.  847 

llall^  on  the  batrachia,  wliicTi  were  performed  with  signal  care,  led  him 
to  the  following  conclusions,  which  agree  with  those  of  Bichat,  so  far 
as  regards  the  independent  existence  of  a  capillary  system.  The 
minute  vessels,  he  says,  may  be  considered  arterial,  so  long  as  they 
continue  to  divide  and  subdivide  into  smaller  and  smaller  branches. 
The  minute  veins  are  the  vessels  that  gradually  enlarge  from  the  suc- 
cessive addition  of  small  roots.  The  true  capillary  vessels  are  distinct 
from  these.  They  do  not  become  smaller  by  subdivision,  or  larger  by 
conjunction,  but  are  characterized  by  continual  and  successive  union 
and  division  or  anastomoses,  whilst  they  retain  a  nearly  uniform  dia- 
meter. The  last  branches  of  the  arterial  system,  and  the  first  root  of 
the  venous,  Dr.  Hall  remarks,  may  be  deuoiiiinated  minute,  but  the 
term  "  capillary"  must  be  reserved  for,  and  appropriated  to,  vessels  of 
a  distinct  character  and  order,  and  of  an  intermediate  station,  carrying 
red  globules,  and  perfectly  visible  by  means  of  the  microscope. 

Of  late,  M.  Bourgery^  has  maintained,  that  besides  the  interme- 
diate vessels,  which  form  the  direct  communication  between  the  arte- 
ries and  veins,  there  is  a  special  capillary  arrangement  in  every  tissue 
by  which  the  functions  of  nutrition  and  secretion  are  accomplished. 
The  diameter  of  these  capillaries,  according  to  M,  Bourgery,  is  not 
more  than  one-half,  one-third,  or  even  one-fourth  of  that  of  the  blood 
corpuscles ;  and  they  can,  consequently,  convey  only  liquor  sanguinis. 
But  the  existence  of  these  vessels  is  not  considered  to  be  demonstrated ; 
whilst  their  absence  in  tissues — as  cartilage — which  they  were  formerly 
supposed  to  penetrate,  has  been  established,^ 

The  capillary  arteries  are  distinct  in  structure — as  they  are  in 
office — from  the  larger  arteries.  All  the  coats  diminish  in  thickness 
and  strength,  as  the  tubes  lessen  in  size;  but  this  is  more  especially 
the  case  with  the  middle  coat,  which,  according  to  Wedemeyer,  may 
still  be  distinguished  by  its  colour  in  the  transverse  section  of  any 
vessel  whose  calibre  is  not  less  than  the  tenth  of  a  line ;  but  entirely 
disappears  in  vessels  too  small  to  receive  the  wave  of  blood  in  a  mani- 
fest jet.  While  the  coats  diminish,  the  nervous  filaments,  distributed 
to  them,  increase ;  the  smaller  and  thinner  the  capillary,  the  greater 
the  proportionate  quantity  of  its  nervous  matter.  The  coats  of  the 
capillaries  become  successively  thinner  and  thinner,  and  at  length  dis- 
appear altogether ;  and  the  vessels — many  of  them  at  least — seem  to 
terminate  in  membraneless  canals  or  interstitial  passages,  formed  in 
the  substance  of  the  tissues.     The  blood  is  contained — according-  to 

O 

Wedemeyer,  Gruithuisen,  Dollinger,  Cams,  and  others — in  the  differ- 
ent tissues  in  channels,  which  it  forms  in  them:  even  under  the  micro- 
scope, the  stream  is  seen  to  work  out  for  itself,  easily  and  rapidly,  a 
new  passage  in  the  tissues,  and  it  is  esteemed  certain,  that  in  the 
figura  venosa  of  the  egg,  the  blood  is  not  surrounded  by  vascular 
parietes.  Most  histologists  of  the  day  are  disposed,  however,  to  be- 
lieve, that  the  capillaries  are  provided  with  distinct  coats.  Such,  as 
has  been  seen,  appeared  to  Wagner  to  be  the  case  in  the  frog's  foot, 

'  A  Critical  and  Experimental  Essay  on  the  Circulation,  &o,,  Lond.,  1830;  Amer. 
edit.,  Philad.,  1835, 

^  Comptes  Rendus,  &c.,  1848,  and  Gazette  Medicale,  No.  37,  1848. 
*  British  and  Foreign  Medioo-Chirurgical  Review,  p.  527,  Oct,,  1848. 


3^8 


CIECULATIOX. 


wlien  magnified  45  diameters;  and  it  has  even  been  announced,  that 
thej  are  composed  of  a  fibrous  structure,  analogous  to  the  muscular. 

Fig.  106. 


1^  ^^:}^~P^^^^i*  IT^^^^^  ^\\ 


^c-- 


v./.^., . 


r\ 


Capillaries  of  the  "Web  of  the  Frog's  Foot. 

1.  Deep  venous  trunk,  composed  of  three  principal  branches,  2,  2,  2;  and  covered  with  a  rete  of  smaller 
vessels. 

Fig.  106,  from  Wagner,  exhibits  the  vascular  rete  and  circulation  of 
the  web  of  the  hind  foot  of  a  frog — Rana  temjporaria — magnified  110 
times:  here  the  parietes  are  very  distinct.  In  another  figure  in 
"Wagner,  which  represents  a  portion  of  a  live  newt,  magnified  150 
diameters,  the  capillaries  are  exceedingly  delicate,  and  their  Avails  by 
no  means  as  distinct.  The  arterial  and  venous  trunks  and  the  capil- 
laries that  form  the  medium  of  communication  between  them  are  well 
seen,  as  well  as  the  islets  of  the  substance  of  the  lung,  in  which  a 
granular  or  areolar  texture  is  indistinctly  perceptible.  Dr.  Carpenter^ 
is  of  opinion,  that  the  mode  of  origin  of  the  capillaries  refutes  the 
supposition,  that  they  are  mere  passages  channeled  out  of  the  tissues 
through  which  they  convey  the  blood.  lie  thinks  there  can  be  no 
doubt,  that  they  are  produced,  in  any  newly  forming  tissue,  not  by 
the  retirement  of  the  cells,  one  from  the  other,  so  as  to  leave  passages 
between  them,  but  by  the  formation  of  communications  among  cer- 
tain cells,  whose  cavities  become  connected  with  each  other,  so  -as  to 
constitute  a  plexus  of  tubes,  of  which  the  original  cell-walls  become 
the  parietes. 

Of  the  minute  capillaries, — the  diameter  of  which,  in  parts  finely 
injected,  varies  from  the  yo'oo^^  ^^  the  4o'oo^^»  ^^^  ^^^^  ^o'oo^^^  o^  ^^ 
inch  and  even  more, — some,  according  to  Wedemeyer,  communicate 


Human  Physiology,  §  477,  Lond.,  1S42. 


CIKCULATOEY  APPARATUS.  849 

with  veins ;  in  others,  there  are  no  visible  openings  or  pores  in  the 
sides  or  ends,  by  which  the  blood  can  be  extravasated  preparatory  to 
its  being  imbibed  by  the  veins.  There  is  nowhere  apparent  a  sudden 
passage  of  the  arterial  into  the  venous  stream;  no  abrupt  boundary 
between  the  division  of  the  two  systems.  The  arterial  streamlet  winds 
through  long  routes  before  it  assumes  the  nature,  and  takes  the  direc- 
tion, of  a  venous  streamlet.  The  ultimate  capillary  rarely  passes 
from  a  large  arterial  into  a  large  venous  branch.  Many  speculations 
have  been  indulged  regarding  the  mode  in  which  the  vascular  extre- 
mities of  the  capillary  system  are  arranged.  Bichat  regarded  it  as  a 
vast  reservoir,  whence  originate,  besides  veins,  vessels  of  a  particular 
order,  whose  office  it  is  to  pour  out,  by  their  free  extremity,  the  mate- 
rials of  nutrition, — vessels,  which  had  been  previously  imagined  by 
Boerhaave,  and  are  commonly  known  under  the  appellation  of  exlia- 
lants.  Mascagni^  supposed  that  the  iinal  arterial  terminations  are 
pierced,  towards  their  point  of  junction  with  the  veins,  by  lateral 
pores,  through  which  the  secreted  matters  transude  ; — but  these  points 
will  farther  engage  attention  under  Nutrition  and  Secretion. 

d.    Veiiis. 

The  origin  of  the  veins,  like  that  of  all  capillary  vessels,  is  imper- 
ceptible. By  some  they  are  regarded  as  continuous  with  the  capillary 
arteries ;  Malpighi^  and  Leeuenhoek^  state  this  as  the  result  of  their 
microscopic  observations  on  living  animals;  and  it  has  been  inferred, 
from  the  facility  with  which  an  injection  passes  from  the  arteries  into 
the  veins.  According  to  others,  cells  exist  between  the  arterial  and 
the  venous  capillaries,  in  which  the  former  deposit  their  fluid  contents, 
and  whence  the  latter  obtain  it.  Others,  again,  substitute  a  spongy 
tissue  for  the  cells.  It  has  also  been  asked, — whether  there  may  not 
be  more  delicate  vessels  communicating  with  their  radicles,  similar  to 
the  exhalants  which  are  presumed  to  exist  at  the  extremities  of  the 
arteries,  and  which  are  regarded  as  the  agents  of  exhalation.  All  this 
is,  however,  conjectural.  It  has  already  been  observed,  that  the  me- 
senteric veins  have  been  supposed  by  some  to  terminate  by  open 
mouths  in  the  villi  of  the  intestines ;  and  the  same  arrangement  has 
been  conceived  to  prevail  with  regard  to  other  veins ;  but  there  is  no 
evidence  of  this.  M.  Eibes  concludes,  from  the  results  of  injecting 
the  veins,  that  some  of  the  venous  capillaries  are  immediately  conti- 
nuous with  the  minute  arteries,  whilst  others  open  into  the  cells  of  the 
areolar  tissue,  and  into  the  substance  of  different  organs. 

When  the  veins  become  visible,  they  appear  as  an  infinite  number 
of  extremely  small  tubes  communicating  very  freely  with  each  other; 
so  as  to  form  a  very  fine  network.  These  vessels  gradually  become 
larger  and  less  numerous,  but  still  preserve  their  reticular  arrangement; 
until,  ultimately,  all  the  veins  of  the  body  empty  themselves  into  the  heart 
by  three  trunks — the  vena  cava  hiftrlor^  vena  cava  superior^  and  coronary 
vein.     The  first  of  these  receives  the  veins  from  the  lower  j^art  of  the 

'  Vasor.  Lymph..  Corpor.  Human.  Histor.,  Sen.  1817;  and  Prodromo  della  Grande 
Anatomie,  Firenz.,  1819. 

^  Secuuda  Epistola  de  Pulmonibus,  Opera,  Loud.,  16S7. 
3  EpistoL  59,  Opera,  Lugd.  Bat.,  1722. 


350 


CIRCULATION". 


body,  and  extends  from  the  fourth  lumbar  vertebra  to  the  right  auricle ; 
the  second  receives  all  those  of  the  upper  part  of  the  body.     It  extends 

from  the  cartilage  of  the  first  rib  to 
the  right  auricle.  The  coronary 
vein  belongs  to  the  heart  exclusive- 
ly; between  the  superior  and  inferior 
cava  a  communication  is  formed  by 
means  of  the  vena  azygos. 

Certain  organs,  as  the  spleen,  ap- 
pear to  be  almost  wholly  composed 
of  venous  radicles.  Fig.  107  repre- 
sents the  ramifications  of  the  splenic 
vein,  in  the  substance  of  that  organ; 
and  if  we  consider,  that  the  splenic 
artery  has  corresponding  ramifica- 
tions, the  viscus  would  seem  to  be 
almost  wholly  formed  of  bloodves- 
sels. The  same  may  be  said  of  the 
corpus  cavernosum  of  the  penis 
and  clitoris,  nipple,  urethra,  glans 
penis,  &c.  If  an  injection  be  thrown 
into  one  of  the  veins  that  issue 
from  these  different  tissues,  they  are 
filled  by  the  injection ;  this  rarely 
occurs,  if  the  injection  be  forced  into 
the  artery.  j\[.  Magendie*  affirms, 
that  the  communication  of  the  cavernous  tissue  of  the  penis  with  the 
veins  occurs  through  apertures  two  or  three  millimetres — in.  0*117 — 
in  diameter. 

In  their  course  towards  the  heart,  particularly  in  the  extremities,  the 
veins  are  divided  into  two  planes; — one  subcutaneous  or  superficial; 
the  other  deep-seated,  and  accompanying  the  deep-seated  arteries. 
Numerous  anastomoses  occur  between  these,  especially  when  the  veins 
become  small,  or  are  more  distant  from  the  heart.  We  find,  that  their 
disposition  differs  according  to  the  organ.  In  the  brain,  they  con- 
stitute, in  great  part,  the  pia  mater;  and  enter  the  ventricles,  where 
they  contribute  to  the  formation  of  the  plexus  choroides  and  tela  cho- 
roidea.  On  leaving  the  organ  we  find  them  situate  between  the  laminaa 
of  the  dura  mater ;  when  they  take  the  name  of  sinuses.  In  the 
spermatic  cord,  they  are  extremely  tortuous ;  anastomose  repeatedly, 
and  form  the  corpus  paminn if orme  ;  around  the  vagina,  they  constitute 
the  corpus  retiforme ;  in  the  uterus,  the  uterine  sinuses.  They  have 
three  coats  in  superposition,  according  to  most  anatomists;  but  many 
modern  anatomists  are  disposed  to  assign  them  six.  The  outer  coat  is 
areolar;  dense,  and  very  difficult  to  rupture.  The  middle  coat  has 
been  termed  the  proper  membrane  of  the  veins.  The  generality  of 
anatomists  describe  it  as  composed  of  longitudinal  fibres,  which  are 
more  distinct  in  the  vena  cava  inferior  than  in  the  vena  cava  superior; 
in  the  superficial  veins  than  in  the  deep-seated;  in  the  branches  than 


Splenic  Vein  with  its  Branches  and  Ramifi- 
cations. 

1.  Trunk  of  the  vein.  2.  Gastric  branch  of 
this  vein  coming  from  the  stomach.  3.  Branches 
coming  from  the  substance  of  the  spleen.  4. 
Small  mesenteric  vein  cut  off.  5.  Branches  com- 
ing from  external  coat  of  the  spleen.  6.  Branches 
of  lymphatic  vessels  of  spleen. 


Precis,  &c.,  ii.  238. 


CIRCULATORY   APPARATUS.  851 

in  the  trunks.  M.  Magendie^  states,  that  he  has  never  been  able  to 
observe  the  fibres  of  the  middle  coat;  but  has  always  seen  a  multitude 
of  filaments  interlacing  in  all  directions;  and  assuming  the  appearance 
of  longitudinal  fibres,  when  the  vein  is  folded  or  wrinkled  longitudi- 
nally, which  is  frequently  the  case  in  the  large  veins.  It  exhibited  to 
him  no  signs  of  muscularity;  even  when  the  galvanic  stimulus  was 
applied ;  yet  M.  Magendie  suspected  its  chemical  nature  to  be  fibrinous. 
It  was  remarked,  in  an  early  part  of  this  volume,^  that  the  bases  of  the 
areolar  and  muscular  tissue  are,  respectively,  gelatin,  and  fibrin ;  and 
that  the  various  resisting  solids  may  all  be  brought  to  one  or  other  of 
those  tissues.  The  middle  coat  of  the  veins  doubtless  belongs  essen- 
tially to  the  former,  and  is  a  variety  of  the  iissn  javne  of  the  French 
anatomists.  M.  IMagendie  merely  states  its  fibrinous  nature  to  be  a 
suspicion;  and,  lii^e  numerous  suspicions,  this  may  be  devoid  of  founda- 
tion. Yet  we  have  reason  to  believe,  that  it  is  contractile ;  and,  of  late,^ 
it  has  been  described  as  formed  of  one  or  two  or  even  more  layers  be- 
tween the  external  and  internal  coats;  these  layers  consisting  of  fibres, 
which  agree,  in  all  respects,  with  the  white  areolar  tissue;  and  are 
either  quite  pure,  or  mixed  in  one  or  other  of  the  layers  with  a  greater 
or  less  amount  of  fibres,  resembling  those  of  the  middle  coat  of  the 
arteries  in  having  the  anatomical  characters  of  the  nonstriated  or  un- 
striped  muscular  fibres.  The  muscular  fibre-cells  are,  however,  much 
fewer  in  number,  and  are  sometimes  wanting.  Kolliker'*  says  they  do 
not  exist  in  the  uterine  portion  of  the  placenta,  the  veins  of  the  cere- 
bral substance  and  pia  mater;  the  sinuses  of  the  dura  mater;  the  veins 
of  the  bones;  the  venous  sinuses  of  the  corpora  cavernosa  of  the  male 
and  female ;  and  probably  in  those  of  the  spleen.  M.  Broussais^  affirms, 
that  the  contraction  of  the  middle  coat  is  one  of  the  principal  causes 
of  the  return  of  the  blood  to  the  heart.  He  conceives,  that  the  alter- 
nate movements  of  contraction  and  relaxation  are  altogether  similar 
to  those  of  the  heart ;  but  that  they  are  so  slight  as  not  to  have  been 
rendered  perceptible  in  the  majority  of  the  veins,  although  they  are 
very  visible  in  the  vena  cava  of  frogs,  where  it  joins  the  right  auricle. 
In  some  experiments  by  M.  Sarlandi^re  on  the  circulation,  he  observed 
these  movements  to  be  independent  of  those  of  the  heart.  After  the 
organ  was  removed,  and  even  after  blood  had  ceased  to  flow,''  the  con- 
traction and  relaxation  of  the  vein  continued  for  many  minutes  in  the 
cut  extremity  ;  and  it  has  been  elsewhere  remarked,  that  Mr.  Wharton 
Jones  had  discovered  in  the  veins  of  the  bat's  wing  a  regular  rhythmi- 
cal contraction  and  dilatation. 

The  inner  coat  is  extremely  thin  and  smooth  at  its  inner  surface,  and 
has  an  epithelial  lining.  It  is  very  extensible,  and  yet  presents  con- 
siderable resistance  ;  bearing  a  very  tight  ligature  without  being  rup- 
tured.    In  many  of  the  veins,  parabolic  folds  of  the  inner  coat  exist, 

'  Op.  cit.,  ii.  242.  See  on  the  researches  of  histologists,  Mr.  Paget,  Brit,  and  For. 
Med.  Review,  July,  1842,  ii.  242. 

^  Page  59. 

'  Qiiain's  Human  Anatomy,  by  Quain  and  Sharpey,  Amer.  edit.,  by  Leidy,  i.  518, 
Philad.,  1849. 

*  Manual  of  Human  Histology,  Amer.  edit.,  by  Dr.  Da  Costa,  p.  689,  Philad.,  1854. 

'  Op.  citat.,  American  trautilation,  p.  391. 

'  See,  on  this  subject,  the  remarks  on  the  Circulation  in  the  Veins. 


352 


CIRCULATION. 


like  tliose  in  the  lymphatics,  which  are  inservient  to  a  similar  purpose; 
the  free  edge  of  these  valves  is  directed  towards  the  centre  of  the 
circulation,  showing  that  their  office  is  to  permit  the  blood  to  flow  in 
that  direction,  and  prevent  its  retrogression.  Thej  do  not  seem,  how- 
ever, in  many  cases,  well  adapted  for  the  purpose ;  inasmuch  as  their 
size  is  insufficient  to  obliterate  the  cavity  of  the  vein.  By  most  anato- 
mists, this  arrangement  is  considered  to  depend  upon  primary  organi- 
zation; but  Bichat  conceives  it  to  be  wholly  owing  to  the  state  of  con- 
traction, or  dilatation  of  the  veins,  at  the  moment  of  death.  M.  Ma- 
gendie  affirms,  that  he  has  never  seen  the  distension  of  the  veins  exert 
any  influence  on  the  size  of  the  valves;  but  that  their  shape  is  some- 
what modified  by  the  state  of  contraction  or  dilatation ;  and  this  he 
thinks  probably  misled  Bichat.^  Moreover,  they  are  covered  by  the 
epithelial  coat  and  consist  of  tissue  like  that  of  fibrous  membrane, 
which,  as  Mr.  Hunter^  observed,  shows,  that  they  are  not  duplicatures 
of  the  lii;ing  membrane.  Their  number  varies  in  different  veins.  As 
a  general  rule,  they  are  more  numerous,  where  the  blood  proceeds 
against  its  gravity,  or  where  the  veins  are  very  extensible,  and  receive 
but  a  feeble  support  from  the  circumambient  parts,  as  in  the  extremi- 
ties. They  are  entirely  wanting  in  the  veins  of  the  deep-seated  vis- 
cera; in  those  of  the  brain  and  spinal  marrow,'and  of  the  lungs;  in  the 
vena  porta,  and  in  the  veins  of  the  kidneys,  bladder,  and  uterus.  They 
exist, however,  in  the  spermatic  veins;  and,  sometimes,  in  the  internal 
mammary,  and  in  the  branches  of  the  vena  azygos.  On  the  cardiac 
side  of  these  valves,  cavities  or  sinuses  exist,  which  appear  externally 
in  the  form  of  varices.  These  dilatations  enable  the  refluent  blood  to 
catch  the  free  edges  of  the  valves,  and  thus  depress  them,  so  as  to  close 

the  cavity  of  the  vessel ;  serving,  in  this 
respect,  precisely  the  sanie  functions  as 
the  sinuses  of  the  pulmonary  artery  and 
aorta  serve  in  regard  to  the  semilunar 
valves.  The  valves  exist  in  veins  of  less 
than  a  line  in  diameter. 

The  three  coats  united  form  a  solid 
vessel, — which,  according  to  Bichat,  is 
devoid  of  elasticit}',  but  in  the  opinion 
of  M.  Magendie^  is  elastic  in  an  eminent 
degree.  The  elasticity  is  certainly  much 
less  than  in  the  arteries.  The  veins  are 
nourished  by  vasa  vasorum^  or  by  small 
arteries,  that  have  their  accompanying 
veins.  Every  vessel,  indeed,  in  the 
body,  if  we  may  judge  from  analogy, 
draws  its  nutriment,  not  from  the  blood 
circulating  in  it,  but  from  small  arterial 
vessels,  hence  termed  vasa  vasorum.  This 
applies  not  only  to  the  veins,  but  to  the 
The  heart,  for  example,  is  not  nourished  by  the  fluid  con- 


Fig.  108. 


Ditigrams  showing  Valves  of  Veins. 

A.  Part  of  a  vein  laid  open  and  spread 
out,  with  two  pairs  of  valves.  B.  Longitu- 
dinal section  of  a  vein,  showing  the  apposi- 
tion of  the  edges  of  the  valves  in  their  closed 
state.  C.  Portion  of  a  distended  vein,  ex- 
hibiting a  swelling  in  the  situation  of  a  pair 
of  valves. 


arteries. 


■  Precis,  &c.,  ii.  Ml. 

2  Trt^atise  on  the  Blood,  &c.,  by  Palmer,  Amer.  edit.,  p.  216,  Philad.,  1840. 

^  Precis,  &c.,  ii.  243. 


CIRCULATORY   APPARATUS. 


853 


stantlj  passing  tL rough  it;  but  by  vessels,  wbich  arise  from  the  aorta, 
and  are  distributed  over  its  surface,  and  in  its  intimate  texture.  The 
coronary  arteries  and  their  corresponding  veins  are,  consequently,  the 
vasa  vasonmi  of  the  heart.  In  like  manner,  the  aorta  and  all  its 
branches,  as  well  as  the  veins,  receive  their  vasa  vasorum.  There 
must,  however,  be  a  term  to  this ;  and  if  our  powers  of  observation 
were  sufficient  we  ought  to  be  able  to  discover  a  vessel,  that  must  de- 
rive its  support  or  nourishment  exclusively  from  its  own  stores. 

The  nerves  that  have  been  detected  on  the  veins  are  branches  of  the 
great  sympathetic. 

The  capacity  of  the  venous  system  is  generally  esteemed  to  be  double 
that  of  the  arterial.     It  is  obvious,  however,  that  we  can  only  arrive 


Fig.  109. 


Fig.  110. 


r  \ 


Roots,  Trunk,  and  Divisions  of  the 
Vena  Porta. 

1,  1.  Veins  coming  from  intestines. 
2.  Trunk  of  vena  porta.  3,  3.  Branch- 
es distributed  in  the  liver. 


Portal  System. 

1.  Inferior  mesenteric  vein  :  traced  by  means  of  dotted  lines 
beliind  the  pancreas  (2)  to  terminate  in  splenic  vein  (3).  4. 
Spleen.  5.  Gastric  veins,  opening  into  splenic  vein.  6.  Supe- 
rior mesenteric   vein.     7.    D(?scending  portion   of  duodenum. 

8.  Its  transverse  portion  vrhich  is  crossed  by  superiur  mesen- 
teric vein  and  by  a  part  of  trunk  of  superior  mesenteric  artery. 

9.  Portal  vein.  10.  Hepatic  artery.  11.  Ductus  communis  cho- 
ledochus.  12.  Divisions  of  duct  and  vessels  at  transverse  fis- 
sure of  liver.     13.  Cystic  duct  leading  to  gall-bladder. 


at  an  approximation,  and  that  not  a  very  close  one.  The  size  and 
number  of  the  veins  are  usually  so  much  greater  than  those  of  the 
corresponding  arteries,  that  when  the  vessels  of  a  membranous  part 
are  injected,  the  veins  are  observed  to  form  a  plexus,  and,  in  a  great 
measure,  to  conceal  the  arteries;  in  the  intestines,  the  number  is  more 
nearly  equal.  The  difficulty  of  arriving  at  any  exact  conclusion  re- 
garding the  relative  capacities  of  the  two  sj'stems  is  forcibly  indicated 
VOL.  I. — 23 


854  CIRCULATION. 

by  the  fact,  that  whilst  Borelli  conceived  the  preponderance  in  favour 
of  the  veins  to  be  as  four  to  one,  Sauvages  estimated  it  at  nine  to  four; 
Haller  at  sixteen  to  nine;  and  Keill  at  twentj-fivetonine.'  The  ratio 
between  the  capacity  of  individual  arteries  and  veins  is  very  different 
in  different  parts.  Between  the  carotid  and  internal  jugular  it  is  as 
196  to  441 ;  the  subclavian  artery  and  vein,  3844  to  7396 ;  the  aorta 
and  venaj  cavse,  9  to  16;  and  between  the  splenic  artery  and  vein,  136 
to  676. 

There  is  one  portion  of  the  venous  system,  to  which  allusion  has 
already  been  made,  that  is  peculiar; — the  ahdoininal  venous  or  portal 
system.  All  the  veins,  that  return  from  the  digestive  organs  situate  in 
the  abdomen  unite  into  a  large  trunk  called  vena  j)orta.  This,  instead 
of  passing  into  a  larger  vein — into  the  vena  cava,  for  example — pro- 
ceeds to  the  liver,  and  ramifies,  like  an  artery,  in  its  substance.  From 
the  liver  other  veins,  called  supra-hepatic,  arise,  which  empty  themselves 
into  the  vena  cava ;  and  correspond  to  the  branches  of  the  hepatic 
artery  as  w^ell  as  to  those  of  the  vena  porta.  The  portal  system  is 
concerned  only  with  the  veins  of  the  digestive  organs  situate  in  the 
abdomen;  as  the  spleen,  pancreas,  stomach,  intestines,  and  omenta. 
The  veins  of  all  the  other  abdominal  organs, — of  the  kidney,  suprarenal 
capsules,  &c.,  are  not  connected  with  it.  The  first  part  of  the  vena 
portce  is  called,  by  some  authors,  vena  jjorta  ahdominalis  sen  ventralis  to 
distinguish  it  from  the  hepatic  portion,  which  is  of  great  size,  and  has 
been  called  sinus  of  the  vena  porta. 

2.    BLOOD. 

It  is  not  easy  to  ascertain  the  total  quantity  of  blood  circulating  in 
both  arteries  and  veins.  Many  attempts  have  been  instituted  for  this 
purpose,  but  the  statements  are  most  diversified,  partly  owing  to  the 
erroneous  direction  followed  by  experimenters,  but,  still  more,  to  the 
variation  that  must  be  perpetually  occurring  in  the  amount  of  fluid, 
according  to  age,  sex,  temperament,  activity  of  secretion,  &c.  Harvey 
and  the  earlier  experimenters  formed  their  estimates  by  opening  the 
veins  and  arteries  freely  on  a  living  animal,  collecting  the  blood  that 
flowed,  and  comparing  this  with  the  weight  of  the  body.  The  plan  is, 
however,  objectionable,  as  the  whole  of  the  blood  can  never  be  ob- 
tained in  this  manner,  and  the  proportion  discharged  varies  in  differ- 
ent animals  and  circumstances.  By  this  method,  Moulins  found  the 
proportion  in  a  sheep  to  be  o'^d;  King,  in  a  lamb,  2^0^^)  ^"^  ^  duck, 
■g'gth ;  and  in  a  rabbit  3'oth.  From  these  and  other  observations, 
Harvey  concluded,  that  the  weight  of  the  blood  of  an  animal  is  to  that 
of  the  whole  animal  as  1  to  20.  Drelincourt,  however,  found  the  pro- 
portion in  a  hog  to  be  nearly  -,-'-oth;  and  Moor,  y'oth.^  Sir  George 
Lefevre^  cites  from  Wrisberg,  that  from  a  plethoric  young  woman, 
who  was  beheaded,  25  pounds  [?]  of  blood  were  collected ;  and  some 
recent  experiments  by  Mr.  Wanner*  led  to  the  following  results :  A 
bullock,  weighing  1659  pounds  imperial,  yielded  69  pounds  of  blood, 

'  Elemeuta  Physiologiae,  lib.  ii.,  sect.  2,  §  10,  Lausauu,,  1757. 

2  Haller,  op.  cit.,  lib.  v.  sect.  1,  §  2. 

3  All  Apology  for  tlio  Nerves,  p.  30,  London,  1844. 
*  Etliuburgli  MeJ.  and  Surg.  Juuru.,  July,  1845. 


BLOOD. 


855 


or  in  the  ratio  of  1  to  23*81 ;  another  weighing  1640  pounds,  yielded 
65  pounds,  or  in  the  ratio  of  1  to  28*73  ;  a  cow,  weighing  1298  pounds, 
yielded  59  pounds,  or  as  1  to  21*77;  a  sheep,  weighing  110  pounds, 
yielded  5|  pounds,  or  in  the  proportion  of  1  to  22*72 ;  another  weigh- 
ing 88  pounds,  yielded  -A*-!  pounds,  or  as  1  to  20 ;  and  in  a  rabbit,  the 
proportion  was  as  1  to  25  exactly. 

An  animal,  according  to  Sir  Astley  Cooper,^  generally  expires,  as 
soon  as  blood,  equal  to  about  ^'gth  of  the  weight  of  the  body,  is  ab- 
stracted. Thus,  if  it  weighs  sixteen  ounces,  the  loss  of  an  ounce  of 
blood  will  be  sufficient  to  destroy  it ;  and,  on  examining  the  body, 
blood  will  still  be  found — in  the  small  vessels  especially — even 
although  every  facility  may  have  been  afforded  for  draining  them. 
Experiments  have,  however,  shown  that  no  fixed  proportion  of  the 
circulating  fluid  can  be  indicated  as  necessary  for  the  maintenance  of 
life.  In  the  experiments  of  Rosa,  asphyxia  occurred  in  young  calves 
when  from  three  to  six  pounds,  or  from  g'^d  to  o'gth  of  their  weight, 
had  been  abstracted;  but  in  older  ones  not  until  they  had  lost  from 
twelve  to  sixteen  pounds,  or  from  j',th  to  ^th  of  their  weight.  In  a 
lamb,  asphyxia  supervened  on  a  loss  of  twenty-eight  ounces,  or  ^'gth 
of  its  weight;  and  in  a  wether,  on  a  loss  of  sixty-one  ounces,  or  o'gd 
of  its  weight.  Dr.  Blundell^  found  that  some  dogs  died  after  losing- 
nine  ounces,  or  -g'jjth  of  their  weight;  whilst  others  withstood  the  ab- 
straction of  a  pound,  or  y'^th  of  their  weight ;  and  M.  Piorry  affirms, 
that  dogs  can  bear  the  loss  of  -g'sth  of  their  weight,  but  if  a  few  ounces 
more  be  drawn  they  succumb.  From  all  the  experiments  and  obser- 
vations, Burdach^  concludes,  that,  on  the  average,  death  occurs  when 
fths,  or  |ths,  of  the  mass  of  blood  is  lost,  although  he  has  observed  it 
in  many  cases,  as  in  hasmoptysis,  on  the  loss  of  ^th,  and  even  of  |th. 

The  following  table  exhibits  the  computations  of  different  physiolo- 
gists regarding  the  weight  of  the  circulating  fluid — arterial  and  venous. 

lbs.  I  lbs. 


Harvey,  "1 

Lister,  1 

Moulins,  j 

Abildguard,  J 
Blumeubacli,     "| 

Lobb,  y     . 

Lower,  J 
Sprengel, 
Giinther  and  Bock, 


Weber  and  Lehmann,  .  17^  to  19 
Miiller,  Burdacli  and  P.  Berard,  20 
Wagner,  .         .         .      20  to  25 

.  27 
28 
28  to  30 
.  40 
.  80 
.     100 


.       10 

Quesnai, 

F.  Hoflmann, 

Haller,    . 

10  to  15 
15  to  20 

Young,    . 
Hambereter, 
Keill,     \ 

Although  the  absolute  estimate  of  Hoffmann  has  been  regarded  as 
below  the  truth,  the  proportion  has  seemed  to  many  to  be  nearly 
accurate;  but  it  is  evidently  too  high.  He  conceives,  that  th^  weight 
of  the  blood  is  to  that  of  the  whole  body  as  1  to  5.  Accordingly,  an 
individual  weighing  one  hundred  and  fifty  pounds,  will  have  about 
thirty  pounds  of  blood;'  one  of  two  hundred  pounds,  forty;  and  so 
on.  Of  this,  one-third  is  supposed  to  be  contained  in  the  arteries,  and 
two-thirds  in  the  veins.     The  estimate  of  Haller^  is,  perhaps,  near  the 

'  Principles  and  Practice  of  Surgery,  p.  33,  Lee's  edition,  Lond.,  1836. 
^  Researelies,  Physiological  and  Pathological,  pp.  <JG  and  94,  Lond.,  1825. 
»  Die  Physiologic  als  Erfalirungs\visseusL-liaft,  iv.  lUl  and  334,  Leipzig,  1832. 
■•  Op.  cit.,  lib.  v.,  sect.  1,  §  3. 


856  CIRCULATIOX. 

truth ;  the  arterial  blood  being,  he  conceives,  to  the  venous,  as  4  to  9. 
Were  we,  therefore,  to  assume  with  Hoftmann  that  the  whole  quantity 
of  the  blood  is  thirty  pounds  in  a  man  weighing  one  hundred  and 
fifty  pounds,  which  is,  however,  allowing  too  much, — nine  pounds,  at 
at  least,  may  be  contained  in  the  arteries,  and  the  remainder  in  the 
veins. 

An  ingenious  plan,  proposed  by  Valentin'  for  estimating  the  quan- 
tity of  blood  in  the  body,  aftbrds  an  approximation  to  the  truth,  and  is 
confirmatory  of  the  estimate  made  from  other  data.  Having  weighed 
an  animal,  and  determined  the  proportion  of  solid  matter  in  a  portion 
of  its  blood,  he  injects  into  its  vessels  a  given  quantity  of  distilled  water, 
which  soon  becomes  mixed  with  the  blood.  He  then  takes  away  a  fresh 
portion  of  blood,  and  ascertains  the  proportion  of  solid  matter  in  it. 
The  relation  between  the  amount  of  solid  matter  in  the  blood  first 
taken,  and  that  in  the  blood  diluted  with  the  given  quantity  of  water, 
enables  him  to  calculate  the  quantity  of  blood  in  the  body  of  the  ani- 
mal. The  following  question  and  solution  are  given,  in  order  to  show, 
how  the  quantity  of  blood  may  be  estimated  in  the  manner  proposed 
by  Valentin. 

A  portion  of  blood  (=  1190  grains),  drawn  from  a  dog,  yielded  24'5-i 
per  cent,  of  solid  matter.  After  injecting  10,905  grains  of  water  into 
the  bloodvessels,  a  portion  of  blood  drawn  yielded  21'86  (or,  by  another 
trial,  2i'89)  per  cent,  of  solid  matter.  What  was  the  amount  of  blood 
in  the  body  at  the  commencement  of  the  experiment? 

Let  X  be  the  amount  of  blood  after  the  first  experiment.  Then,  since 
it  contained  2-±'54  per  cent,  of  solid  residue,  the  amount  of  solid  matter 
in  it  was  '2454  x.  After  injecting  the  water  the  whole  amount  of  the 
diluted  blood  was  x  -f  10905 ;  and  (by  the  experiment)  the  solid  matter 
which  it  contained  was  ==  '2186  {x+  10905).  But  the  solid  matter  was 
of  the  same  amount  in  both  cases.     Therefore  we  have, 

•2454  x=  -2186  {x  +  10905) 
or,  (-2454— -2186)  3:  = -218(3  x  10905 

2388-8330 
or,  X  =  —7^268"  =  ^^^^^  S^^- 

Add  for  the  blood  first  drawn       .         .         .         .         1190 


And  we  get 90185  grs. 

the  weight  of  blood  in  the  body  at  the  commencement  of  the  experi- 
ment. 

The  ratio  21-89  per  cent,  gives     ....       91269  grs. 

And  the  mean  of  the  two  is  ....       90702    " 

In  this  manner,  Valentin  found  the  ratio  of  blood  to  the  weight  of 
the  body  to  be  in  the  dog  as  1  to  4*86  in  the  male  sex,  and  1  to  4-98  in 
the  female;  and  adapting  these  proportions  to  M,  Quetelet's  table  of  the 
weight  of  the  human  subject  at  different  ages,  he  infers,  that  the  mean 
quantity  of  blood  in  the  male  adult,  at  the  time  when  the  weight  of  the 
body  may  be  presumed  to  be  greatest,  namely  at  80  j^ears,  should  be 
about  84|  pounds;  and  that  of  the  female  at  50,  when  the  weight  is 
generally  greatest,  at  about  26  pounds.     It  is  difficult,  however,  to  be- 

'  Lelirbuch  der  Physiologic  des  Mensclien,  i.  490,  Braunschweig,  1S44. 


BLOOD — QUANTITY.  357 

lieve,  that  there  is  not  some  follacy  in  these  calculations.  The  propor- 
tion of  blood  to  the  rest  of  the  body,  judging  from  the  quantity  that 
has  usually  flowed  from  animals  bled  to  death,  and  the  apparent  quan- 
tity remaining  in  the  vessels,  seems  to  be  excessive;  and  such  is  the 
view  of  Professor  Blake  of  Saint  Louis.  In  a  letter  to  the  author,  he 
refers  to  experiments  instituted  by  him,  which  consisted  in  injecting  a 
weighed  quantity  of  sulphate  of  alumina  into  the  veins,  and  analyzing 
a  weighed  portion  of  the  blood.  As  the  salt  had  time  to  be  well  mixed 
with  the  blood  before  the  animal  died,  such  an  analysis,  he  conceived, 
would  enable  the  whole  quantity  of  blood  with  which  the  salt  had  been 
mixed  to  be  determined.  The  only  error  which — it  appeared  to  him — 
might  arise  would  be  from  a  portion  of  the  salt  having  combined  with 
some  of  the  tissues,  or  having  been  rapidly  excreted,  which  could  only 
affect  the  result  in  one  direction,  viz.  in  furnishing  a  greater  quantity 
of  blood  than  really  exists.  The  results  led  Dr.  Blake  to  infer,  that 
there  was  no  such  source  of  error,  as  he  found  by  this  method,  that  the 
weight  of  blood  in  the  body  of  a  dog  does  not  amount  to  more  than 
between  one-eighth  or  one-ninth  part  of  the  weight  of  the  animal,  a 
ratio  much  lower — as  has  been  shown — than  is  generally  conceived. 
"That  this,  however,  is  nearer  the  truth  is  probable  from  the  considera- 
tion of  the  velocity  of  the  circulation  and  the  capacity  of  the  heart,  as, 
on  the  generally  received  opinion  of  the  quantity  of  the  blood,  it  is 
difficult  to  imagine  how  it  can  circulate  so  rapidly."^  This  estimate 
would  give  the  quantity  of  blood  in  a  man  weighing  150  pounds  from 
16|  lbs.  to  18| — not  very  far  from  the  estimates  of  Giinther^,  Bock,' 
and  of  Weber  and  Lehmann,''  who  determined  the  weights  of  two 
criminals  both  before  and  after  their  decapitation.  The  quantity  of 
blood  which  escaped  from  the  body  was  estimated  in  the  following 
manner.  Water  was  injected  into  the  vessels  of  the  trunk  and  head, 
until  the  fluid  escaping  from  the  veins  had  only  a  pale  red  or  yellow 
colour:  the  quantity  of  blood  remaining  in  the  body  was  then  calcu- 
lated, by  instituting  a  comparison  between  the  solid  residue  of  the 
pale-red  aqueous  fluid  and  that  of  the  blood  which  first  escaped. 
They  found  the  weight  of  the  whole  of  the  blood  was  to  that  of  the 
body  nearly  in  the  proportion  of  1  to  8.  More  recentl}^,  Welcker  has 
estimated  it  as  1  to  10.* 

The  blood  strongly  resembles  the  chyle  in  properties ; — the  great  dif- 
ference consisting  in  the  colour.  The  venous  blood,  the  chjde,  and  the 
lymph  become  equally  converted  into  the  same  fluid — arterial  blood — 
in  the  lungs:  both  the  chyle  and  lymph  may,  indeed,  be  regarded  as 
rudimental  blood. 

Venous  blood,  which  chiefly  concerns  us  at  present,  is  contained  in  all 

'  Medical  Examiner,  August,  1849,  p.  459. 

*  Lelirbucli  der  Physiologie  des  Menschen,  2ter  Band,  Iste  Abtheiluag,  S.  122,  Leipzig, 
1848. 

^  Lehrbuch  der  pathologiachen  Anatomie,  3te  Auflasre,  S.  275,  Leipzig,  1852, 

*  Lehrbuch  der  pliysiologisclien  Chemle,  ii.  259,  Leipzig,  1850 ;  or  Anier.  edit.,  by 
Dr.  R.  E.  Rogers,  i.  638,  Phiiad.,  1855  ;  and  R.  Wagner's  Lehrbuoh  der  spociellen  Phy- 
siologie, von  Fnnke,  Iste  Liefm-nng,  S.  4,  Leipzig,  1S54. 

*  Prager  Vierteljahrsthrift,  iv.  11 ;  and  Caustatt's  Jahresbericlit,  1854,  i.  44,  Wiirz- 
biirg,  1855. 


858  CIRCULATION. 

the  veins,  in  the  right  side  of  the  heart,  and  in  the  pulmonary  artery; — 
organs  which  constitute  the  apparatus  of  venous  circulation.  As  drawn 
from  the  arm  its  appearance  is  familiar  to  every  one.  At  first,  it  seems 
to  be  entirely  homogeneous;  but,  after  resting  for  some  time,  separates 
into  difterent  portions.  The  colour  of  venous  blood  is  much  darker 
than  that  of  arterial;  so  dark,  indeed,  as  to  have  led  to  the  epithet  Hack 
blood  applied  to  it.  Its  smell  is  faint  and  peculiar;  by  some  compared 
to  a  fragrant  garlic  odour,  but  sui  generis ;  its  taste  is  slightly  saline, 
and  also  peculiar.  It  is  viscid  to  the  touch;  coagulable;  and  its  tem- 
perature has  been  estimated  at  96°  Fahrenheit;  simply,  we  believe,  on 
the  authority  of  the  inventor  of  the  thermoraetric  scale,  who  marked 
96°  as  blood  heat.  This  is  too  low  by  at  least  three  or  four  degrees. 
Kudolphi,^  and  the  German  writers  in  general,  estimate  it  at  29°  of 
E^aumur,  or  "from  98°  to  100°  of  Fahrenheit;''  whilst,  by  the  French 
writers  in  general,  its  mean  temperature  is  stated  at  31°  of  Eeaumur, 
or  102°  of  Fahrenheit;  M.  Magendie,^  who  is  usually  very  accurate, 
fixes  the  temperature  of  venous  blood  at  31°  of  Eeaumur,  or  102°  of 
Fahrenheit;  and  that  of  arterial  blood  at  32°  of  Eeaumur,  or  10-1°  of 
Fahrenheit.  100°  may  perhaps  be  taken  as  the  average.  This  was  the 
natural  temperature  of  the  stomach  in  the  case  related  by  Dr.  Beau- 
mont,^ which  has  been  so  often  referred  to  in  these  pages.  In  many 
animals,  the  temperature  is  considerably  higher.  In  the  sheep  it  is 
102°  or  103°;  but  it  is  most  elevated  in  birds.  In  the  duck  it  is  107°. 
On  this  subject,  however,  further  information  will  be  given  under  the 
head  of  Calorification. 

The  specific  gravity  of  blood  is  differently  estimated  by  different 
observers.  Hence  it  is  probable,  that  it  varies  in  individuals,  and  in 
the  same  individual  at  difterent  periods.  Compared  with  water,  the 
mean  has  been  estimated,  by  some,  to  be  as  1*0527;  by  others,  as 
1'0800,  to  1*0000.  It  is  stated,  however,  to  have  been  found  as  high 
as  1*126 ;  and,  in  disease,  as  low  as  1'022.  It  has,  moreover,  been 
conceived,  that  the  effect  of  disease  is,  invariably,  to  make  it  lighter; 
and  that  the  more  healthy  the  individual,  the  greater  is  its  specific 
gravity;  but  our  information  on  this  point  is  vague.  That  it  is  not 
always  the  same  in  health  is  proved  by  the  discrepancy  of  observers. 
Boyle  estimated  it  to  be  I'Oil ;  Martine,  1.045;  Jurin,  1-05-1 ;  Mus- 
chenbroek,  1*056:  Denis,  1.059;  Senac,  1*082 ;  Berzelius,  from  1*052 
to  1*126;  J.  Muller,  from  1*0527  to  1*0570;  Mandl,  from  1*050  to 
1*059 ;  and  Dr.  G.  O.  Eees,  from  1*057  to  1*060.  In  a  large  number 
of  experiments  made  upon  the  blood  of  man,  the  ox,  and  horse,  M. 
Simon"  found  it  to  be  between  1*051  and  1*058.  The  average  was 
1*042,  [1052?]  which,  he  sa3^s,  corresponds  very  nearly  with  the  state- 
ment of  Berzelius.  The  average  of  human  blood  may  perhaps  be 
1*050.  Nasse  says  1*055 ;  Zimmerman,  1*056.  A  part  of  the  dis- 
crepancy may  be  owing  to  the  specific  gravity  not  having  been  always 
taken  at  the  same  temperature.  Dr.  B.  Babington  found  experi- 
mentally that  four  degrees  of  temperature  corresponded  with  a  dift'er- 

'  Grundriss  der  Physiologie.  i.  143,  Berlin,  1S21.  ^  Precis,  &c.,  ii.  229. 

2  Experiments,  &:c.,  on  the  fiastric  Juice,  &c.,  p.  2T4,  Plattshurg,  1S33. 
•  Animal  Chemistry,  Sydenham  edition,  i.  100,  Lond.,  1645. 


BLOOD — SPECIFIC   GKAVITY. 


859 


ence  of  "001  of  specific  weight;  consequently,  if  one  author  states  the 
specific  gravity  of  blood  at  about  its  circulating  temperature — say  98° 
of  Fahr. — while  another  states  it  at  60°  Fahr. — the  usual  standard — 
the  former  will  make  it  .0095  lighter  than  the  latter. 

The  blood  of  man  is  thicker,  and  at  least  one- thousandth  heavier 
than  that  of  woman. 

When  blood  is  examined  with  a  microscope  of  high  magnifying  power, 
it  is  found  to  be  composed  of  numerous,  minute,  red  particles  or  cor- 
jmscles, — commonly  called  red  globules,  blood  corpuscles^  and  blood  dislrs, 
— suspended  in  the  serum.  These  corpuscles  have  a  different  shape 
and  dimension,  according  to  the  nature  of  the  animal.  In  the  mam- 
malia, they  are  circular;  and,  in  birds  and  cold-blooded  animals,  ellip- 
tical. In  all  animals,  they  are  affirmed,  by  some  observers,  to  be 
flattened,  and  marked  in  the  centre  with  a  luminous  point,  of  a  shape 
analogous  to  the  general  shape  of  the  corpuscle.  Professor  Giacomoni,' 
of  Padua,  has,  however,  affirmed,  that  the  red  corpuscles  swimming  in 
serum, — which  have  been  described,  by  so  many  writers,  in  the  circu- 
lating fluid,  exist  only  in  the  imagination.  As  in  most  cases  that  rest 
on  microscopic  observation,  discrepancy  has  prevailed,  not  only  as 
regards  the  shape,  but  the  size  of  the  corpuscles.  These  were  first 
noticed  by  Malpighi  f  and  afterwards  more  minutely  examined  by 
Leeuenhoek,  who  at  first  described  thein  correctly  enough  in  general 
terms  ;  but  subsequently  became  hypothetical ;  and  advanced  the  fan- 
tasy, that  the  red  corpuscles  are  composed  of  a  series  of  globular  bodies, 
descending  in  regular  gradations ;  each  of  the  red  corpuscles  being  com- 
posed of  six  particles  of  serum  ;  a  par- 
ticle of  serum  of  six  particles  of  lymph, 
&G.  Totally  devoid  of  foundation  as 
the  whole  notion  was,  it  was  believed 
fora  considerable  period,  even  until  the 
time  when  Haller  wrote.  Mr.  Hewson' 
described  the  corpuscles  as  consisting 
of  a  solid  centre,  surrounded  by  a  vesi- 
cle, filled  with  a  fluid  ;  and  to  be  "  as 
flat  as  a  guinea."  Mr.  Hunter,''  on  the 
other  hand,  did  not  regard  them  as 
solid  bodies,  but  as  liquids  possessing 
a  central  attraction  that  determines 
their  shape.  Delia  Torre*  supposed 
them  to  be  a  kind  of  disk  or  ring, 
pierced  in  the  centre  ;  whilst  Dr.  Monro  conceived  them  to  be  circu- 
lar, flattened  bodies,  like  coins,  with  a  durk  spot  in  the  centre,  which  he 
thought  was  not  owing  to  a  perforation,  as  Delia  Torre  had  imagined, 
but  to  a  depression.     Cavallo,^  again,  conceived,  that  all  these  appear- 

'  Encyclogr.  des  Sciences  Medicales,  Avril,  1840,  p.  529. 

*  Opera,  Lond.,  1687. 

'  Experimental  Inqiiiries,  part.  iii.  p.  16,  Lond.,  1777,  or  Ilewson's  Works,  by  Gulli- 
ver, Sydenham  Society's  edit.,  p.  215,  Lond.,  1846. 

*  On  the  Blood,  &c.,  by  Palmer,  Amer.  edit.,  p.  63,  Philad.,  1840. 
5  Philos.  Trans,  for  1765,  p.  252. 

^  An  Essay  on  the  Medicinal  Projjerties  of  Factitious  Air,  &c.,  p.  237,  Lond.,  1798. 


Fig.  111. 


Red  Corpuscles  of  Human  Blood. 

Represented  at  a,  as  they  are  seen  whea 
rather  hei/oiid  the  focvis  of  the  microscope  ; 
and  at  h  as  they  appear  when  loiihin  the  focus. 
MaL'uilied  iOO  diameters. 


860  CIRCULATION. 

ances  are  deceptive,  depending  upon  tlie  peculiar  modilication  of  the 
rajs  of  light,  as  affected  by  the  form  of  the.  particle ;  and  he  concluded, 
that  they  are  simple  spheres.  Amici  found  them  of  two  kinds  ;  both 
with  angular  margins ;  but,  in  the  one,  the  centre  was  depressed  on  both 
sides ;  whilst,  in  the  other,  it  was  elevated.  The  observations  of  Dr. 
Young,'  of  Sir  Everard  Home  and  Mr.  Bauer,^  and  of  MM.  Prevost 
and  Dumas,^  accord  chiefly  with  those  of  Mr.  ITewson.  All  these  gen- 
tlemen consider  the  red  corpuscles  to  be  composed  of  a  central  globule, 
which  is  transparent  and  whitish ;  and  of  a  red  envelope,  which  is  less 
transparent.  Dr.  Hodgkin  and  Mr.  Lister''  have  denied  that  they  are 
spherical,  and  consist  of  a  central  nucleus  enclosed  in  a  vesicle.  They 
affirm,  on  the  authority  of  a  microscope,  which,  on  comparison,  was 
found  equal  to  a  celebrated  one,  taken  a  few  years  ago  to  Great  Britain 
by  Professor  Amici, ^  that  the  particles  of  human  blood  consist  of  circu- 
lar, flattened,  transparent  cakes,  their  thickness  being  about  ^'^  part  of 
their  diameter.  These,  when  seen  singly,  appear  to  be  nearly  or  quite 
colourless.  Their  edges  are  rounded,  and  being  the  thickest  part,  occa- 
sion a  depression  in  the  middle,  which  exists  on  both  surfaces.  The 
view  of  these  gentlemen,  consequently,  appears  to  resemble  that  of 
Dr.  Monro.  Mr.  Gulliver,^  however,  thinks  that  the  ratio  of  1  to  45, 
given  by  Dr.  Hodgkin  and  Mr.  Lister,  must  be  a  misprint.  From 
measurements  of  the  thickness,  at  the  circumference  of  the  corpuscles 
of  several  mammalia,  he  found  it  to  be  generally  one-third  and  one- 
fourth  the  diameter :  the  average  thickness  of  the  human  blood  cor- 
puscle he  estimates  at  yo^oo^^^  ^^  ^^  English  inch,  and  the  diameter 

Amidst  this  discordance,  it  was  difficult  to  know  which  view  to 
adopt.  The  belief  in  their  consisting  of  circular,  flattened,  transpa- 
rent bodies,  with  a  depression  in  the  centre,  and  of  an  external  enve- 
lope and  a  central  nucleus,  the  former  of  which  is  red  and  gives  colour 
to  the  blood,  has  had,  perhaps,  the  greatest  weight  of  authority  in  its 
favour.  The  nucleus  has  appeared  to  observers  to  be  devoid  of  colour, 
and  to  be  independent  of  the  envelope;  as,  when  the  latter  was  de- 
stroyed, the  central  portion— it  was  conceived — preserved  its  original 
shape.  The  nucleus  was  considered  to  be  much  smaller  than  the  enve- 
lope, being,  according  to  Dr.  Young,  only  about  one-third  the  length, 
and  one-half  the  breadth  of  the  entire  corpuscle.  According  to  Sir 
Everard  Home,^  the  corpuscles,  enveloped  in  the  colouring  matter,  are 
y^igoth  part  of  an  inch  in  diameter,  requiring  2,81)0,000  to  a  square 
inch;  but  deprived  of  their  colouring  matter  they  appear  to  be  sq'od^^ 
part  of  an  inch  in  diameter,  requiring  4,000,000  corpuscles  to  a  square 
inch.  From  these  measurements,  the  corpuscles,  when  devoid  of  co- 
louring matter,  are  not  quite  one-fifth  smaller.  The  views  of  MM, 
Prevost  and  Dumas,  who  have  investigated  the  subject  with  extreme 

'  Introiluct.  to  Med.  Literature,  p.  545. 

2  Philosopli.  Transact,  for  1811-1818  ;  and  Lectures  on  Comp.  Anat.,  iii.  4,  Lend., 
1823. 

3  Annales  do  Chimie,  &c.,  xxiii.  50,  90  ;  and  Journal  of  Science  and  Arts,  xvi.  115. 
*  Plillosoph.  Magazine  and  Annals  of  Philosopliy,  ii.  130,  Lond.,  1827. 

^  Edinb.  Medical  and  Surgical  Journal,  xvi.  120. 

^  Hewson's  Works,  Sydenham  Society's  edit.,  note  to  page  215,  Lond.,  1846. 

^  Lectures  on  Comparative  Anatomy,  iii.  4,  aud  v.  100,  Lond.,  1828. 


BLOOD — EED   COEPUSCLES,  361 

care  find  signal  ingenuity,  are  deserving  of  great  attention.  They 
conceive  the  blood  to  consist  essentially  of  serum,  in  which  a  quantity 
of  red  corpuscles  is  suspended ;  that  each  of  these  corpuscles  consists 
of  an  external  red  vesicle,  which  encloses,  in  its  centre,  a  colourless 
globule ;  that  during  the  progress  of  coagulation,  the  vesicle  bursts, 
and  permits  the  central  globule  to  escape ;  that,  on  losing  their  enve- 
lope, the  central  globules  are  attracted  together;  that  they  are  dis- 
posed to  arrange  themselves  in  lines  and  fibres ;  that  these  fibres  form 
a  network,  in  the  meshes  of  which  they  mechaiiically  entangle  a  quan- 
tity of  both  the  serum  and  the  colouring  matter;  that  these  latter  sub- 
stances may  be  removed  by  draining,  and  by  ablution  in  water;  that, 
when  this  is  done,  there  remains  only  pure  fibrin ;  and  that,  conse- 
quently, fibrin  consists  of  an  aggregation  of  the  central  globules  of 
the  red  corpuscles,  while  the  general  mass,  that  constitutes  the  crassa- 
mentum  or  clot,  is  composed  of  the  entire  particle.  So  far  this  seems 
satisfactory ;  but,  we  have  seen.  Dr.  Hodgkin  does  not  recognise  the 
existence  of  external  vesicle,  or  central  nucleus ;  and  he  affirms,  con- 
trary to  the  notion  of  Sir  Everard  Home  and  others,  that  the  particles 
are  disposed  to  coalesce  in  their  entire  state.  This  is  best  seen  when 
the  blood  is  viewed  between  two  slips  of  glass.  Under  such  circum- 
stances, the  following  appearances  are  distinctly  perceptible.  When 
human  blood,  or  that  of  any  other  animal  which  has  circular  corpus- 
cles, is  examined  in  this  manner,  considerable  agitation  is,  at  first,  seen 
to  take  place  among  the  corpuscles ;  but,  as  this  subsides,  they  apply 
themselves  to  each  other  by  their  broad  surfaces,  and  form  piles  or 
rouleaux,  sometimes  of  considerable  length.  These  rouleaux  often 
again  combine, — the  end  of  one  being  attached  to  the  side  of  another, — • 
so  as  to  produce,  at  times,  very  curious  I'amifications. 

The  fact  of  the  corpuscles  being  flattened  disks  is  now  admitted; — • 
but  the  form  of  the  disk  is  found  to  be  altered  by  various  substances. 
Its  external  envelope  readily  admits  the  endosmose  of  fluids;  so  that, 
if  placed  in  water,  it  may  assume  a  truly  globular  shape.  In  examin- 
ing the  blood,  consequently,  it  is  advisable  to  dilute  it  with  a  fluid  of  as 
nearly  as  possible  the  same  character  as  the  serum.  In  the  particles 
of  the  blood  of  the  frog — as  represented  in  Fig.  112 — a  nucleus  is  ob- 
served projecting  somewhat  from  the  central  portion :  this  is  rendered 
extremely  distinct  by  the  action  of  acetic  acid,  which  dissolves  the 
rest  of  the  particle,  and  renders  the  nucleus  more  opaque.  It  then 
appears  to  consist  of  a  granular  substance.  The  vesicular  character 
of  the  red  corpuscles  was  clearly  shown  by  Dr.  (j.  O.  liees,'  by  the 
readiness  with  which  they  become  collapsed  or  distended  by  increasing 
or  diminishing  the  specific  gravity  of  the  medium  in  which  they  float. 
In  order  to  collapse  the  corpuscles,  a  solution  of  sp.  gr.  I'OBO  is  suffi- 
cient, but  a  solution  of  I'OTO  or  more  is  required  to  produce  a  decided 
effect.  Solutions  cease  to  distend  the  corpuscles  when  of  sp.  gr.  1'050 
to  1-055,  and  to  distend  them  well  a  solution  of  1'015  or  1-OiO  is  de- 
sirable. He,  moreover,  established,  what  is  now  generally  admitted, 
that  the  red  colouring  matter  of  the  corpuscle  is  seated,  not  in  the 

'  Ranking's  Half- Yearly  Abstract  of  the  Medical  Sciences,  vol.  i.,  Jan.  to  June,  1845, 
p.  250. 


862  CIECULATION. 

envelope,  but  iu  the  fluid  within  the  vesicle,  and  that  the  envelopes 
themselves  are  white  and  colourless  membranes.  This  is  shown  by 
increasing  the  specific  gravity  of  the  liquid  in  which  the  corpuscles 
float,  the  result  of  which  is  the  escape  by  exosmose  of  the  red  coloured 
fluid  from  within  the  corpuscles;  and,  again,  b}''  applying  water  to  the 
corpuscles,  and  inducing  endosmose,  the  vesicles  become  distended  and 
burst;  their  colouring  matter  mixes  with  the  water,  and  the  envelopes 
subside  to  the  bottom  of  the  vessel,  forming  a  white  layer.  The  red 
corpuscles  of  man  have  no  nuclei,  and  their  contents  are  probably 
homogeneous.  They  appear  so  at  least  when  their  surfaces  are  flat  or 
slightly  convex ;  but  when  concave  the  unequal  refraction  of  trans- 
mitted light  gives  the  appearance  of  a  central  spot,  which  is  brighter 
or  darker  than  the  border  according  as  it  is  viewed  in  or  out  of  focus. 
(See  Fig.  111.) 

Microscopical  discordances  are  no  less  evidenced  by  the  estimates, 
which  have  been  made  of  the  size  of  the  red  corpuscles ;  yet  all  are 
adduced  on  the  faith  of  positive  admeasurements.  Leaving  out  of  view 
the  older,  and,  consequently,  it  might  be  presumed,  less  accurate  ob- 
servations, the  following  table  shows  their  diameter  in  human  blood, 
on  the  authority  of  some  of  the  most  eminent  microscopic  observers 
of  modern  times. 

Sir  E.  Home  and  Mr.  Bauer,  with  colouring  matter,  j,'(^^th  part  of  an  inch. 

Ejler,     .     .         .         .         .         .         .         .         .         .  ^^Vd 

Sir  E.  Home  and  Mr.  Bauer,  without  colouring  matter,  ^f,'g^ 

Muller, 25V0-  to  uAiy 

Mandl,       ._       .         .         .       _.         .     '    .         .         .  z?"??  to  gy's^ 

Hodgkin,  Lister,  and  Rudolphi,         ....  ^oVij 

Sprengel 3fi',7S  ^^  57.'<J5 

Cavallo, 5„\,-o  to  ^-^'n^ 

I>"nne,        .       _ 3i''o  *"  uAff 

Jurin  and  Gulliver,    .......  ^c'lff 

Blumenbach  and  Senac      ......  s^'^tj 

I'-^'jor, se^n-ij 

Milne  Edwards, jts'ojt 

Wagner ^^V,, 

Kater, >,'  pv  to 


Prevost  and  Dumas, -^i, 

Haller,  Wollaston  and  Weber,  .... 
Young, 


isss  ""^  55 as 


^offir 


The  blood  of  different  animals  is  found  to  differ  greatly  in  the  rela- 
tive quantity  of  the  red  corpuscles  it  contains,  the  number  seeming  to 
bear  a  pretty  exact  ratio  with  the  temperature  of  the  animal.  The 
higher  the  natural  temperature,  the  greater  the  proportion  of  corpus- 
cles; arterial  always  containing  a  much  greater  proportion  than  ve- 
nous blood.  In  the  greater  part  of  the  mammalia  they  have  the  same 
shape  as  those  of  man;  but  their  size  varies  greatly  iu  different  fami- 
lies. It  would  appear,  from  the  researches  of  Mandl,'  that  of  the 
mammalia  the  elephant  has  the  largest,  (y^fith  of  a  millimetre,)  and 
the  ruminantia  the  smallest;  that  the  family  of  camels  is  the  only  one, 
whose  corpuscles  are  not  round  like  those  of  the  other  mammalia,  but 

'  Manuel  d'Anatomie  Generale,  p.  248,  Paris,  1843.  For  numerous  admeasurements 
of  the  red  corpuscles  of  the  blood  of  man  and  animals,  see  Note  by  Mr.  Gulliver  to 
Hewson's  Works,  Sydenham  Society's  edit.,  p.  237,  Lond.,  184(i. 


BLOOD — RED   CORPUSCLES. 


363 


Fig.  112. 


elliptical  like  those  of  birds,  reptiles,  and  fishes,^     In  all  oviparous 
vertebrata,  without  any  known  ex- 
ception, the  red  corpuscles  are  oval. 

The  chemical  constitution  of  the 
blood  corpuscles  is  not  definitely 
settled.  Two  proximate  principles 
have  been  discovered  in  them — 
hematin  or  hematosiyi,  and  ghlm- 
lin, — hemaioglohulin  of  Simon.  The 
former,  as  mentioned  hereafter,  is 
the  colouring  matter.  The  latter, 
which  differs  from  the  globulin 
of  Laennec,  —  an  impure  hematin 
mingled  with  some  albumen, — is 
the  main  constituent  of  the  globules, 
and  is  the  same  as  the  hlood-casein 
of  Simon.  It  has  not  been  separated ;  but  is  presumed  to  differ  but 
little  in  its  properties  from  protein. 

It  has  been  supposed  that  the  red  corpuscles  are  formed  originally 
in  the  germinal  membrane  of  the  embryo :  but,  throughout  the  re- 
mainder of  existence,  in  the  blood  from  the  chyle.  Their  origin  is, 
however,  by  no  means  settled.  Normally,  they  are  not  found  outside 
the  vessels  ;  and  are  manifestly,  therefore,  not  inservient  to  nutrition ; 
but  connected,  in  all  probability,  as  shown  elsewhere,  with  respiration 


Blood  Corpuscles  of  Rana  Esculenta. — Mag- 
nified 400  diameters. 

1,  1,  1,  2  Blood  corpuscles.  2.  Seen  edgewise. 
3.  Lymph  corpuscle.  4.  Altered  by  dilute  acetic 
acid. 


Fig.  113. 


Fig.  114. 


^^'  (1) 


Red  corpuscles  of  Pigeon's  Blood,  magnified  400 
diameters. 
A.  Red  particles  unaltered,  with  two  or  three  colourless  par- 
ticles.    B.  Treated  with  acetic  acid,  which  develops  the  cell- 
wall  and  nucleus  more  clearly. 


Red  Corpuscle  of  Fishes. 
a.  Lamprey.  6.  Skate. — After  Whar- 
ton Junes. 


and  calorification.  It  is  not  determined  whether  they  are  capable  of 
reproduction,  or  possess  independent  life.  Dr.  Carpenter'^  thinks,  that 
there  can  be  no  reasonable  doubt,  that  they  are  to  be  regarded  as 
nucleated  cells,  conformable  in  general  character  with  the  isolated 
cells  that  constitute  the  whole  of  the  simplest  plants;  having  each  an 
independent  life,  and  therefore  the  power  of  reproduction.  Such  too, 
is  the  view  of  Dr.  Martin  Barry  and  other  microscopists.  Wagner, 
Gulliver,  and  others,^  from  observation  of  the  blood  of  the  batrachia, 
ascribe  their  origin  to  the  colourless  corpuscles  to  be  mentioned  pre- 
sently, which,  they  consider,  become  red  blood  corpuscles  when  fully 
developed ;  whilst  Dr.  Carpenter  strenuously  maintained,  that  there  is 
an  entire  functional  as  well  as  structural  difterence  between  the  red 


Op.  citat.,  and  Annales  cles  Sciences  Natnrelles,  1824  and  182,5. 
Principlf-s  of  Human  Physiology,  2il  edit.,  p.  400,  Loinlon,  1^44. 
V.  Bruns,  Lehrbuch  dor  Allgemeiuen  Auatomie,  s.  140,  Braunschweig,  1841. 


364:  CIRCULATION. 

and  the  colourless  corpuscles  of  the  blood  of  vertebrata;  but  since  then 
his  views  have  undergone  an  entire  change.^  Observations  by  Dr.  G. 
O.  Rees^  led  him  to  infer,  that  they  multiply  by  division.  On  ex- 
amining a  portion  of  blood,  kept  at  about  its  natural  temperature,  he 
observed  the  corpuscles  assume  an  hour-glass  form,  which,  increasing, 
eventually  divided  each  corpuscle  into  two  unequal-sized  circular 
bodies.  These,  when  treated  with  a  strong  saline  solution,  underwent 
the  same  exosmotic  changes  as  are  observed  in  common  blood  cor- 
puscles. 

In  addition  to  the  red,  ivldte  corjnisclcs  are  observed  in  the  blood. 
These  were  noticed  by  Prof.  Muller  in  that  of  frogs ;  and  by  M.  MandP 
in  that  of  the  mammalia.  They  are  small,  colourless  corpuscles,  finely 
granulated;  insoluble  in  water,  and  strongly  refracting  light.  Accord- 
ing to  Mandl,  they  may  be  separated  into  two  species, — some  round, 

and  containing  two  or  three  granules,  which  become  more 

Fig.  115.      evident  when  they  are  treated  with  acetic  acid :  these  are 

^o^  the  true  lymph  corpuscles,  described  already  (p.  245);  the 

^^  others,  generally  also  round ;  sometimes  oblong ;   and  at 

A^   A        others  irregular ;  the  edges  slightly  notched  ;  and  the  sur- 

\^  ^)       face  finely  granulated.     They  appear  to  be  composed  of  a 

multitude  of  small  molecules,  from  yj^'g^th  to  yg'gj^th  of  a 

^^^''^1  ^'^^}   millimetre  in  diameter :  some  are  also  found  single.    These 

the  Blood,     corpuscles  are  seen  forming  under  the  microscope,  when 

blood,  placed  between  two  glasses,  is  attentively  examined. 
They  are,  in  Mandl's  opinion,  produced  b}^  the  coagulation  of  fibrin, 
and  hence  are  called  by  him  Jibrinoxs  glolmks.  More  recently,  how- 
ever, he  has  abandoned  this  name,  "because  it  rests  on  a  chemical 
character,  that  requires  confirmation;  and  because  it  is  not  drawn 
from  anatomical  characters,  which  ought  chiefly  to  fix  the  attention  of 
the  microscopist."  He  now  terms  them  white  rjranulattd  corpuscles.*' 
These  are  the  f/Iolnlins  of  M.  Donne,  and  are  considered  by  him^  as 
well  as  by  M.  Bernard,^  to  be  the  first  elements  of  blood  corpuscles. 

The  white  cor[)uscles  are  much  less  numerous  than  the  red.  In 
health  the  proportion  has  been  stated  as  1  to  50;  but  in  disease  often 
as  high  as  1  to  10.^  Accurate  observations,  however,  by  Welcker*  and 
Moleschott^  make  the  proportion  much  smaller.  In  Welcker's  own 
blood,  it  was  as  1  to  341,  Moleschott's  observations  made  it  I  to  357; 
or  about  2'8  parts  in  the  1000;  and  Donders  and  K6lliker^°  appear  to 
agree  with  him.  In  certain  morbid  conditions,  especially  of  the  spleen 
and  other  vascular  glands,  an  unusual  number  of  colourless  corpuscles 
is  observed  in  the  blood;  along  with  a  marked  diminution  of  the  red 

'  Principles  of  Human  Physiology,  Amer.  edit.,  p.  178,  Philad.,  1855. 

2  Gulstonian  Lecture  ;  see  Ranking,  Half- Yearly  Abstract,  Jan.  and  July,  1845, 
Amer.  edit.,  p.  251. 

^  Grazette  M  'dicale,  1837 ;  and  Manuel  d'Anatomie  Gen6rale,  p.  252,  Paris,  1S43. 

*  Manuel  d'Anatomie  Gen/rale,  p.  554,  Paris,  1843. 

^  Cours  de  Microscopie,  p.  86,  Paris,  1845. 

6  W.  F.  Atlee,  Notes  on  M.  Bernard's  Lectures  on  the  Blood,  p.  38.  Philad.,  1854. 

''  Kirkes  and  Paget,  Manual  of  Physiology,  2d  Amer.  edit.,  p.  52,  Philad.,  1853. 

^  Prager  Vierteljahrschrift,  iv.  11,  in  Canstatt,  Jahresbericht,  1854,  i.  44  and  1G5. 

^  Wiener  Wochenschrift,  No.  8,  in  Canstatt,  op.  cit.,  S.  44. 

'"  Mikroskopische  Anatomie,  ii.  577,  Leipzig,  1854;  and  Manual  of  Histology,  Syden- 
ham Society's  edit. ;  or  Amer.  edit.,  by  Dr.  Da  Costa,  p.  708,  Philad.,  1854. 


BLOOD — WHITE   CORPUSCLES.  865 

corpuscles,  and  an  increase  of  the  ratio  of  fibrin.     To  this  condition 
Professor  Bennett,  of  Edinburgh,  gives  the  name  leucocytha^mia.^ 

Dr.  Barry  and  Mr.  Addison  think,  that  the  colourless  corpuscles, — 
which  have  generally  been  regarded  as  lymph  corpuscles, — are  formed 
from  the  central  portion  of  the  blood  corpuscle^:  they  consider  them 
to  hold  an  intermediate  position  between  the  true  red  corpuscles,  and 
the  greatly  modified  forms  of  corpuscles,  which,  in  their  view,  are  the 
basis  of  the  tissues,  as  well  as  of  pus  and  other  globules.  The  most 
probable  opinion,  however,  is  that  the  white  corpuscles  of  the  blood  are 
identical  with  the  lymph  and  chyle  corpuscles;  and  all,  in  the  opinion 
of  Dr.  Carpenter,"^  are  connected  with  the  elaboration  of  plastic  fibrin, 
which  must  be  constantly  dravvn  oft"  by  the  nutritive  processes,  and 
therefore  require  to  be  reproduced.  His  arguments  on  this  head  are 
certainly  forcible.  It  was  first  observed  by  Wagner,^  that  whilst  the 
colourless  corpuscles  are  met  with  in  the  nutritious  fluids  of  all  animals 
that  possess  a  distinct  circulation,  red  corpuscles  are  restricted  to  the 
vertebrata.  The  truth  of  this  has  been  confirmed  by  Dr.  Carpenter, 
who  infers  from  it,  that  the  function  of  the  colourless  corpuscles  must 
be  of  a  general  character,  and  intimately  connected  with  the  nutritious 
properties  of  the  circulating  fluid ;  whilst  that  of  the  red  corpuscles 
must  be  of  a  limited  character,  being  only  required  in  one  division  of 
the  animal  kingdom.  One  of  the  strongest  arguments,  however,  in 
favour  of  the  function  of  the  white  corpuscles  mentioned  above,  is  the 
connexion  between  the  generation  of  white  corpuscles  in  the  blood, 
and  the  production  of  fibrin  in  the  inflammatory  process.  This  in- 
crease is  evidently  the  result  of  the  local  inflammation,  and  is  observed 
to  commence  before  the  occurrence  of  any  constitutional  phenomena. 
The  microscopic  observations  of  Messrs.  Addison,"  Williams,^  Gulliver, 
and  others,  have  established,  that  a  great  accumulation  of  white  cor- 
puscles takes  place  in  the  vessels  of  an  inflamed  part, — partly  owing 
to  an  attraction  of  the  corpuscles  towards  the  seat  of  inflammation,  and 
partly,  they  were  satisfied,  by  an  actual  reproduction  of  fresh  corpuscles, 
which  must  have  been  owing  either  to  their  own  power  of  generating 
themselves,  or  to  some  change  in  the  blastema  or  fluid  of  circulation  in 
the  part,  which  favoured  a  more  abundant  production.  Dr.  Carpenter 
was  a  believer  in  the  first  mode  of  production ;  and  certainly  his  view, 
that  the  formation  of  fibrin  in  the  blood  is  closely  connected  with  the 
developement  of  white  corpuscles,  had  strong  arguments  in  its  favour; 
but  he  does  not  now  urge  that  the  fibrin  is  formed  by  them.  ISIessrs. 
Kirkes  and  Paget^  are  firm  believers  in  the  developement  of  the  human 
lymph  or  chyle  corpuscle  into  the  red  corpuscle, — a  view  which  appears 
to  be  the  most  philosophical  from  the  phenomena  recorded  by  difterent 
observers.  Mr.  Lane,  for  example,  found  the  ruddy  colour  of  the  horse's 
chyle  due  to  the  presence  of  red  corpuscles ;  and  he  and  Mr.  Ancell  ob- 
served imperfect  blood  corpuscles  in  the  large  lymphatics,  and  ascribed 

'  Edinb.  Monthly  Journ.  of  Med.  Science,  for  1851  ;  and  his  work  on  Lencocythaemia, 
Edinb.,  1851. 

2  Op.  cit.,  2d  edit.,  p.  506,  Lond.,  1844.  3  Op.  cit. 

*  Med.  Gazette,  Dec,  1840;  Jan.  and  March,  1841. 

^  Principles  of  Medicine,  Anier.  edit.,  by  Dr.  Clymer,  pp.  214,  215,  P  lilad.,  1844. 
8  Manual  of  Physiology,  2d  Amer.  edit.,  p.  6G,  Philad.,  1853. 


366 


CIRCULATION. 


Developement  of  Human  Lymph  and  Chyle  Corpuscles 
into  Red  Corpuscles  of  Blood. 

A.  A  lymph  or  white  blood-corpuscle.  B.  The  same,  in  pro- 
cess of  conversion  into  a  red  corpuscle,  c.  A  lymph  corpuscle, 
with  the  cell-wall  raised  up  round  it  by  the  action  of  water. 
D.  A  lymph  corpuscle,  from  which  the  granules  have  almost 
all  disappeared,  e.  A  lymph  corpuscle,  acquiring  colour  :  a 
.single  granule,  like  a  nucleus,  remains.  i\  A  red  corpuscle, 
fully  developed. 


the  ro.se-colour  of  the  lymph  to  them.    Tlie  thoracic  duct  of  the  horse, 
according  to  Mr.  Gulliver/  often  appears  as  a  coloured  tube  from  the 

number  of  these  corpuscles 
in  the  chyle,  which  he  gene- 
rally found  to  be  smaller, 
more  irregular  and  less  per- 
fect in  shape  than  the  red 
corpuscles  in  the  blood. 
Schultz  and  Gurlt^  also  no- 
ticed the  chyle  of  a  reddish 
colour  from  the  presence  of 
blood  corpuscles,  of  which 
they  suppose,  with  Simon 
of  Berlin,^  the  formation  to 
begin  in  the  chyle ;  and  Mr. 
Gulliver  adds,  that  the  tran- 
sition of  the  corpuscles  of 
the  chyle  or  lymph  into  the 
red  corpuscles  of  the  blood, 
seems  now  to  be  commonly 
admitted  in  Germany;  and, 
lono-  ao-o,  Mr.  Hewson''  thought  "it  could  not  be  denied,"  that  the  office 
of  the  thymus  and  lymphatic  glands  is  to  form  the  central  particles 
found  in  the  red  corpuscles. 

It  has  been  long  observed,  that  crystals  might  form  in  blood,*  but 
only  recently  has  the  subject  attracted  much  attention;  and  especially 
since  they  were  depicted,  and  investigated,  by  Dr.'^Otto  Funke;^  who 
affirmed,  that  "  the  organic  coloured  matters,  which  form  the  essential 
contents  of  the  red  corpuscles"  can  assume,  under  special  circumstances, 
the  crystalline  form  ;  and  that  the  contents  of  the  corpuscles,  in  each 
kind  of  blood  have  a  constantly  characteristic  crystalline  form.  The 
essential  condition  for  the  crystallization  of  this  hematocnjstaUin,  as  it 
has  been  called  by  Lehmann,^  or  hemaioicUn^  is  that  it  should  be  freed 
from  the  cells.  In  fishes,  however,  he  has  observed  it  crystallize  within 
the  cells.  The  crystals  have  a  different  shape  in  different  animals,  and 
they  would  seem  to  be  a  crystallization  of  the  protein  or  albuminoid 
contents  of  the  corpuscles ;  but  nothing  definite  has  as  yet  been  esta- 
blished in  regard  to  them. 

When  blood  is  drawn  from  a  vessel,  and  left  to  itself,  it  exhales,  so 
lon<T  as  it  is  warm,  a  fetid  vapour  consisting  of  water  and  animal  mat- 
ter, of  a  nature  not  known.     This  vapour  or  halitus  of  the  blood, — 

'  Appendix  to  English  edition  of  Gerber's  Anatomy,  p.  93;  and  Hewson's  Works, 
Sydenham  Society's  edit.,  p.  27t3,  Lond.,  1846. 
"^  Miiller,  Elements  of  Physiology,  by  Baly,  i.  563,  Lond.,  1838. 

3  Animal  Chemistry,  Sydenham  Society's  edit.,  i.  121,  Lend.,  1845 ;  or  Amer.  edit., 
Philad.,  1846. 

•*  Works,  Sydenham  Society's  edit.,  p.  286,  Lond.,  1846. 

5  KoUiker,  Mikroskopische  Anatomie,  ii.  587,  Leipzig,  1854 ;  or  Amer.  edit,  of  his 
Hnraan  Histology  by  Dr.  Da  Costa,  p.  714,  Philad.,  1854 ;  and  Sieveking  on  Albumin- 
ous Crystallization,  in  Brit,  and  For.  Med.-Chir.  Rev.,  Oct.,  1853,  p.  349. 

"  Funke's  Wagner's  Speciellen  Physiologie,  s.  20,  Leipz.,  1854  ;  and  Atlas,  Taf.  x. 
Fiij.  1-6  ;  also,  Robin  and  Verdeil,  Traite  de  Chimie  Anatomique,  iii.  430,  Paris. 

'  Lehmann,  Physiological  Chemistry,  Amer.  edit.,  i.  347,  Philad.,  1855. 


BLOOD — HALITUS. 


367 


1.   Prismatic, 


dral,  from  pig's  blood, 
squirrel's  blood. 


Blood  Crystals, 
from  human  blood. 


2.   Tetrahe- 


3.  Hexagonal  plates,  from 


gas  animale  sanguinis^  of  Plenck — was  conceived  by  him  to  be  com- 
posed of  carbon  and  hydrogen,  and  to  be  inservient  to  many  suppositi- 
tious uses  in  the  economy.  The  odour  exhaled  by  the  blood  would 
appear  to  have  the  same  general 
characters  under  all  circumstances. 
After  a  time,  the  blood  coagulates, 
giving  off",  at  the  same  time,  it  has 
been  said,  a  quantity  of  carbonic 
acid  gas.  This  disengagement  is  not 
evident  when  the  blood  is  suffered 
to  remain  exposed  to  the  air,  except, 
perhaps,  by  the  apertures  or  canals 
formed  by  its  passage  through  the 
clot ;  but  it  can  be  collected  by  plac- 
ing the  blood  under  the  receiver  of 
an  air-pump,  and  exhausting  the 
air.  On  this  fact,  however,  observers 
do  not  all  accord.  The  experiments 
of  VogeV  Brande,^  Sir  E.  Home,-' 
and  Sir  C.  Scudamore,^  are  in  favour  of  such  evolution ;  and  the  last 
gentleman  conceives  it  even  to  be  an  essential  part  of  the  process;  but 
other  distinguished  experimenters  have  not  been  able  to  detect  it. 
Neither  Dr.  John  Davy,*  nor  Dr.  Duncan,  Jr.,  nor  Dr.  Christison, 
could  procure  it  during  the  coagulation  of  the  blood.  Dr.  Turner'^ 
suggests,  that  the  appearance  of  the  carbonic  acid,  in  the  experiments 
of  Vogel,  Brande,  and  Scudamore,  might  easily  have  been  occasioned 
by  casual  exposure  of  the  blood  to  the  atmosphere,  previous  to  its 
being  placed  under  the  receiver;  but  we  have  no  reason  for  believing, 
that  this  source  of  fallacy  was  not  guarded  against  as  much  by  one  set  of 
experimenters  as  by  the  other.  Our  knowledge  on  this  point  is  confined 
to  the  fact,  that,  by  some,  carbonic  acid  gas  has  been  found  exhaled 
during  the  process  of  coagulation;  by  others,  not.  Experiments  by 
Stromeyer,^  Gmelin,  Tiedemann,  and  Mitscherlich,^  would  seem  to 
show,  that  the  blood  does  not  give  off  free  carbonic  acid,  but  that  it 
holds  a  certain  quantity  in  a  state  of  combination;  and  that  this  com- 
bination is  intimate  is  shown  by  the  fact,  mentioned  by  Miiller,^  that 
blood,  artificially  impregnated  with  carbonic  acid,  yields  no  appreciable 
quantity  of  the  gas,  when  subjected  to  the  air-pump.  Magnus, '°  how- 
ever, found,  in  his  experiments,  that  not  only  venous,  but  arterial  blood, 
contains  carbonic  acid,  oxygen,  and  nitrogen ;  and  that,  as  regards  car- 

'  Annales  de  Chimie,  t.  xciii.  ^  Philosophical  Transactions  for  1818,  p.  181. 

*  Lectures,  &c.,  iii.  8. 

*  Philosophical  Transactions  for  1820,  p.  6 ;  and  an  Essay  on  the  Blood,  p.  107,  Lond., 
1824. 

*  Phil.  Trans.,  for  1823,  p.  506  ;  and  Edinb.  Med.  and  Surg.  Journ.,  xxix.  253.  Since 
that  time,  however,  Dr.  Davy  has  succeeded  in  extricating  it  botli  from  venous  and 
arterial  blood.  See  his  Researches,  Physiological  and  Anatomical,  Amer.  Med.  Lib. 
edit.,  p.  82,  Philad.,  1840. 

^  Elements  of  Chemistry,  5th  edit.,  by  Dr.  Bache,  p.  607,  Philad.,  1835. 
'  Schweigger's  Journal  fiir  Cheniie,  u.  s.  >w.  Ixiv.,  105. 

*  Tiedemann  und  Treviranus,  Zeitschrift  fiir  Physiologie,  B.  v.  H.  i. ;  cited  in  Bri- 
tish and  Foreign  Med.  Review,  No.  0,  p.  590,  April,  1836.  ^  Op.  cit.,  p.  329. 

"*  Annales  de  Chimie  et  de  Pliysi(iue,  Nov.,  1837,  and  page  318,  of  this  volume. 


368 


CIRCULATION. 


bonic  acid,  arterial  blood  contains  more  than  venous;  and  lie  accounts 
for  the  failure  of  those,  who  have  attempted  to  elicit  carbonic  acid 
from  venous  blood  by  the  air-pump,  to  the  air  in  the  receiver  not  hav- 
ing been  sufficiently  rarefied.  Prof.  C.  A.  Schultz,  of  Berlin — who 
believes,  that  the  vesicles  of  the  blood,  in  a  perfect  state,  are  composed 
of  a  membranous  covering,  whose  interior  is  filled  with  an  aeriform 
fluid  in  the  midst  of  which  is  found  the  nucleus^ — succeeded  in  so 
evident  a  manner  by  the  following  simple  method  in  extracting  air 
from  the  blood,  "  that  it  is  impossible  to  doubt  there  exists  a  great 
quantity  of  air  in  the  vesicles."  He  completely  filled  a  bottle  with 
warm  blood  flowing  immediately  from  the  vein  of  a  horse,  and  her- 
metically sealed  the  bottle  so  that  the  cork  was  plunged  into  the 
blood,  thus  absolutely  preventing  the  contact  of  air.  The  blood,  on 
cooling,  diminished  in  volume,  and  thus  produced  a  perfect  vacuum  in 
the  upper  part  of  the  bottle;  and  in  proportion  as  this  took  place, 
bubbles  of  air  arose  from  the  blood  and  filled  the  vacuum.  Chemical 
analysis  of  this  air  demonstrated  that  it  was  carbonic  acid.  In  arterial 
blood,  he  found  oxygen  mixed  with  more  or  less  carbonic  acid.^  The 
experiments  of  Dr.  Stevens,^  and  of  Dr.  Robert  E.  Rogers,"'  also  show, 
that  carbonic  acid  is  contained  in  the  blood.  The  latter  observer  found, 
when  a  portion  of  venous  blood  was  placed  in  a  bag  of  some  membrane, 
and  the  bag  was  immersed  in  an  atmosphere  of  gas — as  of  oxygen, 
hydrogen,  or  nitrogen — that  carbonic  acid,  was  pretty  freely  evolved.* 

Whilst  the  blood  is  circulating  in  the  vessels,  it  consists  of  liquor 
sangvinis  and  red  corpuscles;  but  during  coagulation  it  separates  into 
two  distinct  portions; — a  yellowish  liquid,  called  serum;  and  a  red 
solid,  known  by  the  name  of  clot^  cruor,  crassamentvm^  coagnhim,  lyla- 
centcij  insula  and  Jiepar  sanguinis.  The  proportion  of  the  serum  to  the 
crassamentum  varies  greatly  in  different  animals,  and  in  the  same  ani- 
mal at  different  times,  according  to  the  state  of  the  system.  The  latter 
is  more  abundant  in  healthy  vigorous  animals,  than  in  those  that  have 
been  impoverished  by  depletion,  low  living,  or  disease.  Sir  Charles 
Scudamore  found,  by  taking  the  mean  of  twelve  experiments,  that  the 
crassamentum  amounted  to  53'307  per  cent,  in  healthy  blood. 

The  difference  between  living  and  coagulated  blood  maj^  be  expressed 
in  a  tabular  form  as  follows: — • 


w 


The  serum  is  viscous,  transparent,  of  a  slightly  yellowish  hue,  and 
alkaline  owing  to  the  presence  of  a  little  free  soda.  Its  smell  and  taste 
resemble  those  of  the  blood.     Its  average  specific  gravitj^  has  been 


■  Water, 

■ 

o 

Various  salts, 

Liquor  Sanguinis,     ■ 

Fatty  matters, 

Serum, 

e^ 

Extractive  do. 

5' 

Albumen, 

■    a> 

Fibrin. 

W 

■  Crassamentum, 

o" 

Red  Corpuscles, 

J 

1                                 J 

P- 

'  London  Lancet,  Aucrust  10,  1839,  p.  713.  ^  jiji^.^  p.  714. 

3  Philos.  Transact.,  for  1834-5,  p.  334. 

*  American  Journal  of  the  iled.  Sciences,  August,  1836,  p.  283. 

*  See,  on  all  this   subject,  Dr.  John  Reid,  art.  Respiration,  Cyclop,  of  Anat.  and 
Physiol.,  Pt.  xxxii.  p.  359,  Lond.,  August,  1S4S. 


BLOOD — SERUM.  369 

estimated  at  about  1-027 ;  but  on  this  point,  also,  observers  differ.  Dr. 
Jolin  Davy'  found  it  to  vary  from  1-020  to  1-031.  Martine,  Muschen- 
broek,  Jurin,  and  Haller,  from  1*022  to  1*037;  Berzelius  and  Wagner,* 
from  1*027  to  1*029;  Dr.  Christison,^  from  1*029  to  1*031;  Lauer," 
from  1*009  to  1*011 ;  whilst  Mr.  Thackrali*  found  the  extremes  to  be 
1*001  and  1*080.  At  158^^  of  Fahrenheit,  it  coagulates;  forming  at 
the  same  time,  numerous  cells,  containing  a  fluid,  which  oozes  out  from 
the  coagulum  of  the  serum,  and  is  called  serosity.  It  contains,  accord- 
ing to  Dr.  Bostock,  about  g'^th  of  its  weight  of  animal  matter,  to- 
gether with  a  little  chloride  of  sodi  um.  Of  this  animal  matter,  a  portion 
is  albumen,  which  may  be  readily  coagulated  by  means  of  galvanism; 
but  a  small  quantity  of  some  other  principle  is  present,  which  differs 
from  albumen  and  gelatin,  and  to  which  Dr.  Marcet**  gave  the  name 
muco-extractive  matter^  and  Dr..Bostock,^  uncoagidable  matter  of  the  blood 
— as  a  term  expressive  of  its  most  characteristic  property.  Serum  pre- 
serves its  property  of  coagulating,  even  when  largely  diluted  with  water. 
According  to  Mr.  Brande,^  it  is  almost  pure  liquid  albumen,  united  with 
soda  which  keeps  it  fluid.  Consequently,  he  affirms,  any  reagent,  that 
takes  away  the  soda,  produces  coagulation;  and  by  the  agency  of 
caloi'ic,  the  soda  may  transform  a  part  of  the  albumen  into  mucus. 
The  action  of  the  galvanic  pile  coagulates  the  serum,  and  forms  glo- 
bules in  it  analogous  to  those  of  the  blood. 

From  the  analysis  of  serum,  by  Berzelius,^  it  appears  to  consist,  in 
1000  parts; — of  water,  903;  albumen,  80;  substances  soluble  in  alco- 
hol,— as  lactate  of  soda  and  extractive  matter,  chlorides  of  sodium 
and  potassium,  10;  substances  soluble  in  water, — as  soda  and  animal 
matter,  and  phosphate  of  soda,  4;  loss,  3.  Dr.  Marcet  assigns  it  the 
following  composition: — water,  900  parts;  albumen,  86*8  ;  chlorides 
of  potassium  and  sodium,  &Q ;  muco-extractive  matter,  -l;  carbonate  of 
soda,  1*65 ;  sulphate  of  potassa,  0-35,  and  earthy  phosphates,  0*60 ; — 
a  result,  which  closely  corresponds  with  that  of  Berzelius,  who  states 
that  the  extractive  matter  of  Dr.  Marcet  is  lactate  of  soda,  united  with 
animal  matter.  According  to  M.  Lecanu,^°  1000  parts  contain, — water, 
906  parts ;  albumen,  78  ;  animal  matter,  soluble  in  water  and  alcohol, 
1*69  ;  albumen  combined  with  soda,  2*10  ;  crystallizable  fatty  matter, 
1*20;  oily  matter — seroUn^  1;  chlorides  of  sodium  and  potassium,  6; 
subcarbonate  and  phosphate  of  soda,  and  sulphate  of  potassa,  2*10 ; 
phosphate  of  lime,  magnesia  and  iron,  with  subcarbonate  of  lime  and 
magnesia,  0*91  ;  loss,  1,  A  more  recent  analysis  by  Scherer,"  gives 
the  following  constituents  : — • 

'  Researches,  Physiological  and  Anatomical,  Amer.  Med.  Lib.  edit.,  p.  11,  Philad., 
1840. 

2  Elements  of  Physiology,  by  R.  Willis,  ?  103,  Lond.,  1842. 

"  On  Granular  Degeneration  of  the  Kidneys,  p.  (Jl,  Lend.,  1S39  ;  or  American  Medical 
Library  edition,  Philad.,  1839. 

*  Hecker's  Annalen,  xviii.  393. 

^  Inquiry  into  the  Nature  and  Properties  of  the  Blood,  &c.,  Lond.,  1819. 

^  Medico-Cliirurg.  Transact.,  ii.  3«4.  ''  Op.  cit.,  p.  292. 

«  Plulosoph.  Transact,  for  1809,  p.  373. 

'  Medico-Chirurg.  Transactions,  iii.  231. 

'"  Journal  de  Pharmacie,  xvii.  ;  and  Annales  de  Chimie,  kc,  xlviii.  308. 

.'  Canstatt  and  Eisenmann's  .Jahresbericht  liber  die  Fortscliritte  in  der  Biologic  im 
Jahre,  1848,  s.  65,  Erlangen,  1849. 
VOL.  1. — 21 


370  CIRCULATION. 

Water         .......         910-45 

Solid  parts  ......  89.55 

1000. 
Albumen     .......  7-4"15 

Extractive  matters  .....  5*96 

Salts  soluble  in  water         .....  8-75 

Occasiouall}^,  the  serum  presents  a  wliitisli  hue,  ^ybicll  has  given  rise 
to  the  opinion  that  it  contains  chyle ;  but  it  would  seem  that  this  is 
fatty  matter,  and  is  always  present.  In  the  serum  of  the  blood  of 
spirit-drinkers,  Dr.  Traill  found  a  considerable  portion,  Avhich  has  been 
considered  to  favour  the  notion,  that  the  human  body  may,  by  intem- 
perance, become  preternaturally  combustible ;  and  has  been  used  to 
account  for  some  of  the  strange  cases  of  sjjontaneous  combustion,  or 
rather  o1  preternatural  comhustihility,  whicli  are  on  record.  Dr.  Christi- 
son  has  likewise  met  with  fat  mechanically  diffused  through  the  serum, 
like  oil  in  an  emulsion.  On  one  occasion,  he  procured  five  per  cent, 
of  fat  from  milky  serum,  and  one  per  cent,  from  serum  which  had  the 
aspect  of  whey.^ 

The  crassamentum  or  dot  is  a  solid  mass,  of  a  reddish-brown  colour, 
which,  when  geatly  washed  for  some  time  under  a  small  stream  of 
water,  separates  into  two  portions, — colouring  matter  and  fibrin.  As 
soon  as  the  blood  is  drawn  from  a  vessel,  the  colouring  matter  of  the 
red  corpuscles  leaves  the  central  nucleus  free ;  these  then  unite,  as  we 
have  seen,  and  form  a  network,  containing  some  of  the  colouring  mat- 
ter, and  many  whole  corpuscles.  By  washing  the  clot  in  cold  water, 
the  free  colouring  matter  and  the  globules  can  be  removed,  and  the 
fibrin  will  alone  remain.  "When  freed  from  the  colouring  matter,  the 
fibrin  is  solid,  whitish,  insipid,  inodorous,  heavier  than  water,  and  with- 
out action  on  vegetable  colours ;  clastic  when  moist,  and  becoming  brittle 
by  desiccation.  It  yields,  on  distillation,  much  carbonate  of  ammonia, 
and  a  bulky  coal,  the  ashes  of  which  contain  a  considerable  quantity 
of  phosphate  of  lime,  a  little  phosphate  of  magnesia,  carbonate  of  lime, 
and  carbonate  of  soda.  One  hundred  parts  of  fibrin,  according  to  Ber- 
zelius,  consist  of  carbon,  58-360 ;  oxygen,  19*685  ;  hydrogen,  7"021 ; 
nitrogen,  19*934.  Fibrin  has  been  designated  by  various  names:  it  is 
the  gluten,  coagulable  lymph,  and  Jibre  of  the  blood,  of  different  writers. 
Its  specific  gravity  is  said  to  be  greater  than  that  of  serum ;  but  the 
difference  has  not  been  accurately  estimated,  and  cannot  be  great.  The 
red  corpuscles  are  manifestly,  however,  heavier  than  either,  as  we  find 
them  subsiding  during  coagulationto  the  lower  surface  of  the  clot,  when 
the  blood  has  flowed  freely  from  the  orifice  in  the  vein.  Fibrin  is  an 
important  constituent  of  the  blood.  It  exists  in  animals  in  which  the 
red  corpuscles  are  absent,  and  a  form  of  it — syntonin — is  the  basis  of 
muscular  tissue. 

The  colouring  matter  of  the  blood,  called,  by  some,  cniorin,  hematin, 
hematosvi,  zoo-hematin,  Jiemachroin,  globulin  (of  Lecanu),  and  rubrin,  has 
been  the  subject  of  anxious  investigation  with  the  analytical  chemist. 
It  has  been  already  remarked,  that  it  resides  in  distinct  particles  or 
corpuscles,  and  in  the  fluid  within  the  enveloping  membrane.     For- 

'  Edinb.  Med.  and  Surg.  Journal,  xvii.  235,  and  xxxiii.  274. 


BLOOD — COLOURING   MATTER.  371 

merly,  however,  the  opinion  was  universal,  that  the  vesicular  envelope 
is  the  seat  of  colour.  The  colouring  principle  is  dissolved,  by  pure 
water,  acids,  alkalies,  and  alcohol.  M.  EaspaiP  asserts,  that  the  cor- 
puscles are  entirely  soluble  in  pure  water,  but  MM.  Donne  and  Boudet, 
who  repeated  his  experiments,  declare  that  they  are  wholly  insoluble, 
and  Muller^  is  of  the  same  opinion.  Great  uncertainty  has  always 
existed  regarding  the  cause  of  the  colour  of  the  corpuscles.  As  soon 
as  the  blood  was  found  to  contain  iron,  the  peroxide  of  which  has  a 
red  hue,  their  colour  was  ascribed  to  the  presence  of  that  metal.  MM. 
Fourcroy  and  Vauquelin-''  held  this  opinion,  conceiving  the  iron  to  be 
in  the  state  of  subphosphate ;  and  they  affirmed,  that  if  this  salt  be 
dissolved  in  serum  by  means  of  an  alkali,  the  colour  of  the  solution  is 
exactly  like  that  of  the  blood.  Berzelius,**  however,  showed,  that  the 
subphosphate  of  iron  cannot  be  dissolved  in  serum  by  means  of  an 
alkali,  except  in  very  minute  quantity  ;  and  that  this  salt,  even  when 
rendered  soluble  by  phosphoric  acid,  communicates  a  tint  quite  difi'er- 
ent  from  that  of  the  red  corpuscles.  He  found,  that  the  ashes  of  the 
colouring  matter  always  yield  oxide  of  iron  in  the  proportion  of  200^^ 
of  the  original  mass ;  whence  it  was  inferred,  that  iron  is  somehow  or 
other  concerned  in  the  production  of  the  colour ;  but  the  experiments 
of  Berzelius  did  not  indicate  the  state  in  which  that  metal  exists  in  the 
blood.     He  could  not  detect  it  by  any  of  the  liquid  tests. 

The  views  of  Berzelius,  and  the  experiments  on  which  they  were 
founded,  were  not  supported  by  the  researches  of  Mr.  Brande.^  He 
endeavoured  to  show,  that  the  colour  of  the  blood  does  not  depend 
upon  iron;  for  he  found  the  indications  of  the  presence  of  that  metal 
as  considerable  in  the  parts  of  the  blood  that  are  devoid  of  colour,  as 
in  the  corpuscles  themselves;  and  in  each  it  was  present  in  such  small 
quantity,  that  no  eft'ect,  as  a  colouring  agent,  could  be  expected  from 
it.  He  supposed  that  the  tint  of  the  red  corpuscles  is  produced  by  a 
peculiar,  animal  colouring  principle,  capable  of  combining  with  me- 
tallic oxides.  Pie  succeeded  in  obtaining  a  compound  of  the  colouring 
matter  of  the  blood  with  the  oxide  of  tin :  but  its  best  precipitants  are 
the  nitrate  of  mercury  and  corrosive  sublimate.  Woollen  cloths,  im- 
pregnated with  either  of  these  compounds,  and  dipped  in  an  aqueous 
solution  of  the  colouring  matter,  acquire  a  permanent  red  dye,  un- 
changeable by  washing  with  soap.  The  conclusions  of  Mr.  I3rande 
have  been  supported  by  M.  Vauquelin,®  but  the  fact  of  the  presence  of 
iron  has  been  decided  by  many  observers.  Engelhart^  demonstrated, 
that  the  fibrin  and  albumen  of  the  blood,  when  carefully  separated 
from  colouring  particles,  do  not  contain  a  trace  of  iron;  whilst  he  pro- 
cured it  from  the  red  corpuscles  by  incineration.  He  also  succeeded 
in  proving  the  presence  of  iron  in  the  colouring  matter  by  liquid  tests; 
for  on  transmitting  a  current  of  clilorine  gas  through  a  solution  of  red 
corpuscles,  the  colour  entirely  disappeared  ;  white  flocks  were  thrown 

'  Chimie  Organique,  p.  368,  Paris,  1833. 

^  Handbucli  der  Physiologie,  Baly's  translation,  p.  105,  Lond.,  1838. 
^  System.  Chym.,  ix.  207.  *  Med.-Cliir.  Trans.,  iii.  213. 

*  Philosophical  Transactions  for  1812,  p.  90. 
'  Annales  de  Chimie  et  de  Physique,  toni.  i.  p.  0. 

'  Edinb.  Med    and  Surg.  Journal,  Jan.  1827 ;  and   Turner's   Chemistry,  5th  Amer. 
edit.,  p.  005,  Philad.,  1S35. 


372  CIRCULATIONS'. 

down,  and  a  transparent  solution  remained,  in  which  peroxide  of  iron 
was  discovered  by  the  usual  reagents.  The  results,  obtained  by  Engel- 
hart,  as  regards  the  quantity  of  iron,  correspond  with  those  of  Berze- 
lius.  These  facts  have  since  been  confirmed  by  Rose,^  of  Berlin; — 
and  Wurzer,^  of  Marburg,  by  pursuing  Engelhart's  method  by  liquid 
tests,  detected  the  existence  of  the  protoxide  of  manganese  likewise. 
The  proportion  of  iron  does  not  appear  to  be  more  than  one-half  per 
cent.;  yet,  as  it  is  contained  only  in  the  colouring  matter,  there  is 
some  reason  for  believing,  that  it  may  be  concerned  in  the  coloration 
of  the  blood,  although  probably  in  the  form  of  oxide.  Sulphocyanic 
acid  has  been  detected  in  the  saliva;  and  this  acid,  when  united  with 
peroxide  of  iron,  forms  a  colour  exactly  like  that  of  venous  blood ;  so 
that,  it  has  been  presumed,  it  may  be  connected  with  the  coloration 
of  tlie  blood;  but  this  is  not  probable;  for  Dr.  Stevens  found,  that 
venous  blood  is  darkened  by  sulphocyanic  acid.  M.  Lecanu-^  has 
subjected  the  colouring  matter  to  analysis,  and  found  it  to  be  com- 
posed of: — loss,  representing  the  weight  of  the  animal  matter,  97*742; 
subcarbonate  of  soda,  alkaline  chlorides,  subcarbonates  of  lime  and 
magnesia,  and  phosphates  of  lime  and  magnesia,  1*724;  peroxide  of 
iron,  0'534.  The  result  of  his  researches  induces  him  to  conclude, 
that  the  colouring  matter  is  a  compound  of  albumen  with  some  co- 
louring substance  unknown.  This  substance  yielded  on  analysis : — 
loss,  98'26;  peroxide  of  iron,  1*74;  and  M.  Lecanu  suggests,  that  it 
may  result  from  the  combination  of  some  animal  matter  with  certain 
ferruginous  compounds  analogous  to  cyanides.  The  views  of  Liebig 
in  regard  to  the  agency  of  the  iron  of  the  blood  in  respiration  have 
been  given  elsewhere." 

After  all,  therefore,  our  ignorance  on  this  subject  is  still  great ;  and 
all  that  we  seem  to  know  is,  that  peroxide  of  iron  is  contained  in  the 
colouring  matter  of  the  blood;  but  it  can  scarcely  be  the  cause  of  the 
colour,  for  Scherer  found,  that  the  iron  may  be  wholly  dissolved  by 
the  agency  of  acids,  and  yet  the  animal  matter,  boiled  afterwards  in 
alcohol,  colours  the  spirit  deeply  red.  Dr.  G.  O.  Eees,*  however,  ob- 
jects to  this  being  received  as  a  conclusive  argument  against  the  iron 
being  essential  to  the  formation  of  the  red  colour. 

The  redness  of  the  blood  is  one  of  its  most  obvious  characteristics; 
and  the  change  effected  in  the  lungs  as  regards  colour  has  been  esteemed 
of  eminent  importance.  It  is  no  farther  so,  however,  than  as  it  indi- 
cates the  conversion  of  venous  into  arterial  blood.  There  is  nothing 
essential  connected  with  the  mere  coloration.  In  the  insect,  the  blood 
is  transparent ;  in  the  caterpillar,  of  a  greenish  hue ;  and  in  the  internal 
vessels  of  the  frog,  yellowish.  In  man,  it  differs  according  to  numer- 
ous circumstances;  and  the  hue  of  the  skin,  which  is  partly  dependent 
upon  these  differences,  thus  becomes  an  index  of  the  state  of  indivi- 
dual health  or  disease.  In  'morbus  ccBrideiis^  cyanopathy  or  hlue  disease, 
the  whole  surface  is  coloured  blue,  especially  in  those  parts  where  the 

'  Poggendorf  s  Annalen,  vii.  81 ;  and  Annales  de  Cliimie,  &c.,  xxxiv.  268. 
2  ychweigger's  Journal,  Iviii.  481. 

'  Annales  de  Chimie  et  de  Physique,  xlv.  5.  *  Page  320  of  this  volume. 

^  Gulstonian  Lecture;  see  banking's  Abstract,  Jan.  to  July,  1845,  p.  251,  Amer. 
edit.,  New  York,  1S45. 


BLOOD — COAGULATION. 


Coagulation  of  Nurmal  Human  Blood  under 
the  Microscope. 


skin  is  delicate,  as  in  the  lips;  and  the  appearance  of  the  jaundiced  is 
familiar  to  all. 

The  formation  of  the  clot,  and  its  separation  from  the  serum,  are 
manifestly  dependent  upon  the  fibrin,  which,  by  assuming  the  solid 
state,  gives  rise  to  the  coagulation 

of  the  blood; — a  phenomenon,  that  ^^S-  H^. 

has  occasioned  much  fruitless  spe- 
culation and  experiment;  yet,  if  the 
views  of  M.  Kaspail'  were  proved 
to  be  correct,  it  would  be  sufficiently 
simple.  The  alkaline  character  of 
the  blood,  and  the  production  of 
coagulation  by  a  dilute  acid,  leave 
no  doubt,  in  his  mind,  that  an  alkali 
is  the  menstruum  of  the  albumen 
of  the  blood.  The  alkaline  matter, 
he  thinks,  is  soda,  but  more  espe- 
cially ammonia,  of  which,  he  says, 
authors  take  no  account;  but  whose 
different  salts  are  evident  under  the 
microscope.  Now,  "the  carbonic 
acid  of  the  atmospheric  air,  and  the 
carbonic  acid,  that  forms  in  the 
blood  by  its  avidity  for  oxygen,  saturate  the  menstruum  of  the  albu- 
men, which  is  precipitated  as  a  clot.  The  evaporation  of  the  ammonia, 
and,  above  all,  the  evaporation  of  the  water  of  the  blood,  which  issues 
smoking  from  the  vein,  likewise  set  free  an  additional  quantity  of  dis- 
solved albumen,  and  the  mass  coagulates  the  more  quickly  as  the  blood 
is  less  aqueous." 

The  process  of  coagulation  is  influenced  by  exposure  to  air.  Mr. 
Hewson  affirmed,  that  it  is  promoted  by  such  exposure,  but  Mr.  Hunter 
was  of  an  opposite  opinion.  If  the  atmospheric  air  be  excluded, — by 
completely  filling  a  bottle  with  recently  drawn  blood,  and  closing^ the 
orifice  with  a  good  stopper, — coagulation  is  retarded.  Yet  Sir  C.  Scu- 
daraore  affirms,  that  if  blood  be  confined  within  the  exhausted  receiver 
of  an  air-pump,  coagulation  is  accelerated;  and  MM.  Gmelin,  Tiede- 
mann,  and  Mitscherlich^  found  that,  under  such  circumstances,  both 
venous  and  arterial  blood  coagulated  as  perfectly  as  usual  The  pre- 
sence of  air  is  certainly  not  essential  to  the  process.  Experiments  have 
also  been  made  on  the  eft'ect  produced  by  different  gases  on  the  process 
of  coagulation;  but  the  results  have  not  been  such  as  to  afford  much 
information.  It  is  asserted,  for  example,  by  some,  that  it  is  promoted 
by  carbonic  acid;  and  certain  other  irrespirable  gases;  and  retarded 
by  oxygen:  by  others,  the  reverse  is  aflirmed:  whilst  Sir  Humphry 
Davy^"  and  Schroder  van  der  Kolk"  inform  us,  that  they  could  not 

'  Chimie  Organique,  p.  373. 

2  Tiedemanii  and  Treviranus,  Zeitsclirift  fiir  PhysioL,  B.  v.  Heft  i. 

^  Researches,  &c.,  chiefly  concerninsr  nitrous  oxide,  p.  380,  Lond.,  1800 ;  and  Dr.  Jolm 
Davy.  Researches,  Physiological  and  Anatomical,  Amer.  Med.  Libr.  edit,,  p.  48,  Philad., 
18-40.  ■ 

*  Dissert,  sisteus  Sang.  Coag.  IIistor.,p.  81,Gruning.,  1620;  and  Burdach,  op.  citat., 
iv.  37. 


374  CIRCULATION". 

perceive  any  difference  in  the  period  of  the  coagulation  of  venous 
blood,  when  it  was  exposed  to  nitrogen,  nitrous  gas,  oxygen,  nitrous 
oxide,  carbonic  acid,  hydrocarbon,  or  atmospheric  air. 

The  time,  necessar}^  for  coagulation,  is  affected  by  temperature.  It 
is  promoted  by  warmth;  retarded,  but  not  prevented,  by  cold.  Mr. 
Hewson  froze  blood  newly  drawn  from  a  vein,  and  afterwards  thawed 
it:  it  first  became  fluid,  and  then  coagulated  as  usual.  Hunter  made 
a  similar  experiment  with  the  like  result.  It  is  obviously,  therefore, 
not  from  simple  refrigeration  that  the  blood  coagulates.  Sir  C.  Scuda- 
more  found,  that  blood,  which  begins  to  coagulate  in  four  minutes  and 
a  half,  in  a  temperature  of  53°  Fahr.,  undergoes  the  same  change  in  two 
minutes  and  a  half  at  98°;  and  that,  which  coagulates  in  four  minutes 
at  98°  Fahr.,  becomes  solid  in  one  minute  at  120°.  On  the  contrary, 
blood,  that  coagulates  firmly  in  five  minutes  at  60°  Fahr.,  remains  quite 
fluid  for  twenty  minutes  at  the  temperature  of  40°  Fahr.,  and  requires 
upwards  of  an  hour  for  complete  coagulation.  The  observations  of  M. 
Olendrin^  were  similar.  As  a  general  rule,  it  would  seem,  from  those 
of  Hewson,^  Schroder  van  der  Kolk,^  and  Thackrah,^  that  coagulation 
takes  place  most  readily  at  the  temperature  of  the  body.  During  the 
coagulation,  a  quantity  of  caloric  is  disengaged.  M.  Fourcroy^  relates 
an  experiment,  in  which  the  thermometer  rose  no  less  than  11°  during 
the  process;  but  as  certain  experiments  of  Mr.  Hunter^  appeared  to 
show,  that  no  elevation  of  temperature  occurred,  the  observation  of 
Fourcroy  was  disregarded.  It  was,  however,  confirmed  by  experiments 
of  Dr.  Gordon,^  of  Edinburgh,  in  which  the  evolution  of  caloric  during 
coagulation  was  rendered  more  manifest  by  moving  the  thermometer 
during  the  formation  of  the  clot,  first  into  the  coagulated,  and  after- 
wards into  the  fluid  part  of  the  blood:  ho  found,  that  by  this  means  he 
could  detect  a'difterence  of  6°,  which  continued  to  be  manifested  for 
twenty  minutes  after  the  process  had  commenced.  In  repeating  the 
experiment  on  blood  taken  from  a  person  labouring  under  inflamma- 
tory fever,  the  thermometer  was  found  to  rise  12°.  Sir  C.  Scudamore 
affirms,*  that  the  rate  at  which  the  blood  cools  is  distinctly  slower  than 
it  would  be  were  no  caloric  evolved;  and  that  he  observed  the  ther- 
mometer rise  one  degree  at  the  commencement  of  coagulation.  On 
the  other  hand.  Dr.  John  Davy,'  Mr.  Thackrah,  and  Schroder  van  der 
Kolk,^°  accord  with  Mr.  Hunter  in  the  belief,  that  the  increase  of  tem- 
perature from  this  cause  is  very  slight  or  null,  whilst  M.  Easpail  asserts 
that  the  temperature  falls.''  Again  we  have  to  deplore  the  discordance 
amongst  observers;  and  it  will  perhaps  have  struck  the  reader  more 
than  once,  that  such  discordance  applies  as  much  to  topics  of  direct 

'  Hist.  Anatom.  des  Inflammations,  ii.  42G,  Paris,  1826. 

'  Experiment.  Inquiries,  i.  19,  Lond.,  1774;  or  Sydenham  Society's  edit.,  Lond.,  1846. 

3  Op.  cit.,  p.  48. 

*  Inquiry  into  the  Nature,  kc,  of  the  Blood,  p.  38,  Lond.,  1819. 

^  Aniiales  de  Chimie,  xii.  147. 

6  A  Treatise  on  the  Blood,  &e.,  p.  27,  Lond.,  1794. 

'  Annals  of  Pliilosophy,  iv.  139. 

8  An  Essay  on  the  Blood,  p.  68,  Lond.,  1824. 

9  Researches,  Physiological  and  Anatomical,  Amer.  Med.  Libr.  edit.,  p.  6,  Phila.,  1840. 
'0  Miiller's  Physiology,  Baly's  trausla|jjon,  p.  98,  Lond.,  1838. 

"  Chimie  Organique,  p.  361. 


BLOOD — COAGULATIO:?^.  *  375 

observation  as  to  those  of  a  theoretical  character.  The  discrepancy 
regarding  anatomical  and  physical /acte  is  even  more  glaring  than  that 
which  prevails  amongst  physiologists  in  accounting  for  the  corporeal 
phenomena;  a  circumstance,  which  tends  to  confirm  the  notion  promul- 
gated by  one  of  the  most  distinguished  teachers  of  his  day  (Dr.  James 
Gregory),  that  "there  are  more  false  facts  in  medicine"  (and  the  remark 
might  be  extended  to  the  collateral  or  accessory  sciences)  "than  false 
theories." 

Tiiere  are  certain  substances,  again,  which,  when  added  to  the  blood, 
prevent  or  retard  its  coagulation.  Mr.  Hewson  found,  that  sulphate  of 
soda,  chloride  of  sodium,  and  nitrate  of  potassa  were  amongst  the  most 
powerful  salts  in  this  respect.  Muriate  of  ammonia  and  a  solution  of 
potassa  have  the  same  effect.  On  the  contrary,  coagulation  is  pro- 
moted by  alum,  and  by  the  sulphates  of  zinc  and  copper.^  IIow  these 
salts  act  on  the  libri)],  so  as  to  prevent  its  particles  from  coming  toge- 
ther, it  is  not  easy  to  explain.  But  these  are  not  the  only  inscrutable 
circumstances  that  concern  the  coagulation  of  the  blood.  Many  causes 
of  sudden  death  have  been  considered  to  have  this  result : — lightning 
and  electricity ;  a  blow  upon  the  stomach ;  injury  of  the  brain ;  bites 
of  venomous  animals ;  certain  narcotico-acrid  vegetable  poisons;  ex- 
cessive exercise,  and  violent  mental  emotions,  when  they  suddenly 
destroy,  &c.  Many  of  these  affirmations,  doubtless,  rest  on  insufficient 
proof.  For  example,  Sir  C.  Scudamore  asserts  that  lightning  has  not 
this  effect.  Blood,  through  which  electric  discharges  were  transmitted, 
coagulated  as  quickly  as  that  which  was  not  electrified;  and  in  animals 
killed  by  the  discharge  of  a  powerful  galvanic  battery,  that  in  the 
veins  was -always  found  in  a  solid  state.  M.  Mandl  has  summed  up 
the  results  of  modern  experiments  on  the  subject  as  follows.  First. 
The  alkalies — potassa,  soda,  and  ammonia — completely  prevent  coagu- 
lation :  lime  retards  it.  Secondly.  The  soluble  alkaline  salts — combi- 
nations of  soda,  potassa,  ammonia,  magnesia,  baryta  and  lime,  with  car- 
bonic, acetic,  nitric,  phosphoric,  tartaric,  citric,  boracic,  sulphuric  and 
cyano-hydric  acid — also  the  chlorides,  in  very  small  quantity — favour 
coagulation.  On  the  other  hand,  these  substances  in  concentrated 
solution  retard,  and  even  prevent  it  entirely.  The  most  active  salts 
are  the  carbonates;  the  least  so,  combinations  of  chlorine,  and  sul- 
phates. 0'007  of  carbonate  of  soda  retards  coagulation  for  several 
hours,  whilst  the  sulphates  do  not  act  in  the  proportion  of  14  per  1000. 
The  action  of  a  salt  is  more  marked  in  proportion  as  it  reddens  more 
the  blood;  whilst  combinations  of  chrome,  chlorine  and  iodine  do  not 
redden  it,  and  do  not  prevent  its  coagulation.  When  water  is  added 
to  blood  thus  liquefied  by  a  salt  it  coagulates  again — the  fibrin  being 
precipitated.  Thirdly.  Metallic  salts  decompose  the  blood;  some 
causing  coagulation ;  others  preventing  it.  Fourthly.  Very  dilute 
vegetable  acids  favour  it;  when  a  little  more  concentrated,  they  pre- 
vent it;  and  when  highly  concentrated,  decompose  it  like  the  mineral 
acids.  Fifthly.  The  action  of  vegetable  substances  has  not  been  suf- 
ficiently studied :  some  affirm,  for  instance,  that  narcotics  prevent 
coagulation;  others  that  they  favour  it.     The  same  doubt  exists  in 

'  Magcndie,  Lectures  on  the  Blood,  in  Loud.  Lancet,  reprinted  in  Bell's  Select  Medi- 
cal Library,  Pliilad.,  1839. 


376  CIRCULATION. 

regard  to  the  action  of  poisons ;  it  is  generally  believed,  however,  that 
they — as  well  as  lightning,  a  violent  discharge  of  electricity,  the  in- 
stantaneous destruction  of  the  nervous  system,  kc. — prevent  coagula- 
tion. Sixthly.  Very  dilute  solutions  of  gum  Arabic,  sugar,  albumen, 
milk,  &c.,  appear  to  act  only  in  a  mechanical  manner  by  preventing 
the  approximation  of  the  coagulated  particles. 

We  shall  find,  hereafter,  that  the  action  of  some  of  these  agents  has 
been  considered  evidence  that  the  blood  may  be  hilled;  and,  conse- 
quently, that  it  is  possessed  of  life.  All  the  phenomena,  indeed,  of 
coagulation,  inexplicable  in  the  present  state  of  our  knowledge,  have 
been  invoked  to  prove  this  position.  The  preservation  of  the  fluid 
state,  whilst  circulating  in  the  vessels — although  agitation,  ^vhen  it  is 
out  of  the  body,  does  not  prevent  its  coagulation — has  been  regarded 
of  itself,  sufficient  evidence  in  favour  of  the  doctrine.  Dr.  Bostock,^ 
indeed,  asserts,  that  perhaps  the  most  obvious  and  consistent  view  of 
the  subject  is,  that  fibrin  has  a  natural  disposition  to  assume  the  solid 
form,  when  no  circumstance  prevents  it  from  exercising  this  inherent 
tendency.  As  it  is  gradually  added  to  the  blood,  particle  by  particle, 
whilst  that  fluid  is  in  a  state  of  agitation  in  the  vessels,  it  has  no  op- 
portunity, he  conceives,  of  concreting;  but  when  suffered  to  remain 
at  rest,  either  within  or  without  the  vessels,  it  is  liable  to  exercise  its 
natural  tendency. 

It  is  not  our  intention,  at  present,  to  enter  into  the  subject  of  the 
vitality  of  the  blood.  The  general  question  will  be  considered  in  a 
subsequent  part  of  this  work.  AVe  may  merely  observe,  that,  by  the 
generality  of  physiologists,  the  blood  is  presumed,  either  to  be  en- 
dowed with  a  principle  of  vitality,  or  to  receive  from  the  organs, 
with  which  it  comes  in  contact,  a  vital  impression  or  influence,  which, 
together  with  the  constant  motion,  counteracts  its  tendency  to  coagu- 
lation.^ Even  M.  Magendie,^ — who  is  unusually  and  properly  chary 
in  having  recourse  to  this  method  of  explaining  the  notum  per  igno- 
tius, — affirms,  that  instead  of  referring  the  coagulation  of  the  blood 
to  any  physical  influence,  it  should  be  considered  as  essentially  a  vital 
process;  or,  in  other  words,  as  affording  a  demonstrative  proof,  that 
the  blood  is  endowed  with  life; — a  position,  which — as  will  be  seen 
hereafter — is  not  tenable.'* 

M.  Vauquelin  discovered  in  the  blood  a  considerable  quantity  of 
fatty  matter,  of  a  soft  consistence,  Avhicli  he,  at  first,  regarded  as  fat ; 
but  M.  Chevreul,^  after  careful  investigation,  declared  it  to  be  identical 
with  the  matter  of  the  brain  and  nerves,  and  to  form  the  singular 
compound  of  an  azoted  or  nitrogenized  fat.  Cholesterin  has  been  de- 
tected in  it  by  Gmelin,^  and  by  Boudet.''  MM.  Prevost  and  Dumas, 
Segalas,  and  others,  have  likewise  demonstrated  the  existence  of  urea 
in  the  blood  of  animals,  whose  kidnej's  had  been  removed.  Chemical 
analysis  is,  indeed,  adding  daily  to  our  stock  of  information  on  this 
matter;  and  exhibiting  to  us,  that  many  of  the  substances,  which 
compose  the  tissues,  exist  in  the  blood  in  the  very  state  in  which  we 

'  Physiology,  Sd  edit.,  p.  271,  Lond.,  1836. 

2  J.  Miiller,  llaudbuch,  u.  s.  w.,  Baly's  translation,  p.  07,  Lond.,  1838. 

'  Precis,  &c.,  ii.  234.  *  See  Book  iv.,  chap.  5,  on  Life. 

8  Bostock's  Physiology,  p.  204.  «  Chimie,  iv.  11(33. 

'  Journ.  de  Pharmacie,  Paris,  1833,  and  Anuales  de  Chimie,  lii.  337. 


BLOOD — ANALYSIS, 


377 


meet  with  them  there.  This  is  signally  shown  by  the  following  table 
by  Simon'  of  the  constituents  found  in  the  blood  of  man,  and  certain 
mammalia. 


Protein  compounds. 
Colouring  matters. 


Extractive  matters. 


Fats. 


Water. 

fFi])rin. 
Albumen. 
Globulin. 
(  Hematin. 
(  Hemaph?ein. 
Alcohol-extract. 
Spirit-extract. 
Water-extract. 
'  Cholesterin. 
Serolin. 

Red  and  white  solid 
fats     containing 
phosphorus. 
Margaric  acid. 
[  Oleic  acid. 


Salts. 


Oases. 


Iron  (peroxide). 
'  Albuminate  of  soda. 
Phosphates  of  lime,  magnesia, 

and  soda. 
Sulphate  of  potassa. 
Carbonates  of  lime,  magnesia, 

and  soda. 
Chlorides  of  sodium  and  potas- 

s'nixn. 
Lactate  of  soda. 
[  Oleate  and  margarate  of  soda. 
Oxygen. 
Nitrogen. 
Carbonic  acid. 
Sulphur. 
Phosphorus. 


The  analyses  of  M.  Lecanu^  are  generally  regarded  as  among  the 
best.  Blood  obtained  by  him  from  two  stout  healthy  men  was  found 
to  be  composed  as  follows : — 

Water,  .... 

Fibrin,  .... 

Albumen,      .... 
Colouring  matter  (globules). 
Fatty  crystallizable  matter. 
Oily  matter, 

Extractive  matter  soluble  in  water 
Albumen  combined  with  soda, 
Chloride  of  sodium, 

potassium. 
Carbonates    \ 

Phosphates   >  of  potassa  and  soda 
Sulphates     J 

Carbonates  of  lime  and  magnesia,  'I 

Phosphates  of  lime,  magnesia,  and  iron,  I 
Peroxide  of  iron,  J 

Loss,     ....... 


and  alcol 


780-145 

785-590 

2-100 

3-5G5 

65-090 

69-415 

133-000 

119-626 

2-430 

4-300 

1-310 

2-270 

1-790 

1-920 

l-2()5 

2-010 

1 


8-370 

2-100 
2-400 
100-000 


7-304 

1-414 

2-586 
100-000 


On  these  analyses,  Dr.  Pront^  has  remarked,  that  gelatin  is  never 
found  in  the  blood,  nor  any  product  of  glandular  secretion ;  and  he  adds, 
that  a  given  weight  of  gelatin  contains  at  least  three  or  four  per  cent, 
less  carbon  than  an  equal  weight  of  albumen.  Hence,  the  production 
of  gelatin  from  albumen,  he  conceives,  must  be  a  reducing  process. 
We  have  seen,  under  the  head  of  Respiration,  what  application  he 
makes  of  these  consideration s.'^ 

Researches  on  the  ashes  of  human  blood  by  Enderlin,''  in  the  labo- 
ratoiy  of  Giessen,  give  the  following  as  the  quantitative  analysis  in 
100  parts: — - 

'  Animal  Chemistry,  Sydenham  Society's  edit.,  p.  166,  Lond.,  1845. 
^  Annales  de  Chimie  et  de  Physique,  xlviii.  308,  and  Journal  de  Phai-macie,  Sept., 
1831. 

■^  Bridgewater  Treatise,  Amer.  edit.,  p.  280,  Philad.,  1834. 

*  For  the  methods  of  analyzing  the  blood,  see  Simon,  op.  cit.,  p.  166. 

*  Annalcn  dor  Cliemie  und  Pharmacie,  Marz  und  April,  1844,  cited  by  Mr.  Paget,  in 
Brit,  and  For.  Med.  llev.,  Jan.,  1845,  p.  255. 


878  CIECULATIOX. 

Tribasic  pliospliate  of  soda, 22"1 

Chloride  of  sodium       ........  5-i"769 

jx)tassium,  .......  4-416 

Sulphate  of  soda, 2-4(Jl 

Phosphate  of  lime,       ........  3-(j3G 

magnesia,        .......  0-769 

Oxide  of  iron,  with  some  phosphate  of  iron,  .         .         .  10-77 

It  has  been  inferred,  from  these  analyses,  that  the  albumen  of  the 
blood  is  not  in  the  form  of  an  albuminate  of  soda,  or  of  a  combina- 
tion with  carbonate  or  bicarbonate  of  soda,  but  in  combination  with  the 
alkaline  tribasic  phosphate,  and  chloride  of  sodium, — the  former  salt 
possessing,  in  a  high  degree,  the  power  of  dissolving  protein  compounds 
and  phosphates  of  lime,  and  probably  being  the  solvent  of  those  con- 
stituents in  the  blood.  Dr.  John  Davy,^  however,  thinks,  that  even 
admitting  the  accuracy  of  Enderlin's  results,  the  propriety  of  applying 
them  to  the  condition  of  the  alkali  in  liquid  blood  may  be  questioned. 
Carbonate  of  soda,  he  observes,  is  decomposed  when  heated  with  phos- 
phate of  lime  ;  and  when  added  in  small  quantity  to  blood  is  not  to  be 
detected  in  its  ashes.  This  may  account  for  its  not  having  been  found 
there.  Were  the  opinion,  referred  to,  correct,  an  acid  added  to  blood 
or  its  serum,  after  the  action  of  the  air-pump,  ought  not  on  re-exhaustion 
to  occasion  a  farther  disengagement  of  air ;  but  Dr.  Davy  finds  that  it 
does.  This  and  other  results  induce  him  to  give  the  preference  to  the 
conclusion,  that  blood  contains  sesquicarbonate  of  soda, 

M.  Dutrochet  believed,  that  he  had  formed  muscular  fibres  from 
albumen  by  the  agency  of  galvanism ;  and  supposed,  that  the  red  cor- 
puscles of  the  blood  formed  each  a  pair  of  plates,  the  nucleus  being 
negative,  the  envelope  positive ;  but  A[uller^  has  shown,  that  all  the 
appearances,  which  he  attributed  to  difterent  electric  properties  of  the 
blood,  are  explicable  by  the  precipitation  of  the  albumen  and  fibrin  in 
consequence  of  the  decomposition  of  the  salts  of  the  serum  and  of  the 
oxidation  of  the  copper  wire  used  in  the  experiments, — both  the  decom- 
position of  the  salts  and  the  oxidation  of  the  copper  being  the  usual 
effects  of  galvanic  action.  With  the  galvanometer  he  was  unable  to 
discover  any  electric  current  in  the  blood ;  and  he  perceived  no  varia- 
tion in  the  needle  of  the  rnultiplicator,  when  he  inserted  one  wire  into 
an  artery  of  a  living  animal,  and  the  other  into  a  vein. 

Interesting  experiments  and  observations  on  the  blood  were  pub- 
lished several  years  ago  by  Dr.  Benjamin  G.  Babington.^  The  prin- 
cipal experiment  was  the  following.  He  drew  blood  in  a  full  stream 
into  a  glass  vessel  filled  to  the  brim,  from  the  vein  of  a  person  labour- 
ing under  acute  rheumatism.  On  close  inspection,  a  colourless  fluid 
was  immediately  perceived  around  the  edge  of  the  surface,  and  after 
a  rest  of  four  or  five  minutes,  a  bluish  appearance  was  observed 
forming  an  upper  layer  on  the  blood,  which  was  owing  to  the  subsid- 
ence of  the  red  corpuscles  to  a  certain  distance  below  the  surface,  and 
the  consequent  existence  of  a  clear  liquor  between  the  plane  of  the  cor- 
puscles and  the  eye.  A  spoon,  previously  moistened  with  water,  was 
now  immersed  into  the  upper  laj-er  of  liquid,  by  a  gentle  depression  of 

'  Proceedings  of  the  Rojal  Society  of  Edinburgh,  vol.  ii.  No.  26,  for  1845. 
^  Handbuch,  u.  s.  w.,  Baly's  translation,  p.  133. 

3  Med.-Chirurg.  Transact.,  vol.  xvi.,  Part  2,  Lond.,1831;  and  art.  Blood  (Morbid 
Conditions  of  the)  in  Cyclop.  Anat.  and  Physiol.,  Lond.,  1S36. 


BLOOD — BUFFY  COAT.  379 

one  border.  The  liquid  was  thus  collected  quite  free  from  red  corpus- 
cles, and  was  found  to  be  an  opalescent,  and  somewhat  viscid  solution, 
perfectly  homogeneous  in  appearance.  By  repeating  the  immersion, 
it  was  collected  in  quantity,  and  transferred  to  another  vessel.  That 
which  Dr.  Babington  employed  was  a  bottle  holding  about  180  grains, 
of  globular  form,  with  a  narrow  neck  and  perforated  glass  stopper.  The 
solution  with  which  the  globular  bottle  was  filled,  though  quite  homo- 
^geneous  at  the  time  it  was  thus  collected,  was  found,  after  a  time,  to 
separate  into  two  parts,  viz.,  into  a  clot  of  fibrin,  which  had  the  precise 
form  of  the  bottle  into  which  it  was  received ;  and  a  clear  serum,  pos- 
sessing all  the  usual  characters  of  the  fluid.  From  this  experiment.  Dr. 
Babington  inferred,  that  buffed  blood,  to  which  we  shall  have  to  refer 
under  another  head,  consists  of  only  two  constituents,  red  corpuscles, 
and  a  liquid  to  which  he  gives  the  name  liquor  sanguinis — plasma  of 
Schultz — so  called  by  him,  because  he  esteems  it  to  be  the  true  nutri- 
tive and  plastic  portion  of  the  blood,  from  which  all  the  organs  of  the 
body  are  formed  and  nourished. 

It  has  long  been  observed,  that  the  blood,  of  inflammation  is  longer 
in  coagulating  than  the  blood  of  health,  and  that  the  last  portion  of 
blood  drawn  from  an  animal  coagulates  quickest.  The  immediate 
cause  of  the  buffy  coat  is  thus  explained  by  Dr.  Babington.  The 
blood,  consisting  of  liquor  sanguinis  and  insoluble  red  corpuscles,  pre- 
serves its  fluidity  long  enough  to  permit  the  corpuscles,  which  are  of 
greater  specific  gravity,  to  subside  through  the  liquor  sanguinis.  At 
length,  the  liquor  sanguinis  separates,  by  a  general  coagulation  and 
contraction,  into  two  parts;  and  this  phenomenon  takes  place  uni- 
formly throughout  the  liquor.  That  part  of  it,  through  which  the  red 
corpuscles  had  time  to  fall,  furnishes  a  pure  fibrin  or  buiied  crust, 
whilst  the  portion  into  which  the  red  corpuscles  had  descended  fur- 
nishes the  coloured  clot.  This,  in  extreme  cases,  may  be  very  loose 
at  the  bottom,  from  the  great  number  of  red  corpuscles  collected  there, 
each  of  which  has  supplanted  its  bulk  of  fibrin,  and  consequently 
diminished  its  firmness  in  that  part.  There  is,  however,  with  this 
limitation,  no  more  fibrin  in  one  part  of  the  blood  than  another.  Re- 
searches by  Mr.  Gulliver^  would  seem  to  show,  that  the  rate  at  which 
the  red  corpuscles  sink  in  a  fluid  may  give  a  very  incorrect  measure 
of  its  tenuity,  since  they  subside  much  slower  in  serum,  or  in  liquor 
sanguinis  made  thinner  and  lighter  by  weak  saline  solutions,  than  in 
the  same  animal  fluids  made  thicker  and  heavier  by  gum.  The  blood, 
too,  may  have  its  coagulation  retarded,  whilst  it  is  thinned  and  re- 
duced in  specific  gravity  ;  and  yet  no  bufty  coat  appear.  The  greater 
aggregation  of  the  corpuscles,  observed  by  Mr.  T.  Wharton  Jones,^ 
and  subsequently  in  his  experiments,  seemed  to  him  to  be  connected 
with  the  accelerated  rate  of  subsiding  ;  as  it  was  prevented  or  reversed, 
by  salts,  which  dispersed  the  corpuscles,  and  increased  by  viscid 
matters,  which  increased  the  aggregation.  It  is  a  well-known  fact, 
that  the  shape  of  the  vessel  into  which  the  blood  is  received  influences 
the  depth  of  the  buff.  The  space,  left  by  the  gravitation  of  the  red 
corpuscles,  bears  a  proportion  to  the  whole  perpendicular  depth  of  the 


'  Diihlin  Med.  Press,  Dec.  11,  1844. 

*  Ediiiburijh  Med.  and  Surg.  Juunual,  Oct.  1843,  p. 


309. 


380  CIRCULATIOX. 

blootl,  so  that  in  a  shallow  vessel  scarcely  any  buff  may  appear,  whilst 
the  same  blood  in  a  deep  vessel  would  have  furnished  a  crust  of  con- 
siderable thickness ;  but  Dr.  Babington  asserts,  that  even  the  quantity 
of  the  crassamentum  is  dependent,  within  certain  limits,  on  the  form 
of  the  vessel.  If  this  be  shallow,  the  crassamentum  will  be  abundant; 
if  approaching  the  cube  or  sphere  in  form,  it  will  be  scanty.  The  dif- 
ference is  owing  to  the  greater  or  less  distance  of  the  coagulating  par- 
ticles of  fibrin  from  a  common  centre,  which  causes  a  more  or  less 
powerful  adhesion  and  contraction  of  those  particles.  This  is  a  matter 
of  practical  moment,  inasmuch  as  blood  is  conceived  to  be  thick  or 
thin,  rich  or  poor,  in  reference  to  the  quantity  of  crassamentum :  and 
pathological  views  are  entertained  in  consequence  of  conditions,  which, 
after  all,  may  depend  not  perhaps  on  the  blood  itself,  but  on  the  ves- 
sel into  which  it  is  received. 

To  remove  an  objection,  that  might  be  urged  against  a  general  con- 
clusion deduced  fi'om  the  experiment  cited, — that  it  was  made  upon 
blood  in  a  diseased  state, — Dr.  Babington  received  healthy  blood  into 
a  tall  glass  vessel  half  filled  with  oil,  which  enabled  the  red  corpuscles 
to  subside  more  quickly  than  would  otherwise  have  been  the  case. 
This  blood  was  found  to  have  a  layer  of  liquor  sanguinis,  which  formed 
a  buffy  coat,  whilst  a  portion  of  the  same  blood,  received  into  a  similar 
vessel,  in  which  there  was  no  oil,  had  no  buff.  Hence,  it  appeared, 
that  healthy  blood  is  similarly  constituted  as  blood  disposed  to  form  a 
buff}"  coat,  the  only  difference  being,  that  the  former  coagulates  more 
quickly  than  the  latter.  Dr.  J.  Dav}',^  however,  has  observed,  that 
inflammatory  blood,  in  some  instances,  does  not  coagulate  more  slowly 
than  health}'-  blood,  and  as  from  the  experiments  of  Professor  Miiller' 
it  would  appear  that  the  presence  of  fibrin  in  the  blood  favours  the 
subsidence  of  the  red  particles,  Muller  was  led  to  infer,  that  the  forma- 
tion of  the  buffy  coat  may  arise  from  the  blood  containing  a  larger 
quantity  of  fibrin,  which  the  blood  of  inflammation  is  known  to  do. 
So  that  the  principal  causes,  he  thinks,  of  the  subsidence  of  the  red 
particles  and  the  formation  of  the  bufl^y  coat  in  inflammatory  blood, 
appear  to  be — the  slow  coagulation  of  the  blood,  and  the  increased 
quantity  of  fibrin.  The  most  correct  view,  however,  is,  perhaps,  that 
of  M.  Andral,^  that  the  essential  condition  of  the  buffy  coat  is  an  in- 
crease in  the  quantity  of  fibrin  in  proportion  to  the  red  corpuscles. 
Hence,  if  there  be  an  absolute  increase  of  fibrin,  the  red  corpuscles 
remaining  the  same,  as  in  inflammation;  or,  if  there  be  a  diminution 
in  the  proportion  of  the  red  corpuscles,  the  fibrin  remaining  the  same, 
as  in  chlorosis,  the  buffy  coat  may  result ;  provided  only  there  be — 
as  there  probably  always  is  under  such  circumstances — a  greater 
aggregation  of  the  corpuscles. 

An  interesting  fact  connected  with  this  subject  has  been  noticed  by 
Mr.  T.  Wharton  Jones.'*  If  a  single  drop  of  inflammatory  blood  be 
examined  by  the  microscope,  it  Avill  be  seen  that  the  red  corpuscles 
have  an  unusual  attraction  for  each  other,  which  occasions  them  to 
coalesce  in  piles  and  masses,  as  in  the  marginal  illustration,  ^,  Fig.  119, 

'  Philosopliical  Transactions,  for  1822.  *  Op.  citat.,  p.  117. 

3  Hcmatologie  Patholoifique,  p.  75,  Paris,  1843,  or  Meigs's  and  Stille's  translation, 
Philad.,  1844. 

*  Edinburgh  Medical  and  Surgical  Journal,  Oct.,  1843,  p.  309. 


BLOOD — OF   DIFFEREXT  VEINS. 


381 


leaving  wide  interspaces  for  the  fibrin,  lymph-corpuscles,  and  serum. 
It  is  probable,  too,  that  there  is  an  increased  attraction  between  the 
particles  of  the  fibrin,  which  will  account  for 
the  firmer  clot  of  the  blood  of  inflammation,  Fig-  119. 

The  fact  of  a  single  drop  of  blood  being 
sufficient   to  indicate   the    character   of  the  ^^ 

whole  mass  may  be  important  in  cases  where         " 
a  doubt  exists  as  to  the  propriety  of  bleeding 
to  any  extent. 

It  is  proper  to  remark,  that  the  researches  ^    ^ 

of  Mulder^  have  led  him  to  infer,  that  the  ^      ^ 

buff'y  coat  does  not  consist  of  true  fibrin,  but  ^^^w^^^^^ 

is  a  compound  of  a  binoxide  of  protein,  which        j   g  ^    ^^^ 
is  insoluble  in  boiling  water,  and  a  tritoxide,    ^^^^      ^-  iMv^   ^^^ 
which  is  soluble.     These  oxides  Mulder  com-    ^^  £"^^1^  ^^^^  -^^ 
prehends  under  the  name  oryprotein.  ^^^p8,  J^-   ^'^^W^ 

It  may,  also,  be  remarked,  that  in  all  expe-  ^4^ 

riments  on  the  horse,  whenever  the  blood  Aggregntion  of  Corpuscles  in 
flows  from  an  opened  vein  in  a  continuous  ^if^^^  *"*^  "^  ^''^'"^'^ 
stream,  with  a  sufficiently  strong  iet,  and  is 

T    .     .  1    ii      i   •  -ii  1.  11  (i-  Healthy   blood.      6.  Inflamed 

received  into  a  vessel  that  is  neither  too  shai-    biood. 
low  nor  too  wide,  the  upper  part  of  the  clot 

is  instantly  found  occupied  by  a  white  mass,  which  perfectly  resem- 
bles the  buff  of  the  blood  of  man.  Such  was  the  result  of  the  obser- 
vations of  MM.  Andral,  Gavarret,  and  Delafoud.^ 

It  need  scarcely  be  said,  that  venous  blood,  composed  as  it  is  in  part 
of  the  products  of  heterogeneous  absorption,  must  differ  in  its  character 
in  the  different  veins.  In  its  passage  through  the  capillary  or  inter- 
mediate circulation,  the  arterial  blood  is  deprived  of  several  of  its  ele- 
ments, but  this  deprivation  is  different  in  different  parts  of  the  body. 
That,  for  example,  which  returns  from  the  salivary  glands,  must  vary 
from  that  which  returns  from  the  kidneys.  In  the  blood  of  the  abdo- 
minal venous  system,  the  greatest  variation  is  observed.  Professor 
Schultz^  has  inquired  into  the  chemical  and  physiological  differences 
between  that  of  the  vena  porta  and  of  the  arteries  and  other  veins. 
He  found,  that  it  is  not  reddened  by  the  neutral  salts,  or  by  exposure 
to  the  atmosphere,  or  to  oxygen;  that  it  does  not  generally  coagulate; 
contains  less  fibrin;  proportionably  more  cruor,  and  less  albumen;  and 
has  twice  as  much  fat  in  its  solid  parts  as  that  of  the  arteries  and  other 
veins ;  the  j^roportions  being  as  follows : — 

Blood  of  the  vena  porta, 1-66  per  cent. 

of  ilie  arteries,    .         .         •         .         .         •         •         04)2 
of  the  other  veins,       .         .         .      '  .         .         .         0'83 

Simon,'*  in  his  researches,  also  found  a  much  less  proportion  of  fibrin 
and  a  larger  of  fat  and  of  colouring  matter.  The  flit  he  ascribes  to  the 
fluids  produced  during  the  act  of  digestion,  which  are  conveyed  into 
the  portal  vein. 

'  Annalen  der  Chemie,  ii.  s.  w.,  Bd.  xlviii.,  ITeidelb.,  1843 ;  cited  by  Mr.  T.  Whar- 
ton Jones,  in  Brit,  and  For.  Med.  Rev.,  July,  1844,  p.  259. 

^  Essai  d'Hematologie  Pathologique,  p.  27,  Paris,  1843. 

^  Rust,  Magazin  fiir  die  cesammt.  Ileilkund.,  Bd.  44,  H.  i. ;  and  Lond.  Lancet,  Aug. 
10,  1839,  p.  717. 

*  Animal  Chemistry,  Sydenham  Society's  edition,  p.  208,  Lond.,  1845. 


882 


CIRCULATION. 


M.  Jules  Beclard^  always  found  the  cipher  of  red  corpuscles  in  the 
blood  of  the  splenic  vein  less  than  in  that  of  the  jugular;  with  a  cor- 
responding augmentation  in  the  amount  of  solid  matters  in  the  serum, 
and  a  constant  increase  of  fibrin.  Otto  Fanke,^  however,  contests  the 
accuracy  of  M.  Beclard's  analyses,  and  affirms,  as  the  result  of  numerous 
careful  observations,  that  there  is  always  a  diminution  of  the  fibrin  in 
the  blood  of  the  splenic  vein;  and  that  this  is  the  only  constant  article 
of  difference  between  the  blood  that  enters  and  that  which  issues  from 
the  spleen ;  and  Lehmann'  remarks,  that  the  investigations  of  Funke 
"afford,  at  all  events,  a  proof,  that  the  greatest  caution  is  necessary  in 
deducing  conclusions  from  individual  analyses,  and  investigations  of 
individual  fluids,  without  reference  to  the  simultaneous  constitution  of 
the  other  animal  juices.  Many  ingenious  conclusions  would  no  doubt 
have  been  deduced  from  analyses  of  the  blood  of  the  splenic  vein,  if 
the  arterial  blood  had  not  been  simultaneously  compared  with  it."  The 
mean  of  four  observations  of  the  blood  of  the  splenic  vein  of  a  crimi- 
nal, by  Vierordt,  is  said  to  have  given  the  ratio  of  colourless  corjDuscles 
to  the  coloured  as  4*9  to  1.  \?y 

The  following  table  by  Mr.  Gray,*  who  was  assisted  in  his  chemical 
researches  by  Dr.  Noad,  exhibits  in  a  tabular  form  the  average  results 
of  111  analyses  of  the  aortic,  jugular,  and  splenic  venous  blood  of  the 
horse : — 


Aortic. 

Jugular. 

Splenic. 

159-50 

141-00 

95-12 

1-04 

0-86 

0-71 

840-50 

859^00 

904-88 

032-5 

1031-14 

1032-24 

7S9-14 

793-42 

829-81 

42-00 

54-40 

63-00 

2-26 

4-15 

6-32 

•04 

0-05 

0-22 

157-20 

136-80 

88-58 

•35 

•64 

•30 

•49 

•92 

2-42 

1-61 

3^27 

6-(54 

8^73 

7-24 

Clot, 

Ash  in  ditto, 
Serum,   ..... 

Spec,  gravity  of  ditto, 
Water,    ..... 
Albumen,         .... 
Fibrin,    ..... 

Fat  in  ditto, 
Globules,         .... 
Oily  matters,  .... 
Crystalline  fat, 
Alcohol  extract, 
Water  extract, 

Mr.  Gray  considers  the  chief  chemical  peculiarities  of  splenic  venous 
blood  to  consist  in  a  very  considerable  diminution  of  the  blood  cor- 
puscles, an  increase  of  the  iron,  albumen,  and  fibrin,  and  a  deep  red- 
dish-brown colour  of  the  serum. 

The  subject  of  the  changes  produced  on  the  portal  blood,  more 
especially  as  regards  the  quantity  of  red  corpuscles,  will  be  referred 
to  when  considering  the  functions  of  the  Spleex. 

The  character  and  quantit}'  of  the  different  constituents  of  the  blood, 
as  well  as  its  coagulation,  vary  greatly  in  disease ;  and  the  investigation 
is  one  of  the  most  important  in  the  domain  of  pathology.  It  is  one 
that  has  attracted  the  attention  of  modern  pathologists,  and  especially 
of  MM.  Andral  and  Gavarret,  and  of  Simon,  and  5^1.  Becquerel  and 
Eodier,  who  have  endeavoured  to  detect  the  changes  that  occur  in  dis- 

'  Arcliiv.  General,  de  Med.,  Oct.,  1848;  and  Traite  Elementaire  de  Physiologie  Hu- 
maine,  p.  411,  Paris,  1855. 

^  Rudolpli  Wagner's  Lehrbuch  der  speciellen  Physiologie,  S.  119,  Leipzig,  1854. 

'  Physiological  Chemistry,  translated  from  the  2d  edit.,  by  Dr.  Day ;  Amer.  edit., 
by  Dr.  Rogei-s,  i.  C31,  Philad.,  1855. 

*  Schmidt's  Jahrbiich.,  x.  789,  in  Brit,  and  For.  Med.-Chir.  Rev.,  April,  1855,  p.  559. 

=  Cited  by  Dr.  Day,  in  Brit,  and  For.  Med.-Chir.  Rev.,  July,  1855,  p.  216. 


BLOOD — CONSTITUENTS.  383 

ease  in  the  amount  of  tlie  organic  elements  of  the  fluid.  These  the 
author  has  referred  to  in  their  appropriate  pLices  in  another  work.' 
The  usual  proportions  of  each  element,  in  1000  parts  of  healthy  blood, 
according  to  M.  Lecanu,  adopted  by  MM.  Andral  and  Gavarret,  are  as 
follows: — 

Fibrin, 3 

Red  corpuscles, 127 

Solid  matter  of  serum,         ........  80 

Water, 790 

The  average  of  analyses  of  the  blood  of  nine  healthy  individuals — 
four  females  and  five  males,  by  Dr.  Ch.  Frick,^  of  Baltimore,  corre- 
sponds nearly  with  the  above. 

According  to  Simon,^  the  proportions  are  somewhat  different, — • 
resulting,  in  a  great  measure,  from  a  different  method  of  analysis. 
The  mean  of  his  observations  gave — 

Water, 795-278 

Solid  residue, 204-022 

Fibrin, 2-104 

Fat, 2-346 

Albumen, 76-600 

Globulin, 103-022 

Hematin, 6-209 

Extractive  matter  and  salts,           ......  12-012^ 

The  following  table  exhibits  the  mean  composition  of  the  blood,  in 
eleven  cases,  as  observed  by  MM.  Becquerel  and  Eodier.* 

Density  of  the  defibrinated  blood, 1060-2 

"        of  tbe  serum,  .......         1028 

Water, 779 

Corpuscles, •         .         .         .  141-1 

Albiimen, 69-4 

Fibrin,          ..........  2-2 

Extractive  matters  and  free  salts,         .....  6*8 

Fatty  matters,     .........  1-6 

Serolin, 0-02 

Fatty  phospliuretted  matter, 0-488 

Cholesterin, 0-088 

Soapy  matter, 1-004 

One  thousand  parts  of  calcined  blood  contained — • 

Chloride  of  sodium,      .         .         .         .         .         .         .         .         .3-1 

Soluble  salts,        ..........     2-5 

Phosphates, 0-334 

Iron, 0-565 

From  these  numbers  they  draw  the  following  deductions.  First.  The 
limits  within  which  the  composition  of  healthy  blood  varies  are  restrict- 
ed, and  probably  dependent  on  constitution,  age,  and  diet.  Secondly. 
The  number  for  the  corpuscles  exceeds  127,  which  has  been  regarded 
as  expressing  the  healthy  mean.  Tlurdhj.  The  number  for  the  fibrin, 
2"2,  is  below  that  usually  admitted  as  the  mean  of  that  element,  o. 

'  Practice  of  Medicine,  3d  edit.,  Philad.,  1848. 

^  American  Journal  of  the  Medical  Sciences,  Jan.,  1848,  p.  27. 

'  Animal  Chemistry,  p.  245. 

■*  It  is  proper  to  remark,  with  Simon,  that  the  sum  of  the  hematin  and  globulin,  in 
his  analysis,  can  never  uipresent  the  aljsolute  quantity  of  blood  corpuscles.  In  his 
method  the  nuclei  and  capsules  of  the  blood  corpuscles  are  estimated  as  albumen ;  in 
that  of  Berzelius  as  fibrin ;  and  in  that  of  MM.  Andral  and  Gavarret,  as  appertaining 
to  the  corpuscles. 

*  Gazette  Medicale  de  Paris,  Nos.  47,  48,  49,  50,  and  51,  for  1844. 


1-3 


8S4  CIKCULATION. 

The  following  tables  have  been  constructed  chiefly  from  the  analyses 
of  Denis,  Lecanu,  Simon,  Nasse,  Lehmann,  Becquerel  and  Rodier,  and 
Gavarret;  and  "are  designed  to  combine,  as  far  as  possible,  the  ad- 
vantage of  accuracy  in  numbers  with  tlie  convenience  of  presenting 
at  one  view  a  list  of  all  the  constituents  of  the  blood."^ 

Average  proportions  of  the  chief  constituents  in  1000  parts : — 

Water, 784 

Red  corpuscles,  .........  131 

Albumen  of  serum,    .........       70 

Saline  matters,  ..........         6-03 

Extractive,  fatty  and  other  matters,  ......         6*77 

Fibrin 2-2 

1000- 

Average  proportion  of  all  the  constituents  of  the  blood  in  1000 
parts : — 

Water, 784 

Albumen,  ...........  70 

Fibrin, 2-2 

Bed  coi-puscles,  ......... 

globulin, 123-5 

hematin,      ..........  7'5 

Fatty  matters: 
Cholesterin,  0*08 "] 

Cerebrin,  0-40 

Serolin,  0-02 

Oleic  and  margaric  acids, 
Volatile  and  odorous  fatty  acid, 
Fat  containing  phosphorus,  ^ 

Inorganic  salts: 

Chloride  of  sodium,    .........  3*6 

Chloride  of  potassium,        ........  0'36 

Tribasic  jjliosphate  of  soda,         .......  0-2 

Carbonate  of  soda,     .........  0*84 

Sulphate  of  soda,        .........  0*28 

Phosphates  of  lime  and  magnesia,     ......  0'25 

Oxide  and  phosphate  of  iron,     .         .         .         .         .         .         .  0*5 

Extractive  matter,  with  salivary  matter,  urea,  biliary  )  ^  ,„ 

colouring  matter,  gases  and  accidental  substances,   ) 

1000- 

The  mode  in  which  the  ratio  of  the  various  elements  of  the  blood 
is  estimated  is  detailed  by  MM.  Andral  and  Gavarret,  Simon,  and 
Becquerel  and  Rodier,  in  the  works  referred  to.  A  simpler  method 
has,  however,  been  given  by  M.  Figuier,^  founded  on  the  fact  made 
known  by  Berzelius,  that  after  the  addition  of  a  solution  of  a  neutral 
salt  to  defibrinated  blood,  the  corpuscles  do  not  pass  through  bibulous 
paper.  On  the  addition  of  two  parts  of  a  solution  of  sulphate  of  soda, 
of  specific  gravity  1*180,  to  one  of  blood,  M.  Figuier  found,  that  the 
whole  of  the  corpuscles  remained  on  the  surface  of  the  filter.  The 
following  is  his  procedure.  The  fibrin  is  removed  in  the  usual  way 
by  whipping ;  and  dried,  and  weighed.  The  weight  of  the  corpuscles 
is  then  ascertained,  and  that  of  the  albumen  by  coagulating  the  filtered 
solution  by  means  of  heat.     The  proportion  of  water  is  determined 

'  Kirkes  and  Paget,  Manual  of  Physiology,  2d  Araer.  edit.,  p.  54,  Philad.,  1853. 
^  Aunales   de  Chimie  et  de  Physique,  ii.  503,  cited  iu  Rauking's  Abstract,  i.  299, 
Anier.  edit.,  New  York,  1845. 


BLOOD  —  CONSTITUENTS. 


385 


by  evaporating  a  small  known  weight  of  the  blood.  The  advantage 
of  this  plan  consists  in  the  facility  with  which  the  most  impoitant 
constituents  may  be  determined  without  any  difficult  manipulations. 

The  proportion  of  fibrin,  according  to  MM.  Andral  and  Gavarret, 
may  vary  perhaps  within  the  limits  of  health,  from  2^  to  3|  parts  in 
a  thousand.  The  quantity  cannot,  however,  be  accurately  estimated, 
inasmuch  as  it  is  always  mixed  with  colourless  corpuscles;  from  which, 
as  ]\[essrs.  Kirkes  and  Paget^  have  remarked,  it  cannot  be  separated  by 
any  mode  of  analysis  yet  invented.  "  In  health,  they  may,  perhaps, 
add  too  little  to  its  weight  to  merit  consideration  ;  but  in  many  dis- 
eases, especially  in  inflammatory  and  other  blood  diseases  in  which  the 
fibrin  is  said  to  be  increased,  these  corpuscles  become  so  numerous  that 
a  large  proportion  of  the  supposed  increase  of  the  fibrin  must  be  due 
to  their  being  weighed  with  it.  On  this  account  all  the  statements 
respecting  the  increase  of  fibrin  in  certain  diseases  need  revision." 

The  amount  of  red  corpuscles  appears  to  be  subject  to  greater  varia- 
tion within  the  limits  of  health  than  that  of  the  fibi'in.  The  maximum 
is  about  140,  but  this  is  connected  with  a  plethoric  condition :  the 
minimum  about  110.  Strength  of  constitution  contributes  most  to 
raise  the  corpuscles  towards  the  maximum;  whilst  debility,  congenital 
or  acquired,  diminishes  them  towards  the  minimum  proportion.  The 
solid  matter  of  the  serum  likewise  varies,  but  there  is  a  certain  point 
of  diminution  in  health  below  which  they  do  not  pass.^ 

The  analyses  of  MM.  Becquerel  and  Kodier  exhibit  a  marked  differ- 
ence in  the  proportion  of  the  constituents  of  the  blood  of  the  two  sexes. 
So  great  is  this,  that  in  order  to  attain  correct  conclusions  in  regard  to 
morbid  blood,  it  is  indispensable  to  contrast  it  with  the  male  or  female 
blood  in  healtli.  The  average  differences  between  the  two  are  seen  in 
the  followins:  table: — 

Male.  Female. 

Density  of  defibrinated  blood,         ....     1060-0  1057-5 


Density  of  serum, 


Water,  . 
Fibrin,  . 
Sum  of  fatty  mattei-s, 

Serolin, 

Phospliorized  fat, 

Cliolesterin, 

Saponified  fat,     . 
Albumen, 
Blood  corpuscles,    . 
Extractive  matters  and 
Chloride  of  sodium, 
Other  soluble  salts. 
Earthy  phosphates. 
Iron, 


salts. 


1028-0 


1027-4 


779-0 

791-1 

2-2 

2-2 

1-GO 

1-62 

0-02 

0-02 

0-488 

0-464 

0-088 

0-090 

1-004 

1-046 

69-4 

70-5 

141-1 

127-2 

6-8 

7-4 

3-1 

3-9 

2-5 

2-9 

0-334 

0-354 

0-566 

0-541 

The  main  difference,  consequently,  between  male  and  female  blood 
is  in  the  amount  of  water  and  blood  corpuscles.^ 

'  Manual  of  Physiology,  2d  Amer.  edit.,  p.  56,  Philad.,  1853. 

'■^  Andral,  Hematologie  Pathoiogique,  p.  2t),  Paris,  1843. 

^  For  the   difierences  in  blood,   according  to   constitution,  temperament,    ^c,  see 
Simon,  Animal  Chemistry,  Sydenham  Society's  edition,  p.  236,  Lond.,  1845,  or  Amer. 
edit.,  Philad.,  1846. 
VOL.  I. — 25 


386 


CIRCULATION". 


The  following  table  by  Henle/  gives  the  results  of  the  analyses  of 
different  observers  as  regards  the  proportion  of  the  organic  constitu- 
ents of  human  blood,  and  the  corresponding  specific  gravities  of  blood 
and  serum. 


S.  G. 

S.  G. 

Blood  Cor- 

Residue  of 

of  Blood. 

of  Serum. 

Water. 

puscles. 

Serum. 

Fibrin. 

Observer. 

Remarks. 

1 

1062 

1031 

772 

128 

97 

2 

Popp.       1 

2 

1061 

781 

121 

86 

10 

do.        iMany    colourless 

corpuscles. 

3 

1057 

773 

142 

82 

3 

Few  do. 

4 

1055 

1028 

799 

130 

75 

3 

Becquerel 
and  Rodier. 

5 

1055 

1027 

793 

126 

78 

2 

do. 

6 

1053 

771 

146 

78 

4 

Popp. 

7 

1053 

781 

140 

76 

2 

do. 

8 

1051 

802 

117 

76 

5 

do. 

9 

1050 

790 

114 

90 

5 

do. 

Many  do. 

10 

1049 

803 

120 

71 

5 

do. 

do. 

11 

1049 

806 

92 

96 

5 

do. 

do. 

12 

1048 

791 

128 

76 

2 

do. 

13 

1048 

814 

104 

76 

5 

do. 

Few  do. 

14 

1048 

806 

124 

66 

4 

do. 

15 

1048 

801 

107 

86 

5 

do. 

Many  do. 

16 

1048 

811 

95 

86 

8 

do. 

A  moderate  num- 
ber of  do. 

17 

1047 

811 

118 

65 

6 

do. 

18 

1047 

794 

121 

81 

4 

do. 

19 

1046 

790 

129 

78 

2 

do. 

20 

1046 

1023 

831 

105 

54 

2 

Becquerel 
and  Rodier. 

21 

1045 

1024 

78 

3 

do. 

22 

1044 

827 

91 

71 

11 

Popp. 

23 

1044 

801 

100 

86 

12 

do. 

24 

1044 

790 

115 

83 

11 

do. 

A     strong     bufiy 
coat. 

25 

1043 

826 

93 

72 

9 

do. 

Few       colourless 
corpuscles. 

26 

1043 

812 

112 

66 

10 

do. 

A  moderate  buffy 
coat. 

27 

1042 

812 

105 

77 

6 

do. 

Few       colourless 
corpuscles. 

28 

1042 

821 

91 

84 

4 

do. 

29 

1042 

828 

95 

74 

3 

do. 

Many    colourless 
corpuscles. 

30 

1042 

1022 

92 

2 

Becquerel 
and  Rodier. 

31 

1041 

816 

77 

94 

13 

Popp. 

Strong  buify  coat. 

32 

1041 

817 

99 

76 

8 

do. 

33 

1040 

831 

92 

68 

9 

do. 

34 

1040 

827 

92 

76 

4 

do. 

35 

1039 

855 

6S 

72 

6 

do. 

Few       colourless 
corpuscles. 

36 

1039 

845 

96 

80 

5 

do. 

37 

1030 

792 

126 

81 

2 

do. 

38 

1026 

788 

124 

82 

6 

Heller. 

39 

1025 

773 

146 

77 

4 

do. 

40 

1025 

834 

78 

83 

5 

do. 

41 

1024 

820 

87 

85 

8 

do. 

42 

1023 

782 

147 

65 

6 

do. 

43 

1011 

58 

Popp. 

Serum  rich  in  fat. 

'  Haudbuch  der  Ratiouellen  Patliologie,  2er  Band.  s.  18,  Braunschweig,  1847. 


BLOOD  —  ORGANIC    COXSTITUENTS. 


587 


There  is  considerable  difference,  however,  amongst  observers  in  re- 
gard to  the  ratio  of  the  different  organic  constituents  of  healthy  blood, 
and  this  is  dependent  upon  the  different  modes  of  evaluation  adopted 
by  them.  It  is  advisable,  therefore,  in  observations  made  on  diseased 
blood,  to  follow  the  method  employed  by  some  one  of  them;  and  that 
of  ^[M.  Andral  and  Gavarret  is  generally  chosen. 

To  exhibit  this  difference  the  following  table  drawn  up  by  Hcnle^ 
may  be  introduced : — 


1000  parts   of  healthy  venous 
blood  contain 

Corpuscles. 

Water. 

Fibrin. 

Albumen. 

Extractive 
matters. 

Salts. 

According  to  Le  Canu, 
"  Becquerel  and  Rodier, 
of  men, 
of  women, 

"   Popp, 

"  Zimmerman, 

"   Simon, 

of  men, 

of  women, 
"  Christison, 

of  men, 

of  women, 
"  Hittorf, 

of  women. 

127 

141-1 

127-2 

120 
127 

112-2 
106-0 

153-5 
120-7 

126-4 

790 
779 

791-1 
790 

791-9 

798-6 

756-2 
795-2 

793-0 

3 

2-2 
2-2 

2-5 
3 

2-0 

2-2 

5-2 
2-5 

1-4 

^ 

8 

7 

69-4 
70-5 

2 

8-4 
9 

75-6 
77-6 

SS 
80 

16-6 
12-6 

67-4 

85-3 
81-6 

11-L 

I. 

II. 

in. 

783-18 

769-64 

775-7 

216-82 

230-36 

224-3 

2-30 

2-03 

2-63 

63-34 

68-45 

70-08 

139-92 

146-22 

138-71 

5-16 

5-34 

3-84 

8-85 

8-86 

9-04 

1-70 

An  analysis  of  healthy  human  blood  by  Scherer^  gives  the  following 
proportion  of  the  various  constituents : — ■ 

Water, 
Fixed  parts, 

Fibrin, 
Albumen,  . 
Blood  corpuscles, 
Extractive  matters. 
Soluble  salts, 
Fat,    . 

It  may  be  added,  that  a  peculiar  entozoon, — i^olijsioma  venarum^ 
liexaOiyridlum  venarian, — has  been  found  in  human  venous  blood, 
especially  in  that  of  persons  affected  with  hasmoptysis;  Treutler  found 
one  in  the  tibial  vein  of  a  young  man,  who  had  lacerated  it  whilst 
bathing.  Yogel,  however,  suggests,  that  it  may  have  been  a  planaria, 
which  had  entered  the  vein  from  without;^  and  Valentin  several  times 
observed  minute  entozoa — anguilhdce  intesiinales — in  the  circulating 
blood  of  frogs.  MM.  Gruby  and  Delafond^  communicated  to  the  xica- 
dtmie  Royale  des  Scitnces  of  Paris,  the  discovery  of  filariio  in  the  circu- 
lating fluid  of  a  living  dog. 

'  Op.  cit.,  s.  73. 

*  Canstatt's  .Tahresbericht  liber  die  Fortschritte  in  der  Biologic  im  Jalire,  1848,  s.  65, 
Erlangen,  1849. 

*  The  Pathological  Anatomy  of  the  Human  Bodv,  Ent^'lish  translation  hy  Day,  n. 
467,  Lond.,  1847. 

••  Phihid.  Med.  Examiner,  Jan.  13,  1844,  from  Comptes  Rendus. 


388  CIRCULATION. 

3.    PHYSIOLOGY  OF  TUE  CIRCULATION. 

The  blood,  contained  in  the  circulatory  apparatus,  is  in  constant 
motion.  The  venous  blood,  brought  from  every  part  of  the  body,  is 
emptied  into  the  right  auricle;  from  the  right  auricle  it  passes  into  the 
corresponding  ventricle;  and  the  latter  projects  it  into  the  pulmonary 
artery,  by  which  it  is  conveyed  to  the  lungs,  passing  through  the  capil- 
lary system  into  the  pulmonary  veins ;  these  convey  it  to  the  left  auri- 
cle; from  the  left  auricle  it  enters  the  corresponding  ventricle ;  and 
the  left  ventricle  sends  it  into  the  aorta,  along  which  it  passes  to  the 
different  organs  and  tissues  of  the  body,  through  the  general  inter- 
mediate or  capillary  system,  wliich  communicates  with  the  veins;  these 
return  it  to  the  part  whence  it  set  out.  This  entire  circuit  includes 
both  the  lesser  and  the  greater  circulation. 

It  was  not  until  the  commencement  of  the  seventeenth  century,  that 
any  precise  ideas  were  entertained  regarding  the  general  circulation. 
In  antiquity,  the  most  erroneous  notions  prevailed ;  the  arteries  being 
generally  looked  upon  as  tubes  for  the  conveyance  of  some  aerial  fluid 
to,  and  from,  the  heart;  whilst  the  veins  conducted  the  blood,  whither 
or  for  what  precise  purpose  was  not  understood.  The  names,  given  to 
the  principal  arterial  vessel — aorta — and  to  the  arteries,  sufficiently 
show  the  functions  originally  ascribed  to  them, — both  being  derived 
from  the  Greek",  a»7P,  "air,"  and  trifynv,  "to  keep;"  and  this  is  farther 
confirmed  by  the  fact,  that  the  trachea  or  windpipe  was  originally 
termed  an  artery, — the  aprjjpia  tpaxeia  of  the  Greek, — aspera  arteria  of 
the  Latin  writers.'  In  the  time  of  Galen,  however,  the  arteries  were 
known  to  contain  blood;  and  he  seems  to  have  had  some  notions  of  a 
circulation.  He  remarks,  that  the  chyle,  the  product  of  digestion,  is 
collected  by  the  meseraic  veins  and  cari-ied  to  the  liver,  where  it  is 
converted  into  blood;  the  supra-hepatic  veins  then  carry  it  to  the  pul- 
monary heart;  whence  a  part  proceeds  to  the  lungs,  and  the  remainder 
to  the  rest  of  the  body,  passing  through  the  median  septum  of  the  auri- 
cles and  ventricles.  This  limited  knowledge  of  the  circulation  con- 
tinued through  the  whole  of  the  middle  ages, — the  functions  of  the 
veins  being  universally  misapprehended;  and  the  general  notion  being, 
that  they  also  convey  blood  from  the  heart  to  the  organs;  from  the 
centre  to  the  circumference. 

It  was  not  until  after  the  middle  of  the  sixteenth  century,  that  the 
lesser  circulation  or  that  through  the  lungs  was  comprehended  by 
Michael  Servetus, — who  fell  a  victim  to  the  persecution  and  intolerance 
of  Calvin, — and  by  Andrew  Ccesalpinus  and  Kealdus  Columbus.  It 
has  been  imagined,  that  they  possessed  some  notion  of  the  greater 
circulation.  Howsoever  this  may  have  been,  all  nations  unite  in 
awarding  to  Harvey  the  merit,  if  not  of  entire  originality  of  at  least 
having  first  clearly  established  it.*  The  honour  of  the  discovery  is, 
therefore,  his;  and  Ijy  it  his  name  has  been  rendered  immortal, — for  its 
importance  to  the  knowledge  of  the  physiology  and  pathology  of  the 

'  "  Spiritns  ex  pulmoue  in  cor  recipitur  et  per  arterias  distribuitur,  sanguis  per  venas." 
Cicero,  De  Natura  Deor.,  Lib.  ii. 

^  "Lorsque  Harvey  parut,  tout,  relativement  a  La  circulation,  avait  ete  indique  ou 
soupconne  ;  rien  notait  etabli."  Flourens,  Histoii'e  de  la  Docouverte  de  la  Circula- 
tion du  Sang,  p.  28,  Paris,  1854. 


PHYSIOLOGY  OF  THE   CIRCULATION".  389 

animal  fabric  is  overwhelming.  How  vague  and  inaccurate  must  have 
been  the  notions  of  the  early  pathologists  regarding  the  doctrine  of 
acute  diseases,  in  which  the  circulation  is  always  largely  affected, — dis- 
eases, which,  according  to  the  estimate  of  some  writers,  constitute  two- 
thirds  of  the  morbid  states  to  which  mankind  are  liable! 

It  was  in  the  year  1619,  that  Harvey  attained  a  full  knowledge  of 
the  circulation  ;  but  his  discovery  was  not  promulgated  until  the  year 
1628,  in  a  tract,  to  which  the  merit  of  clearness,  perspicuity,  and  de- 
monstration has  been  awarded  by  all.'^  Yet  so  strong  is  the  force  of 
prejudice,  and  so  difficult  is  it  to  discard  preconceived  notions,  that 
according  to  Hume,^  it  was  remarked,  that  no  physician  in  IJurope,  who 
had  reached  forty  years  of  age,  ever,  to  the  end  of  his  existence,  adopted 
Harvey's  doctrine  of  the  circulation ;  and  Harvey's  practice  in  London 
diminished  extremely  for  a  time  from  the  reproach  drawn  upon  him 
by  that  great  and  signal  discovery. 

Of  the  truth  of  the  course  of  the  blood,  as  discovered  by  Harvey, 
we  have  numerous  and  incontestable  evidences,  which  it  is  almost  a 
work  of  supererogation  to  adduce.  Of  these  the  following  are  some 
of  the  most  striking.  First.  If  we  open  the  chest  of  a  living  animal, 
we  find  the  heart  alternately  dilating  and  contracting  so  as  manifestly 
to  receive  and  expel  the  blood  in  reciprocal  succession.  Secondly.  The 
valves  of  the  heart,  and  of  the  great  arteries  that  arise  from  the  ven- 
tricles, are  so  arranged  as  to  allow  the  blood  to  flow  in  one  direction, 
and  not  in  another;  and  the  same  may  be  said  of  the  veins,  which  are 
directed  towards  the  heart.  The  tricuspid  valve  permits  the  blood  to 
flow  only  from  the  right  auricle  into  the  corresponding  ventricle ;  the 
sigmoid  valves  admit  it  to  enter  the  pulmonary  artery,  but  not  to 
return;  and,  as  there  is,  in  the  adult,  no  immediate  communication 
between  the  right  and  left  sides  of  the  heart,  the  blood  must  pass  along 
the  pulmonary  artery  and  the  pulmonary  veins  to  the  left  auricle.  The 
mitral  valve,  again,  is  so  situate,  that  the  blood  can  only  pass  in  one 
direction  from  auricle  to  ventricle;  and,  at  the  mouth  of  the  aorta,  the 
same  valvular  arrangement  exists  as  in  the  pulmonary  artery,  which 
permits  the  blood  to  proceed  along  the  artery,  but  prevents  its  reflux. 
Thirdly.  If  an  artery  and  vein  be  wounded,  the  blood  will  be  observed 
to  flow  from  the  part  of  the  vessel  nearest  the  heart  in  the  case  of  the 
artery;  from  the  other  extremity  in  that  of  a  vein.  The  ordinary  ope- 
ration of  bloodletting  at  the  flexui^e  of  the  arm  affords  an  elucidation  of 
this.  The  bandage  is  applied  above  the  elbow,  for  the  purpose  of  com- 
pressing the  superficial  veins,  but  not  so  tightly  as  to  compress  the 
deep-seated  artery  also.  The  blood  passes  along  the  artery  to  the  ex- 
tremity of  the  fingers,  and  returns  by  the  veins;  but  its  progress  back 
to  the  heart  by  the  subcutaneous  veins  being  prevented  by  the  ligature, 
they  become  turgid;  and,  if  a  puncture  be  made,  it  flows  freely.  If, 
however,  the  ligature  be  applied  so  forcibly  as  to  compress  the  main 
artery,  the  blood  no  longer  flows  to  the  extremity  of  the  fingers;  there 
is  none,  consequently,  to  be  returned  by  the  veins ;  they  do  not  rise 
properly  ;   and  if  a  puncture  be  made  no  blood  flows.     This  is  not  an 

'  Exercitat.  Anatom,  de  Motu  Cordis  et  Sanguinis,  Francof.,  1028,  Glasgure,  1751. 
*  History  of  England,  vol.  vii.  chap,  Ixii.  p.  347,  Loudon,  17S2. 


890  CIRCULATION 

unfrequent  cause  of  the  failure  of  au  inexperienced  pblebotomist.  If  the 
baiidage,  under  such  circumstances,  be  slackened,  the  blood  resumes 
its  course  along  the  artery,  and  a  copious  stream  issues  from  the  orifice, 
■which  did  not  previously  transmit  a  drop.  This  operation,  then, 
exhibits  the  fact  of  the  flow  of  blood  along  the  arteries  from  the  heart, 
and  of  its  return  by  the  veins.  From  what  has  been  said,  too,  it  will 
be  obvious,  that  if  a  ligature  be  applied  to  both  vessels,  the  artery 
will  become  turgid  above  the  ligature,  the  vein  below  it.  Fourthly. 
The  microscopical  experiments  of  Leeuenhoek,  Malpighi,  Spallanzani, 
and  others  have  exhibited  to  the  eye  the  passage  of  the  blood  in  suc- 
cessive waves  by  the  arteries  towards  the  veins,  and  its  return  by  the 
latter.  Lasth/.  The  fact  is  forther  demonstrated  by  the  effect  of  trans- 
fusion of  blood,  and  of  the  injection  of  substances  into  the  vessels;  both 
of  which  operations  will  be  alluded  to  in  another  place. 

In  tracing  the  physiological  action  of  the  different  parts  of  the  cir- 
culatory apparatus,  we  shall  follow  the  order  observed  in  the  anatomi- 
cal sketch ;  and  describe,  in  succession,  the  circulation  in  the  heart, 
arteries,  capillary  vessels,  and  veins ;  on  all  which  points  there  has 
been  interesting  diversity  of  opinion,  and  much  room  for  ingenious 
speculation,  and  farther  improvement. 

a.   Circulation  in  the  Heart. 

It  has  been  already  observed,  that  when  the  heart  of  a  living  ani- 
mal is  exposed,  it  is  remarked  to  undergo  alternate  contraction  and 
dilatation.  The  mode,  in  which  the  circulation  through  the  organ  is 
accomplished  is  generally  considered  to  be  as  follows. — The  blood  is 
received  into  the  two  auricles  at  the  same  time,  and  is  transmitted  into 
the  two  great  arteries  synchronously.  In  order  that  the  heart  shall 
receive  blood,  it  is  necessary  that  the  auricle  should  be  dilated.  This 
movement  is  partly  effected  by  virtue  of  the  elasticity  which  it  pos- 
sesses in  its  structure.  Let  us  suppose  it  to  be  once  filled ;  the  stimulus 
of  the  blood  excites  it  to  contraction,  and  the  blood  is  sent  into  the 
corresponding  ventricle.  As  soon,  however,  as  it  has  emptied  itself, 
the  stimulus  is  withdrawn  ;  and,  by  virtue  of  its  elasticity  the  muscular 
structure  returns  to  the  state  in  which  it  was  prior  to  its  contraction. 
An  approach  to  a  vacuum  is  thus  formed  in  the  cavity,  and  the  blood 
from  the  veins  is  solicited  towards  it,  until  it  is  again  filled,  and  its 
contraction  renewed.  When  the  right  auricle  contracts  there  are  four 
channels  by  which  the  blood  might  be  presumed  to  pass  from  it, — the 
two  terminations  of  the  venj©  cavse ;  the  coronary  vein,  and  the  auri- 
culo-ventricular  opening.  The  constant  flow  of  blood  from  every  part 
of  the  body  prevents  it  from  readily  returning  by  the  venae  cavse, 
whilst  the  small  quantity,  which,  under  other  circumstances,  might 
have  entered  the  coronary  vein,  is  prevented  by  its  valve.  To  the  flow 
of  the  blood  through  the  aperture  into  the  ventricle,  which  is  in  a  state 
of  dilatation,  there  is  no  obstacle,  and  accordingly  it  takes  this  course, 
raising  the  tricuspid  valves. 

It  may  be  remarked,  that  physiologists  are  not  entirely  of  accord 
regarding  the  reflux  of  blood  into  the  venas  cava?.  Some  think,  that 
this  always  occurs  to  a  slight  extent;  others,  never  in  the  healthy 
state.     Its  existence  is  unequivocal,  where  an  obstacle  occurs  to  the 


IN  THE   HEAET.  391 

dae  discharge  of  tlie  blood  into  tlie  ventricle.  For  example,  if  there 
is  any  impediment  to  the  flow  of  blood  along  the  pulmonary  artery, 
either  owing  to  mechanical  obstruction  or  to  diminished  force  of  the 
ventricle,  the  reflux  is  manifested  by  a  kind  of  pulsation  in  the  veins, 
which  Haller  has  called  venous  pulse. 

The  blood  having  attained  the  right  ventricle  by  the  effort  exerted 
by  the  contraction  of  the  auricle,  and  by  the  aspiration  exerted  by  the 
dilatation  of  the  cavity  through  the  agency  of  its  elastic  structure,  the 
ventricle  contracts.  Into  it  there  are  but  two  apertures,  the  auriculo- 
ventricular,  and  the  mouth  of  the  pulmonary  artery.  By  the  former, 
much  of  the  blood  cannot  escape,  owing  to  the  tricuspid  valve,  Avhich 
acts  like  the  sail  of  a  ship,^ — the  blood  distending  it  as  the  wind  does 
a  sail,  and  the  chordas  tendinece  retaining  it  in  position,  so  that  the 
greater  part  of  the  blood  is  precluded  from  reflowing  into  the  auricle. 
This  auriculo-ventricular  valve  is  not,  however,  as  perfect  as  that  of  the 
left  heart.  The  observations  of  Mr,  T.  W.  King^  show,  that  whilst  the 
structure  of  the  mitral  valve  is  adapted  to  close  completely  all  commu- 
nication between  the  left  auricle  and  left  ventricle  during  the  contrac- 
tion of  the  latter,  that  of  the  tricuspid  valve  is  designedly  calculated 
to  permit,  when  closed,  the  flow  of  a  certain  quantity  of  blood  into 
the  auricle.  The  comparatively  imperfect  valvular  function  of  the 
tricuspid  was  shown  by  various  experiments  on  recent  hearts,  in  which 
it  was  found,  that  fluids,  injected  through  the  aorta  into  the  left  ven- 
tricle, were  perfectly  retained  in  that  cavity  by  the  closing  of  the  mitral 
valve;  but  when  the  right  ventricle  was  similarly  injected  through  the 
pulmonary  artery,  the  tricuspid  valves  generally  allowed  the  escape  of 
the  fluid  in  streams  more  or  less  copious,  in  consequence  of  the  incom- 
plete apposition  of  their  margins.  This  peculiarity  of  structure  in  the 
tricuspid  Mr.  King  regards  as  an  express  provision  against  the  mis- 
chiefs, that  might  result  from  an  excessive  afflux  of  blood  to  the 
lungs, — thus  acting  as  a  safety  valve,  and  being  more  especially  ad- 
vantageous in  incipient  morbid  enlargements  of  the  right  ventricle. 
The  only  other  way  the  blood  can  escape  from  the  right  ventricle  is 
by  the  pulmonary  artery,  the  sigmoid  valves  of  which  it  raises.  These 
had  been  closed  like  flood-gates,  during  the  dilatation  of  the  ventricle ; 
but  they  are  readily  pushed  outwards  by  the  columns  transmitted  from 
the  ventricle. 

Such  is  the  circulation  through  one  heart, — the  ^jw/wonz'c.  The 
same  explanation  is  applicable  to  the  other, — the  sysleitnic ;  and  hence 
it  is,  that  the  structure,  as  well  as  the  functions  of  the  heart,  is  so  much 
better  comprehended,  by  conceiving  it  to  be  constituted  of  two  essen- 
tially similar  organs. 

The  above  description  is  that  which  is  usually  given  of  the  circula- 
tion through  the  heart.  There  is  great  reason,  however,  for  the  belief, 
that  too  much  importance  has  been  assigned  to  the  distinct  contraction 
of  the  auricles.  If  we  examine  their  anatomical  arrangement  we  dis- 
cover, that  there  are  no  valves  at  the  mouths  of  the  great  veins  which 
open  into  them,  and  that  although  in  the  proper  auricle  or  dog's  ear 

'  Sir  C.  Bell,  Animal  Mechanics — Library  of  Useful  Knowledge,  p.  36. 
^  Guy's  Hospital  Reports,  No.  iv.  for  April,  1837. 


892  CIRCULATION 

portion  muscular  fibres  and  columns  exist, — somewhat  analogous  to 
those  of  the  columnas  carnea3  of  the  ventricles,  and  probably  destined 
for  similar  uses, — the  parietes  of  the  main  portions  of  the  auricles, — 
those  that  constitute  the  venous  sinuses  are  but  little  adapted  for  ener- 
getic contraction.  In  experiments  on  living  animals  observation  shows, 
that  the  rhythmic  acts  of  dilatation  and  contraction  are  more  signally 
exhibited  by  the  ventricle,  and,  moreover,  in  some  monsters  the  auri- 
cles are  wanting,  and  in  birds  very  small.  M.  d'Espine  considers  the 
auricles,  in  receiving  or  transmitting  blood,  to  have  only  ar  vermicular 
motion,  not  one  of  contraction ;  and  in  a  case  of  monstrosity,  described 
by  Dr.  T,  Eobinson,'  of  Petersburg,  Virginia,  no  distinct  systole  and 
diastole  of  the  auricles  could  be  detected.  Besides,  if  we  admit  both 
an  active  power  of  dilatation  and  contraction  in  the  ventricles,  any 
similar  action  of  the  auricles  would  seem  to  be  superfluous.  In  the 
state  of  active  dilatation  of  the  ventricles,  the  blood  is  drawn  into 
their  cavities;  and  as  soon  as  they  enter  into  contraction,  the  auriculo- 
ventricular  valves  prevent  the  farther  entrance  into  them  of  blood 
arriving  in  the  auricles  by  the  large  veins ;  and  give  occasion  to  the 
distension  of  the  auricles;  in  this  way,  the  dilatation  of  the  auricles, 
sjmchronous  with  the  contraction  of  the  ventricles,  is  accounted  for. 
As  soon  as  the  ventricle  has  emptied  itself  of  its  blood,  it  dilates 
actively ;  the  blood  then  passes  suddenly  from  the  auricle  into  its  cavity 
through  the  auriculo- ventricular  opening. 

From  careful  experiments  instituted  by  Drs.  Pennock  and  Moore,' 
they  drew  the  following  conclusions,  which  have  been  confirmed  by 
the  observations  of  others,  and  merit  universal  assent.  The  ventricles 
contract  and  the  auricles  dilate  at  the  same  time,  occupying  about  one- 
half  of  the  whole  time  required  for  contraction,  diastole,  and  repose. 
Immediately  at  the  termination  of  the  systole  of  the  ventricle,  its 
diastole  occurs,  occupying  about  one-fourth  of  the  whole  time,  syn- 
chronously with  which  the  auricle  diminishes,  by  emptying  a  portion 
of  its  blood  into  the  ventricle,  but  without  muscular  contraction.  The 
remaining  fourth  is  devoted  to  the  repose  of  the  ventricles,  near  the 
termination  of  which  the  auricle  contracts  actively,  with  a  short,  quick 
motion,  thus  distending  the  ventricles  with  an  additional  quantity  of 
blood :  this  motion  is  propagated  immediately  to  the  ventricles,  and 
their  systole  follows  so  rapidly  as  to  make  the  contraction  of  auricle 
and  ventricle  almost  continuous.  From  the  termination  of  their  dias- 
tole to  the  commencement  of  the  s_ystole,  the  ventricles  are  in  a  state 
of  perfect  repose ;  their  cavities  remaining  full  but  not  distended ;  whilst 
those  of  the  auricles  are  partially  so,  during  the  whole  time.  It  appears 
probable,  that  the  great  use  of  the  auricles — in  Avhich  we  include  the 
sinuses — is  to  act  as  true  gulfs  for  the  reception  of  the  blood  proceed- 
ing from  every  part  of  the  body ;  and  that  little  effect  is  produced  on 
the  circulation  by  their  varying  condition.^ 

'  American  Journal  of  the  Medical  Sciences,  No.  xxii.  for  February,  1833. 

^  Medical  Examiner,  Nov.  2, 1839,  and  American  Medical  Intelligencer,  Dec.  16,1839, 
p.  277. 

"  See,  on  tliis  subject,  Elliotson's  Human  Physiology,  p.  174,  Lond.,  1840,  and  Hiffel- 
sheiui,  Comptes  Rendus  et  Mcmoires  de  la  Societe  de  Biologic,  Annee  1854,  p.  273. 


IN   THE   HEART — SOUNDS.  893 

The  state  of  tlie  heart  in  which  the  ventricles  are  dilated  is  termed 
Diastole  ;  that,  in  which  they  are  contracted,  Systole. 

Since  the  valuable  improvement,  introduced  by  Laennec  in  the  dis- 
crimination of  diseases  of  the  chest  by  audible  evidences,  it  has  been 
discovered,  that  the  heart  is  not  in  a  state  of  incessant  activity,  but 
has,  like  other  muscles,  its  intervals  of  repose.  If  we  apply  tlie  ear 
or  the  stethoscope  to  the  precordial  region,  we  hear,  first,  a  dull,  length- 
ened sound,  which,  according  to  Laennec,'  is  synchronous  with  the 
arterial  pulse,  and  is  produced  by  the  contraction  of  the  ventricles. 
This  is  instantly  succeeded  by  a  sharp,  quick  sound,  like  that  of  the 
valve  of  a  bellows,  or  the  lapping  of  a  dog.  To  convey  a  notion  of 
these  sounds,  Dr  C.  J.  B.  Williams  employs  the  word  luhb-dup  or  luhh- 
tuh ; — the  first  word  of  the  compound  expressing  the  protracted  first 
sound,  and  the  latter  the  short  second  sound.  The  latter  sound  corre- 
sponds to  the  interval  between  two  pulsations,  and,  according  to  Laen- 
nec, is  owing  to  the  contraction  of  the  auricles.  The  space  of  time, 
that  elapses  between  this  and  the  sound  of  the  contraction  of  the 
ventricles,  is  the  period  of  repose.  The  relative  duration  of  these 
periods  is  as  follows : — one-half,  or  somewhat  less,  for  the  contraction 
of  the  ventricles  ;  a  quarter,  or  somewhat  more,  for  the  contraction  of 
the  auricles ;  and  the  remaining  quarter  for  the  period  of  total  cessa- 
tion from  labour.  So  that  in  the  twenty  four  hours  the  ventricles  work 
twelve  hours,  and  rest  twelve ;  and  the  auricles  work  six,  and  rest 
eighteen. 

The  following  table  by  Messrs.  Kirkes  and  Paget^  exhibits  the  difibr- 
ent  actions  of  the  heart,  and  their  coincidence  with  the  sounds  and 
impulse  of  the  organ.  It  presumes,  that  the  period  from  the  com- 
mencement of  one  pulsation  to  that  of  another — or  that  occupied  by  a 
complete  set  of  the  heart's  actions — is  divided  into  eight  parts ;  and  if 
the  case  of  a  person,  whose  pulse  beats  sixty  times  in  a  minute,  be 
assumed,  each  of  these  joarts  will  represent  the  eighth  part  of  a  second. 

EIGHTHS  OF  A  SECOND. 

Last  part  of  the  pause,  .     1.  Auricles  contracting:  Ventricles  distended. 

First  sound  and  impulse,  .     4.  Ventricles  contracting :  Auricles  dilating. 

Second  sound,      .         .  .2.  Ventricles  dilating:  Auricles  dilating. 

Pause,  .         .         .  .1.  Ventricles  dilating:  Auricles  distended. 

Or  it  may  be  better  exhibited  in  the  following  table.  A  series  of  the 
heart's  actions  {rhytlim)] — 

Time  =  4. 
First  or  inferior  sound.  Second  or  superior  sound.  Interval  or  pause. 

Time  =  2.  Time  =  1 .  Time  =  1 . 


Ventricular  contraction  and     First  stage  of  ventricular  dila-     Short  repose,  followed  by 
auricular  dilatation.  tatiou.  contraction  of  auricles. 

Impulse.  Second  stage  of  ventri- 

cular dilatation. 

The  view  of  Laennec  in  regard  to  the  second  sound  is  manifestly 
erroneous.     Ocular  observation  on  living  animals,  as  Dr.  Alison-'  has 

'  A  Treatise  on  the  Diseases  of  the  Chest,  translated  by  Dr.  Forbes,  4th  edit.,  Lond., 
1834. 
^  Manual  of  Physiology,  2d  Amer.  edit.,  p.  75,  Loud.,  1853. 
*  Outlines  of  Physiology,  Loud.,  1831. 


394  CIRCULATION" 

remarked,  shows  that  the  emptying  of  the  auricle  precedes  that  of  the 
ventricle,  and  that  the  interval  of  rest  is  between  the  contraction  of  the 
ventricle  and  the  next  emptying  of  the  auricle :  between  the  contrac- 
tion of  the  auricle  and  that  of  the  ventricle,  there  is  no  appreciable  in- 
terval. PucheltHhinks  it  most  probable,  that  the  first  sound  is  caused 
by  the  impulse  of  the  blood  against  the  walls  of  the  ventricle  daring 
the  contraction  of  the  auricles,  and  the  second  by  the  impulse  of  the 
blood  against  the  commencement  of  the  arteries  during  the  contraction 
of  the  ventricles.  In  regard  to  the  first  sound,  M.Beau'^ — and  M.  Val- 
leix^  accords  with  him — agrees  pretty  nearly  with  Puchelt.  He  ascribes 
it  to  the  wave  of  blood  striking  against  the  parietes  of  the  ventricles 
during  the  ventricular  diastole.  The  second  sound  he  ascribes,  how- 
ever, to  the  shock  of  the  column  of  blood  arriving  by  the  veins  against 
the  parietes  of  the  auricles.  M.  d'Espine  thinks,  that  the  first  sound 
is  produced  by  the  contraction  of  the  ventricles,  and  that  the  second  is 
owino;  to  their  dilatation.'' 

Our  knowledge  of  the  causes  of  the  sounds  of  the  heart  is,  indeed, 
sufficiently  imprecise ;  as  is  farther  proved  by  the  circumstance,  that 
M.  Magendie  ascribed  the  first  sound  to  the  shock  or  impulsion  of  the 
apex  of  the  heart  during  its  diastole,  and  the  second  to  the  impulsion  of 
the  base  of  the  heart  during  its  systole;  but  the  results  of  more  recent 
experiments^  led  him  to  infer,  that  the  first  sound  is  owing  to  the 
contraction  of  the  ventricles,  and  the  impulse  of  the  apex  of  the  heart 
against  the  ribs;  and  the  second  to  a  similar  impulse  of  the  anterior 
part  of  the  heart,  produced  by  their  dilatation.  Dr.  Billing^  and  M. 
Eouanet^  ascribe  the  first  or  dull  sound  to  the  shock  or  impulse  of  the 
tricuspid  and  mitral  valves  against  the  auriculo- ventricular  orifices; 
and  the  second  or  clear  sound  to  the  succussion  of  the  blood  in  the  dis- 
tended aorta  and  pulmonary  artery  backwards  against  the  semilunar 
valves,  during  the  dilatation  of  the  ventricles;  and  a  similar  opinion  is 
entertained  by  Dr.  Hope  and  by  Messrs.  Mayo*  and  Bouillaud.^  In 
evidence  that  the  first  sound  is  due  to  the  tension  of  the  auriculo-ven- 
tricular  valves,  M.  Valentin^"  states,  that  if  a  portion  of  a  horse's  intes- 
tine tied  at  one  end  be  moderately  filled  with  water,  without  any 
admixture  of  air,  and  have  a  syringe  containing  water  adapted  to  the 
other  end,  the  first  sound  of  the  heart  will  be  exactly  represented  by 
forcing  more  water  in.  It  may  be  distinctly  heard  with  the  stethoscope 
applied  near  the  tied  extremity  of  the  intestine,  at  the  instant  the  water 
from  the  syringe  renders  it  tense.     Mr.  Carlisle^^  and  Dr.  Williams^^ 

'  System  der  Medicin.,  th.  i.  Auflage  2te,  s.  149,  Heidelb.,  1S35. 

2  Archiv.  General,  de  Med.,  Dec,  1835,  Janvier,  1839,  Juillet,  1841. 

^  Guide  du  Medecin  Praticien,  torn.  iii.  p.  34,  Paris,  1843. 

*  Revue  Medicale,  Oct.,  1831.  ^  Annales  des  Sciences  Naturelles,  1834.  . 

^  Lancet,  May  19,  1832.  See,  also,  First  Principles  of  Medicine,  5th  Eng.  edit.,  p.  xx., 
Lond.,  1849,or  2d  Amer.  edit.,  Philad.,1851 ;  and  Practical  Observations  ou  Diseases  of 
the  Lungs  and  Heart,  p.  11,  Lond.,  1852. 

'  Ibid.,  No.  xcvii. ;  and  Journal  Hebdomadaire,  Sept.,  1832. 

^  Outlines  of  Human  Pathology,  p.  465,  Lond.,  1836. 

9  Journal  Hebdomad.,  No.  ix.,  1834. 

'"  Lehrbuch  der  Physiologie  des  Menschen,  i.  427,  Braunschweig,  1844. 

"  Report  of  the  Third  Meeting  of  the  British  Association  for  the  Advancement  of 
Science;  and  Amer.  Journal  of  the  Med.  Sciences,  p.  477,  for  Feb.,  1835. 

'^  A  Rational  Exposition  of  the  Physical  Signs  of  Diseases  of  the  Lungs  and  Pleura, 
Amer.  edit.,  Philad.,  1830. 


IN  THE   HEART — SOUNDS.  395 

refer  tlie  first  sound,  with  Laennec,  to  the  systole  of  the  ventricles, 
and  the  second  to  the  obstacle  presented  by  the  semilunar  valves  to 
the  return  of  the  blood  from  the  arteries  into  the  heart, — and  Messrs. 
Corrigan,^  Pigeaux,^  Stokes,^  and  Mackintosh,"  think  the  first  sound 
is  owing  to  tlie  systole  of  the  venous  sinuses,  and  the  second  to  the 
systole  of  the  ventricles — an  opinion,  which  Burdach^  thinks  is  best 
founded,  but  which,  as  we  have  seen,  is  manifestly  erroneous. 

In  a  case  of  ectopia  cordis,  described  by  M.  Cruveilhier,^  a  distinct 
vibratory  thrill  was  perceived,  by  applying  the  finger  to  the  origin  of 
the  pulmonary  artery,  which  corresponded  with  the  ventricular  systole; 
but  no  such  thrill  could  be  felt  when  the  finger  was  applied  to  any  part 
of  the  base  of  the  ventricles.  He  inferred,  therefore,  that  the  first  sound 
cannot  be  dependent  upon  the  action  of  the  auriculo-ventricular  valves. 
The  greatest  intensity  of  the  first  sound  was,  indeed,  in  the  same  situ- 
ation as  the  greatest  intensity  of  the  second — that  is,  at  the  origin  of  the 
large  arteries.  Dr.  Carpenter'^  thinks  the  results  of  these  observations 
of  Cruveilliier  clearly  establish,  that  the  principal  cause  of  the  first 
sound  exists  at  the  entrances  to  the  arterial  trunks ;  and  it  does  not 
seem  to  him,  that  any  other  reason  can  be  assigned  for  it  than  the  pro- 
longed rush  of  blood  through  their  orifices,  and  the  throwing  back  of 
the  semilunar  valves,  which,  in  suddenly  flapping  down  again,  produce 
the  second  sound.  M.  Cruveilliier  states  it,  in  his  opinion,  to  be  a  uni- 
form occurrence,  that  disease  of  the  semilunar  valves  modifies  both 
sounds; — a  fact,  which  the  author  has  long  noticed.  Without  express- 
ing an  opinion  as  to  the  validity  of  M.  Cruveilhier's  conclusion  re- 
specting the  two  sounds  of  the  heart.  Dr.  Forbes  evidently  regards  it 
with  favour,  under  the  view  long  maintained  by  him,  that  although 
characteristically  difi:erent,  the  two  sounds  have  so  great  a  similarity, 
and  are  so  allied  in  time  and  place,  that  he  could  not  readily  bring 
his  mind  to  believe,  that  they  do  not  both  depend  upon  one  and  the 
same  cause  slightly  modified ;  or  at  least  on  the  different  play  of  the 
same  parts.^ 

Drs.  Pennock  and  Moore,^  who  agree  in  the  main  with  Dr.  Hope, 
found  the  first  sound,  the  impulse,  and  the  systole  of  the  ventricles  to 
be  synchronous ;  and  the  second  sound  to  be  synchronous  with  the 
diastole  of  the  ventricles.  The  first  sound,  they  suggest,  may  be  a 
combination  of  that  caused  by  the  contraction  of  the  ventricles,  the 
flapping  of  the  auriculo-ventricular  valves,  the  rush  of  blood  from  the 
ventricles,  and  the  sound  of  muscular  contraction.  In  four  of  their 
experiments,  when  the  heart  was  removed  from  the  body,  the  ventri- 
cles cut  open  and  emptied  of  their  contents,  and  the  auriculo-ventricular 
valves  elevated,  a  sound  resembling  the  first  was  still  heard,  which 

'  Dublin  Med.  Trans.,  vol.  i.,  New  Series. 

^  Bulletin  des  Sciences  Medicales,  par  Ferussac,  xxv.  272. 

^  Edinb.  Med.  and  Surg.  Journal,  vol.  xxxiv. 

*  Princi^jles  of  Pathology,  &.C.,  2d  Amer.  edit.,  ii.  6,  Pliilad.,  1837. 

^  Die  Physiologic  als  Erfahrungswissenschaft,  iv.  219,  Leipz.,  1832. 
^  Gazette  Med.  de  Paris,  7  Aout,  1841,  p.  535  ;  or  Brit,  and  For.  Med.  Review,  Oct. 
1841,  p.  535. 

^  Human  Physiology,  §  486,  Loud.,  1842,  and  5th  Amer.  edit.,  p.  477,  Philad.,  1853. 

*  Translation  of  Laennec,  4th  edit. ;  and  Brit,  and  For,  Med.  Review,  loc.  cit. 

*  Ox>.  citat. 


896  CIECULATION' 

they  attributed  chiefly  to  muscular  contraction.  The  second  sound 
they  referred  exclusively  to  the  closure  of  the  semilunar  valves  by  the 
refluent  blood  from  the  aorta  and  pulmonary  artery.  "  This,"  they 
remark,  "  is  proved  by  the  greater  intensity  of  this  sound  over  the 
aorta  than  elsewhere,  the  blood  having  a  strong  tendency  to  return 
through  the  valvular  opening;  by  the  greater  feebleness  of  the  sound 
over  the  pulmonary  artery,  which  is  short,  and  soon  distributes  its 
blood  through  the  lungs,  thus  producing  but  slight  impulse  upon  the 
valves  in  the  attempt  to  regurgitate;  by  the  disappearance  of  the  sound 
when  the  heart  becomes  congested  and  contracts  feebly;  and  finally, 
on  account  of  its  entire  extinction  when  the  valve  of  the  aorta  was 
elevated." 

The  main  results  of  the  experiments  of  Drs.  Pennock  and  Moore 
accord  closely  with  what  the  author  has  entertained  and  taught  on  this 
subject;  but  the  views  of  M.  Cruveilhier  are  well  worthy  of  attention. 
The  whole  matter  is  still  open  for  further  investigation.  A  case  of 
thoracic  ectopia  has  been  published  by  M.  Monod,^  in  which  the  maxi- 
mum intensity  of  the  first  sound  did  not  occur  at  the  base  of  the  ven- 
tricles, but  at  the  middle  of  their  fleshy  walls;  and  M.  Monod  thinks, 
that  it  was  caused  by  the  shock  of  the  walls  of  the  ventricles  against 
the  internal  fleshy  columns  at  the  moment  of  contraction.  As  to  the 
second  sound,  he  is  of  opinion,  that  it  was  owing  to  the  return  of  the 
wave  of  blood  against  the  semilunar  valves. 

The  mechanism  by  which  the  valves  of  the  heart  are  closed,  and  its 
sounds  produced,  has  been  subjected  to  fresh  investigation  by  Baum- 
garten,  and  subsequently  by  Hamernjk,^  and  others.  According  to 
them,  there  is,  during  the  systole  of  the  auricles,  very  little  regurgi- 
tation into  the  venous  trunks,  owing,  in  part,  to  an  arrangement  of 
circular  muscular  fibres  surrounding  their  openings  into  the  auricles, 
as  well  as  to  the  other  causes  generally  admitted.  The  auriculo-ven- 
tricular  valves — they  conceive — are  closed  by  the  counterpressure  of 
the  ventricular  blood,  such  counterpressure  being  suddenly  developed 
by  the  contraction  of  the  auricles.  The  cavities  of  the  auricles  and 
ventricles,  during  the  diastole  of  the  heart,  are  distended  by  the  contin- 
uous current  from  the  veins;  and  at  this  period  the  valves  are  floating 
in  the  blood  in  the  form  of  a  funnel.  The  object  of  the  auriculo-ven- 
tricular  systole  is  to  induce  such  a  degree  of  tension  in  the  contents  of 
the  Ventricles,  and  of  necessity  in  the  blood  surrounding  the  funnel- 
shaped  arrangement  of  the  valves,  as  to  cause  their  rapid  closure  and 
prevent  regurgitation.  Such  closure  is  not  due  to  the  contraction  of 
the  musculi  papillares,  but  is  much  facilitated  by  the  small  specific 
gravity  of  the  valves,  which  enables  them  to  float  on  the  surface  of  the 
blood.  The  mechanism,  by  which  the  valves  of  the  arteries  are  closed, 
is  similar  to  that  of  the  auriculo-ventricular  valves.  Immediately  on 
the  contraction  of  the  ventricles,  the  pressure  of  the  blood,  contained 
in  the  large  arterial  trunks,  acting  equally  in  all  directions,  produces 

'  Ballet,  del.  Academ.  Royale  de  Med.,  7  Fevrier,  1843;  cited  in  Edinb.  Med.  and 
Surg.  Journal,  July,  1843. 

^  Edinburgh  Monthly  Journal  for  .Tan.,  1840,  cited  from  Prager  Vierteljalirschrift, 
1847  and  3  848  ;  see  also  Schmidt's  Jahrbiicher,  No.  1,  S.  10,  Jahrgang  1848,  and  No.  5, 
S.  151,  Jahrgang  1849. 


IN   THE   HEART — SOUNDS. 


897 


tlie  closure  of  the  semilunar  valves, — their  complete  closure  occurring 
synchronously  with  the  end  of  the  ventricular  systole.  When  the 
diastole  of  the  ventricle  commences,  the  arterial  retraction  begins,  and 
the  refluent  blood  from  the  large  arteries  falls  on  the  valves  already 
closed,  and  causes  the  second  sound;  but  there  is  no  regurgitation,  as 
there  necessarily  would  be — M.  llamernjk  maintains — 'Were  t]]e  valve 
shut  out  by  the  returning  wave  of  blood.  The  first  sound,  according 
to  this  view,  is  occasioned  by  the  vibration  of  the  tense  auriculo-ven- 
tricular  valves,  caused  by  the  blood  forced  against  them  in  the  systole 
of  the  ventricles,  and  the  vibration  of  the  chordas  tendineie.  In  like 
manner,  the  second  sound  is  produced  by  the  impulse  of  the  blood  on 
tlie  semilunar  valves  already  shut,  and  not  by  their  closure,  as  usually 
supposed. 

The  following  table,  compiled  in  part  by  ISIM.  Barth  and  Roger,' — 
to  which  additions  have  been  made  by  M.  Berard^  and  the  author — 
affords  at  a  glance  the  discordant  opinions  entertained  by  observers  in 
regard  to  this  important  topic  of  physiology, — an  accurate  knowledge 
of  which  is  essential  to  the  correct  understanding:  of  cardiac  diseases. 


Laennec,' 

TCKNEE," 

corrigan,^ 
Makc  D'Espixe,^ 

PlGEAUX,' 

1830, 


PlGEAUX,^ 

1839, 


H0PE,9 

1831, 

Hope,'" 
1839, 

Billing,"  Ror- 

ANET,'^    AND 
Bi,CLAED,"* 


FIRST  SOUNB  CAUSED  BY 

Ventricular  contraction. 
Do. 

Sliock  of  the  blood  against  the 
ventricular  parietes  during 

the  diastole. 

Ventricular  contraction. 

Shock  of  the  blood  against  the 
ventricular  parietes  at  the 
moment  of  the  diastole. 

Friction  of  the  blood  against 
the  parietes  of  the  ventri- 
cles, the  orifices  and  parietes 
of  the  great  vessels,  at  the 
moment  of  the  systole. 

Molecular  collision  of  the  blood 
in  the  systole. 

Sound  of  tension  of  the  auricn- 
lo-ventricular  valves,  sound 
of  muscular  extension,  ro- 
tatory sound  in  the  systole. 

Clacking  of  the  auriculo-ven- 
tricular  valves  in  the  systole. 


SECOND  SOUND  CAUSED  BY 

Auricular  contraction. 

Shock  of  the  heart  falling  back 
upon  the  pericardium  during 
the  diastole. 

Reciprocal  shock  of  the  internal 
surface  of  the  opposite  pa- 
rietes of  the  ventricles  during 
the  systole. 

Ventiicular  dilatation. 

Shock  of  the  blood  against  the 
Ijarietes  of  the  aorta  and  pul- 
monary artery  at  the  moment 
of  the  systole. 
'  Friction  of  the  blood  against  the 
parietes  of  tlie  auricles,  the  au- 
riculo-ventricular  orifices,  and 
the  cavity  of  the  ventricles,  at 
the  moment  of  the  diastole. 
(  Molecular  collision  of  the  blood 
(       in  the  diastole. 

(Clacking  of  the  semilunar  valves 
in  the  diastole. 


Do. 


'  Traite  Pratique  d'Auscultation,  &c.,  2de  edit.,  p.  359,  Paris,  1844. 

^  Cours  de  Physiologic,  iii.  (5(57,  Paris,  1851. 

3  Auscultation  Mediate,  ii.  399,  Paris,  lS2(j. 

■»  Edinburgh  Medico-Chirurgical  Transactions,  iii.  205. 

^  Dublin  Medical  Transactions,  New  Series,  i.  151,  Dublin,  1830. 

®  Journ.  Hebdomad,  de  Med.,  iv.  115,  Paris,  1831. 

'  Ibid.,  iii.  238,  and  v.  187,  Paris,  1831. 

s  Traite  des  Maladies  du  Coeur,  p.  49,  Paris,  1839. 

^  A  Treatise  on  Diseases  of  the  Heart,  1st  edit.,  Lond.,  1831. 

'0  Ibid.,  3d  edit.,  Lond.,  1839  ;  or  2d  Amer.  edit.,  Philad.,  1846. 

"  Op.  cit. 

'2  Theses  de  Paris,  1832,  No.  252. 

'3  Traite  Elementuire  de  Physiologic,  p.  ISS,  Paris,  1855. 


398 


CIRCULATION 


PlOEEY,' 
PltDAGXEL,^ 

Carlisle,' 
Magexdie,* 

BCEDACH,'' 

bocillacd,^ 

Gexdrix,'' 
Ckcyeilhier,^ 

Skoda,' 

Beau,'" 

C.J.  B.Williams," 


DrBLiN 

COJIMITTEE,'^ 


FIRST  SOrXD  CAUSED  BY 

Friction  of  the  molecules  of  the 
blood  agaiust  each  other,  and 
against  the  parietes  of  the 
ventricles,  the  orifices,  and 
the  valves,  during  the  sys- 
tole of  the  left  ventricle. 

Contraction  of  the  left  ventri- 
cle. 

Irruption  of  the  blood  into  the 
arteries  during  the  systole. 

Shock  of  the  apex  of  the  heart 
agaiust  the  thorax  at  the 
moment  of  the  systole. 

Irruption  of  the  blood  into  the 
ventricles  containing  air  (.'') 
at  the  moment  of  the  con- 
traction of  the  auricles. 

Sudden  tension  (redrcssement) 
and  shock  of  the  opposed  sur- 
faces of  the  auriculo-ven- 
tricular  valves,  and  sudden 
depression  of  the  semilunar 
valves  during  the  systole. 

Vibrations  resulting  from  the 
collision  of  the  blood  in  the 
systole. 

Sudden  tension  (redressement) 
of  the  semilunar  valves  by 
the  systole. 

First  ventricidar  sound.  Shock 
of  the  blood  against  the  au- 
riculo-ventricular  valves ; 
impulsion  of  the  aj^ex  of  the 
heart  against  the  thorax. 

First  arterial  sound.  Shock  of 
the  blood  against  the  parie- 
tes of  the  aorta,  and  of  the 
pulmonary  artery  in  the 
systole. 

Shock  of  the  •wave  of  blood 
against  the  parietes  of  the 
ventricles  in  the  systole  of 
the  auricles. 

Muscular  contraction  of  the 
ventricles  during  the  sys- 
tole. 

Friction  of  the  blood  against 
the  parietes  of  the  ventri- 
cles, and  muscular  contrac- 
tion during  the  systole. 


SECOND  SOUND  CAUSED  BY 

Passage  of  the  blood  into  the 
right  cavities.  Into  what 
parts  ?     At  what  moment  ? 

Contraction  of  the  right  ventii- 

cle. 
Clacking  of  the  semilunar  valves 

iu  the  diastole. 
Shock  of  the  anterior  surface  of 

the  heart  at  the  moment  of 

the  diastole. 

Projection  of  the  blood  into  the 
arteries  containing  air  (?)  at 
the  moment  of  the  systole. 

Tension  {redressement)  of  the 
semilunar  valves,  and  shock 
of  their  opjwsed  surfaces,  and 
sudden  depression  of  the  au- 
riculo-ventricular  valves  at 
the  moment  of  the  diastole. 

Percussion  of  the  blood  against 
the  parietes  of  the  ventricles 
at  the  moment  of  the  diastole. 

Depression  of  these  valves  at 
the  moment  of  the  diastole. 

Second  ventricular  sound.  Shock 
of  the  column  of  blood  against 
the  parietes  of  the  ventricles 
in  the  diastole. 

Second  arterial  sou7id.  Retro- 
grade shock  of  the  column  of 
blood  upon  the  semilunar 
valves. 


Shock  of  the  column  of.  blood, 
arriving  by  the  veins  against 
the  parietes  of  the  auricles. 

Keturn  shock  of  the  columns  of 
blood  against  the  semilunar 
valves  during  the  diastole. 

Tension  of  the  semilunar  valves, 
and  return  shock  of  the  co- 
lumns of  blood  during  the 
diastole. 


'  Archives  Generales  de  Medecine,  2de  serie,  v.  245. 

2  L'Union  Medicale,  p.  588,  Paris,  1849. 

"'  Dublin  Journal  of  Medical  Science,  iv.  84,  Dublin,  1834. 

"■  Mem.  de  TAcad.  des  Sciences,  xiv.  155,  Paris,  1838. 

^  Die  Physiologic  als  Erfahrungswissenschaft,  iv.  219,  Leipzig,  1S32. 

«  Traite  Clinique  des  Maladies  du  Cceur,  i.  115. 

'  Le  ons  sur  les  Maladies  du  Coeur,  i.  54.  **  Gaz.  Medicale,  p.  497,  Paris,  1841. 

8  Medicinisch.  Jahrbiich.  des  Oester.  Staat.,  xxii.  227. 

'0  Archiv.  Gen.  de  M  'd.,  2de  sJrie,  ix.  389. 

"  Edinb.  Med.  and  Surg.  Journ.,  xxxii.  297,  and  xxxiii.  333.  See,  also,  his  Lectures 
on  the  Physiology  and  Diseases  of  the  Chest,  Amer.  edit.,  Philad.,  1839;  and  A  Prac- 
tical Treatise  on  the  Diseases  of  the  Respiratory  Organs,  edited  by  Dr.  Clymer,  p.  73, 
Philad.,  1845. 

'^  Dublin  Journal  of  Medical  Science,  viii.  154. 


IN   THE   HEAET — SOUNDS. 


399 


London 
Committee,' 


Pennock  and 

MOORE,^ 


Earth  and 

ROGER,^ 


Baumgarten  and 
Hamernjk* 


FIRST  SOUND  CAUSED  BY 

Sudden  muscular  tension  of 
the  ventricles  in  the  sys- 
tole, and  shock  of  the  heart 
against  the  thorax. 

Muscular  contraction  of  the 
ventricles  and  clacking  of 
the  auriculo-ventricular 
valves  during  the  systole. 

Contraction  of  the  ventricles  : 
shock  at  the  inferior  surface 
of  the  semilunar  valves,  and 
at  the  base  of  the  aortic 
and  pulmonary  columns  of 
blood ;  clacking  of  the  au- 
riculo-ventricular valves ; 
and  impulse  of  the  heart 
against  the  chest. 
C  The  vibration  of  the  tense 
auriculo-ventricular  valves 
acted  on  by  the  blood  sent 
against  them  during  the 
systole  of  the  ventricles,  and 
the  vibration  of  the  chordae 
tendineae. 


SECOND  SOUND  CAUSED  BY 

Sudden  occlusion  of  the  semi- 
lunar valves  by  the  arterial 
columns  of  blood. 

Occlusion  of  the  semilunar 
valves  by  the  return  shock  of 
the  arterial  columns  of  blood. 


Tension  of  the  semilunar  valves ; 
and  return  shock  of  the  blood 
on  their  concave  surface. 


The  impulse  of  the  blood  on  the 
semilunar  valves  already  shut, 
not  by  their  closure. 


It  has  been  a  question  with  physiologists,  whether  the  cavities  of  the 
heart  completely  empty  themselves  at  each  contraction.  Senac/  and 
Thomas  Bartholine,''  from  their  experiments,  were  long  ago  led  to 
answer  the  question  negatively.  On  the  other  hand,  Haller^  enter- 
tained an  opposite  opinion, — suggested,  he  remarks,  by  his  experi- 
ments; but,  perhaps,  notwithstanding  all  his  candour,  connected,  in 
some  manner,  with  his  doctrine  of  irritability,  which  could  not  easily 
admit  the  presence  of  an  irritant  in  a  cavity  that  had  ceased  to  con- 
tract. It  has  been  remarked  by  M.  Magendie,^  that  if  we  notice  the 
heart  of  a  living  animal,  whilst  it  is  in  a  state  of  action,  it  is  obvious, 
that  the  extent  of  the  contractions  cannot  have  the  effect  of  completely 
emptying  the  ventricles;  but  it  must,  at  the  same  time,  be  admitted, 
that  such  experiments  are  inconclusive,  inasmuch  as  they  exhibit  to 
us  the  action  of  the  organ  under  powerfully  deranging  influences,  and 
such  as  could  be  readily  conceived  to  modify  materially  the  extent  of 
the  contractions.  The  same  may  be  said  of  a  case  of  monstrous  foetus 
observed  by  Dr.  Thomas  K.  Mitchell.^  After  each  contraction  of  the 
ventricle  he  was  able  to  make  blood  pass  into  the  aorta.  If  the  heart 
of  a  frog  be  examined  by  cutting  out  the  lower  portion  of  the  sternum, 
owing  to  the  transparency  of  tlie  parietes  of  the  heart,  it  can  be  ob- 
served that  the  ventricle  completel}^  empties  itself  at  each  contraction; 
but  Dr.  Mitchell  is  decidedly  of  opinion,  that  the  frog  is  not  a  fit  sub- 
ject from  which  to  draw  a  conclusion,  and  agrees  with  Mr.  Carlisle, 
that  the  cavities  empty  themselves  more  completely  in  the  lower  order 
of  animals  than  in  the  higher.     These  observations,  however,  are  in- 

'  Lond.  Med.  Gaz.,  xix.  360.  ^  Am.  Joum.  of  the  Med.  Sci.,  xxv.  415. 

3  Op.  cit.  ■*  Op.  cit. 

^  Traiti  de  la  Structure  du  Coeur,  &c.,  2de  6dit.,  Paris,  1774. 

^  Dissertat.  de  Corde,  Hafn.,  1648. 

''  Element.  Physiol.,'  lib.  iv.  sect.  4,  §7,  Lausann.,  1757.         ^  Precis,  &c.,  torn.  ii. 

^  Dublin  Journal  of  Medical  Science,  Nov.,  1844,  p.  275. 


'400  CIRCULATION 

sufficient  to  prove,  that  whilst  an  animal  is  in  a  normal  condition,  the 
auricles  and  veutricles  are  not  emptied  of  their  contents  by  their  con- 
traction. 

The  objection  urged  against  the  opposite  view,  that  there  would 
always  be  stagnant  blood  in  the  cavities  of  the  heart,  is  not  valid.  The 
experiments  of  Venturi^  have  shown,  that  even  in  an  ordinary  hydraulic 
apparatus,  the  motion  of  a  stream  passing  through  a  vessel  of  water  is 
commuuicated  to  the  fluid  at  rest  in  the  vessel,  so  that  an  incessant 
change  is  produced. 

During  the  systole  of  the  heart,  the  organ  is  suddenly  carried  for- 
ward; and  although  it  appears  to  be  rendered  shorter,  its  point  or  apex 
is  generally  considered  to  strike  the  left  side  of  the  chest  opposite  the 
interval  between  the  fifth  and  seventh  true  ribs;  producing  what  is 
called  the  "beating  or  impulse  of  the  heart."  The  cause  of  this  phe- 
nomenon was,  at  one  period,  a  topic  of  warm  controversy.  Borelli,^ 
Wiuslow,  and  others,  affirmed,  that  it  was  owing  to  the  organ  being 
elongated  during  contraction;  but  to  this  it  was  replied  by  Bassuel,^ 
that  if  such  elongation  took  place,  the  tricuspid  and  mitral  valves,  kept 
down  by  the  columnte  carnea3,  could  not  possibly  close  the  openings 
between  the  corresponding  auricles  and  ventricles.  Experiments  by 
Drs.  Pennock  and  Moore"  exhibited  to  them,  that  the  expulsion  of  the 
blood  from  the  ventricles  was  effected  by  an  approximation  of  the  sides 
of  the  heart,  and  not  by  a  contraction  of  the  apex  towards  the  base ; 
and  that,  during  the  systole,  the  heart  performs  a  spiral  movement,  and 
becomes  elongated.  Senac^  ascribed  the  beating  of  the  heart  to  three 
causes,  and  his  views  have  been  adopted  by  most  physiologists: — 1,  to 
the  dilatation  of  the  auricles,  Avhich  occurs  during  the  contraction  of 
the  ventricles;  2,  to  the  dilatation  of  the  aorta  and  pulmonary  arteiy 
by  the  introduction  of  blood  sent  into  them  by  the  ventricles;  and  '6, 
to  the  straightening  of  the  arch  of  the  aorta,  owing  to  the  blood  being 
forced  against  it  by  the  contraction  of  the  left  ventricle.  Dr.  William 
Hunter®  considered  the  last  cause  quite  sufficient  to  explain  the  phe- 
nomenon, and  many  physiologists  have  assented  to  his  view. 

Sir  David  Barry^  instituted  some  experiments  upon  this  subject.  He 
opened  the  thorax  of  a  living  animal,  and  by  passing  his  hand  into  the 
cavity,  endeavoured  to  ascertain  the  actual  condition  of  the  heart  and 
great  vessels,  as  to  distension  and  relative  position.  He  performed 
seven  experiments  of  this  kind,  from  which  he  concluded,  that  the  vena 
cava  is  considerably  increased  in  size  during  inspiration,  which  he 
ascribes,  as  will  be  better  understood  hereafter,  to  the  partial  vacuum 
formed  in  the  chest.  He  supposes  that  the  force  exerted  by  the  venous 
blood  on  entering  the  heart,  in  consequence  of  the  expansion  of  the 
chest  and  the  great  vessels  behind  the  heart,  pushes  the  organ  forwards, 
and  thus  causes  it  to  strike  against  the  ribs.     Dr.  Corrigan  thinks, 

'  Sur  la  Communication  Laterale  du  Jlouvement  dans  les  Fluides,  Paris,  1798 ;    and 
Sir  C.  Bell,  Animal  Mechanics,  p.  35,  Library  of  Useful  Knowledge,  Lond.,  1829. 
^  De  Motu  Animalium,  Lugd.  Bat.,  1710.  ^  Magendie,  Precis,  &c.,  ii.  395. 

*  Med.  Examiner,  Nov.  2,  1839. 

*  Traite  de  la  Structure  du  Coeur,  &c.,  Paris,  1749. 

"  .John  Hunter,  Treatise  on  the  Blood,  p.  146,  Lond.,  1794. 

''  Exper.  Researches  on  the  Influence  of  Atuiosiiheric  Pressure  upon  the  Circulation, 
Lond.,  1826. 


IN   THE   HEART — IMPULSE.  401 

that  tlie  apex  of  the  heart  has  nothing  to  do  with  the  impulse.  He  is 
of  opinion  that  the  heart  acts  like  any  other  muscle, — that  as  soon  as 
the  ventricles  contract,  it  is  shortened  from  below  upwards,  and  by  this 
shortening  becomes  thickened  in  the  middle,  in  a  similar  manner  to  the 
thickening  of  the  belly  of  the  biceps  muscle,  which,  wlien  it  contracts, 
gives  rise  to  an  evident  impulse,  plainly  perceptible  to  the  hand  applied 
to  it;  and  that  in  like  manner  the  heart's  impulse  is  owing  to  the  body 
of  the  ventricles,  and  not  to  the  apex,  striking  against  the  ribs.  Dr. 
Corrigan's  view  is  considered  by  l)r.  T.  E.  Mitchell,'  to  be  confirmed 
by  the  phenomena  observed  by  him  on  a  foetus  born  with  the  left  side 
of  the  thorax  wanting;  and  in  which  the  action  of  the  heart  could  be 
closely  observed.  Drs.  Pennock  and  Moore,^  however,  in  their  experi- 
ments, found  that  the  impulse  was  synchronous  with  and  caused  by  the 
contraction  of  the  ventricles,  and  when  felt  externally,  arose  from 
the  striking  of  the  apex  against  the  thorax.  In  the  celebrated  case, 
too,  of  the  son  of  Yiscount  Montgomery,  detailed  by  Harvey,^  where 
there  was  an  opportunity  of  inspecting  the  movements  of  the  heart, 
it  was  particularly  observed,  "that  in  the  diastole  thef  organ  was  re- 
tracted and  withdrawn ;  whilst,  in  the  systole,  it  emerged  and  protruded ; 
and  the  systole  of  the  heart  took  place  at  the  moment  the  diastole  or 
pulse  in  the  wrist  was  perceived :  to  conclude,  the  heart  struck  the 
walls  of  the  chest,  and  became  prominent  at  the  time  it  bounded  up- 
wards and  underwent  contraction  on  itself."  To  show,  how^ever,  that 
this  apparently  simple  matter  cannot  be  considered  settled.  Professor 
Miiller''  thinks  that  great  uncertainty  rests  as  to  whether  the  impulse  is 
produced  during  the  contraction  or  the  dilatation  of  the  ventricles;  yet 
it  certainly  cannot  occur  during  the  first  stage  of  ventricular  diastole. 
In  proof,  however,  that  the  impulse  of  the  heart  is  dependent  on  the 
contraction  of  the  muscular  fibres  of  the  ventricles,  the  experiments  of 
Valentin*  may  be  cited.  He  cut  off  the  apex  of  the  heart  in  several 
cases,  so  that  the  resistance  of  the  blood  and  the  great  vessels,  and  the 
supposed  consequent  recoil,  were  prevented;  yet  the  tilting  movement 
was  observed  as  much  as  when  the  heart  was  entire.  It  has  even  been 
supposed  that  the  impulse  is  produced  by  the  blood  sent  into  the  ven- 
tricles by  the  contraction  of  the  auricles,  but  it  must  be  borne  in  mind, 
in  the  inquiry,  that  there  is  no  appreciable  interval  between  the  con- 
traction of  the  auricles,  and  that  of  the  ventricles;  and  that,  therefore, 
both  may  be  concerned.^ 

The  systole  of  the  heart  is  admitted  by  all  to  be  active.  Some  are 
disposed  to  think  the  diastole  passive, — that  is,  the  efi'ect  of  relaxation 
of  the  fibres,  or  the  cessation  of  contraction.  Pechlin,  Perrault,  Ham- 
berger,  d'Espine,  Alison,  and  numerous  others,  have  supported  an  oppo- 
site view; — affirming  that  direct  experiment  on  living  animals  shows, 
that  positive  eflbrt  is  exerted  at  the  time  of  the  dilatation  of  the  cavi- 

'  Dublin  Journal  of  Med.  Science,  Nov.,  1844,  p.  271.  ^  Op.  citat. 

^  The  works  of  William  Harvey,  M.  D.,  &c.,p.  384,  Sydenham  Society's  edit.,  Loud. 
1847. 

*  Handbuch,  u.  s.  w.,  Baly's  translation,  p.  175,  Lond.,  1838. 

'  Lehrbuch  der  Physiologie  des  Menschen,  i.  427. 

®  See,  in  favour  of  the  view,  that  the  impulse  is  attributable  to  the  diastole  of  the 
ventricle.  Hardy  and  Behier,  Pathologic  Interne,  i.  326,  Paris,  1844 ;  and  Dr.  A.  Stille, 
Amer.  Journ.  of  tlie  Medical  Sciences,  July,  1846,  p.  174. 
VOL.  I. — 2(5 


402  CIRCULATION 

ties; — a  view  confirmed  by  the  case  of  monstrosity  related  by  Dr. 
Eobinson,^  His  opinion  is,  that  the  force  of  the  diastole  was  in  that 
case  equal  to,  if  not  greater  than,  that  of  the  systole.  In  the  case,  too, 
observed  by  M.  Cruveilhier,  the  diastole  had  the  rapidity  and  energy 
of  a  very  active  movement,  overcoming  pressure  made  upon  the  heart, 
so  that  the  hand,  closed  upon  it  when  it  was  contracted,  was  opened  with 
violence.  It  has  been  suggested,  that  if  the  course  of  all  the  fibres 
composing  the  muscular  parietes  of  the  organ  were  better  known,  this 
apparent  anomaly  might,  perhaps,  be  as  easily  explained  as  in  the 
ordinar}^  case  of  antagonist  muscles.  It  is  probable,  however,  that  the 
active  force  exerted  in  the  dilatation  of  these  cavities  is  that  of  elasti- 
city ;  and  when  the  contraction  of  the  muscular  fibres  has  ceased,  this 
is  aroused  to  action,  and  promptly  restores  the  organ  to  its  previously 
dilated  condition.  According  to  this  view,  the  natural  state  would  be 
that  of  dilatation.  In  treating  of  this  subject.  Dr.  Carpenter^  suggests 
whether  there  may  not  exist  in  muscle  an  active  force  of  elongation, 
as  well  as  an  active  force  of  contraction,  arising  from  the  mutual  re- 
pulsion  of  particles  whose  mutual  attraction  is  the  occasioning  of  the 
shortening.p] 

The  cause  of  the  heart's  action  has  been  a  deeply  interesting  ques- 
tion to  the  physiologist,  and,  in  the  obscurity  of  the  subject,  has  given 
rise  to  many  and  warm  controversies.  From  the  first  moment  of  foetal 
existence,  at  which  the  organ  becomes  perceptible,  till  the  cessation  of 
vitality  it  continues  to  move.  By  many  of  the  ancients  this  was  sup- 
posed to  be  owing  to  an  inherent  pulsijic  virtue,'^  which  enabled  it  to 
contract  and  dilate  alternately, — a  mode  of  expression,  which,  in  the 
infanc}''  of  physical  science,  was  frequently  employed  to  cover  ignorance, 
and  has  been  properly  and  severely  castigated  by  Moliere : — 

"  Mihi  a  docto  doctore 
Domaudatur  causani  et  rationem  quare 
Opium  facit  dormire. 
A  quoi  respondeo  ; 
Quia  est  in  eo 
Virtus  clormitiva, 
Cujus  est  natura 
Seusus  assoupire." 

Le  Malade  Imaginaiee,  Intermede  iii. 

It  was  in  ridicule  of  the  same  failing  that  Swift  represented  the  action 
of  a  smokejack  to  be  depending  on  a  meat-roasting  power.''  Descartes* 
imagined  that  an  explosion  took  place  in  the  ventricles  as  sudden  as 
that  of  gunpowder.  With  equal  nescience,  the  phenomenon  was  as- 
cribed by  Yan  Ilelmont^  to  his  imaginary  archa^us ;  and  by  Stahl,' 
and  the  rest  of  the  aniniists,  to  the  anima^  soul  or  intelligent  principle, 
which  he  supposed  to  preside  over  all  the  mental  and  corporeal  phe- 
nomena. Stahl  was  one  of  the  first  that  attempted  any  rational  expla- 
nation of  the  heart's  action.     Its  muscular  tissue;  the  similarity  of  its 

'  Amer.  Journal  of  the  Medical  Sciences,  No.  xxii.,  Feb.,  1833. 

*  Principles  of  Human  Physiology,  Amer.  edit.,  page  24.9,  Philad.,  1855. 

*  Haller,  Elementa  Physiologise,  lib.  iv.  sect.  v.  §  1. 

«  Fletcher,  Rudiments  of  Physiology,  P.  ii.  a.,  p.  52,  Edinb.,  1836. 

5  Ti-act.  de  Homiue,  p.  1()7,  Amst.,  1677.         *  Ortus  Medicin.  &c.,  Amstel.,  1648. 

'  Theoria  vera  Medica,  Hal.,  1737. 


IN   THE   HEART.  403 

contractions  to  tliose  of  ordinary  muscles,  with  the  exception  of  their 
not  being  voluntary ;  the  fact  of  its  action  being  modified  by  the  pas- 
sions, &c.,  led  him  to  liken  its  movements  to  those  of  muscles.  He 
admitted,  that,  generally,  we  possess  neither  perception  of,  nor  power 
over,  its  motions;  but  he  affirmed,  that  habit  alone  had  rendered  them 
involuntary ;  in  the^  same  manner  as  certain  muscular  twitchings  or 
tics^  which  are  at  first  voluntary,  may  become  irresistible  by  habit.  A 
strong  confirmation  of  this  opinion  was  drawn  from  the  celebrated 
case  of  the  honourable  Colonel  Townshend,  (called  by  M.  Adelon^  and 
other  French  writers,  Captain  Towson,)  who.  was  able,  (not  all  his  life, 
as  Adelon  asserts,  but  a  short  time  before  his  death,)  to  suspend  the 
movements  of  his  heart  at  pleasure.  This  case  is  of  so  singular  a  cha- 
racter, in  a  physiological  as  well  as  pathological  point  of  view,  that  we 
shall  give  it  in  the  woi^ds  of  Dr.  George  Cheyne,^  one  of  tho  physicians 
who  attended  him,  and  whose  character  for  veracity  is  beyond  suspicion. 
"Colonel  Townshend,  a  gentleman  of  excellent  natural  parts,  and  of 
great  honour  and  integrity,  had,  for  many  years,  been  afilicted  with 
constant  vomitings,  which  had  made  his  lite  painful  and  miserable. 
During  the  whole  time  of  his  illness  he  had  observed  the  strictest  re- 
gimen, living  on  the  softest  vegetables  and  lightest  animal  food; 
drinking  asses'  milk  daily,  even  in  the  camp ;  and  foi'  common  drink 
Bristol  water,  which,  the  summer  before  his  death,  he  had  drunk  on 
'the  spot.  But  his  illness  increasing,  and  his  strength  decaying,  he 
came  from  Bristol  to  Bath  in  a  litter,  in  autumn,  and  lay  at  the  Bell 
Inn.  Dr.  Baynard,  who  is  since  dead,  and  I  were  called  to  him,  and 
attended  twice  a  day  for  about  the  space  of  a  week :  but,  his  vomit- 
ings continuing  still  incessant,  and  obstinate  against  all  remedies,  we 
despaired  of  his  recovery.  While  he  was  in  this  condition,  he  sent  for 
us  early  one  morning;  we  waited  on  him  with  Mr.  Skrine,  his  apo- 
thecary (since  dead  also);  we  found  his  senses  clear,  and  his  mind 
calm ;  his  nurse  and  several  servants  were  about  him.  Ue  had  made 
his  will  and  settled  his  aliairs.  He  told  us  he  had  sent  for  us  to  give 
him  some  account  of  an  odd  sensation  he  had  for  some  time  observed 
and  felt  in  himself,  which  was  that,  composing  himself,  he  could  die  or 
expire  when  he  pleased,  and  yet  by  an  effort,  or  somehow,  he  could 
come  to  life  again;  which  it  seems  he  had  sometimes  tried  before  he 
had  sent  for  us.  We  heard  this  with  surprise ;  but  as  it  was  not  to 
be  accounted  for  from  tried  common  principles,  we  could  hardly  be- 
lieve the  fact  as  he  related  it,  much  less  give  any  account  of  it ;  unless 
he  should  please  to  make  the  experiment  before  us,  which  we  were 
unwilling  he  should  do,  lest,  in  his  weak  condition,  he  might  carry  it 
too  far.  lie  continued  to  talk  very  distinctly  and  sensibly  above  a 
quarter  of  an  hour,  about  this  (to  him)  surprising  sensation,  and  in- 
sisted so  much  on  our  seeing  the  trial  made,  that  we  were  at  last 
forced  to  comply.  We  all  three  felt  his  pulse  first;  it  was  distinct, 
though  small  and  thready ;  and  his  heart  had  its  usual  beating.  He 
composed  himself  on  his  back,  and  lay  in  a  still  posture  some  time. 
While  I  held  his  right  hand,  Dr.  B.  laid  his  hand  on  his  heart,  and 

'  Physiol,  de  I'Homme,  edit,  cit.,  iii.  302. 

*  The  English  Malady,  or  Treatise  of  Nervous  Diseases,  p.  307,  Loud.,  1734. 


40-1  CIRCULATION 

Mr.  S.  held  a  clean  looking-glass  to  his  mouth.  I  found  his  pulse 
sink  gradually,  till  at  last  I  could  not  feel  any,  bj  the  most  exact  and 
nice  touch.  Dr.  Baynard  could  not  feel  the  least  motion  in  his  heart, 
nor  Mr.  Skrine  the  least  soil  of  breath  on  the  bright  mirror  he  held  to 
his  mouth.  Then  each  of  us,  by  turn,  examined  his  arm,  heart  and 
breath,  but  could  not  by  the  nicest  scrutiny  discover  the  least  symptom 
of  life  in  him.  We  reasoned  a  long  time  about  this  odd  appearance 
as  well  as  we  could;  and  all  of  us  judging  it  inexplicable  and  unac- 
countable; and  finding  he  still  continued  in  that  condition,  we  began 
to  conclude  indeed  that  he  had  carried  the  experiment  too  far,  and  at 
last  were  satisfied  that  he  was  actually  dead,  and  were  just  ready  to 
leave  him.  This  continued  about  half  an  hour,  by  nine  o'clock  in  the 
morning,  in  autumn.  As  we  were  going  away,  we  observed  some 
motion  about  the  body,  and  upon  examination  found  his  pulse  and 
the  motion  of  his  heart  gradually  returning;  he  began  to  breathe 
gently,  and  speak  softly ;  we  were  all  astonished,  to  the  last  degree, 
at  this  unexpected  change,  and  after  some  fuj'ther  conversation  with 
him,  and  among  ourselves,  went  away  fully  satisfied  as  to  all  the  par- 
ticulars of  this  fact,  but  confounded  and  puzzled,  and  not  able  to  form 
any  rational  scheme,  that  might  account  for  it.  He  afterwards  called 
for  his  attorney,  added  a  codicil  to  his  will,  settled  legacies  on  his  ser- 
vants, received  the  sacrament,  and  calmly  and  composedly  expired 
about  five  or  six  o'clock  that  evening." 

Dr.  Cleghorn,  of  Glasgow,  knew  an  individual  who  could  feign 
death,  and  had  so  completely  the  power  of  suspending,  or  at  least  of 
diminishing  the  action  of  the  heart,  that  its  pulsations  were  imper- 
ceptible; and  the  singular  cases  of  the  Fakeers,  of  India,  which  will 
be  referred  to  hereafter,  indicate — if  they  are  to  be  credited  at  all — that 
somatic  life  may  be  scarcely  or  not  at  all  distinguishable,  whilst 
molecular  life  may  persist;  as  is  witnessed  during  the  hibernation  of 
animals. 

It  is  manifest  that  these  cases — unaccountable  as  they  are,  in  many 
respects — can  add  no  weight  to  the  views  of  the  Stahlians.  They  are  as 
strange,  as  they  are  inexplicable.  The  opinion,  with  them, that  the  heart's 
action  is  a  muscular  function  was  accurate.  The  error  lay  in  placing 
it  amongst  the  voluntary  functions.  It  belongs  to  the  involuntary 
class,  equally  with  many  of  the  muscles  concerned  in  deglutition,  and 
those  of  the  stomach  and  intestines ;  and  how  well  is  it  for  us,  as  Sir 
Charles  Bell  has  remarked,  that  its  action  as  well  as  that  of  other 
organs  directly  instrumental  to  the  organic  functions  is  placed  out  of 
our  control!  "A  doubt — a  moment's  pause  of  irresolution — a  forget- 
fulness  of  a  single  action  at  its  appointed  time — would  otherwise  have 
terminated  our  existence." 

The  doctrine  of  Haller'  on  the  heart's  action  rested  upon  the  vis 
insita  or  irrilability  to  which  he  referred  all  muscular  contractions, 
voluntary  and  involuntary.  This  property,  as  stated  in  another  ])lace, 
he  conceived  to  be  possessed  by  muscles  as  muscles,  independently  of 
all  nervous  influence.  The  heart,  being  a  muscle,  enjoyed  it  of  neces- 
sity:   and  the  irritant,  which  incessantly  developed  it,  was  the  blood, 

'  Op.  citat. 


% 

IN   THE   HEART.  405 

In  evidence  of  this,  he  observes,  that  its  contractions  are  always  more 
forcible  and  rapid,  when  the  blood  is  more  abundant;  and  that  they 
occur  successively  in  the  cavities  of  the  heart  as  the  blood  reaches 
them.  So  wholly  did  Ilaller  assign  the  heart's  action  to  this  irritability, 
that  he  denied  the  nerves  any  influence  over  it;  resting  his  belief  on  the 
admitted  facts, — that  it  will  continue  to  beat  after  decapitation ;  after 
the  division  of  the  spinal  marrow  in  the  neck ;  and  of  the  nerves  dis- 
tributed to  the  organ ;  and,  even  after  it  has  been  entirely  removed 
from  the  body.  How  far  the  opinions  of  this  great  man  are  correct, 
respecting  the  power  of  contraction  residing  in  the  heart,  as  he  con- 
ceived it  to  do  in  other  muscles,  we  shall  inquire  presently.  It  is, 
doubtless,  indirectly  under  the  nervous  influence.  We  see  it  affected 
in  the  various  emotions;  sometimes  augmenting  violently,  at  others, 
retarding  its  action.  These  circumstances  have  led  some  to  adopt  a 
kind  of  intermediate  opinion,  and  to  regard  the  nervous  influence  as 
one  of  the  conditions  necessary  for  all  muscular  contraction,  just  as 
the  due  circulation  of  blood  is:  and  to  admit,  at  the  same  time,  the 
separate  existence  of  a  vis  insita.  Sommering^  and  Behrends^  have, 
indeed,  asserted  that  the  cardiac  nerves  are  not  distributed  to  the  tissue 
of  the  heart,  but  merely  to  the  ramifications  of  the  coronary  arteries ; 
and  hence,  that  these  nerves  are  not  concerned  in  the  motions  of  the 
organ,  but  only  in  its  nutrition:  but  this  special  distribution  is  denied 
by  Scarpa,-''  and  the  generality  of  anatomists. 

Although  the  emotions  manifestly  affect  the  heart,  direct  experi- 
ments exhibit  but  little  influence  over  it  on  the  part  of  the  nerves. 
This,  indeed,  we  have  seen,  is  one  of  the  grounds  for  the  doctrine  of 
Haller.  Willis''  divided  the  eighth  pair  of  nerves ;  yet  the  action  of 
the  heart  persisted  for  days.  Similar  results  followed  the  section  of 
the  great  sympathetic.  M.  Magendie^  states,  that  he  removed,  on 
several  occasions,  the  cervical  ganglions,  and  the  first  thoracic;  but 
was  unable  to  determine  anything  satisfactory  from  the  operation,  in 
consequence  of  the  immediate  death  of  the  animal  from  such  extensive 
injury.     He  observed,  however,  no  direct  influence  on  the  heart.^ 

We  have  numerous  examples  of  the  comparative  independence  of 
the  organ  as  regards  the  encephalon.  Decapitated  reptiles  have  lived 
for  months;  and  anencephalous  infants,  or  those  born  with  part  of  the 
brain  only,  have  vegetated  during  the  whole  period  of  pregnancy,  and 
for  some  days  after  birth.  M.  Legallois^  kept  several  decapitated  mam- 
malia alive ;  and  maintained  the  heart  in  action,  (having  taken  the 
precaution  to  tie  the  vessels  of  the  neck  for  the  purpose  of  preventing 
hemorrhage,)  by  employing  artificial  respiration,  so  as  to  keep  up  the 
conversion  of  venous  into  arterial  blood,  and  thus  insure  to  the  heart 
a  supply  of  its  appropriate  fluid.  We  find,  too,  that  in  fracture  of  the 
skull,  in  apoplexy,  and  congenerous  aftisctions,  the  functions  of  the 

'  Corpor.  Human.  Fabric,  iii.  §  32. 

^  Dissert,  qua  Demoustrat.  Cor  Nervis  Carere,  Mogunt.,  1792;  and  in  Ludwigii 
Script.  Neurol.  Min.,  i.  1. 

^  Tabulae  Neurologicae,  &c.,  Ticin.,  1794. 

*  Cerebri  Anat.,  cap.  xxiv.  in  Oper.,  Uenev.,  177G.  *  Precis,  &c.,  ii.  401. 

^  Brachet,  Physiologie  Elementaire  de  rHomme,  2de  edit.,  i.  142,  Paris  et  Lyon, 
1855.  >  '  1  J      , 

'  Sur  le  Principe  de  la  Vie,  p.  138. 


i 

406  CIRCULATION 

heart  are  the  last  to  be  arrested.  The  result  of  his  own  experiments 
led  Legallois  to  infer,  that  the  power  of  the  heart  is  altogether  derived 
from  the  spinal  marrow ;  and  he  conceived,  that  through  the  cardiac 
nerves  it  is  influenced  by  that  portion  of  the  cerebro-spinal  axis,  and 
is  liable  to  be  atfected  by  the  passions  because  the  spinal  marrow  is 
itself  influenced  by  the  brain.  Dr.  Wilson  Philip'  has,  however,  shown, 
that  the  facts  do  not  warrant  the  conclusions;  and  has  exhibited,  by 
direct  experiment,  that  the  brain  has  as  much  influence  as  the  spinal 
marrow  over  the  motions  of  the  heart,  when  the  circumstances  of  the 
experiment  are  precisely  the  same.  The  removal  of  the  spinal  marrow, 
like  that  of  the  brain,  if  the  experiment  be  performed  cautiously  and 
slowly,  does  not  sensibly  affect  the  motion  of  the  organ, — the  animal 
having  been  previously  deprived  of  sensibility.  In  these  experiments, 
the  circulation  ceased  quite  as  soon  without,  as  with,  the  destruction  of 
the  spinal  marrow.  Loss  of  blood  appeared  to  be  the  chief  cause  of 
its  cessation;  and  pain  would  have  contributed  to  the  same  effect,  if 
the  animal  had  been  operated  on,  without  having  been  previously  ren- 
dered insensible. 

Sir  Benjamin  Brodie'^  inferred,  from  his  experiments,  that  the  influ- 
ence of  the, brain  is  not  directly  necessarj^  to  the  action  of  the  heart; 
and  that  "  when  the  brain  is  injured  or  removed,  the  action  of  the 
heart  ceases  only  because  respiration  is  under  its  influence,  and  if  under 
these  circumstances  respiration  be  artificially  produced,  the  circulation 
will  still  continue."  Eespiration  is  however  only  indirectly  under  the 
influence  of  the  brain;  the  nervous  centre  of  that  function  being 
seated  in  the  medulla  oblongata. 

Mr.  Clift,^  the  former  conservator  of  the  Museum  of  the  Royal  Col- 
lege of  Surgeons  of  London,  made  a  series  of  experiments  to  ascertain 
the  influence  of  the  spinal  marrow  on  the  action  of  the  heart  in  fishes, 
and  found,  that  it  continues  long  after  the  brain  and  spinal  marrow  are 
destroyed,  and  still  longer  when  the  brain  is  removed  without  injury 
to  its  substance.  Similar  results  were  obtained  by  Treviranus  on  the 
frog,  and  by  Saviole  on  the  chick  in  ovo.  Zinn  and  Ent,  too,  found, 
that  after  the  destruction  of  the  cerebellum,  to  which  Willis  ascribed 
its  action,  it  continued  to  beat. 

All  these  facts  plainly  exhibit,  that,  although  the  heart  is  indirectly 
influenced  by  the  brain  or  spinal  marrow,  it  is  not  directly  acted  upon 
by  either  one  or  the  other,  and  that  its  action  can  be  maintained  for 
some  time  after  the  destruction  of  one  or  both,  provided  artificial 
respiration  be  kept  up;  and  even  this  is  unnecessary :  it  will  continue 
to  beat  after  it  has  been  removed  from  the  body.  Dr.  Dowler,  of  New 
Orleans,"*  saw  the  heart  of  the  alligator  beat  for  seven  hours  when  its 
"  annexing  vessels"  had  been  separated.  In  the  case  of  the  rattlesnake, 
Dr.  Harlan*  observed  it,  torn  from  the  body,  continue  its  contractions 
for  ten  or  twelve  hours;  and  in  the  monstrous  foetus,  described  by  Dr. 

'  An  Experimental  Inquiry  into  the  Laws  of  the  Vital  Functions,  &c.,  p.  62,  Lend., 
1817. 

*  Philosophical  Transactions  for  1811,  and  Physiological  Researches,  p.  15,  Lond., 
1851.  3  Philosoph.  Transact,  for  1S15. 

*  Contrihutions  to  Physiology,  p.  17,  New  Orleans,  1849. 

*  Medical  and  Physical  Researches,  p.  103,  Philad.,  1835. 


IN   THE   HEART.  407 

T.  Eobinson/  its  motion  continued  for  some  time  after  the  auricles  and 
ventricles  had  been  laid  open;  the  organ  roughly  handled,  and  thrown 
into  a  basin  of  cold  water.  "We  are  compelled,  then,  if  we  do  not 
admit  the  whole  of  the  Hallerian  doctrine  of  irritability,  to  presume, 
that  there  is  something  inherent  in  the  structure  of  the  heart,  which 
enables  it  to  contract  and  dilate,  when  appropriately  stimulated :  and 
it  is  not  even  necessary  that  this  should  be  by  the  fluid  to  which  it  is 
habituated.  It  is  certain,  that  the  organ,  when  separated  from  the 
body,  may  be  stimulated  to  contraction,  by  being  immersed  in  warm 
water,  or  pricked  with  a  sharp-pointed  instrument ;  yet  it  is  not  pos- 
sessed of  ordinary  sensibility.  In  Harvey's  celebrated  case,  before 
referred  to,  the  subject  of  Avhich  was  presented  to  Charles  IT.,  the  ven- 
tricles were  touched ;  and  "  his  most  excellent  majesty" — Harvey  loy- 
ally observes —  "as  well  as  myself  acknowledged  that  the  heart  was 
without  the  sense  of  touch;  for  the  youth  never  knew  when  we  touched 
his  heart,  except  by  the  sight  or  the  sensation  he  had  through  the 
external  integument,"^  A  similar  experiment  was  made  by  Eicherand 
on  a  physician  from  whom  he  had  removed  a  portion  of  the  pleura 
and  several  ribs.  In  a  case,  too,  of  ectopia  cordis  in  a  calf,  Hering  was 
able  to  knead  the  heart,  as  it  were,  {mcdaxer  le  cceur,)  without  occasion- 
ing any  apparent  uneasiness  to  the  animal,^ 

In  some  experiments  by  Sir  B,  Brodie,*  the  heart  was  emptied  of  its 
blood,  and  still  contracted  and  relaxed  alternately.  Similar  experi- 
ments were  instituted  by  Mr.  Mayo,^and  with  like  results, — from  which 
he  concludes,  that  the  alternations  of  contraction  and  relaxation  of  the 
heart  depend  upon  something  in  its  structure.  The  conclusion  seems, 
indeed,  irrefutable,  if  we  add  to  these  evidences  the  results  of  certain 
experiments  of  Dr.  J.  AViltbank,^  and  of  Dr.  J,  K,  Mitchell,  After  the 
brain  and  medulla  spinalis  of  the  Testudo  serpentana,  snaj^ping -turtle  or 
snapp)er  had  been  destroyed,  the  heart  continued  to  beat  for  thirty-two 
hours  and  upwards.  In  1823,  Dr,  Mitchell,^  being  engaged  in  dissect- 
ing a  sturgeon — Aapenser  hrevirostrum  ? — took  out  its  heart  and  laid  it 
on  the  ground.  After  a  time,  it  ceased  to  beat  and  was  inflated  with 
the  breath,  for  the  purpose  of  being  dried.  Hung  up  in  this  state,  it 
began  again  to  move,  and  continued  for  ten  hours  to  pulsate  regularly, 
though  more  and  more  slowly;  and  when  last  observed  in  motion,  the 
auricles  had  become  so  dry  as  to  rustle  when  they  contracted  and 
dilated.  He  subsequently  repeated  the  experiment  with  the  heart  of  a 
Testudo  serpentaria,  and  found  it  to  beat  well  under  the  influence  of 
oxygen,  hydrogen,  carbonic  acid,  and  nitrogen,  throAvn  into  it  in  suc- 
cession. Water  also  stimulated  it, — perhaps  more  strongly, — but  made 
its  sabstance  look  pale  and  hydropic,  and,  in  one  minvte,  destroyed  ac- 
tion beyond  recovery.     A  few  years  ago,  (1845,)  Dr.  ]\Iitchell  repeated 

'  Amer.  Journ.  of  the  Med.  Sciences,  No.  xxii.,  Feb.,  1833. 

*  The  Works  of  William  Harvey,  M.  D.,  Sydenham  Society's  edit.,  p.  384. 
'  Berard,  Cours  de  Physiologie,  iii.  652,  Paris,  1851. 

*  Cooke's  Treatise  on  Nervous  Diseases,  lutrod.,  p.  61,  Lond.,  1820-23,  Amer.  edit., 
Boston,  1824. 

^  Outlines  of  Human  Physiology,  4th  edit.,  p.  4G,  Lond.,  1837. 

*  The  Pliiladelphia  Journal  of  tlie  Medical  and  Physical  Sciences,  ix.  3G1  ;  Philad., 
1824. 

'  American  Journal  of  the  Medical  Sciences,  vii.  58,  Philad.,  1830. 


408  CIRCULATION 

the  experiment  with  the  sturgeon,  with  the  like  results ;  and  soon  after- 
wards, Dr.  F.  G.  Smith,  junior,'  experimented  on  the  hearts  of  the  stur- 
geon, frog,  and  snapping-turtle.  The  heart  of  one  sturgeon  contracted 
for  twenty-two  hours  after  its  removal  from  the  body;  of  another 
twelve  hours;  of  the  frog  thirteen  hours;  and  of  the  snapping-turtle 
25f  hours.  The  contractions  of  the  last  were  arrested  by  putting  the 
organ  in  Avarra  water  with  the  hope  of  increasing  them.  The  heart  of  a 
sturgeon  inflated  by  Dr.  Smith,  and  kindly  sent  by  him  to  the  author, 
hung  up  in  his  library  and  kept  moist,  contracted  and  dilated  for  up- 
wards of  twenty  hours. 

It  has  been  supposed,  that  when  the  heart  is  empty  of  blood,  the 
contact  of  air  with  its  cavities  is  the  stimulus  by  which  its  irritability  is 
excited,  but  Dr.  John  Keid^  found — as  Caldani,  Wernlein  and  Ktirsch- 
ner  had  already  done — when  he  placed  a  frog's  heart  in  a  state  of 
activity  under  the  receiver  of  an  air-pump,  that  its  action  still  continued 
after  the  receiver  had  been  exhausted.  Experiments,  however,  by  F. 
Tiedemann^  do  not  accord,  in  their  results,  with  those  of  Dr.  Reid;  but 
confirm  those  of  Fontana.  He  placed  the  heart,  immediately  after  it 
was  removed  from  a  living  frog,  under  the  receiver  of  an  air-pump, 
from  which  he  exhausted  the  air:  the  pulsations  of  the  heart  became 
weaker  and  slower,  and  in  thirty  seconds  ceased.  After  five  minutes, 
the  air  was  readmitted,  and  the  pulsations  were  resumed ;  and  this  alter- 
nation was  repeated  several  times;  whilst  another  heart  suspended  in 
air  continued  in  uninterrupted  action  for  an  hour.  These  experiments 
were  repeated  at  the  request  of  the  author  during  the  winter  of  1849-50, 
by  Drs.  S.  Weir  Mitchell,  and  T.  H.  Bache,  with  analogous  results. 
Whether  these  phenomena  indicate  that  some  change  is  produced  phy- 
sically in  the  organ  by  the  altered  density  of  the  air;  or  that  the  pre- 
sence of  oxygen  is  necessary  for  its  contraction  may  admit  of  a  ques- 
tion. Dr.  Brown -Sequard^  has  suggested  that  the  action  of  the  heart 
may  be  owing  to  the  presence  of  carbonic  acid  in  the  blood.  He 
admits,  however,  that  if  a  frog  be  put  under  a  receiver  containing  oxy- 
gen at  40°  or  50°  Fahr.,  after  its  nervous  centres  have  been  destroyed, 
its  heart  will  continue  to  beat  for  a  long  time;  whilst  if  it  be  placed  in 
carbonic  acid  at  the  same  temperature,  the  heart  will  beat  very  quickly 
at  first,  but  soon  cease.  CastelP  found,  from  numerous  observations 
on  the  duration  of  the  heart's  action  in  different  gases,  that  when  frogs 
were  placed  in  carbonic  acid  it  ceased  speedily,  or  in  about  six  minutes; 
whilst  in  moist  air,  it  continued  for  three  hours,  and  when  the  air  was 
exhausted,  the  pulsations  could  not  be  distinguished  after  ten  minutes. 

When  the  density  of  the  air  was  augmented  under  the  receiver,  M. 
Tiedemann  found,  that  the  pulsations  became  quicker  and  stronger. 

The  heart  is  the  a:enerator  of  one  of  the  forces  that  move  the  blood. 
This  force  has  been  the  subject  of  much  calculation,  but  the  results 
have  been  so  discordant  as  to  throw  discredit  upon  all  mathematical 

'Letter  to  the  author,  in  Philadelphia  Medical  Examiner,  for  July,  1845,  p.  o93. 
*  Cyclop,  of  Anat.  and  Physiol.,  ii.  611,  Lond.,  1839. 
'  Miiller's  Ai-chiv.  fiir  Aniitomie.  u.  s.  w.,  s.  490,  Berlin,  1847. 
•*  Experimental  Researche:?  applied  to  Physiology  and  Pathology,  "^evr  York,  1853. 
^  Miiller's  Archiv.,  1854,  s.  22'j  ;  and  Canstatt's  Jahresbericht,  1854,  Iter  Bd.,  s.151, 
Wiirzburg,  1855. 


IN   THE   HEART.  409 

investigations  on  living  organs;  a  circumstance,  whicli  renders  it  un- 
necessary to  state  the  different  plans  that  have  been  pursued  in  these 
estimations.  Many  of  them  are  given  in  the  elaborate  work  of  Haller,' 
to  which  the  reader,  who  may  be  desirous  of  examining  them,  is  referred. 
Borelli^  conceived  the  force  exerted  by  the  left  ventricle  to  be  equiva- 
lent to  180,000  pounds  ;  Senac^  to  40  ;  Hales^  to  51-5  pounds ;  Jurin* 
to  15  pounds  4  ounces;  whilst  KeilP  conceived  it  not  to  exceed  from 
5  to  8  ounces!  The  mode  adopted  by  Hales  has  always  been  regarded 
the  most  satisfactory.  By  inserting  a  glass  tube  into  the  carotid  of 
various  animals,  he  noticed  how  high  the  blood  rose  in  the  tube.  This 
he  found  to  be,  in  the  dog,  6  feet  8  inches ;  in  the  ram,  6  feet  5|  inches; 
in  the  horse,  9  feet  8  inches;  and  he  estimated  that  in  man  it  would 
rise  as  high  as  7|  feet.  Now,  a  tube,  whose  area  is  one  inch  square 
and  two  feet  long,  holds  nearly  a  pound  of  water.  AVe  may  therefore 
reckon  the  weight,  pressing  on  each  square  inch  of  the  ventricle, 
on  a  rough  estimate,  at  three  pounds  and  three-quarters,  or  four 
pounds;  and  if  we  consider  with  Michelotti,  the  surface  of  the  left  ven- 
tricle to  be  fifteen  square  inches,  it  will  exert  a  force,  during  its  con- 
traction, capable  of  raising  sixty  pounds.  Its  extent  is  more  frequently, 
however,  estimated  at  10  square  inches,  and  the  force  developed  would 
therefore,  be  forty  pounds;^  but  this  is,  of  course,  a  rude  approxima- 
tion. In  such  a  deranging  experiment,  the  force  of  the  heart  cannot 
fail  to  be  modified  ;  and  it  is  so  much  affected  by  age,  sex,  tempera- 
ment, idiosyncrasy,  &c.,  that  the  attainment  of  accurate  knowledge  on 
the  subject  is  impracticable.  The  indefinite  character  of  our  informa- 
tion on  this  matter  is  indeed  sufficiently  shown  by  the  investigations  of 
M.  Poiseuille,^  which  led  him  to  suppose,  that  the  force  with  which  the 
organ  propels  the  blood  into  the  human  aorta  is  about  4  pounds,  3 
ounces,  and  43  grains;  and  if  Valentin's  estimate  of  the  muscular  force 
of  the  right  ventricle  being  one-half  that  of  the  left  be  taken,  it  must 
propel  the  blood  into  the  lungs  with  a  force  only  equal  to  about  two 
pounds,  two  ounces. 

By  means  of  an  instrument,  which,  from  its  use,  he  terms  lice.raa- 
dyncmiomeier^  M.  Poiseuille  has  endeavoured  to  show,  that  the  blood 
is  urged  forward  with  as  great  a  momentum  in  a  small  artery,  far 
from  the  heart,  as  in  any  important  branch  near  it.  In  other  words, 
that  there  is  a  uniform  amount  of  pressure  exerted  by  the  blood  upon 
the  coats  of  the  arteries  in  every  part  of  the  body; — those  in  the  im- 
mediate vicinity  of  the  heart  being  distended  by  an  equal  force  with 
those  most  remote  from  it.  M.  Poiseuille^  n)ade  the  experiment  on  the 
carotid,  and  muscular  branch  of  the  thigh  of  the  horse,  and  notwith- 
standing the  very  great  dissimilarity  in  the  diameter  of  the  two  tubes, 
and  in  their  distance  from  the  heart,  the  displacement  of  the  mercury 

'  Elementa  Physiologic,  lib.  i.  sect.  iv.  §  42,  Latisann.,  1757. 
2  De  Motii  Aniuialium,  jjars  ii.,  Lugd.  Bat.,  1710. 

*  Traite  de  la  Structure  du  Coeur,  Paris,  1749. 
■»  Statical  Essays,  &c.,  ii.  40,  Lond.,  1733. 

*  Philosophical  Transactions  for  1718  and  1719. 
^  Tentamina  Medico-Ph,ysica,  &o.,  Lond.,  1718. 

7  Arnott's  Elements  of  Physics,  Amer.  edit.,  pp.  447  and  461,  Philad.,  1841. 

8  Magendie's  Journal  de  Physiologie,  x.  241. 
8  Ibid.,  ix.  46. 


410 


CIRCULATION 


Fig.  120. 


was  exactly  the  same  in  both.  This  inference,  if  correct, — and  the 
experiments  have  been  repeated  by  M.  Magendie'  and  others  with  cor- 
responding resnlts, — is  important  in  a  thera- 
peutical point  of  view,  as  it  leads  to  the  be- 
lief, that  if  it  be  desirable  to  lessen  the  quan- 
tity of  the  circulating  fluid,  it  is  of  little 
consequence  what  vessel  is  opened.  The 
experiments  of  Poiseuille  and  Magendie 
have  not,  however,  been  canfirmed  by  Volk- 
mann,  and  they  do  not  appear  to  be  in  ac- 
cordance with  obvious  hydrodynamic  facts.^ 
The  haemadynamometer  employed  by  M. 
Poiseuille,  consists  of  a  bent  glass  tube,  of 
the  form  represented  in  the  marginal  figure, 
filled  with  mercury  in  the  lower  bent  part, 
a,  (/,  e.  The  horizontal  part  b,  provided  with 
a  brass  head,  is  fitted  into  the  artery,  and  a 
small  quantity  of  a  solution  of  carbonate  of 
soda  is  interposed  between  the  mercury  and 
the  blood,  which  is  allowed  to  enter  the  tube 
with  the  view  of  preventing  coagidation. 
"When  the  blood  is  permitted  to  press  upon 
the  fluid  in  the  horizontal  limb,  the  rise  of 
the  mercury  towards  e,  measured  from  the 
level  to  which  it  has  fallen  towards  d,  gives 
the  pressure  under  which  the  blood  moves. 
Estimates  by  Valentin^  as  to  the  force  of 
the  heart  make  it  even  less  than  those  of  M. 
Poiseuille.  He  states,  that  in  man  and  thehio;her  mammalia,  the  abso- 
lute  force  exerted  by  the  left  ventricle  is  equal  to  g'oth  of  the  weight 
of  the  body;  and  that  by  the  right  ventricle  equal  to  j^^th  of  the 
same. 

During  the  diastole  of  the  ventricles,  the  pressure,  as  indicated  by 
the  instrument,  is  somewhat  diminished.  It  was  observed  by  Hales,** 
that  the  column  of  blood  in  a  tube  inserted  into  an  artery  fell  after 
each  pulsation.  The  pressure  must  obviously  be  augmented  or  dimin- 
ished by  anything  that  adds  to  or  detracts  from  the  heart's  action;  and 
it  will  be  seen  afterwards,  that  it  is  materially  modified  by  the  respira- 
tory movements.* 

b.   Circulation  in  the  Arteries. 

The  blood,  propelled  from  the  heart  by  the  series  of  actions  we  have 
described,  enters  the  two  great  bloodvessels; — the  pulmonary  artery 
from  the  right  ventricle,  and  the  aorta  from  the  left ;  the  former  of 
which  sends  it  to  the  lungs,  the  latter  to  every  part  of  the  system ;  and, 

'  Legons  sur  le  Sang,  &c.,  or  translation  in  Lond.  Lancet,  Sept.,  1638  to  March,  1839 ; 
and  in  Bell's  Select  Medical  Library,  p.  57,  Philad.,  1839. 

2  Todd  and  Bowman,  Tlie  Physiological  Anatomy  and  Physiology  of  Man,  Pt.  iv.  p. 
361,  Lond.,  1852,  or  Amer.  edit.,  Phifad.,  1853. 

3  Lehrbuch  der  Physiologie  des  Menschen,  i.  415,  Braunsch\yeig,  1844. 
••  Op.  cit.,  ii.  2. 

*  Ludwig,  in  Miiller's  Archiy.  fiir  Anatomie,  u.  s.  \y.,  Heft  iy.  s.  242,  Berlin,  1847. 


Haemadynamometer. 


IN   THE   AKTERIES.  411 

in  both  vessels,  it  is  prevented  from  returning  into  the  corresponding 
ventricles  by  the  depression  of  the  semilunar  valves.  We  have  now  to 
inquire  into  the  circumstances,  that  act  upon  it  in  the  arteries,  and 
whether  it  be  the  contraction  of  the  ventricle,  which  is  alone  concerned 
in  its  progression. 

Harvey'  and  all  the  mechanical  physiologists  regarded  the  arteries 
as  entirely  passive  in  the  circulation,  and  as  acting  like  so  many  lifeless 
tubes;  the  heart  being,  in  their  view,  the  sole  agent.  We  have,  how- 
ever, numerous  reasons  for  believing  that  the  arteries  are  concerned  to 
a  certain  degree  in  the  progression  of  the  blood.  If  we  open  a  large 
artery  in  a  living  animal,  the  blood  flows  in  distinct  pulses;  but  this 
effect  gi'adually  diminishes  as  the  artery  recedes  from  the  heart,  and 
ultimately  ceases  in  the  smallest  ramifications ; — seeming  to  show,  that 
the  force,  exerted  by  the  heart,  is  not  the  only  one  concerned.  It  is 
manifest,  too,  that  if  such  was  the  case,  the  blood  ought  to  flow  out  of 
the  aperture,  when  the  artery  is  opened,  at  intervals  coinciding  with 
the  contractions  of  the  organ;  and  that  during  the  diastole  of  the 
artery  no  blood  ought  to  issue..  This,  however,  is  not  the  case,  not- 
withstanding the  authority  of  Bichat  and  some  others  is  in  its  favour. 
The  flow  is  uninterrupted ;  but  in  jets  or  pulses,  coinciding  with  the 
contractions  of  the  ventricles.  Again,  if  two  ligatures  be  put  round 
an  arterial  trunk,  at  some  distance  from  each  other,  and  a  puncture  be 
made  between  the  ligatures,  the  blood  flows  with  a  jet, — indicating  that 
compression  is  exerted  upon  it ;  and  if  the  diameter  of  the  artery  be 
measured  with  a  pair  of  compasses,  before  and  after  puncturing  the 
vessel,  it  will  be  found  manifestly  smaller  in  the  latter  case  ; — an  ex- 
periment which  shows  the  fallacy  of  a  remark  of  Bichat, — that  the  force 
with  which  the  arteries  return  upon  themselves  is  insufficient  to  expel 
the  blood  they  contain.  An  experiment  of  M.  Magendie^  exhibits  this 
more  clearly.  He  exposed  the  crural  artery  and  vein  in  a  dog,  and 
passed  a  ligature  behind  the  vessels,  tying  it  strongly  at  the  posterior 
part  of  the  thigh,  so  that  the  blood  could  only  pass  to  the  limb  by  the 
artery,  and  return  by  the  vein.  He  then  measured,  with  a  pair  of 
compasses,  the  diameter  of  the  artery ;  and  on  pressing  the  vessel  be- 
tween his  fingers,  to  intercept  the  course  of  blood,  it  was  observed  to 
diminish  perceptibly  in  size  below  the  part  compressed,  and  to  empty 
itself  of  its  blood.  On  readmitting  the  blood,  by  removing  the  fingers, 
the  artery  became  gradually  distended  at  each  contraction  of  the  heart, 
and  resumed  its  previous  dimensions. 

These  facts  prove,  that  the  arteries  contract ;  but  the  kind  of  con- 
traction has  given  occasion  to  discussion.  Under  the  idea  that  their 
middle  coat  is  muscular,  it  was  conceived  formerly,  that  they  exert  a 
similar  action  on  the  blood  to  that  of  the  heart ;  dilating  to  receive  it 
from  that  organ,  and  contracting  to  propel  it  forwards ; — their  systole 
being  synchronous  with  that  of  the  auricles  and  the  diastole  of  the 
ventricles,  and  their  diastole  with  that  of  the  auricles  and  the  systole 
of  the  ventricles.  The  principal  reasons  urged  in  favour  of  this  view 
are ; — the  fact  of  the  circulation  being  effected  solely  by  the  arteries  in 

'  Exercitatio  Anat.  De  Motu  Cordis  et  Sanguinis,  &c.,  Rotterd.,  1G48. 
^  Journal  de  Physiologie,  i.  Ill  ;  and  Precis,  &c.,  ii.  386. 


412  CIRCULATION 

acardiac  foetuses,  and  iu  animals  that  have  no  heart; — the  assertion  of 
MM.  Lainure  and  Lafosse,  that  they  noticed,  in  an  experiment  on  the 
carotid  arterj'',  similar  to  that  described  above,  that  the  vessel  continued 
to  beat  between  the  ligatures; — the  affirmations  of  Verschuir,^  Bikker, 
Giulio,  and  Rossi,^  Thomson,^  Parry,''  Hastings,*  Wedemeyer,  and  nu- 
merous others,  that  when  they  irritated  arteries  with  the  point  of  a 
scalpel,  or  subjected  them  to  the  electrical  and  galvanic  influences, 
they  exhibited  manifest  contractility ;  and  lastly,  the  fact,  that  the 
pulse  is  not  perfectly  synchronous  in  different  parts  of  the  body, 
which  ought  to  be  the  case,  were  the  arteries  not  possessed  of  distinct 
action. 

The  chief  objection  to  the  views  founded  on  the  muscularity  of  the 
middle  coat  was  the  want  of  evidence  of  the  fact.  In  the  anatomical 
proem  to  the  function  of  the  circulation  it  was  stated,  that  this  coat 
had  not  seemed  to  anatomists  to  consist  of  fibrous  or  muscular  tissue ; 
and  that  the  experiments  of  MM.  Magendie,  Nysten,  and  others,  had 
not  been  able  to  exhibit  any  contraction,  on  the  application  to  it  of  the 
ordinary  excitants  of  muscular  irritability.  The  chemical  analyses  of 
Berzelius^  and  Young^  also  appeared  to  show,  that  the  transverse  fibres 
differ  essentially  from  those  of  proper  muscles.  It  has  been  suggested, 
however,  that  the  older  analyses  may  have  been  made  on  the  largest 
arteries  in  which  muscular  fibres  scarcely  exist  f  for  histologists — as 
elsewhere  shown — are  now  agreed,  that,  in  the  smaller  arteries,  more 
especially,  the  middle  coat  is  partly  composed  of  nonstriated  or  un- 
striped  muscular  tissue.  Moreover,  if  any  doubt  existed  in  regard  to 
the  contractile  action  of  the  smaller  arteries,  it  ought  to  be  removed  by 
the  experiments  of  MM.  E.  and  E.  H.  Weber,^  accurate  observers, 
which  were  made  with  the  rotating  magneto-electric  apparatus  upon 
the  arteries  of  the  mesentery  of  frogs  between  4th  and  y'^yth  of  a  Fans 
line  in  diameter.  When  vessels  between  these  dimensions  were  ex- 
posed to  the  electric  stream,  they  did  not  immediately  respond  to  the 
irritation ;  but  in  a  few  seconds  they  began  to  contract,  so  that  in  from 
five  to  ten  seconds  their  diameter  was  diminished  one-third.  If  the 
stimulus  was  continued,  the  diminution  of  size  went  on  until  the  dia- 
meter was  reduced  to  one-third  or  even  one-sixth  of  what  it  was  ori- 
ginally, so  that  only  a  single  row  of  blood-corpuscles  could  pass  along 
the  vessel,  and  at  last  became  completely  closed  unless  the  stimulus 
was  removed.  They  found,  however,  no  change  produced  in  tha 
capillaries  when  the  magneto-electric  current  was  applied  to  them; 
but  it  appeared  to  cause  an  unusual  adhesion  of  the  corpuscles  to  each 
other,  and  to  tlie  parietes  of  the  vessels,  and  a  consequent  stagnation 
of  the  circulating  fluid  in  them.     Nor  did  the  larger  arteries  exhibit 

'  De  Arteriar.  et  Venar.  Vi  Irritabili,  &c.,  Gri3ning.,  1766. 

2  Elemens  de  Medec.  Operat.,  Turin,  1806. 

3  Lectures  on  Inflammation,  p.  83,  Edinb.,  1813  ;  also,  2d  Amer.  edit.,  PliiLad.,  1831. 
*  On  tlie  Arterial  Pulse,  p.  52,  Bath,  1816. 

5  On  Inflammation  of  the  Mucous  Membrane  of  the  Lungs,  p.  20,  Lond.,  1820. 
s  View  of  the  Progress  of  Animal  Chemistry,  p.  25,  Loud.,  1813. 
"^  An  Introduction  to  Medical  Literature,  p.  501,  Lond.,  1813. 

8  Kirkes  and  Paget,  Manual  of  Physiology,  p.  91,  2d  Amer.  edit.,  Philad.,  1853. 

9  Miiller's  Archiv.  fiir  Anatomie,  u.  s.  w.,  H.  ii.  s.  232,  Jahrgang,  1847. 


IN   THE   AKTERIES. 


413 


any  signs   of  contraction  when    the   stream  was   directed   to   them. 
Similar  results  were  obtained  in  analogous  experiments  by  Kcilliker.^ 

If  an  artery  be  exposed  in  a  living  animal,  we  observe  none  of  that 
contraction  and  dihitation  which  is  perceptible  in  the  heart;  although 
a  manifest  pulsation  is  communicated  to  the  tinger  placed  over  it. 
The  phenomena  of  the  pulse  will  engage  attention  speedily.  We 
may  merely  remark,  at  present,  that  the  pulsations  are  manifestly 
more  dependent  upon  the  action  of  the  heart  than  upon  that  of  the 
arteries.  In  syncope,  they  entirely  cease ;  and  whilst  they  continue 
beneath  an  aneurismal  tumour,  because  the  continuity  of  the  vessel 
is  not  destroyed,  they  completely  cease  beneath  a  ligature  so  applied 
around  an  artery  as  to  cut  off'  the  flow  of  blood.  Bichat  attached  an 
inert  tube  to  the  carotid  artery  of  a  living  animal,  so  that  the  blood 
could  flow  through  it:  the  same  kind  of  pulsation  was  observed  in  it 
as  in  the  artery.  To  this  he  adapted  a  bag  of  gummed  taffeta,  so  as 
to  simulate  an  aneurismal  tumour :  the  pulsations  were  evidenced  in 
the  bag.  If,  again,  arterial  blood  be  passed  into  a  vein,  the  latter 
vessel,  which  has  ordinarily  no  pulsation,  begins  to  beat;  whilst,  if 
blood  from  a  vein  be  directed  into  an  artery,  the  latter  ceases  to  beat.^ 

Another  class  of  physiologists  have  reduced  the  whole  of  the  arte- 
rial action  to  simple  elasticity;  a  property,  which  the  yellow  tissue 
that  composes  the  proper  membrane  of  the  artery  seems  to  possess  in 
an  unusual  degree.  Such  is  the  opinion  of  M.  Magendie.'  "  Admit- 
ting it  to  be  certain,"  he  remarks,  "  that  contraction  and  dilatation 
occur  in  arteries,  I  am  far  from  thinking,  with  some  authors  of  the  last 
century,  that  they  dilate  of  themselves,  and  contract  in  the  manner  of 
muscular  fibres.  On  the  contrary,  I 
am  certain,  that  they  are  passive  in 
both  cases, — that  is,  that  their  dilata- 
tion and  contraction  are  the  simple 
effect  of  the  elasticity  of  their  parietes, 
put  in  action  by  the  blood,  which  the 
heart  sends  incessantly  into  their  ca- 
vity,"— and  he  farther  remarks,  that 
there  is  no  difference,  in  this  respect, 
between  the  large  and  small  arteries. 
As  regards  the  larger  arteries,  it  is  pro- 
bable that  this  elasticity  is  the  prin- 
cipal but  not  the  only  action  exerted  ; 
and  that  it  is  the  cause  why  the  blood 
flows  in  a  continuous,  though  pulsa- 
tory, stream,  when  an  opening  is  made 
into  them ;  thus  acting  like  the  reser- 
voir of  air  in  certain  pumps.  In  the 
pump  A  B,  represented  in  the  margi- 
nal figure,  were  there  no  air-vessel  C,  section  of  a  Forcing  Pump. 

'  Killliker  and  Siebold's  Zeitschrift,  1849  ;  and  Brit,  and  For.  Med.-Cliir.  Rev  July 
1850,  p.  241.  '       ^' 

^  Adelon,  art.  Circulation,  in  Diet,  de  M  decine,  lere  edit.,  v.  321,  Paris,  1822,  and 
Physiol,  de  I'Homme,  edit,  cit.,  iii.  380. 

^  Precis,  &c.,  edit,  cit.,  ii.  387 


Fig.  121. 


414  CIRCULATION 

tlie  water  would  flow  tlirougli  the  pipe  E  at  each  stroke  of  the  piston, 
but  the  stream  would  be  interrupted.  By  means  of  the  air-vessel  this 
is  remedied.  The  water,  at  each  stroke,  is  sent  into  the  vessel ;  the 
air  contained  in  the  air-vessel  is  thus  compressed,  and  its  elasticity 
thereby  augmented  ;  so  that  it  keeps  up  a  constant  pressure  on  the 
surface  of  the  water,  and  forces  it  out  of  the  vessel  through  the  pipe 
D  in  a  nearly  uniform  stream. — Now,  ia  the  heart,  tlie  contraction  of 
the  ventricle  acts  like  the  depression  of  the  piston ;  the  blood  is  pro- 
pelled into  the  artery  in  an  interrupted  manner,  but  the  elasticity  of 
the  bloodvessel  presses  upon  the  blood,  in  the  same  manner  as  the  air 
in  the  air-vessel  presses  upon  the  water  within  it;  and  the  blood  flows 
along  the  vessel  in  an  uninterrupted,  although  pulsatorj^,  stream.^ 
There  are  many  difficulties,  however,  in  the  way  of  admitting  the 
whole  of  the  action  of  the  arteries  in  the  circulation  to  be  dependent 
upon  simple  elasticity.  The  heart  of  a  salamander  was  opened  by 
Spallanzani  f  the  blood  continued  to  flow  through  the  vessels  for 
twelve  minutes  after  the  operation.  The  heart  of  a  tadpole  was  cut 
out ;  the  circulation  was  maintained  for  some  time  in  several  of  the 
vascular  ramifications  of  the  tail.  The  heart  of  the  chick  in  ovo  was 
destroyed  immediately  after  contraction;  the  arterial  blood  took  a 
retrograde  direction,  and  the  momentum  of  the  venous  blood  was  re- 
doubled. The  circulation  continued  in  this  manner  for  eighteen 
minutes.  Dr.  Wilson  Philip^  states,  that  he  distinctly  saw  the  circu- 
lation in  the  smaller  vessels,  for  some  time  after  the  heart  had  been 
removed  from  the  body,  and  a  similar  observation  was  made  by  Dr. 
Hastings."  The  last  gentleman  aflirms,  that  in  the  large  arterial 
trunks,  and  even  in  the  veins,  he  has  noticed,  in  the  clearest  manner, 
their  contraction  on  the  application  of  various  stimulants,  both  che- 
mical and  mechanical.  It  is,  moreover,  well  known,  that  if  a  small 
living  artery  be  cut  across,  it  soon  contracts  so  as  to  arrest  the  hemor- 
rhage ; — that  whilst  an  animal  is  bleeding  to  death  the  arteries  will 
accommodate  themselves  to  the  decreasing  quantity  of  blood  in  the 
vessels,  and  contract  beyond  the  degree  to  which  their  elasticity  could 
be  presumed  to  carry  them  ;  and  that  after  death  they  will  again  relax. 
Dr.  Parry  found,  that  an  artery  of  a  living  animal,  if  exposed  to  the 
air,  sometimes  contracts  in  a  few  minutes  to  a  great  extent ;  in  such 
case,  only  a  single  fibre  of  the  artery  may  be  aft'ected,  narrowing  the 
channel  in  the  same  way  as  if  a  thread  were  tied  round  it. 

The  experiments  that  have  been  instituted  for  the  purpose  of  disco- 
vering the  dependence  of  the  arterial  action  on  the  nervous  system 
have  likewise  afforded  evidences  of  their  capability  of  assuming  a  con- 
tractile action,  and  have  led  to  a  better  comprehension  of  cases  of  what 
have  been  called  local  detcrviinations  of  blood.  Dr.  Philip  found,  that 
the  motion  of  the  blood  in  the  capillaries  is  influenced  by  stimulants 

'  Haller,  Elmnenta  Physiologise,  ii.  212,  Lavisan.,  1760;  Hales.  Htemastatics,  p.  22, 
§  26,  Lond.,  1733  ;  Hunter  on  the  Blood,  by  J.  F.  Palmer,  Amer.  edit.,  p.  162,  Pliilad., 
1840 ;  Sir  C.  Bell,  Animal  Mechanics,  Library  of  Useful  Knowledge,  p.  44  ;  and  Todd 
and  Bowman,  The  Physiological  Anatomy  and  Physiology  of  Man,  Pt.  iv.  p.  352,  Loud., 
1852;  or  Amer.  edit.,'Philad.,  1853. 

'^  Experiments  on  the  Circulation,  &c.,  translated  by  R.  Hall,  Lond.,  1801. 

^  An  Experimental  hKiuiry  into  the  Laws  of  the  Vital  Functions,  Lond.,  1817  ;  and 
Lond.  Med.  Gazette,  for  March  25th,  1837,  p.  952.  «  Op.  citat.,  p.  51. 


IN   THE   ARTERIES.  415 

applied  to  the  central  parts  of  tte  nervous  system,  wliicli  must  be 
owing  to  these  vessels,  possessing  a  power  of  contractility,  capable  of 
being  aroused  to  action  by  the  nervous  influence.  The  experiments 
of  Sir  Everard  Home^  are,  however,  more  applicable,  as  they  were 
directed  to  the  larger  arteries,  respecting  which  the  greatest  doubts 
have  been  entertained.  The  carotid  artery  of  a  dog  was  laid  bare ; 
the  par  vagum  and  great  sympathetic,  which,  in  that  animal,  form  one 
bundle,  were  separated  from  it  by  a  flattened  probe  for  one-tenth  of 
an  inch  in  length ;  the  head  and  neck  of  the  dog  were  then  placed  in 
an  easy  position,  and  the  pulsations  of  the  carotid  artery  were  attended 
to  by  all  present  for  two  minutes,  in  order  that  the  eye  might  be 
accustomed  to  their  force  in  a  natural  state.  The  nerve  passing  over 
the  probe  was  then  slightly  touched  with  caustic  potassa.  In  a  minute 
and  a  half,  the  pulsations  of  the  exposed  artery  became  more  distinct. 
In  two  minutes,  the  beats  were  stronger;  in  four  minutes,  their  vio- 
lence was  lessened;  and  in  five  minutes  the  action  was  restored  to  its 
natural  state.  The  experiment  was  repeated  with  analogous  results 
upon  a  rabbit.  The  par  vagum  was  separated  from  the  intercostal 
nerve;  and  when  the  former  nerve  alone  was  irritated  no  increase  took 
place  in  the  force  of  the  action  of  the  artery.  "  The  carotid  artery," 
says  Sir  Everard,  "was  chosen  as  the  only  artery  in  the  body  of  suf- 
ficient size,  that  can  be  readily  exposed,  to  which  the  nervous  branches, 
supplying  it,  can  be  traced  from  their  trunk.  This  experiment  was 
repeated  three  different  times,  so  as  to  leave  no  doubts  respecting  the 
result." 

These  experiments  demonstrate,  that,  under  the  nervous  influence,  an 
increase  or  a  diminution  may  take  place  in  the  contraction  of  an  artery ; 
and  they  aid  us  in  the  explanation  of  cases,  in  which  the  circulation  has 
been  accomplished  where  the  heart  has  been  altogether  wanting  or  com- 
pletely defective  in  structure.  Sir  Everard  instituted  farther  experi- 
ments, with  the  view  of  determining  whether  heat  or  cold  has  the  greater 
agency  in  stimulating  the  nerves  to  produce  this  efiect  upon  the  artery. 
The  wrist  of  one  arm  was  surrounded  by  bladders  filled  with  ice ;  and 
after  it  had  remained  in  that  state  for  five  minutes,  the  pulse  of  the  two 
wrists  was  felt  at  the  same  time.  The  beats  in  that  which  had  been 
cooled  were  found  to  be  manifestly  stronger.  A  similar  experiment 
was  now  made  with  water,  heated  to  from  120°  to  130°  of  Fahrenheit. 
The  pulse  was  found  to  be  softer  and  feebler  in  the  heated  arm.  When 
one  wrist  was  cooled  and  the  other  heated,  the  stroke  of  the  pulse  of 
the  cooled  arm  had  much  greater  force  than  that  of  the  heated  one. 
These  experiments  were  re])eated  upon  the  wrists  of  several  young 
men  and  young  women  of  different  ages,  with  uniform  results. 

Lastly,  we  have  remarked,  and  shall  have  occasion  to  refer  to  the 
matter  again,  that  certain  animals,  that  have  no  heart,  have  circulating 
vessels  in  which  contraction  and  dilatation  arc  perceptible.  This  is 
the  case  with  the  class  vermes  of  Cuvier,  and  distinctly  so  in  the  lum- 
hricus  marmus  or  lug^  the  leech^  &c.  The  fact  has  been  invoked  both 
by  the  believers  in  the  muscular  contractility  of  arteries,  and  by  those 
who  conceive  the  contractility  to  be  peculiar;  but  our  acquaintance 

'  Lectures  on  Comparative  Anatomy,  iii.  57,  Lond.,  1823. 


416  CIRCULATIOIT 

wifh.  the  intimate  structure  of  tlie  coats  of  the  vessels  in  those  animals 
is  too  imperfect  for  us  to  assert  more  than  that  they  are  manifestly 
contractile.  In  an  interesting  case  of  acardiac  fcetus  examined  by  Br. 
Houston,  of  Dublin,  it  seemed  impossible  that  the  heart  of  a  twin  foetus 
could  have  occasioned  the  movement  of  blood  in  the  acardiac  one;  and 
hence  that  there  must  have  been  some  power  in  the  vessels  of  the  lat- 
ter— general,  or  capillary,  or  both — to  effect  the  circulation  through 
it.  In  most  or  all  of  these  cases,  however,  a  perfect  twin  foetus  exists, 
whoso  placenta  is  in  some  degree  united  with  that  of  the  imperfect 
one;  and  the  circulation  in  the  latter  has  usually  been  attributed  to 
the  influence  of  the  heart  of  the  former  propagated  through  the  pla- 
cental vessels. 

From  these  and  other  considerations,  the  majority  of  phj^siologists 
have  admitted  a  contractile  action,  in  perhaps  all  except  the  larger 
arterial  trunks ;  and,  at  the  present  day,  the  most  general  and  satis- 
factory opinion  appears  to  be,  that,  in  addition  to  the  highly  elastic 
property  possessed  by  the  middle  coat,  it  is  capable  of  being  thrown  into 
contraction  through  the  organic  muscular  fibres,  which  exist  in  greater 
quantity  in  the  small  arteries  than  in  the  large;  that,  consequently 
in  the  larger  vessels  this  contraction-* is  little  evidenced,  the  action  of 
the  artery  being  mainly  produced  by  its  elasticity;  but  that,  in  the 
smaller  arterial  ramifications,  the  contractility  is  more  manifest;  its 
great  object  being  to  regulate  the  quantity  of  blood  to  be  distributed 
to  a  part;  or  to  adjust  the  vessel  to  the  amount  of  fluid  circulating  in 
it.  To  this  contractility,  necessarily  connected  with  the  life  of  the 
vessel,  and  which  he  considered  to  differ  from  both  muscular  contrac- 
tility and  simple  elasticity,  Dr.  Parry^  gave  the  name  tonicity. 

c.   Ci)xuIatio)i  through  the  Capillaries. 

The  agency  of  the  capillary  vessels  in  the  circulation  has  been  a 
subject  of  contention.  The  opinion  of  Harvey,  embraced  by  J.  Miil- 
ler,^  was,  that  the  action  of  the  heart  alone  is  sufficient  to  send  the 
blood  through  the  whole  circuit ;  but  we  have  seen,  that,  even  when 
aided  by  the  elasticity  and  contractility  of  the  arterial  trunks,  the  pul- 
sations of  that  organ  become  imperceptible  in  the  smaller  arteries ;  and, 
hence,  there  is  some  show  of  reason  for  the  belief,  that  in  the  capillary 
vessels  the  force  may  be  entirely  spent.  Were  we,  indeed,  to  admit 
that  the  force  of  the  heart  is  sufficient  to  send  the  blood  through  a 
single  capillary  circulation,  it  would  be  difficult  to  admit  that  it  could 
send  it  through  two — as  in  the  portal  circulation.  Still,  we  can  by  no 
means  accord  with  Professor  Draper,^  of  New  York,  that  "  it  is  now 
on  all  hands  conceded,"  that  this  powerful  muscular  organ — the  heart — 
discharges  "  a  very  subsidiary  duty." 

Bichat  regarded  the  capillaries  as  organs  of  propulsion,  and  alone 
concerned  in  returning  the  blood  to  the  heart  through  the  veins.  Dr. 
Marshall  Hall,'*  on  the  other  hand,  denies,  that  we  have  any  proof  of 

'  On  the  Arterial  Pulse,  p.  52,  Bath,  1816. 

2  Handbuch,  u.  s.  w.,  Baly's  translation,  p.  220,  Lond.,  1838. 

3  A  Text-Book  on  Chemistry,  p.  392,  New  York,  184(J. 

*  A  Critical  and  Experimental  Essay  on  the  Circulation,  &c.,  p.  78,  Lond.,  1831, 
reprinted  in  this  country,  Philad.,  1835. 


IN   THE   CAPILLARIES.  417 

irritability  in  the  true  capillaries ;  and  Magendie^  conceives  the  con- 
traction of  the  heart  to  be  the  principal  cause  of  the  passage  of  the 
blood  through  those  vessels.  In  support  of  this  view  he  adduces  the 
following  experiment.  Having  passed  a  ligature  round  the  thigh  of  a 
dog,  so  as  not  to  compress  the  crural  artery  or  vein,  he  tied  the  latter 
near  the  groin,  and  made  a  small  opening  into  the  vessel.  The  blood 
immediately  issued  with  a  considerable  jet.  He  then  pressed  the 
artery  between  the  fingers,  so  as  to  prevent  the  arterial  blood  from 
passing  to  the  limb.  The  jet  of  venous  blood  did  not,  however,  stop. 
It  continued  for  some  moments,  but  went  on  diminishing,  and  the  flow 
was  arrested,  although  the  vein  was  filled  through  its  whole  extent. 
When  the  artery  was  examined  during  these  occurrences,  it  was  ob- 
served to  contract  gradually,  and  at  length  became  completely  empty 
when  the  course  of  the  blood  in  the  vein  ceased.  At  this  stage  of  the 
experiment,  the  compression  was  removed  from  the  artery;  the  blood 
immediately  passed  into  the  vessel,  and,  as  soon  as  it  had  reached  the 
final  divisions,  began  to  flow  again  through  the  opening  in  the  vein, 
and  the  jet  was  gradually  restored.  On  compressing  the  artery  again 
until  it  was  emptied,  and  afterwards  allowing  the  arterial  blood  to 
pass  slowly  along  the  vessel,  the  discharge  from  the  vein  took  place, 
but  without  any  jet:  the  jet  was  resumed,  however,  as  soon  as  the 
artery  was  entirely  free. 

This  experiment  is  not  so  convincing  to  us  as  it  appears  to  have 
been  to  M.  Magendie.  The  chief  fact,  which  it  exhibits,  is  the  elastic, 
and  probably  contractile,  power  of  the  arteries.  It  might  have  been 
expected,  a  priori.,  under  any  hypothesis,  that  the  quantity  of  blood 
discharged  from  the  vein  would  hold  a  i^atio  to  that  sent  by  the  artery; 
and,  consequently,  the  experiment  appears  to  us  to  bear  but  little  on 
the  question  regarding  the  separate  contractile  action  of  the  capillaries. 
It  is  difficult,  indeed,  to  believe  that  such  an  action  does  not  exist.  In 
addition  to  the  circumstance,  already  mentioned,  of  the  absence  of  pul- 
sation in  the  smaller  arteries,  almost  every  writer  on  the  theory  of  in- 
flammation has  considered  the  fact  of  a  distinct  action  of  the  capillaries 
established,  and  leaves  to  the  physiologist  the  by  no  means  easy  task 
of  proving  it.  Dr.  Wilson  Philip^  placed  the  web  of  a  frog's  foot 
under  the  microscope,  and  distinctly  saw  the  capillaries  contract  on  the 
application  of  those  stimulants  that  produce  contraction  of  the  mus- 
cular fibre.  The  results  of  Dr.  Thomson's^  experiments  in  investi- 
gating inflammation,  as  well  as  those  of  Dr.  Hastings,^  were  the  same. 
The  facts,  already  referred  to,  regarding  the  continuance  of  the  circu- 
lation in  the  minute  vessels  after  the  heart  had  been  removed,  as  well 
as  the  observation  of  Dr.  Philip,  that  the  blood  in  the  capillaries  is 
influenced  by  stimulants  applied  to  the  central  parts  of  the  nervous 
system,  are  confirmator}^  of  the  same  point.  The  experiments  of  Drs. 
Thomson,  Philip,  and  Hastings,  were  repeated  by  Wedemeyer,*  with 

'  Precis,  &c.,  ii.  390. 

^  A  Treatise  on  Febrile  Diseases,  3d  edit.,ii.  17,  London,  1813;  and  Medico-Cliirurg. 
Transact.,  vol.  xii.  p.  401. 

*  Lectures  on  Intiammation,  p.  83,  Edinb.,  1813.  ''  Op.  citat. 

^  Untersuch.  tiber  die  Kreislauf,  u.  s.  w.,  Hannover,  1828  ;  cited  in  Edinb.  Med.  and 
Surg.  Journ.,  vol.  xxxii. 
VOL.  I.— 27 


418  CIRCULATION 

great  care.  The  circulation  in  the  mesentery  of  the  frog,  and  in  the 
web  of  its  foot,  being  observed  through  the  microscope,  it  was  evident, 
that  no  change  occurred  in  the  diameter  of  the  small  arteries,  or  in 
that  of  the  capillaries,  so  long  as  the  circulation  was  allowed  to  go  on 
in  its  natural  state ;  but  as  soon  as  excitants  were  applied  to  them,  an 
alteration  of  their  calibre  was  perceptible.  Alcohol  arrested  the  flow 
of  blood  without  inducing  much  apparent  contraction  of  the  vessels. 
Chloride  of  sodium,  in  the  course  of  three  or  four  minutes,  caused  them 
to  contract  one-fifth  of  their  calibre,  which  was  followed  by  their  dila- 
tation, and  a  gradual  retardation  and  stoppage  of  the  blood.  In  a 
space  of  time  varying  from  ten  to  thirty  seconds,  and  sometimes  im- 
mediately after  the  application  of  the  galvanic  circle,  they  contracted, 
some  one-fourth,  others  one-half,  and  others  three-fourths  of  their 
calibre.  The  contraction  at  times  continued  for  a  considerable  period, 
occasionally  for  several  hours;  in  other  instances  it  ceased  in  ten 
minutes,  and  the  vessels  resumed  their  natural  diameter.  A  second 
application  of  galvanism  to  the  same  capillaries  seldom  caused  any 
material  contraction.  Schwann'  likewise  found,  that  when  cold  water 
was  poured  on  the  vessels  of  a  frog,  which  had  been  previously  in  a 
warm  atmosphere,  the  capillaries  immediately  contracted,  but  after  a 
time  regained  their  diameter.  Farther,  Mr.  Hunter^  found,  on  ex- 
posing arteries  to  the  air,  that  they  contracted  so  much  as  to  occasion 
obliteration  of  their  cavities;  and  it  is  well  known,  that  when  arteries — ■ 
as  the  temporal — are  divided,  the  hemorrhage  is  arrested  by  the  spon- 
taneous contraction  of  the  divided  vessel, — a  contraction,  which,  as 
remarked  by  Dr.  Carpenter,  is  much  greater  than  could  be  accounted 
for  by  simple  elasticity  of  tissue,  and  is  more  marked  in  small  than  in 
large  vessels.^ 

All  these  facts  prove  the  existence  of  a  vital  power  in  the  capillaries, 
capable  of  modifying,  to  a  considerable  extent,  the  flow  of  blood  through 
them. 

Again : — the  phenomena  of  local  inflammation  have  been  considered 
to  favour  this  view  of  an  independent  action  of  the  capillaries,  in  which 
there  may  be  increased  flow  or  retardation  of  the  blood  in  a  part, 
without  the  general  circulation  exhibiting  augmented  action  or  excite- 
ment. In  the  natural  state,  the  vessels  of  the  tunica  conjunctiva 
covering  the  white  of  the  eye  receive  little  blood  ;  but  if  any  cause  of 
irritation  exists,  as  a  grain  of  sand  entering  between  the  eyelids,  blood 
is  rapidly  sent  into  them,  giving  the  appearance  that  has  been  not 
inappropriately  termed  "  blood-shot.""'  In  the  experiments  of  Kalten- 
brunner,*  which  were  fully  confirmed  on  repetition,  the  blood  in 
inflammation  was  at  first  observed  streaming  to  the  irritated  part,  in 
consequence  of  which  the  capillary  vessels  became  distended ;  after- 
wards ii'regularity  of  circulation  occurred  in   the  gorged  capillary 

»  Miillers  Arcliiv.,  1836,  and  Lond.  Med.  Gazette,  May,  1837. 

*  A  Treatise  on  the  Blood,  luflammation,  and  Gunshot  Wounds,  Amer.  edit.,  ii.  156, 
Philad.,  1840. 

*  Principles  of  Human  Physiology,  Amer.  edit.,  p.  259,  Philad..  1855. 

*  Thomson's  Lectures  on  Inflammation,  Edinb.,  1813. 

*  Experimenta  circa  Statum  Sanguinis  et  Vasorum  in  Inflammatione,  p.  23,  Monach., 
1826. 


IN   THE   CAPILLARIES.  419 

system ;  and  subsequently  complete  arrest  of  the  flow,  and  disorgani- 
zation. These  phenomena  are  of  themselves  sufficient  to  prove  the 
existence  of  a  separate  action  of  the  capillaries,  and,  taken  in  con- 
junction with  other  facts,  are  overwhelming.  The  blush  of  modesty, 
and  the  paleness  of  guilt,  the  hectic  glow,  and  the  translucency  of 
congelation  are  circumstances  that  go  to  establish  the  same  point. 

The  contractile  power  of  the  capillaries  is  doubtless  modified  by  the 
condition  of  the  nerves  distributed  to  them,  which,  as  we  have  seen, 
are  observed  to  increase  as  the  size  of  the  vessels  and  the  thickness  of 
their  coats  diminish.  Their  influence  is  strikingly  evinced  in  actions, 
that  are  altogether  ne?vous,  as  in  the  flushed  countenance  occasioned 
by  sudden  mental  emotion.  By  some,  however,  the  whole  capillary 
circulation  has  been  ascribed  to  a  motive  faculty  inherent  in  the  cor- 
puscles of  the  blood;  whilst  others,  again,  have  asserted,  that  the 
"electro-galvanic  power," — or  in  other  words — the  nervous  power, 
generated  in  the  nervous  system,  and  acting  on  the  blood  corpuscles 
through  the  parietes  of  the  capillaries,  is  the  immediate  agent  that 
directs  the  circulation  in  the  capillaries.  All  this,  however,  enters 
into  the  inscrutable  question, — what  is  the  cause  of  life  in  the  tissues. — 
a  question  to  be  agitated,  but  not  solved,  in  a  subsequent  part  of  this 
volume. 

But,  not  only  has  a  vital  power  of  contraction  been  conceded  to  the 
capillaries;  it  has  been  imagined,  that  they  possess  what  the  Germans 
call  a  Lehenstnr  go r  {turgor  vilalis)  or  \itixl  property  of  expansi- 
bility or  turgescence.  Such  is  the  opinion  of  Hebenstreit'  and  of 
Prus  f  and  it  has  been  embraced,  in  this  country,  by  Professor  Smith 
of  Yale  College;  by  his  son.  Professor  N.  K.  Smith  of  Baltimore,  in 
his  excellent  work  on  the  "  Arteries,"^  and  by  Professor  Hodge,"  of 
Philadelphia.  The  idea  has  been  esteemed  to  be  confirmed  by  the  fact 
of  excitants  having  been  seen  under  the  microscope,  by  Hastings,  Wede- 
meyer,  and  others,  to  occasion  not  only  contraction  but  dilatation  of 
the  capillaries.  The  phenomena  observed  in  the  erectile  tissues  have 
likewise  been  considered  to  favour  the  hypothesis ;  but  in  answer  to 
these  arguments  it  may  be  replied,  that  the  irregular  excitation,  pro- 
duced in  the  parts  by  the  application  of  powerful  stimulants,  might 
readily  give  occasion  to  an  appearance  of  expansibility  under  the  mi- 
croscope, without  our  being  justified  in  inferring,  that  these  vessels  pos- 
sess an  innate  vital  property  of  expansibility;  and,  in  many  of  the  cases, 
in  which  ammonia  and  galvanism  were  applied  by  Thomson,  Hastings, 
Wedemeyer,  and  others,  the  action  of  contraction  ought  rather  to  be 
esteemed  physical  or  chemical  than  vital.  The  results  of  the  applica- 
tion of  such  excitants,  as  diluted  alcohol,  dilute  solutions  of  ammonia 
and  chloride  of  sodium,  can  alone  be  adduced  as  evidences  of  such  vital 
action  on  the  part  of  those  vessels.  The  dilatation  of  the  capillary 
system  and  of  the  smaller  arteries,  which  has  been  remarked  on  the 

'  Dissert,  de  Turgore  Vitali,  Lips.,  1795  ;  Hildebrandt's  Pliysiologie,  Auflag.  5,  § 
84;  and  Tiedemann's  Physiologie,  trad,  par  Jourdan,  p.  625,  Paris,  1831. 

*  De  rirritation,  &c.,  Paris,  1825. 

'  Surgical  Anatomy  of  the  Arteries,  2d  edit.,  Baltimore,  1835. 

*  North  Amer.  Med.  and  Surg.  Journal,  June,  1828. 


420  CIRCULATION" 

contact  of  those  agents,  is  not,  as  Oesterreicber^  has  remarked,  the 
primary  effect :  it  is  the  consequence  of  the  afllux  of  blood  to  the  irri- 
tated part,  as  was  demonstrated,  also,  in  the  experiments  of  Kalten- 
brunner  on  inflammation,  to  which  allusion  has  been  made.  Lastly, 
attentive  observation  of  the  phenomena  presented  by  the  erectile  tissues 
must  lead  to  the  conclusion,  that  turgescence  of  vessels  is  not  the 
first  link  in  the  chain  of  phenomena;  excitation  is  first  induced  in  the 
nerves  of  the  part, — generally  through  the  influence  of  the  brain,  and 
thence,  perhaps,  through  the  sympathetic  nerve, — and  the  afflux  of 
fluid  supervenes  on  this.  The  vital  expansibility  of  the  capillaries 
cannot,  we  think,  be  regarded  as  proved,  or  proSable. 

Professor  Draper,  of  New  York,  maintains,  that  the  great  agency  in 
the  circulation  of  the  blood  is  of  a  physical  character;  and  is  dependent 
upon  the  chemical  relations  of  that  fluid  to  the  tissues  with  which  it  is 
brought  in  contact.  On  the  principles  of  capillary  attraction — he  says 
— a  liquid  will  readily  flow  through  a  porous  body  for  which  it  has  a 
chemical  affinity ;  but  it  will  refuse  to  flow  through  it,  if  it  has  no 
affinity  for  it.  On  this  principle  he  explains  why  the  arterial  blood 
presses  the  venous  before  it  in  the  systemic  circulation,  and  why  the 
reverse  takes  place  in  the  pulmonic.  "The  systemic  circulation  takes 
place  because  arterial  blood  lias  a  high  affinity  for  the  tissues,  and 
venous  blood  little  or  none.  The  pulmonary  circulation  takes  place 
because  venous  blood  has  a  high  affinity  for  atmospheric  oxygen,  which 
it  finds  in  the  air  cells  of  the  lungs ;  and  arterial  blood  little  or  none. 
On  the  same  principle  we  may  explain  the  rise  of  sap  in  trees,  the  cir- 
culatory movements  in  the  different  animal  tribes,  and  the  minor 
circulations  of  the  human  system."^  Dr.  Dowler,^  of  New  Orleans, 
whilst  he  earnestly  combats  the  views  of  Professor  Draper,  is  a  strong 
advocate  for  the  distinct  action  of  the  capillary  vessels,  and  he  adduces 
a  number  of  striking  experiments  to  establish  his  position.  In  perhaps' 
one-fourth  of  the  dissections  which  he  records,  the  bodies  were  carried 
to  the  dissecting-room  a  few  minutes  after  death.  The  external  veins, 
chiefly  those  of  the  arms  and  neck,  sometimes  became  distended ;  and 
when  they  were  opened,  the  blood  often  flowed  in  a  good  stream,  and 
was,  at  times,  projected  to  the  distance  of  a  foot  or  more.  In  some 
cases,  by  putting  a  ligature  around  the  arm,  or  by  grasping  it  above  the 
elbow,  the  blood  was  made  to  flow  more  freely,  and  by  moving  the 
muscles,  as  is  done  in  ordinary  bloodletting,  the  blood  shot  forth  for 
some  distance.  Punctures  in  the  middle  of  the  subclavian  discharged 
blood,  which  arose  in  a  full  stream,  against  gravity,  two  or  three  inches; 
sometimes  forming  an  arch  as  it  fell.  The  coronary  veins  discharged 
blood  rapidly  and  "  with  surprising  force."  These  dissections  are  con- 
sidered by  Dr.  Dowler  to  show  conclusively  the  independent  action  of 
the  capillaries ;  "which  in  yellow  fever,  and  other  acute  fevers,  probably 
survives  respiration  and  the  heart's  action ;  and  when  it  ceases  cada- 
veric  hyperaemia  takes   place."     Such  is  doubtless  the  fact ;    but  it 

'  Versuch  einer  Darstellmig  der  Lelire  vom  Kreislaiif  des  Blutes,  Niirnberg,  1826. 

2  A  Text-Book  of  Chemistiy,  p.  392,  New  York,  lS4(i;  and  On  the  Forces  which  Pro- 
duce the  Organization  of  Plants,  chap.  iii. 

3  Researches,  Critical  and  Experimental,  on  the  Capillary  Circulation.  (Reprinted 
from  the  New  Orleans  Medical  and  Surgical  Journal.)     January,  1849. 


IN   THE   CAPILLAEIES. 


421 


Fig.  122. 


may  still  be  questioned,  whether  anything  more  than  the  physical 
capillarity  invoked  by  Professor  Draper  is  concerned  in  the  pheno- 
menon. In  a  case  observed  by  the  author,  and  referred  to  elsewhere, 
blood  flowed  freely  from  the  vessels  of  the  brain,  and  coagulated  fifteen 
hours  after  the  cessation  of  respiration  and  circulation ;  and  many 
similar  cases  are  on  record. 

The  circulation  through  the  capillaries  has  long  been  an  interesting 
topic  of  microscopic  research.     According  to  Wagner,^  a  magnifying 
power  of  from  two  to  three  hundred 
diameters  is  required  to  make  out  the 
particular    details.     The    blood    in 
mass,  or  in  the  larger  channels,  he 
says,  is  seen  to  flow  more  rapidly 
than  in  the  smaller.    Here  the  blood 
corpuscles  advance  with  great  rapid- 
ity, especially  in    the  arteries,  and 
with  a  whirling  motion,  and  form  a 
closely  crowded  stream  in  the  middle 
of  the  vessel,  without  ever  touching 
its  parietes.     With  a  little  attention, 
a  narrower  and  clearer,  but  always 
very  distinct  space  is  seen  to  remain 
between  the  great  middle  current  of 
blood  corpuscles  and  the  walls  of  the 
vessel,  in  which  a  few  white  corpus- 
cles, or  what  Wagner  considers  to 
be  lymph  corpuscles,  are  moved  on- 
wards, but  at  a  much  slower  rate. 
These    white    corpuscles    swim    in 
smaller  numbers  in  the  transparent 
liquor  sanguinis,  and  glide  slowly, 
and  in  general  smoothly,  though  they  sometimes  advance  by  fits  and 
starts  more  rapidly,  but  with  intervening  pauses ;  and,  as  a  general 
rule,  at  least  ten  or  twelve  times  more  slowly  than  the  corpuscles  of 
the  central  stream.     The  clear  space,  filled  with  liquor  sanguinis  and 
white  corpuscles,  is  obvious  in  all  the  larger  capillaries,  whether  arte- 
rial or  venous,  but  ceases  to  be  apparent  in  the  smaller  intermediate 
vessels  which  admit  but  one  or  two  rows  of  blood  corpuscles  (Fig.  102). 
In  these  vessels,  two  sets  of  corpuscles  proceed  pari  passu  ;  but,  accord- 
ing to  Wagner,  it  is  easy  to  see,  that  the  blood  corpuscles  glide  more 
readily  onwards, — the  white  corpuscles  seeming  often  to  be  detained  at 
the  bendings  of  vessels,  and  at  the  angles,  where  anastomosing  branches 
are  given  off;  here  they  remain  adherent  for  an  instant,  and  then  sud- 
denly proceed  onwards.     These  phenomena  are  observed  in  every  part 
of  the  peripheral  systemic  circulation;  but  an  exception  appears  to 
exist  in  the  pulmonic  circulation ;  the  capillaries  there  being  filled  with 
both  kinds  of  corpuscles  to  their  very  walls. 

It  is  in  this — the  intermediate — part  of  the  sanguiferous  system,  that 
most  important  functions  take  place.     In  the  smallest  artery  we  find 


Small  Venous  Branch,  from  the  Web  of  a 
Frog's  Foot,  magnified  350  diameters. 

6,  h.  Cells  of  pavement  epithelium,  containing 
nuclei.  In  the  space betwetm  the  current  of  oval 
blood  corpuscles,  and  the  walls  of  the  vessel,  the 
round  transparent  lymph  globules  (?)  are  seen. 


'  Elements  of  PLiysiology,  translated  by  R.  Willis,  §  122,  Lond.,  1842. 


422 


CIRCULATION" 


Fig.  123. 


Large  Vein  of  Frog's  Foot,  magnified  600  diameters. 

6,  c.  Blood  corpuscles,  a,  a.  Lymph  corpuscles  (?) 
principally  conspicuous  in  the  clear  space  near  the  pa- 
rietes  of  the  vessel. 


arterial  blood ;  and  in  the  smallest  vein  communicating  with  it  blood 
always  possessing  venous  properties.     Between  those  points,  a  change 

must  have  occurred,  the  reverse 
of  that  which  happens  in  the 
lungs.  It  is  here,  too — in  the 
tissues — that  nutrition,  secre- 
tion, and  calorification  are 
effected.  In  the  explanation 
of  these  functions,  we  shall 
find  it  impossible  not  to  sup- 
pose a  distinct  and  elective 
agency  in  the  tissues  concern- 
ed; and  as  it  is  by  such  agency, 
that  the  varying  activity  of 
the  different  functions  is  regu- 
lated, we  are  constrained  to 
believe,  that  the  capillary  ves- 
sels may  be  able  to  exert  a 
controlling  influence  over  the 
quantity  and  velocity  of  the 
blood  circulating  in  them.  In 
disease,  the  agency  of  this  sys- 
tem of  vessels  is  an  object  of 
attentive  study  with  the  patho- 
logist. To  its  influence  in  in- 
flammation we  have  already 
alluded ;  but  it  is  no  less  exemplified  in  the  more  general  diseases  of 
the  frame, — as  in  the  cold,  hot,  and  sweating  stages  of  an  intermittent. 
Local,  irregular  capillary  action  is,  indeed,  one  of  the  most  common 
causes  or  effects  of  acute  diseases,  and  this  generally  occurs  in  some 
organ  at  a  distance  from  the  seat  of  the  deranging  influence.  It  is  a 
common  and  just  observation,  that  getting  the  feet  wet,  and  sitting  in 
a  draught  of  air,  are  more  certain  causes  of  catarrh  than  sudden  atmo- 
spheric vicissitudes  that  apply  to  the  whole  body;  and  so  extensive  is 
the  sympathy  between  the  various  portions  of  the  system  of  nutrition, 
that  the  most  diversified  effects  are  produced  in  different  individuals 
exposed  to  the  same  common  cause ;  one  may  have  inflammatory  sore 
throat;  another,  ordinary  catarrh;  another,  inflammation  of  the  bowels; 
according  to  the  precise  predisposition,  existing  in  the  individual  at 
the  time,  to  have  one  structure  morbidly  affected  rather  than  another; 
— but  these  are  interesting  topics,  which  belong  more  strictly  to  the 
pathologist.' 

By  the  united  action,  then,  of  the  heart,  arteries,  and  capillary  or 
intermediate  system  of  vessels,  the  blood  attains  the  veins.  We  have 
now  to  consider  the  circulation  in  these  vessels. 

d.   Circulation  in  the  Veins. 

It  has  been  already  observed,  that  Harvey  considered  the  force  of 
the  heart  to  be  of  itself  sufficient  to  return  the  blood,  sent  from  the  left 

'  See,  on  the  Capillary  Circulation,  William  S.  Savory,  in  Brit,  and  For.  Med.-Chir, 
Rev.,  Jan.,  1855,  p.  390,  and  July,  1S55,  p.  12. 


^  IN    THE   VEINS.  423 

ventricle,  to  the  heart;  whilst  Bichat  conceived  the  whole  propulsorj 
effort  to  be  lost  in  the  capillaries,  and  the  transmission  of  the  blood 
along  the  veins  to  be  entirely  effected  by  the  agency  of  the  capillary 
system.  It  is  singular,  that  an  individual  of  such  distinguished  powers 
of  discrimination  should  have  been  led  into  an  error  of  this  magaitude. 
It  is  a  well-known  principle  in  hydrostatics,  that  although  water,  when 
unconfined,  can  never  rise  above  its  level  at  any  point,  and  can  never 
move  upwards ;  yet,  by  being  confined  in  pipes  or  close  channels  of 
any  kind,  it  will  rise  to  the  height  from  which  it  came.  Hence  the 
blood  in  the  right  auricle  would  stand  at  the  same  height  as  that  in  the 
left  ventricle, — were  they  inanimate  tubes.  We  need  be  at  no  loss, 
therefore,  in  understanding  how  the  blood  might  attain  the  right  auri- 
cle, when  the  body  is  erect,  by  this  hydrostatic  principle  alone ;  but 
we  have  seen,  that  the  force  exerted  by  the  heart,  arteries,  and  capil- 
lary system  is  superadded  to  this,  so  that  the  blood  would  rise  much 
higher  than  the  right  auricle,  and  consequently  exert  a  manifest  effort 
to  enter  it.  It  may  be  remarked,  also,  that  the  left  ventricle  is  not  the 
true  height  of  the  source,  but  the  top  of  the  arch  of  the  aorta,  which  is 
more  elevated  by  several  inches  than  the  right  auricle.  A  similar  view 
is  embraced  by  Dr.  Billing;^  but  Dr.  Carpenter^ — in  commenting  on 
the  author's  observations  on  this  subject — suggests,  that  the  influence 
of  this  hydrostatic  force  would  scarcely  be  felt  through  the  plexus  of 
capillary  vessels;  "for  the  interposition  of  a  system  of  tubes  even  of 
much  larger  calibre  would  be,  by  the  friction  created  between  the  fluid 
and  their  walls,  an  effectual  obstacle  to  the  rapid  ascent  of  a  current, 
which  had  so  slight  an  impetus  as  that  derived  from  its  previous  ffill." 
The  author  did  not  mean,  however,  to  say  more  than  that  the  blood 
"might  attain"  the  right  auricle  by  the  hydrostatic  force  alone;  he  did 
not  wish  to  convey  the  idea,  that  the  circulation  could  be  carried  on 
without  the  aid  of  an  additional  force ;  but  that  a  slight  effort  only  on 
the  part  of  the  heart,  arteries,  and  capillaries  might  be  needed  to  enable 
the  blood  to  perform  its  entire  circuit.  It  is  proper  to  add,  that  in  the 
last  editions  of  his  valuable  work,  Dr.  Carpenter  has  omitted  those 
comments  on  the  observations  of  the  author. 

Are  we  then  to  regard  the  veins  as  simple  elastic  tubes  ?  This  is 
the  prevalent  belief.  Their  elasticity  is,  however,  much  less  than  that 
of  the  arteries.  Some  physiologists  have  conceived  them  to  possess 
contractile  properties  also.  Such  is  the  opinion  of  M.  Broussais,^  who 
founds  it,  in  part,  upon  certain  experiments  by  M.  Sarlandiere,  already 
referred  to,  in  which  contraction  and  relaxation  of  the  vence  cavee  of 
the  frog  were  seen  for  many  minutes  after  the  heart  was  removed 
from  the  body.  These  pulsations  of  the  vena3  cavas,  and  of  the  pul- 
monary veins  in  their  natural  state,  have  been  seen  by  numerous 
observers — by  Steno,  Lower,  Wepfer,  Borrachius,  Whytt,  Haller, 
Lancisi,   MUller,   Marshall  Hall,  Flourens,  J.  J.  Allison,  and  others.* 

'  First  Principles  of  Medicine,  Amer.  edit.,  p.  36,  Philad.,  1842;  2d  Amer.  edit., 
Pliilad.,  1851. 

^  Human  Physiology,  §  516,  Lond.,  1842. 

3  Traite  de  Physiol.,  &c.,  translat.  by  Drs.  Bell  and  La  Roche,  p.  391,  Philad.,  1832. 

*  See  the  experiments  of  the  last  named  gentleman,  proving  the  existence  of  a  ve- 
nous pulse  independent  of  the  Heart  and  Nervous  System,  in  Amer.  Journal  of  the 
Medical  Sciences,  Feb.,  1839,  p.  306. 


424:  CIRCULATION. 

The  experiments  of  Dr.  Allison,  in  reference  to  tlie  veuas  cavas  and 
pulmonary  veins,  appeared  to  him  to  prove ; — that  they  pulsate  near 
the  heart  in  the  four  classes  of  the  vertebrata ; — that  in  dying  animals 
they  pulsate  long  after  the  auricle  and  ventricle  have  ceased ; — that 
they  also  beat  even  in  quadrupeds  for  hours  after  they  have  been 
separated  from  the  heart  and  from  the  body ; — and  that  they  can  be 
stimulated  to  contract,  either  in  or  out  of  the  body,  b}''  mechanical 
and  galvanic  agenc}^,  especially  by  the  latter,  after  all  motion  has 
ceased  for  some  time. 

Tt  has  been  deemed  doubtful,  however,  whether  the  veins  generally 
possess  any  contraction  like  that  of  the  venai  cava3  and  the  pulmonary 
veins  near  the  heart,  for  although  irritated  by  galvanic  and  mechanical 
stimuli  by  Haller,  Nysten,  Muller,  J.  J.  Allison,  and  others,  no  motion 
whatever  could  be  detected  in  them.  It  has  been  before  shown,  how- 
ever, that  non-striated  muscular  fibres  enter  into  their  composition,  and 
Gerber  affirms,  that  the  fibres  of  their  middle  coat  bear  a  stronger 
resemblance  to  those  of  muscular  tissue  than  do  those  of  the  corre- 
sponding coat  of  the  arteries,  which  more  resemble  ordinary  elastic 
fibres.  In  the  veins  of  the  bat's  wing  Mr.  Wharton  Jones'  observed 
rhythmical  contractions  and  dilatations,  and  that  the}'  were  provided 
with  valves,  some  of  which  completely,  and  others  only  partially, 
opposed  the  regurgitation  of  the  blood.  During  the  contraction  the 
flow  of  blood  in  the  vein  was  accelerated,  and  on  the  cessation  of  con- 
traction the  flow  was  checked,  and  there  was  a  tendency  to  regurgita- 
tion. The  action  of  the  heart  appeared  to  maintain  the  onward  flow 
of  blood  during  the  dilatation  of  the  vein,  whilst  the  contraction  of 
the  vein  was  added  to  the  action  of  the  heart,  and  occasioned  the 
acceleration. 

In  the  experiments  of  Dr.  Marshall  HalP  on  the  circulation  in  the 
web  of  the  frog's  foot,  he  was  almost  invariably  able  to  detect,  with  a 
good  microscope,  a  degree  of  pulsatory  acceleration  of  the  blood  in  the 
arteries  at  each  contraction  of  the  heart ;  and  he  is  disposed  to  con- 
clude, that  the  natural  circulation  is  rapid,  and  entirely  pulsatory  in 
the  minute  arteries,  and  slow  and  equable  in  the  capillary  and  venous 
systems.  But  whenever  the  circulation  was  in  the  slightest  degree 
impeded,  the  pulsatory  movement  became  very  manifest  at  each  sys- 
tole of  the  heart,  and  it  was  seen  in  all  the  three  systems — arterial, 
capillary,  and  venous.  He  observed,  that  in  the  arteries  there  was 
generally  an  alternate,  more  or  less  rapid  flow  of  the  corpuscles  at 
each  systole  and  diastole  of  the  ventricle ;  and  that  in  the  capillaries 
and  veins  the  blood  was  often  completely  arrested  during  the  diastole, 
and  again  propelled  by  a  pulsatory  movement  during  the  systole ; — 
all  which  he  esteems  conclusive  proof,  that  the  power  and  influence  of 
the  heart  extend  through  the  arteries  to  the  capillaries,  and  through 
these  to  the  veins,  even  in  the  extreme  parts  of  the  body.  The  ex- 
periments of  Valentin^  would  seem,  however,  to  show,  that  but  little 
of  the  force  of  the  left  ventricle  remains  to  propel  the  blood  in  the 
veins.     lie  found,  that  the  pressure  of  the  blood  in  the  jugular  vein 

'  Philosophical  Transactions,  1852,  p.  158. 

2  Essay  on  the  Circulation,  ch.  i..  Lend.,  1831,  and  Philad.,  1835. 

^  Lehrbuch  der  Physiologic  des  Menschen,  i.  477,  Braunschweig,  1844. 


FORCES   THAT   PROPEL   THE   BLOOD — SUCTION"   POWER,       425 

of  a  clog,  as  estimated  by  the  h^emadynamometer  of  Poiseuille,  was 
not  more  than  y'j- th  or  ^'oth  of  that  in  the  carotid  artery.  In  the  upper 
part  of  the  vena  cava  inferior,  he  could  scarcely  detect  any  pressure  ; 
almost  the  whole  force  of  the  heart  having  been  apparently  consumed 
during  the  passage  of  the  blood  through  the  capillaries  :^  still — as 
Messrs.  Kirkes  and  Paget^  suggest — slight  as  this  remanent  force 
might  be,  it  would  be  enough  to  complete  the  circulation,  inasmuch  as 
although  the  spontaneous  dilatation  of  the  auricles  and  ventricles  may 
not  be  forcible  enough  to  assist  the  movement  of  blood  in  them,  it  is 
adapted  to  present  no  obstacle  to  the  movement. 

That  the  veins  are  possessed  of  elasticity  is  proved  by  the  operation 
of  bloodletting,  in  which  a  part  of  the  jet,  on  puncturing  the  vein,  is 
owing  to  the  over-distended  vessel  returning  upon  itself;  but  that  this 
property  exists  to  a  trifling  extern  only  is  shown  by  the  varicose  state 
of  the  vessels,  which  is  so  frequently  seen  in  the  lower  extremities. 

e.  Forces  that  j^Topel  the  Blood. 

From  the  inquiry  into  the  agency  of  the  different  circulatory  organs 
in  propelling  the  blood,  it  is  manifest,  that  the  action  of  the  heart,  the 
elasticity  of  the  arteries,  and  a  certain  degree  of  contractile  action  in 
the  smaller  vessels  more  especially,  a  distinct  action  of  the  capillary 
vessels,  and  a  slight  elastic  and  perhaps  contractile  action  on  the  part 
of  the  veins,  may  be  esteemed  the  efficient  motors.  Of  these,  the 
action  of  the  heart  and  capillaries,  and  the  contraction  of  the  arteries 
and  veins,  can  alone  be  regarded  as  sources  of  motion,  the  elasticity  of 
the  vessels  being  simple  directors,  not  generators  of  force.  But  there 
is  another  agency,  which  is  probably  more  efficient  than  has  been 
generally  conceived.  This  is  the  suction  power  of  the  heart,  or  deriva- 
tion as  it  has  been  termed,  to  which  attention  has  been  chiefly  directed 
by  Haller,^  Wilson,^  Carson,*  Zugenbiihler,  Schubarth,  Platner,  Blu- 
menbach,^  and  others ;  but  which  is  not  assented  to  by  Oesterreicher,' 
Mliller,^  and  othei's.^  It  is  presumed,  that  the  muscular  fibres  of 
the  heart  are  mixed  up  with  a  large  quantity  of  areolar  tissue ;  and 
that  whilst  the  contraction  of  the  cavities  is  effected  by  the  action  of 
the  muscular  fibres,  dilatation  is  produced  by  the  relaxation  of  the 
contracted  fibres,  and  the  elasticity  of  the  areolar  tissue ;  so  that  when 
the  heart  has  contracted,  and  sent  its  blood  onwards,  its  elasticity 
instantly  restores  it  to  its  dilated  condition  ;  a  vacuum  is  formed,  and 
the  blood  rushes  in  to  fill  it.  This  action  has  been  compared  by  Dr. 
Bostock,^"  and  by  Dr.  Southwood  Smith,"  Prof.  Turner,'^  and  others,  to 

'  Magendie,  Lemons  sur  les  Phenomenes  Physiques  de  la  Vie,  iii.  152,  Paris,  1837. 
2  Manual  of  Physiology,  2d  Amer.  edit,,  p.  112,  Philad.,  1853. 
'  Elem.  Physiol.,  ii.  lib.  vi. 

*  Enquiry  into  the  Moving  Powers  employed  in  the  Circulation  of  the  Blood,  Lond., 
1784. 

^  Inquiry  into  the  Causes  of  the  Motion  of  the  Blood,  2d  edit.,  Lend.,  1833. 

*  Institutiones  Physiol ogicse,  §  12G,  Gotthig.,  1798. 
^  Lehre  vom  Kreislauf  des  Bhites,  Nlirnberg,  1826. 
®  Handbuch,  u.  s.  w.,  Baly's  translation,  p.  173. 

^  Burdach,  Physiologie  als  Erfahrungswissenschaft,  iv.  270,  Leipz.,  1832. 
'"  Physiology,  3d  edit.,  p.  251,  Lond. ^1830. 

"  Animal  Physiology,  (Library  of  Useful  Knowledge,)  j).  83,  Loud.,  1829. 
'^  Edinb.  Medico-Chirurg.  Transact,,  iii.  225. 


426  CIRCULATION. 

that  of  an  elastic  gum  bottle,  wliich,  when  filled  with  water,  and  com- 
pressed by  the  hand,  allows  the  fluid  to  be  driven  from  its  mouth  with 
a  velocity  proportionate  to  the  compressing  force ;  but  the  instant  the 
pressure  is  removed  elasticity  begins  to  operate,  and  if  the  mouth  of 
the  bottle  be  now  immersed  in  water,  a  considerable  quantity  of  that 
fluid  will  be  drawn  up  into  the  bottle,  in  consequence  of  the  vacuum 
formed  within  it.  This  power  of  elasticity  in  the  tissues  composing 
the  parietes  of  the  heart  is  the  only  one  whose  existence  has  been  ad- 
mitted as  concerned  in  the  phenomenon.  Dr.  Carpenter,'  however — 
as  before  remarked — has  suggested,  whether  there  may  not  exist  in 
muscle  an  active  force  of  elongation,  as  well  as  an  active  force  of  con- 
traction— arising  from  the  mutual  repulsion  of  particles  whose  natural 
contraction  is  the  occasion  of  the  shortening.  The  suggestion — it  need 
scarcely  be  said — is  altogether  hypothetical. 

The  existence  of  this  force  is  confirmed  by  Dollinger,^ — who,  when 
examining  the  embryos  of  birds,  saw  the  blood  advance  along  the  veins, 
and  the  venous  trunks  pour  it  into  the  auricles  at  the  moment  they 
dilated  to  receive  it;  as  well  as  by  Dr.  T.  Robinson,^  and  M.  Cruveil- 
hier,"  who  were  forcibly  struck  with  the  activity  with  which  the  diastole 
was  effected,  in  the  cases  of  monstrosity  more  than  once  referred  to. 
Dr.  Carpenter*  thinks  it  very  doubtful  "how  far  the  auricles  have 
such  a  power  of  active  dilatation  as  would  be  required  for  this  purpose;" 
but  the  question  need  not  regard  the  auricles.  It  is  but  necessary  to 
suppose,  that  an  action  or  power  of  dilatation  exists  in  the  ventricles; 
and  this  is  now  generally  admitted.  He  farther  remarks,  that  it  has 
been  shown  experimentally  by  Dr.  Arnott  and  others,  that  no  suction 
power  exerted  at  the  farther  end  of  a  long  tube,  whose  walls  are  as 
deficient  in  firmness  as  those  of  the  veins  are,  can  occasion  any  accele- 
ration in  a  current  of  fluid  transmitted  through  it;  for  the  effect  of  the 
suction  is  destroyed  at  no  great  distance  from  the  point  at  which  it  is 
applied  by  the  flapping  together  of  the  sides  of  the  vessel ;  but  in 
answer  to  this  it  may  be  observed,  that  it  remains  to  be  shown,  that 
such  flapping  of  the  sides  would  necessarily  occur  in  the  veins,  which 
are  living  vessels,  and  constantly  receiving  blood  from  the  capillaries 
under  the  action  of  vital  forces. 

Another  accessory  force,  that  has  been  invoked,  is  the  suction  power 
of  the  chest  or  inspiration  of  venous  blood,  as  it  has  been  termed. 
This  is  conceived  to  be  effected  by  the  same  mechanism  as  that  which 
draws  air  into  the  chest.  The  chest  is  dilated  during  inspiration;  an 
approach  to  a  vacuum  occurs  in  it;  and  the  blood,  as  well  as  the  air, 
is  forcibly  drawn  towards  that  cavity.  On  the  other  hand,  during  ex- 
piration, all  the  thoracic  viscera  are  compressed ;  the  venous  blood  is 
repelled  from  the  chest,  and  the  arterial  blood  reaches  its  destination 
with  greater  celerity,  owing  to  the  action  of  the  expiratory  muscles 

'  Principles  of  Human  Physiology,  Anier.  edit.,  p.  249,  (note),  Philad.,  1855. 

*  Denkschriften  der  Kiinigl.  Akademie  der  Wisseuschaft.  zu  Miinchen,  vii.  217;  and 
Burdacli,  op.  citat.,  p.  272. 

^  American  Journal  of  the  Medical  Sciences,  No.  xxii. 

*  Gazette  Medicale  de  Paris,  7  Aout,  1841,  p.  535 ;  cited  in  Brit,  and  Foreign  Medical 
Review,  Oct.,  1841,  p.  535. 

s  Ibid.,  p.  270. 


FOKCES   THAT   PROPEL   THE   BLOOD — RESPIRATION.        427 

being  added  to  that  of  the  left  ventricle.  Haller,^  Lamure,^  and  Lorrj,* 
had  observed,  that  the  blood  in  the  external  jugular  vein  moves  under 
manifestly  different  influences  during  inspiration  and  expiration.  Gene- 
rally, when  the  chest  is  dilated  in  inspiration,  the  vein  empties  itself 
briskly ;  becomes  flat,  and  its  sides  are  occasionally  accurately  applied 
against  each  other; — but  during  expiration  it  rises,  and  becomes  filled 
with  blood; — effects,  which  are  more  evident,  when  the  respiratory 
movements  are  extensive.  The  explanation  of  this  phenomenon  by 
Haller  and  Lorry  is  the  one  given  above. 

To  discover  whether  the  same  thing  happens  to  the  venaB  cav£e,  M. 
Magendie  introduced  a  gum  elastic  catheter  into  the  jugular  vein,  so  as 
to  penetrate  the  vena  cava  and  even  the  right  auricle : — the  blood  was 
observed  to  flow  from  the  extremity  of  the  tube  at  the  time  of  expira- 
tion only.  During  inspiration,  air  was  rapidly  drawn  into  the  heart, 
giving  rise  to  the  symptoms,  elsewhere  mentioned,  which  attend  the 
reception  of  air  into  that  organ.  Similar  results  were  obtained,  when 
the  tube  was  introduced  into  the  crural  vein  in  the  direction  of  the 
abdomen.  So  far  as  regards  the  larger  venous  trunks,  therefore,  the 
influence  of  respiration  on  the  circulation  is  sufficiently  evidenced.'' 

It  can  be  easily  shown,  by  opening  an  artery  of  the  limbs,  that  expi- 
ration— especially  forced  expiration,  and  violent  efforts — manifestly 
accelerate  the  motion  of  arterial  blood.  In  animals  subjected  to  expe- 
riment, it  is  impracticable  to  excite  either  the  forced  expiration  or  vio- 
lent effort  at  pleasure;  but  we  can,  as  a  substitute,  compress  the  sides 
of  the  chest  with  the  hands,  according  to  the  plan  recommended  by 
Lamure ;  when  the  *blood  will  be  found  to  flow  more  or  less  copiously 
in  proportion  to  the  pressure  exerted.  It  occurred  to  M.  Magendie, 
that  this  effect  of  respiration  on  the  course  of  the  blood  in  the  arteries 
might  influence  the  flow  along  the  veins.  To  prove  this,  he  passed  a 
ligature  around  one  of  the  jugular  veins  of  a  dog.  The  vessel  emptied 
itself  beneath  the  ligature,  and  became  turgid  above  it.  He  then  made 
a  slight  puncture  with  the  lancet  in  the  distended  portion;  and  in  this 
way  obtained  a  jet  of  blood,  which  was  not  sensibly  modified  by  the 
ordinary  respiratory  movements,  but  became  of  triple  or  quadruple  the 
size,  when  the  animal  struggled.  As  it  might  be  objected  to  this  expe- 
riment, that  the  effect  of  respiration  was  not  transmitted  by  the  arteries 
to  the  open  vein,  but  rather  by  the  veins  that  had  remained  free,  which 
might  have  conveyed  the  blood  repelled  from  the  vena  cava  towards 
the  tied  vein  by  means  of  anastomoses,  the  experiment  was  varied. 
The  dog  has  not,  like  man,  large  internal  jugular  veins,  which  receive 
the  blood  from  the  interior  of  the  head.  The  circulation  from  the  head 
and  neck  is,  in  it,  almost  wholly  confined  to  the  external  jugular  veins, 
which  are  extremely  large ;  the  internal  jugulars  being  little  more 
than  vestiges.  By  tying  both  of  these  veins  at  once,  M.  Magendie 
made  sure  of  obviating,  in  great  part,  the  reflux  in  question ;  but,  in- 
stead of  this  double  ligature  diminishing  the  phenomenon  under  con- 
sideration, the  jet  became  more  closely  connected  with  the  respiratory 

'  Elementa  Physiologife,  torn.  ii.  lib.  vi.  sect.  iv.  §  8,  Lausann.,  1760. 

*  Mem.  de  I'Acad.  des  Sciences,  pour  1749.  ^  Magendie,  Precis,  &c.,  ii.  416. 

*  Poiseuille,  in  Magendie's  Journal  de  Physiologie,  viii,  272. 


428  '  CIRCULATION. 

movement;  for  it  was  manifestly  modified  even  by  ordinary  respira- 
tion, which  was  not  the  case  when  a  single  ligature  was  employed. 
From  these  and  other  experiments,  he  properly  concluded  that  the  tur- 
gescence  of  the  veins  must  not  be  ascribed,  with  Haller,  Lamure,  and 
Lorry,  simply  to  the  reflux  of  the  blood  of  the  venae  cavas  into  the 
branches  opening  directly  or  indirectly  into  them;  but  partly  to  the 
blood  being  sent  in  larger  quantity  into  the  veins  from  the  arteries.* 
In  the  same  manner  are  explained, — the  rising  and  sinking  of  the 
brain,  which,  as  will  be  observed  in  an  after  part  of  this  volume, 
are  synchronous  with  expiration  and  inspiration.  During  expira- 
tion, the  thoracic  and  abdominal  viscera  are  compressed-  the  blood 
is  driven  more  into  the  branches  of  the  ascending  aorta,  and  is,  at  the 
same  time,  prevented  from  returning  by  the  veins:  owing  to  the  com- 
bination of  these  causes,  the  brain  is  raised  during  expiration.  In  in- 
spiration, all  this  pressure  is  removed ;  the  blood  is  free  to  pass  equally 
by  the  descending  and  ascending  aorta ;  the  return  by  the  veins  is 
ready,  and  the  brain  therefore  sinks.^  "We  can  thus,  also,  explain  why 
the  face  is  red  and  swollen  during  crying,  running,  straining,  and  the 
violent  emotions ;  and  why  pain  is  augmented  in  local  inflammation 
of  an  extremity, — as  in  cases  of  whitlow;  and  when  respiration  is  hur- 
ried or  impeded  by  running,  crying,  &c.  The  blood  accumulates  in 
the  part,  owing  to  the  compound  efi:ect  of  increased  flow  by  the  arte- 
ries, and  impeded  return  by  the  veins.  The  same  explanation  applies 
to  the  production  of  hemorrhage  by  any  violent  exertion  ;  and  M. 
Bourdon^  affirms,  that  he  has  always  seen  hemorrhage  from  the  nose 
largely  augmented  during  expiration ;  diminished  at  the  time  of  in- 
spiration; and  arrested  by  prolonged  inspiration; — a  therapeutical  fact 
of  some  interest. 

Experiments  with  the  haemadynamometer  by  Poiseuille,  and  Ludwig,^ 
confirm  those  mentioned  above: — the  column  of  mercury  having  been 
found  to  rise  at  each  expiration,  and  to  sink  dui'ing  inspiration. 

It  has  often  been  remarked,  too,  that  in  forced  and  deep  inspiration 
the  force  of  the  heart  becomes  so  much  diminished,  that  the  pulse  is 
very  slow  and  feeble,  and  in  some  cases  cannot  be  felt.*  This  pheno- 
menon had  attracted  the  attention  of  Weber®  and  Bonders  ;^  and  has 
been  the  subject  of  numerous  experiments  by  Dr.  S.  W.  Mitchell.^  All 
admit  that  an  accumulation  of  blood  takes  place  in  the  right  side  of 
the  heart  under  such  circumstances ;  and  that  such  is  the  fact  was  de- 
monstrated in  the  subject  of  a  remarkable  case  of  congenital  absence 

'  Precis,  &c.,  ii.  421. 

2  This  motion  of  the  hrain  must  not  he  confounded  with  that  which  is  synchronous 
with  the  contraction  of  the  left  ventricle  ;  and  is  owing  to  the  pulsation  of  the  arteries 
at  the  base  of  the  brain. 

*  Recherches  sur  la  Meclianisme  de  la  Respiration  et  sur  la  Circulation  du  Santr.  Paris, 
1820 :  see,  also,  Longet,  Anatomic  et  Physiologie  du  Systeme  Nerveux,  pp.  777  and  779. 

••  Miiller's  Archiv.  fiir  Anatomie,  u.  s.  w.,  Heft.  iv.  s.  242,  Berlin,  1847. 

5  J.  xMiiller,  Lehrbuch  der  Physioloc;.,  i.  198  ;  and  Todd  and  Bowman,  The  Physiolo- 
gical Anatomy  and  Physiology  of  Man,  Pt.  iv.  p.  363,  Loud.,  1S52,  or  Amer.  edit., 
Philad.,  1853. 

6  Miiller  s  Archiv.,  1851,  p.  88  ;  and  Canstatt's  Jahresbericht,  1851,  s.  124. 

'  Henle  and  Pfeuffer's  Zeitschrift,  B.  iii.  and  iv.  ;  and  Funke's  Wagner's  Lehrbuch 
der  Ph3^siologie,  s.  296,  Leipz.,  1854. 

*  American  Journal  of  the  Med.  Sciences,  April,  1854,  j).  387. 


FORCES  THAT  PROPEL  THE  BLOOD — RESPIRATION.   429 

of  the  sterniTiTi,  in  wliicli  the  movements  of  the  heart  were  visible.  It 
was  distinctly  seen,  that  when  the  young  man  held  his  breath  the  right 
auricle  was  made  once  and  a  half  larger,  and  thns  became  engorged.' 
In  prolonged  and  deep  inspiration  the  flow  of  blood  to  the  heart  by 
the  veins — as  has  been  shown — is  greatly  promoted,  whilst  its  export 
by  the  arteries  is  correspondingly  diminished;  and  it  is  probable  that 
the  temporary  cessation  of  the  heart's  action  is  the  result  of  the  conse- 
quent engorgement.  These  experiments  sufficiently  show,  that  a  power 
exists  of  suspending  the  heart's  action  momentarily ;  and  they  throw 
some  light  on  the  extraordinary  cases  of  suspended  animation  referred 
to  elsewhere,  (p.  403.) 

It  is  manifest,  then,  that  the  circulation  is  modified  by  the  move- 
ments of  inspiration  and  expiration,^ — the  former  facilitating  the  flow 
of  blood  to  the  heart  by  the  veins,  and  the  latter  encouraging  the  flow 
from  it  by  the  arteries;  and  we  shall  see  hereafter,  that  the  dilatation  of 
the  chest, — which  constitutes  the  first  inspiration  of  the  new-torn  child, 
— is  the  cause  of  the  establishment  of  the  new  circulation ;  the  same  dila- 
tation, which  causes  the  entrance  of  air  into  the  air-cells,  soliciting  the 
flow  of  blood,  or  the  "  inspiration  of  venous  blood,"  as  M.  Magendie^ 
has  termed  it.  In  a  paper  read  before  the  Eoyal  Society  of  London, 
in  June,  1835,  Dr.  Wardrop,'' — after  remarking,  that  he  considers  in- 
spiration as  an  auxiliary  to  the  venous,  and  expiration  to  the  arterial, 
circulation, — attempts,  on  this  principle,  to  explain  the  influence  exerted 
on  the  circulation,  and  on  the  action  of  the  heart,  by  various  modes  of 
respiration,  whether  voluntary  or  involuntary,  under  different  circum- 
stances. Laughing,  crying,  weeping,  sobbing,  and  sighing,  he  regards 
as  efforts  made  with  a  view  to  effect  certain  alterations  in  the  quantity 
of  blood  in  the  lungs  and  heart,  when  the  circulation  has  been  dis- 
turbed by  mental  emotions.  The  influence  of  ordinary  respiration  can, 
however,  be  trifling ;  yet  it  has  been  brought  forward  by  Sir  David 
Barry*  as  the  efficient  cause  of  venous  circulation.  His  reasons  for  this 
belief  are, — the  facts  just  mentioned,  regarding  the  influence  of  in- 
spiration on  the  flow  of  blood  towards  the  heart;  and  certain  ingeni- 
ously modified  experiments,  tending  to  the  elucidation  of  the  same 
result.  He  introduced  one  end  of  a  spirally  convoluted  tube  into  the 
jugular  vein  of  an  animal,— the  vein  being  tied  above  the  point  where 
the  tube  was  inserted, — and  plunged  the  other  into  a  vessel  filled  with 
a  coloured  fluid.  During  inspiration,  the  fluid  passed  from  the  vessel 
into  the  vein :  during  expiration,  it  remained  stationary  in  the  tube,  or 
was  repelled  into  the  vessel.  Dr.  Bostock^  remarks,  that  he  was  pre- 
sent at  some  experiments,  which  were  performed  by  Sir  David  at  the 
Veterinary  College  in  London,  and  it  appeared  sufficiently  obvious, 
that  when  one  end  of  a  glass  tube  was  inserted  either  into  the  large 

'  Lancet,  June  23,  1855;  and  Anier.  Journ.  of  the  Med.  Sciences,  Oct.,  1855,  p.  483. 

*  Dr.  Clendinning's  Report  to  the  Brit.  Association,  1839-40,  in  Lond.  Med.  Gazette, 
Nov.  13,  1840,  p.  270. 

3  Precis,  &c.,  ii.  416. 

*  On  the  Nature  and  Treatment  of  the  Diseases  of  the  Heart ;  with  some  new  views 
of  the  Physiology  of  the  Circulation,  Lond.,  1837. 

*  Experimental  Researches  on  the  Influence  of  Atmospheric  Pressure  upon  the 
Circulation  of  the  Blood,  &c.,  Lond.,  182(3. 

«  Physiology,  3d  edit.,  p.  330,  note,  Lond.,  1836. 


430  CIRCULATION. 

veins,  into  the  cavity  of  tlie  thorax,  or  into  the  pericardium, — the 
other  end  being  plunged  into  a  vessel  of  coloured  water, — the  water 
rose  up  the  tube  during  inspiration,  and  descended  during  expiration. 
The  conclusion  of  Sir  David  from  these  experiments  is  most  compre- 
hensive ; — that  "the  circulation  in  the  great  veins  depends  upon  atmo- 
spheric pressure  in  all  animals  possessing  the  power  of  contracting 
and  dilating  a  cavity  around  that  point,  to  which  the  centripetal  cur- 
rent of  their  circulation  is  directed ;  and  he  conceives,  that  as,  during 
inspiration,  a  vacuum  is  formed  around  the  heart,  the  equilibrium  of 
pressure  is  destroyed,  and  the  atmos])here  acts  upon  the  superficial 
veins,  propelling  their  contents  onwards  to  supply  the  vacuum;  but  in- 
dependently of  other  objections,  there  are  a  few  that  appear  convincing 
against  the  sole  agency  of  ordinary  respiration  in  effecting  venous  cir- 
culation. According  to  Sir  David's  hypothesis,  blood  ought  to  arrive 
at  the  heart  at  the  time  of  inspiration  onl}^ ;  and  as  there  are,  on  the 
average,  seventj^-two  contractions  of  the  heart  for  every  eighteen  in- 
spirations; or  four  contractions,  or — what  is  the  same  thing — four 
dilatations  of  the  auricle  for  each  respiration;  one  of  these  only  ought 
to  be  concerned  in  the  propulsion  of  blood,  whilst  the  rest  should  be 
bloodless;  yet  we  feel  no  ditlerence  in  the  strength  of  the  four  pulsations. 
It  is  clear,  too,  if  we  adopt  Sir  David's  reasoning,  that,  of  the  four 
pulsations,  two,  and  consequently  two  dilatations  must  occur  during 
expiration,  at  which  time  the  capacity  of  the  chest  is  actually  dimi- 
nished; and,  again,  the  respiratory  influence  cannot  be  invoked  to  ex- 
plain the  circulation  in  the  foetus  or  in  aquatic  animals.  At  the  most, 
therefore,  respiration  can  only  be  regarded  as  a  feeble  auxiliary  in  the 
circulation.  In  favour  of  his  opinion  of  the  efficiency  of  atmospheric 
pressure  in  causing  the  return  of  the  blood  by  the  veins.  Sir  David 
adduces  the  fact, — already  referred  to,  under  the  head  of  Absorption, 
— that  the  application  of  an  exhausted  vessel  over  a  poisoned  wound 
prevents  the  absorption  of  the  poison ;  but  this,  as  we  have  seen,  ap- 
pears to  be  a  physical  efiect,  which  would  apply  equally  to  any  view 
of  the  subject. 

In  all  these  cases,  the  elastic  resilience  of  the  lungs,  b}^  contributing 
to  diminish  the  atmospheric  pressure  from  the  outer  surface  of  the 
auricles,  may  likewise,  as  suggested  by  Dr.  Carson,^  have  some  agency 
in  soliciting  the  blood  into  these  cavities;  but  the  agency  cannot  be 
great.  It  has  recently  been  suggested  by  Liebig,^  that  the  fluids  of 
the  body,  in  consequence  of  the  cutaneous  and  pulmonary  transpira- 
tion, acquire  a  motion  towards  the  skin  and  lungs ;  but  it  is  not  easy 
to  see  that  this  could  have  any  important  eft'ect  on  the  circulation. 

There  is  another  circumstance  of  a  purely  physical  nature,  which 
may  exert  some  influence  upon  the  flow  of  the  blood  along  the  veins; 
the  expanded  termination  of  the  venas  cavee  in  the  right  auricle.  To 
explain  this,  it  is  necessary  to  premise  a  detail  of  a  few  hydraulic  facts. 
If  an  aperture  A,  Fig.  12-i,  exist  in  a  cistern  X,  the  water  will  not  issue 
at  the  aperture  by  a  stream  of  uniform  size;  but,  at  a  short  distance 

'  Pliilosopliical  Transactions  for  1820,  and  An  Inquiry  into  the  Causes  of  Resjiiration, 
&c.,  3d  edit.,  Liverpool,  1833. 

2  Researches  on  the  Motion  of  the  Juices  in  the  Animal  Body,  by  W.  Gregory,  M.  D., 
p.  74,  London,  1848. 


FORCES  THAT  PROPEL  THE  BLOOD — VENA  CONTRACTA,  431 


from  the  reservoir,  it  will  be  contracted  Fig.  124. 

as  at  B,  constituting  what   has   been 

termed  the  vena  contracta.     Now,  it  has 

been  found,  that  if  a  tube  technically 

called  an  adjutage  be  attached  to  this 

aperture,   so   as   to   accurately  fit   the 

stream,  as  at  A  B,  Fig.  125,  as  much 

fluid  will  flow  from  the  reservoir  as  if 

the  aperture  alone  existed. 

Again,  if  the  pipe  B  C  be  attached  to 
the  adjutage  A  B,  the  expanded  ex- 
tremity at  A  will  occasion  the  flow  of 
water  from  the  reservoir  to  be  greater 
than  it  would  be  if  no  such  expanded 

extremity  existed,  in  the  ratio,  accord-  Vena  Contracta. 

ing  to  Venturi,  of  12"1  to  10;  and  if  to 

the  tube  B  C,  a  truncated  conical  tube  C  D  be  attached,  the  length  of 
which  is  nearly  nine  times  the  diameter  of  C ;  and  the  diameter  of  C 
to  that  of  D  be  as 

1  to8;  the  flow  of  Fig.  125. 

water  will  be  aug- 
mented in  the  pro- 
portion of  24  to 
12*1;  so  that,  by  the 
two  adjutages  A  B 
and  C  D,  the  ex- 
penditure through 
the  pipe  B  C  is  in- 
creased in  the  ratio 

of  24  to  10.      This  Vena  Contracta. 

fact, — the  result  of 

direct  experiment,  and  so  important  to  those  who  contract  to  supply 
water  by  means  of  pipes, — was  known  to  the  Komans.  Private  per- 
sons, according  to  Frontinus,'  were  in  the  habit  of  purchasing  the  right 
of  delivering  water  in  their  houses  from  the  public  reservoirs,  but  the 
law  prohibited  them  from  making  the  conducting  pipe  larger  than  the 
opening  allowed  them  in  the  reservoir,  within  the  distance  of  fifty  feet. 
The  Roman  legislature  must,  therefore,  have  been  aware  of  the  fact, 
that  an  adjutage  with  an  expanded  orifice,  would  increase  the  flow  of 
water ;  but  they  were  ignorant  that  the  same  effect  would  be  induced 
beyond  the  fifty  feet.  A  case — "The  Schuylkill  Navigation  Company 
agaiiist  Moore" — was  tried  in  March  term,  1837,  before  the  Supreme 
Court  in  Pennsylvania,  in  which  these  hydraulic  principles  were  in- 
volved. The  defendant  had  conveyed  to  him  by  the  plaintifts  a  certain 
lot  of  ground,  together  with  the  privilege  of  drawing  from  the  Schuyl- 
kill canal  as  much  water  as  would  pass  through  two  metallic  apertures 
of  a  size  mentioned.  He  applied,  however,  to  the  aperture  a  conical 
tube  or  adjutage  by  which  the  flow  of  water  was  proved  to  have  been 

'  De  Aquseductibus  Urbis  Romse  Commentarius,  190,  37,  Patav.,  1722. 


432  CIRCULATION. 

greatly  augmented.  It  was  decided,  that  lie  had  no  right  to  increase 
the  flow  by  such  agency/ 

Let  us  apply  this  law  of  hj^draulics  to  the  circulation.  In  the  first 
place,  at  the  origin  of  the  pulmonary  artery  and  aorta,  there  is  a  mani- 
fest narrowness,  formed  b}^  the  ring  at  the  base  of  the  semilunar  valves: 
this  might  be  conceived  unfavourable  to  the  flow  of  the  blood  along 
those  vessels  during  the  sj^stole  of  the  ventricles ;  but  from  the  law, 
which  has  been  laid  down,  the  narrowness  would  occupy  the  natural 
situation  of  the  vena  contracta,  and,  therefore,  little  or  no  effect  would 
be  induced.  The  discharge  would  be  the  same  as  if  no  such  narrow- 
ness existed.  We  have  seen,  again,  that  the  vena  cava  becomes  of 
larger  calibre  as  it  approaches  the  right  auricle,  and  finally  terminates 
in  that  cavity  by  an  expanded  aperture.  This  may  have  a  similar  effect 
with  the  expanded  tube  0  D,  Fig.  125,  which  doubles  the  expenditure.* 

In  making  these  conjectures, — some  of  which  have  been  adduced  by 
Sir  Charles  Bell, — it  is  proper  to  observe,  that,  in  the  opinion  of  some 
natural  philosophers,  the  effect  of  the  adjutage  is  entirely  due  to  atmo- 
spheric pressure,  and  that  no  such  acceleration  occurs,  provided  the 
experiment  be  repeated  in  vacuo.  Sir  Charles  BelP  conceives,  that 
"  the  weight  of  the  descending  column  in  the  reservoir  being  the  force, 
and  this  operating  as  a  vis  a  tergo^  it  is  like  the  water  propelled,  from 
the^e^  cTeau^  and  the  gradual  expansion  of  the  tube  permits  the  stream 
from  behind  to  force  itself  between  the  filaments,  and  disperses  them, 
without  producing  that  pressure  on  the  sides  of  the  tube,  which  must 
take  place,  where  it  is  of  uniform  calibre."  It  is  on  this  latter  view 
only,  that  these  hydrostatic  facts  can  be  applied  to  the  doctrine  of  the 
circulation. 

In  addition  to  the  movements  impressed  on  the  blood  by  the  parietes 
of  the  cavities  in  which  it  moves,  it  has  been  considered  by  many  phy- 
siologists,— as  by  Ilarvey,  Glisson,  Bohn,  Albinus,  Rosa,  Tiedemann, 
G.  R..  Treviranus,^  Rogerson,^  Alison,^  and  others, — to  possess  a  power 
of  automatic  or  self-motion.  M.  Broussais^  asserts,  that  he  has  seen 
experiments, — originally  performed  by  M.  P.  A.  Fabre,  which  showed, 
that  the  blood,  in  the  capillary  system,  frequentl}^  moves  in  an  oppo- 
site direction  to  that  given  it  by  the  heart, — repeated  by  M.  Sarlan- 
diere  on  the  mesentery  of  the  frog.  In  these,  the  blood  was  seen  to 
rush  for  some  moments  towards  the  point  irritated ;  and,  when  a  con- 
gestion had  taken  place  there,  they  remarked,  that  the  corpuscles  took 
a  different  direction,  and  traversed  vessels  which  conveyed  them  in  an 
opposite  course;  and,  a  few  seconds  afterwards,  they  were  again  ob- 
served to  return  with  equal  rapidit}''  to  the  point  from  which  they  had 
been  repelled.     Tiedemann"  has  collected  the  testimonies  of  various 

'  Reports  of  Cases  adjudged  in  the  Supreme  Court  of  Pennsylvania,  in  the  Eastern 
District,  by  Thomas  I.  Wharton,  voL  ii.  p.  477,  PhiLndelphia,  1837. 

^  Ventui'i,  Sur  la  Communication  Laterale  du  Mouvement  dans  les  Fluides,  Paris,  179S. 

3  Animal  Mechanics,  p.  40,  in  Library  of  Useful  Knowledge,  Lond.,  1829. 

■•  Tietleniann,  Traite  Complet  de  Physiologic  de  I'Homme,  traduit  par  Jourdan,  i. 
348,  Paris,  1831. 

^  A  Treatise  on  Inflammation,  &c.,  Lond.,  1832. 

^  Edinburgh  Med.  and  Surg.  Journal  for  Jan.,  1836. 

''  Traite  de  Physiologie,  &c.,  translated  by  Drs.  Bell  and  La  Roche,  3d  edit.,  p.  374, 
Philad.,  1832.  »  Op.  citat. 


FORCES   THAT   PROPEL   THE    BLOOD  —  AUTOMATIC    POWER.     433 

individuals  on  this  ]-)oint.  Ilaller/  Spallanzani,^  Wilson  Philip,^  Gr.  R. 
Treviranns,"  and  others,  have  remarked,  by  the  aid  of  the  microscope, 
that  the  blood  continued  to  move  in  the  vessels  of  different  animals, 
but  chiefly  of  frogs,  for  some  time  after  the  great  vessels  had  been  tied, 
or  the  heart  itself  removed ; — a  fact  which  Tiedemann,  also,  often  wit- 
nessed. C.  F.  Wolff"^  Rolando,'^  Dollinger  and  Pander,^  Provost  and 
Dumas,*  Von  Baer,^  and  others,^"  saw  blood  corpuscles  in  motion  in 
the  incubated  egg,  before  the  formation  of  either  vessels  or  heart ;  and 
Hunter,  Gruithuisen,  and  Kaltenbrunner  observed, — in  the  midst  of  the 
areolar  tissue  of  inflamed  parts,  in  tissues  undergoing  regeneration, 
and  during  the  cicatrization  of  wounds, — bloody  points  placed  suc- 
cessively in  contact  with  each  other,  forming  small  currents,  which 
represented  new  vessels,  and  united  to  those  already  existing.  The 
fact,  indeed,  that  the  embryo  forms  its  own  vessels,  and  that  blood  in 
motion  can  be  detected  before  vessels  are  m  esse,  is  a  sufficient  proof, — 
were  there  no  other, — that  the  corpuscles  of  the  blood  possess  the 
faculty  of  motion,  either  in  themselves,  or  by  virtue  of  an  attraction 
exerted  upon  them  by  the  solid  parietes  in  which  they  move.  Miiller^^ 
thinks  the  idea  of  spontaneous  motion  in  a  fluid,  independently  of 
attraction  or  repulsion  from  the  sides  of  another  object,  is  inconceiv- 
able ;  and  as  Tiedemann'^  has  remarked,  if  we  admit  this  faculty  in 
animals  provided  witli  a  heart,  the  progression  of  the  blood  must  be 
mainly  owing  to  that  viscus ;  for,  after  the  heart  ceases  to  act,  the  cir- 
culation is  soon  arrested.  The  blood,  too,  only  remains  fluid,  and 
possesses  the  faculty  of  motion,  whilst  it  is  in  connexion  with  the  living 
body.  When  taken  from  the  vessel  in  which  it  circulates,  it  soon 
coagulates,  and  loses  its  motive  power.  This  motion  has,  by  some, — 
and,  according  to  Brand t,^'^  not  without  grounds, — been  presumed  to  be 
owing  to  electro-chemical  agency. 

Burdach^^  has  properly  observed,  that  the  ^Id  but  perfectly  correct 
saying,  "  ubi  stimulus  ibi  affiuxus,^''  means  nothing  more  than  that 
where  the  vital  activity  of  an  organ  is  augmented,  more  blood  will  be 
drawn  to  it ;  whence  it  naturally  follows,  that  the  progression  of  blood 
in  the  capillaries  must  be,  in  some  measure,  dependent  on  the  activity 
of  the  vital  manifestations  in  the  tissue.  It  has  been  already  shown, 
that  if  the  capillary  action  be  excited  by  stimulants,  a  greater  flow  of 
blood  takes  place  into  that  system  of  vessels;  and  as  the  functions  of 

'  Oper.  Minor.,  i.  115,  sect.  8. 

^  Exper.  on  the  Circulation,  &c.,  in  Eng.  by  R.  Hall,  Lond.,  1801. 

*  Pliilos.  Transact.,  1815 ;  and  Medico-Chirurg.  Trans.,  vol.  xii. 

*  Vermischte  Scliriften,  i.  102. 

^  Tlieoria  Generationis,  Hal.,  1759. 
^  Dizionario  Periodico  di  Medicina,  Torino,  1822-1823. 

'  Dissert,  sist.  Hist.  Metamorijhoseos  quam  Ovum  Incubatum  prioribus  quinque 
Diebus  subit,  Wirceb.,  1817. 

*  Annales  des  Sciences  Naturelles,  torn.  xii.  p.  415,  Dec,  1827. 

^  Ueber  die  Entwickelungsgeschiclite  der  Thiere,  u.  s.  w.,  Th.  i.  KiJnigsberg,  1828. 

'"  Allen  Thomson,  On  the  Formation  of  New  Bloodvessels,  Edinb.,  1832;  and  art. 
Circulation,  in  Cyclopajdia  of  Anat.  and  Ph3^siology,  p.  7,  Lond.,  183G. 

"  Handbuch,  u.  s.  w.,  Baly's  translation,  p.  224,  Lond.,  1838. 

'^  Op.  cit.,  p.  349. 

"  Art.  Blut,  in  Encyclopiid.  Worterb.  der  Medicinisch.  Wissenschaft.  v.  596,  Berlin, 
1830. 

'*  Die  Physiologie  als  Erfalirungswissenschaft,  &c.,  Band,  iv.,  Leipz.,  1832. 
VOL.  I. — 28 


434  CITvCULATION. 

nutrition  and  secretion  are  accomplished  by  that  sj^stem,  it  is  olDvious, 
that  any  increase  in  the  activity  of  those  functions  must  attract  a  harger 
afflux  of  fluids,  and,  in  this  manner,  modify  the  circulation  independ- 
entl}^  of  the  heart  and  larger  vessels.  But  this,  again,  can  have  but  a 
subordinate  influence  on  the  general  circulation. 

Lastly,  M.  RaspaiP  resolves  the  whole  of  the  circulation,  as  h^ 
does  other  functions,  into  a  double  action  of  aspiration  and  expiration 
by  the  tissues  concerned.  As  the  blood  is  the  bearer  of  life  to  every 
part  of  the  organism,  and  of  nourishment  and  reparation  to  the  organs, 
— to  prevent  its  destination  being  annulled,  a  part  of  the  fluid,  he  says, 
must  be  absorbed  by  the  surfaces,  which  it  bathes:  these  surfaces  must 
attract  nutritive  juices  from  the  blood,  and  they  must  return  to  the 
blood  the  refuse  of  their  elaboration, — in  other  words,  they  must  aspire 
and  expire.  Now,  this  double  function  cannot  take  place  without  the 
fluid  being  set  in  motion,  and  this  motion  must  be  the  more  constant 
and  uniform  as  the  double  function  is  inherent  in  every  molecule  of 
the  surface  of  the  vessels.  In  this  way  he  accounts  for  the  mercur}'', 
placed  in  a  tube  communicating  with  an  artery,  being  kept  at  the  same 
height  near  to,  or  at  a  distance  from,  the  heart ;  because,  he  says,  it  is 
not  the  action  of  the  heart  which  supports  it,  but  the  action  of  the 
parietes  of  the  vessels.  Every  surface,  which  aspires,  provided  it  is 
flexible,  must  be,  in  its  turn,  he  conceives,  attracted  by  the  substance 
aspired,  and,  consequently,  by  the  act  of  aspiration  alone,  the  motions 
of  systole  and  fcliastole  of  the  heart  and  arteries  may  be  explained. 
When  their  inner  parietes  aspire — or  assimilate  the  fluid, — the  heart 
will  contract;  when,  on  the  contrary,  they  expire, — owing  to  the 
mutual  repulsion  between  the  heart  and  the  fluid,  the  former  dilates; 
and,  as  the  movements  of  the  heart  are  energetic  on  account  of  its  size, 
its  movements  will  add  to  the  velocity  of  the  circulation  in  the  arte- 
ries, which  will,  therefore,  besides  their  proper  actions  of  aspiration 
and  expiration,  present  movements  isochronous  with  the  pulsations  of 
the  heart.  "  Add  to  this  accessory  cause  of  arterial  pulsations  the 
movements  impressed  by  the  aerial  aspiration,  which  takes  place  in 
the  lungs,  and  the  circulation  of  the  blood  will  no  longer  present  in- 
surmountable problems." 

All  this,  it  need  scarcely  be  said,  is  ingenious;  but  nothing  more. 

f.  Accelerating  and  Retarding  Forces. 

The  above  are  the  chief  accelerating  causes  of  the  circulation.  There 
are  others,  that  at  times  accelerate,  and  at  times  retard ;  and  others, 
again,  that  must  always  be  regarded  as  impeding  influences.  All  these 
are  of  a  physical  character,  and  applicable  as  well  to  inert  hydraulic 
machines  as  to  the  pipes  of  the  human  body. 

1.  Friction  always  acts  as  a  retarding  force.  That  which  occurs 
between  a  solid  and  the  surface  on  which  it  moves,  can  be  subjected 
to  calculation,  but  not  so  with  a  fluid,  inasmuch  as  all  its  particles  do 
not  move  equally :  whilst  one  part  is  moving  i-apidly,  another  may  be 
stationary,  moving  slowly,  or  even  in  a  contrary  direction,  as  is  seen  in 
rivers,  where  the  middle  of  the  stream  always  flows  with  greater  velo- 

'  Chimie  Organique,  p.  364,  Paris,  1833. 


ACCELERATING   AND   RETAEDING   FORCES  —  CURVATURES.    435 

city  than  the  sides.  The  same  thing  happens  to  water  flowing  through 
pipes;  the  water,  which  is  in  contact  with  the  sides  of  the  pipe,  moves 
more  slowly  than  that  at  the  centre.  This  retarding  force  is  much 
diminished  by  the  polished  state  of  the  inner  surface  of  the  bloodves- 
sels, as  is  proved  by  the  circumstance,  that  if  we  introduce  an  inert 
tube  into  an  artery,  the  blood  will  jiot  flow  through  it  for  any  length 
of  time.  M.  Poiseuille^  infers,  from  his  investigations,  that  a  still  layer 
of  serum  lines  the  interior  of  the  capillary  vessels,  which  may  have 
some  effect  in  retarding  the  blood  globules  in  their  progress  through 
the  intermediate  system.  Yet  the  viscosity  of  the  blood,  within  certain 
limits,  would  seem  to  be  important  to  enable  it  to  pass  through  the 
capillary  system.  M.  Magendie,  indeed,  pronounces  it  to  be  an  indis- 
pensable condition  for  its  free  circulation  through  the  capillaries.^ 

2.  Gravity  may  either  be  an  active  or  retarding  force,  and  is  always 
exerting  itself,  in  both  ways,  on  different  sets  of  vessels.  If,  for  ex- 
ample, the  flow  of  blood  to  the  lower  extremity  by  the  arteries  is  aided 
in  the  erect  attitude  b}^  the  force  of  gravity,  its  return  by  the  veins  is 
retarded  by  the  same  cause.  The  pulse  of  a  person  in  health  beats 
slower  when  he  is  in  the  recumbent,  than  in  the  erect,  attitude.  This 
is  owing  to  there  being  no  necessity  for  the  heart  to  make  use  of  un- 
usual exertions  for  the  purpose  of  forcing  the  blood,  against  gravity, 
towards  the  upper  part  of  the  body.  In  therapeutics,  the  physician 
finds  great  advantage  from  bearing  this  influence  in  mind;  and,  hence, 
in  diseases  of  the  head, — as  in  inflammation  of  the  brain,  in  apoplectic 
tendency,  ophthalmia,  &c., — he  directs  the  patient's  head  to  be  kept 
raised;  whilst  in  uterine  affections  the  horizontal  posture,  or  one  in 
which  the  lower  part  of  the  body  is  raised  even  higher  than  the  head, 
is  inculcated ;  and  in  ulcers  or  inflammatory  diseases  of  the  lower 
extremities,  the  leg  is  recommended  to  be  kept  elevated.  Every  one, 
who  has  had  the  misfortune  to  suffer  from  whitlow,  has  experienced  the 
essential  difference  in  the  degree  of  pain  produced  by  position.  If  the 
finger  be  held  down,  gravity  aids  the  flow  of  blood  by  the  arteries,  and 
retards  its  return  by  the  veins:  the  consequence  is  turgescence  and 
painful  distension ;  but  if  it  be  held  higher  than  the  centre  of  the  cir- 
culation, the  flow  by  the  arteries  is  impeded,  whilst  its  return  by  the 
veins  is  accelerated,  and  hence  the  marked  relief  afforded. 

8.  Curvatures. — Besides  friction,  the  existence  of  curvatures  has  con- 
sic|prablc  effect  on  the  velocity  and  quantity  of  the  fluid  passing  through 
pipes.  A  jet  does  not  rise  as  high  from  the  pipe  or  adjutage  of  a  reser- 
voir, if  there  be  an  angular  turn  in  it,  as  if  the  bend  were  a  gradual 
curve  or  sweep.  The  expense  of  force,  produced  by  such  curvatures 
in  arteries,  is  seen  at  each  contraction  of  the  ventricle, — the  tendency 
in  the  artery  to  become  straight  producing  an  evident  movement,  which 
has  been  called  locomotion  of  the  artery^  and  has  been  looked  upon,  by 
some,  as  the  principal  cause  of  the  pulse.  This  motion  is,  of  course, 
more  perceptible  the  nearer  to  the  heart,  and  the  greater  the  vessel ; 
hence  it  is  more  obvious  at  the  arch  of  the  aorta;  and  we  can  now 
understand  why  this  arch  should  be  so  gradual.     There  is  a  good  ex- 

'  Biblioth.  Universelle,  Nov.,  1835. 

2  Lectures  on  the  Blood,  edit,  cit.,  p.  102,  Philad.,  1839. 


436  CIRCULATIOX. 

ample  of  the  force  used  in  this  effort  at  straightening  the  arterj^,  in  the 
case  of  the  popliteal  artery,  when  the  legs  are  crossed,  and  a  curvature 
is  thus  produced.  The  force  is  sufficient  to  raise  a  weight  of  upwards 
of  iifty  pounds  at  each  contraction  of  the  ventricle,  notwithstanding 
it  acts  at  the  extremity  of  so  long  a  lever.  This  fact  is  sufficient  to 
exhibit  the  inaccuracy  of  the  notion  of  MM.  Bichat  and  Bricheteau,^ 
that  the  curvatures  in  the  arteries  can  have  no  effect  in  retarding  the 
flow  of  blood.  Such  could  only  be  the  case,  Bichat  thinks,  if  the  ves- 
sels were  empty  at  each  systole. 

4.  Anastomoses. — The  anastomoses  of  vessels  have,  doubtless,  also 
some  influence  on  the  course  of  the  blood ;  but  it  is  impossible  to  ap- 
preciate it.  The  superficial  veins  are  especially  liable  to  have  the 
circulation  impeded  by  compression  in  the  different  postures  of  the 
body ;  but  by  means  of  the  numerous  anastomoses  if  the  blood  cannot 
pass  by  one  channel,  it  is  diverted  into  others.  Although,  however, 
a  forcible  compression  may  arrest  or  retard  the  flow  by  those  vessels, 
a  slight  degree  of  support  prevents  the  vein  from  being  dilated  by  the 
force  of  the  blood  passing  into  it,  and  thus  favours  its  motion.  The 
constant  pressure  of  the  skin  hence  facilitates  the  circulation  through 
the  subcutaneous  veins,  and  if,  by  any  means,  the  pressure  be  dimin- 
ished, especially  in  those  parts  in  which  the  blood  has  to  make  its  way 
against  gravity — as  in  the  lower  extremities — varices  or  dilatations  of 
the  vessels  supervene,  which  are  remedied  b}^  the  mechanical  compres- 
sion of  an  appropriate  bandage. 

Attempts  have  been  made  to  calculate  the  velocity  with  which  the 
blood  proceeds  in  its  course ;  and  how  long  it  would  take  for  a  blood 
corpuscle,  setting  out  from  the  left  side  of  the  heart,  to  attain  the  riglit 
side.  It  is  clear,  that  the  data  are,  in  the  first  place,  totally  insuffi- 
cient for  any  approximation.  We  know  not  the  exact  quantity  of 
blood  contained  in  the  vessels ; — the  amount  sent  into  the  artery  at 
each  contraction  of  the  ventricle;  the  relative  velocity  of  the  arterial, 
venous,  and  capillary  circulations; — and,  if  we  knew  them  at  any  one 
moment,  they  are  liable  to  incessant  fluctuations,  which  would  preclude 
any  accurate  average  from  being  deduced.  Were  these  circumstances 
insufficient  to  exhibit  the  inanity  of  such  researches,  the  varying  esti- 
mates of  difi'erent  observers  would  establish  it.  These  assign  the  time 
occupied  in  the  circulation  from  two  minutes  to  fifteen  or  twenty  hours ! 
Moreover,  the  distances  which  the  corpuscles  have  to  traverse  must  be 
various.  In  the  heart,  the  passage  from  one  side  to  the  other  by  the 
coronary  vessels  is  very  short ;  whilst  if  the  blood  has  to  proceed  to 
a  remote  part  of  the  body,  the  distance  is  considerable. 

Were  we  to  regard  the  vascular  system  as  forming  a  single  tube; — 
by  knowing  the  weight  of  the  blood  and  the  quantity  which  the  left 
ventricle  is  capable  of  sending  forward  at  each  contraction,  we  could 
calculate  with  facility  the  period  that  must  elapse  before  an  amount 
equal  to  the  whole  mass  is  distributed.  Thus,  if  we  estimate,  with 
many  physiologists,  the  quantity  propelled  forward  at  each  contraction 
of  the  ventricle  to  be  two  ounces ;  and  the  whole  mass  of  blood  to  be 

'  Clinique  Medicale,  p.  145,  Paris,  1835  ;  or  the  author's  transLition  in  his  American 
Medical  Library,  Philad.,  1837. 


VELOCITY   OF   THE   CIECULATION.  437 

30  pounds,  it  will  require,  on  an  average,  about  240  beats  of  the  heart 
to  send  it  onAvards;  which  can  be  accomplished  in  little  more  than  3 
minutes,  yet,  notwithstanding  the  absence  of  the  requisite  data,  a 
modern  writer  has  gone  so  far  as  to  affirm  the  average  velocity  of  the 
blood  in  the  aorta  to  be  about  eight  inches  per  second;  whilst  "the 
velocity  in  the  extreme  capillaries  is  found  to  be  often  less  tban  one 
inch  per  minute!"  A  similar  estimate  was  made  by  Dr.  Young:' 
Hales^  estimated  the  velocity  of  the  blood,  leaving  the  heart  at 
149'2  feet  per  minute,  and  the  quantity  of  blood  passing  through  the 
organ  every  hour  at  twenty  times  the  weight  of  the  blood  in  the  body; 
but  the  judicious  phj^siologist  knows  well,  that  in  all  operations,  which 
are,  in  part,  of  a  vital  character,  the  results  of  every  kind  of  calcula- 
tion must  be  received  with  caution.  In  the  larger  animals,  as  the 
whale,  the  quantity  of  the  fluid  circulating  in  the  aorta  must  be  pro- 
digious. Dr.  Hunter,  in  his  account  of  the  dissection  of  a  whale,  states 
that  the  aorta  was  a  foot  in  diameter,  and  that  ten  or  fifteen  gallons  of 
blood  were  probably  thrown  out  of  the  heart  at  each  stroke;  so  that 
this  vessel  is,  in  .the  whale,  actually  larger  than  the  main  pipe  of  the 
old  water- works  at  London  Bridge;  and  the  water,  rushing  through 
the  pipe,  it  has  been  conceived,  had  less  impetus  and  velocity  than  that 
gushing  from  the  heart  of  this  leviathan.^ 

But  the  highest  of  these  estimates,  as  to  the  velocity  of  the  circula- 
tory current,  is  probably  far  beneath  the  truth,  inasmuch  as  experi- 
ments have  shown,  that  substances  introduced  into  the  venous  circula- 
tion may  be  detected  in  the  remotest  parts  of  the  arterial  circulation 
in  animals  larger  even  than  man  in  less  than  thirty  seconds.  Ten 
seconds  after  having  injected  a  solution  of  nitrate  of  baryta  into  the 
jugular  vein  of  a  horse,  Dr.  Blake,'*  formerly  of  Saint  Louis,  drew 
blood  from  the  carotid  of  the  opposite  side:  after  allowing  this  to  flow 
for  five  seconds,  he  received  the  blood  that  flowed  during  the  next  five 
seconds  into  another  vessel;  and  that  which  flowed  after  the  twentieth 
second,  by  which  time  the  action  of  the  lieart  had  stopped,  was  re- 
ceived into  a  third  vessel.  No  trace  of  baryta  could  be  detected  in 
the  blood  that  flowed  between  the  tenth  and  fifteenth  seconds ;  but  it 
was  discovered  in  that  which  flowed  between  the  fifteenth  and  twenti- 
eth. In  a  dog,  the  poisonous  effects  of  strychnia  on  the  nervous  sys- 
tem appeared  in  twelve  seconds  after  injection  into  the  jugular  vein; 
in  a  fowl  in  six  and  a  half  seconds;  and  in  a  rabbit  in  four  and  a  half 
seconds, — the  interval  being  in  an  inverse  ratio  to  the  velocity  of  their 
respective  circulations.  From  the  results  of  these  and  other  experi- 
ments, Dr.  Carpenter  thought  it  difficult  to  resist  the  conclusion,  that 
some  other  force  than  the  contractions  of  the  heart  must  have  a  share 
in  producing  the  movement  of  the  blood  through  the  vessels.^  If, 
however,  we  adopt  the  estimate  of  the  average  quantity  of  blood  dis- 

'  An  Introduction  to  Med.  Literature,  p.  G09,  Lond.,  1813. 

*  Statical  Essays,  vol.  ii.  p.  40,  Lond.,  1733. 

'  Paley's  Natural  Theology,  and  Animal  Physiology,  p.  75,  Library  of  Useful  Know- 
ledge, Lond.,  1829. 

''  Edinb.  Med.  and  Surg.  Journal,  Oct.,  1841 ;  St.  Louis  Medical  and  Surgical  Journal, 
Nov.  and  Dec,  1848 ;  and  American  Journal  of  the  Medical  Sciences,  p.  lOU,  July,  1841. 

"  Human  Physiologj^,  §  491,  Lond.,  1842. 


438  CIRCULATIOZS". 

charged  by  tbe  left  ventricle  at  each  contraction, as  given  bj^  Valentin,' — 
(oz.  5'o,)  and  still  more  that  given  by  Volkmann  (oz.  (3'2) — a  part  of 
the  difficulty  is  removed.  According  to  the  data  of  the  former  thirty 
pounds  of  blood  would  require  90  contractions  of  the  ventricle,  which 
would  be  accomplished  in  about  a  minute  and  a  third, — Mr.  Paget 
says  in  from  -ISf  to  62f  seconds, — the  discordance  being  owing  to  the 
varying  estimates  as  to  the  quantity  of  blood  in  the  body.  If  we 
take  the  estimate  of  the  amount  of  blood  by  Dr.  Blake  (page  357),  it 
could  be  accomplished  in  from  58  to  60  contractions  of  the  ventricle, 
or  in  from  44  to  50  seconds.  Valentin's  estimate  of  the  quantity  sent 
out  at  each  contraction  is  probably,  however,  too  high: — three  ounces 
may  be  nearer  the  mark. 

With  this  velocity  of  the  general  circulation,  it  seems  at  first  diffi- 
cult to  comprehend  its  slowness  of  progression  in  the  capillary  vessels, 
which  in  the  frog,  according  to  Valentin,^  from  many  careful  micro- 
metric  examinations,  is  from  0'938  to  l'-4  English  inch  per  minute. 
In  the  small  veins,  he  says,  it  is  about  |th  faster.  These  velocities,  as 
Mr.  Paget'^  remarks,  agree  nearly  with  those  of  Hales,^  who  estimated 
the  velocity  at  an  inch  in  a  minute  and  a  half;  and  more  nearly  still 
with  those  of  Weber,  who  found  it  1|:  inch  per  minute.  On  examin- 
ing with  the  microscope  the  circulation  in  the  tongue  of  the  frog,  the 
blood  is  observed  streaming  with  immense  velocity  through  the  larger 
vessels,  whilst  in  those  that  admit  but  a  single  file  of  red  corpuscles, 
the  motion  is  as  slow  as  described  by  those  observers. 

It  has  been  well  remarked  by  Messrs.  Kirkes  and  Paget,*  that  the 
speed  at  which  the  blood  may  be  seen  moving  in  transparent  parts  is 
not  opposed  to  the  calculations  of  Valentin  and  others;  inasmuch  as, 
although  the  movement  through  certain  capillaries  may  be  very  slow, 
the  length  of  capillary  through  which  any  portion  of  blood  has  to 
pass  is  very  small.  "  If  we  estimate  that  length  at  the  tenth  of  an 
inch,  and  suppose  the  velocity  of  the  blood  therein  to  be  only  one 
inch  per  minute,  then  each  portion  of  blood  may  traverse  its  own  dis- 
tance of  the  capillar}^  system  in  about  six  seconds.  There  would  thus 
be  plenty  of  time  left  for  the  blood  to  travel  through  its  circuit  in  the 
larger  vessels,  in  which  the  greatest  length  of  tube  that  it  can  have  to 
traverse  in  the  human  subject  does  not  exceed  ten  feet."  The  obser- 
vations of  Volkmann,^  on  the  mesenteric  arteries  of  the  dog  make  the 
rate  of  flow  about  'OS  inch  per  second  or  1'8  per  minute;  and  com- 
paring this  with  the  rate  in  the  larger  arteries,  which  appeared  to  be, 
on  the  average,  11 '8  inches  per  second,  it  is  calculated  by  him,  that 
the  aggregate  area  of  the  capillaries  must  be  nearly  four  hundred  times 
that  of  the  arterial  trunks,  which  supply  them.  The  instrument  with 
which  he  measured  the  velocity  of  the  current  in  the  vessels  and  to 
which  he  gave  the  name  hcemodrometer  consists  of  a  glass  tube,  fifty- 
two  inches  long,  bent  into  the  form  of  a  hair  pin,  and  containing 
water,  which  he  substituted  for  a  segment  of  the  bloodvessel,  the  velo- 
city of  whose  blood   current  he  was   desirous  of  estimating.     The 

'  Lehrbncli  der  Physiologie  des  Menschen,  i.  415,  Bramisoliweig,  1844. 
2  Op.  cit.  '  "  '  Loc.  cit.  ^  Op.  citat.,  ii.  68. 

5  Maimal  of  Physioloey,  2d  Amer.  edit.,  p.  117,  Pliilad.,  1853. 

*■  Haemodjnamik,  s.  184,  204,  and  Carpenter,  Principles  of  Human  Physiol.,  Amer. 
edit.,  p.  269,  Pliilad.,  1855. 


VELOCITY   OF   THE   CIRCULATION.  439 

columii  of  blood  from  the  heart  pushes  the  column  of  water  before  it, 
without  much  admixture  of  the  fluids  taking  place;  and  the  distance 
through  which  it  passes  in  a  given  time  is  a  measure  of  its  velocity.^ 

The  velocity  of  the  circulating  fluid  in  the  smaller  arterial  vessels  is 
generally  thought  to  be  less  than  in  the  larger ;  and  their  united  cali- 
bres to  be  much  greater  than  that  of  the  trunk  with  which  they  com- 
municate. Were  this  the  case,  the  diminution  of  velocity  would  be  in 
accordance  with  a  law  of  hydrodynamics ; — that  when  a  liquid  flows 
through  a  full  pipe,  the  quantity  which  traverses  the  different  sections 
of  the  pipe  in  a  given  time  must  be  every  where  the  same ;  so  that 
where  the  pipe  is  wider  the  velocity  diminishes :  and,  on  the  contrary, 
where  it  is  narrower  the  velocity  increases.  This  would  not  seem, 
however,  to  be  consistent  with  the  calculations  of  Dr.  T.  Young,  and 
Weber,  and  the  experiments  of  M.  Poiseuille,  already  referred  to, 
which  Drs.  Spengler^  and  Valentin^  concur  in,  but  Yolkmann  and 
Ludwig  oppose,''  which  show,  that  the  pressure  exerted  on  the  blood 
in  different  parts  of  the  body — as  measured  by  the  column  of  mer- 
cury, which  the  blood  in  different  arteries  will  sustain — is  almost 
exactly  the  same. 

The  cause  of  error  in  the  common  belief, — that  the  capacity  of  the 
arterial  tubes  increases  in  proportion  to  their  distance  from  the  heart, — 
has  been  explained  by  Mr.  Ferneley^  and  others.  It  is  true,  he  ob- 
serves, that  the  sum  of  the  diameters  of  the  branches  is  considerably 
greater  than  that  of  the  trunk.  Thus  a  trunk,  7  lines  across,  may 
divide  into  two  branches  of  5  lines  each;  or  a  trunk  of  17  into  three 
branches  of  10,  10,  and  9|-;  but  when  their  areas  are  compared,  which 
is  the  only  mode  of  arriving  at  their  calibres,  the  correspondence  is  as 
close  as  can  be  reasonably  expected,  when  the  nature  of  the  measure- 
ment is  taken  into  account.  In  the  first  case,  the  area  of  the  trunk  is 
represented  by  the  square  of  7 — that  is  49 ;  whilst  the  area  of  each 
branch  will  be  25,  and  the  sum  of  the  two  will  be  50.  In  the  second 
instance,  the  area  of  the  trunk  will  be  17  squared,  or  289 ;  whilst  that 
of  the  branches  is  the  sum  of  100,  100,  and  90^,  making  290|.  This 
will  be  more  strikingly  seen  from  the  following  table  of  measurements 
of  the  mesenteric  artery  of  the  sheep  by  Mr.  Ferneley. 


Trunks. 

Branches 

Diameter. 

Square 

of  Diameter. 

Diameter. 

Sum  of  S(£uares  o 

)iameter. 

I. 

9 

81 

7-5  +  5 

81-25 

n. 

7-2 

51-64 

6-f  4 

52 

TIL 

3-5 

12-25 

3+2 

13 

IV. 

7-0 

49 

5+5 

50 

V. 

17 

289 

10  +  10  +  9-5 

290-25 

VI. 

10 

100 

7+7  +  2 

102 

VII. 

4-5 

20-25 

3-5  +  3 

21-25 

VIII. 

8 

64 

4+7 

65 

'  Todd  and  Bowman's  Physiological  Anatomy,  &c.,  Pt.  iv.  p.  3G5,  Lond.  1852,  or 
Amer.  edit.,  Philad.,  1853. 

^  Miiller's  Archiv.,  1844,  Heft  i.  ^  Op.  cit.,  p.  456. 

*  Carpenter,  Op.  cit.,  p.  266;  Todd  and  Bowman,  Op.  cit.,  Pt.  iv.  p.  361,  Lend., 
1852,  or  Amer.  edit.,  Philad.,  1853;  and  Funke's  Wagner's  Lehrbuch  der  specielleu 
Physiologie,  s.  85,  Leipzig,  1854. 

"  Loudon  Medical  Gazette,  Dec.  7,  1839. 


440  CIRCULATION. 

It  will  be  observed,  that  the  sum  of  the  squares  of  the  diameters  of 
the  branches  is  in  every  case  slightly  more  than  the  square  of  the 
diameter  of  the  trunk.  The  discrepancy  was  found  to  be  somewhat 
greater  in  subsequent  experiments  made  by  Mr.  Paget.^  The  follow- 
ing table  gives  the  ratio  of  the  area  of  each  arterial  trunk  to  the  joint 
area  of  its  branches,  as  observed  by  him  :— - 

Trunk.  Branches. 

Arch  of  the  aorta       ......  1 

Innominata        .......  1 

Common  carotid        ......  1 

External     do.   .......  1 

Subclavian        .......  1 

Abdominal  aorta  to  the  last  lumbar  arteries       .  1 

just  before  dividing        .         .  1 


Common  iliac    .......         1 

External  iliac   .......         1 


1-055 
1-147 
1-013 
1-19 
1-055 
1-183 
•893 
-982 
1-15 


Analogous  experiments  by  actual  admeasurement,  made  by  Mr. 
Erskine  Hazard,^  of  Philadelphia,  lead  to  a  similar  conclusion.  In 
many  of  them,  however,  the  area  of  the  trunks  was  found  to  be 
greater  than  that  of  the  branches  near  them.  It  would  appear,  that 
where  the  aorta  divides  into  the  common  iliacs,  or  at  the  division  next 
lower  down,  the  stream  is  always  contracted ;  the  effect  of  which  must 
necessarily  be  to  accelerate  the  circulation  not  only  in  the  iliacs  them- 
selves, but  in  the  arteries  given  oft"  from  the  trunk  above  them, — as 
the  mesenteric  and  the  renal. 

From  what  has  been  said  regarding  the  curvatures  and  angles  of 
vessels,  it  will  be  understood,  that  the  blood  must  proceed  to  different 
organs  with  different  velocities.  The  renal  artery  is  extremely  short, 
straight,  and  large,  and  must  transmit  the  blood  very  differently  to  the 
kidney,  from  what  the  tortuous  carotid  does  to  the  brain;  or  the 
spermatic  artery  to  the  testicle.  A  different  impulse  must,  conse- 
quently, be  made  on  the  corresponding  organs  by  these  different  ves- 
sels. A  great  portion,  however,  of  the  impulse  of  the  heart  must  fail 
to  reach  the  kidney,  short  as  the  renal  artery  is,  owing  to  its  passing 
off  from  the  aorta  at  a  right  angle ;  and,  hence,  the  impulse  of  the 
blood  on  that  organ  may  not  be  as  great  as  might  be  imagined  at 
first. 

The  tortuosity  of  the  carotid  arteries  is  such  as  to  greatly  destroy 
the  impetus  of  the  blood;  so  that  but  trifling  hemorrhage  takes  place 
when  the  brain  is  sliced  away  on  a  living  animal,  although  it  is  pre- 
sumed, that  one-eighth  of  the  whole  quantity  of  blood  is  sent  to  the 
encephalon.  Dr.  Push  supposed,  that  the  use  of  the  thyroid  body  is 
to  break  the  afflux  of  blood  to  the  brain ;  for  which  its  situation  be- 
tween the  heart  and  head  appeared  to  him  to  adapt  it;  and  he  adduced, 
as  farther  arguments, — firsts  the  number  of  arteries  it  receives,  although 
effecting  no  secretion ;  secondly^  the  effect  on  the  brain,  which  he  con- 
ceived to  be  caused  by  disease,  and  extirpation,  of  the  thyroid ;  the 
operation  having  actually  occasioned,  in  his  opinion,  in  one  case,  in- 
flammation of  the  brain,  rapidly  terminating  fatally ;  and,  thirdly^  the 
fact  that  goitre  is  often  accompanied  by  idiotism.     The  opinion,  how- 

'  London  Medical  Gazette,  July  8,  1842. 

*  Horner,  Special  Anatomy  and  Histology,  8th  edit.,  ii.  167,  Philad.,  1851. 


VELOCITY   OF   THE    CIRCULATION  —  DIVERTICULA.  441 

ever,  is  so  entirely  conjectural,  and  some  of  the  fads,  on  whicli  it  rests, 
so  questionable,  that  it  does  not  demand  serious  examination. 

This  leads  us  to  remark,  that  the  thyroid  body  as  well  as  other 
organs,  with  Avhose  precise  functions  we  are  not  well  acquainted, — as 
the  thymus,  spleen,  and  supra-renal  capsules, — have  been  conceived  to 
serve  as  diverticula  or  temporary  reservoirs  to  the  blood,  when,  owing 
to  special  circumstances,  that  fluid  cannot  circulate  properly  in  other 
parts  of  the  frame.  M.  Lieutaud  having  observed,  that  the  spleen  is 
always  larger  when  the  stomach  is  empty  than  when  full,  considered 
that  the  blood,  when  digestion  is  not  going  on,  reflows  into  the  spleen, 
and  that  thus  this  organ  becomes  a  diverticulum  to  the  stomach.  The 
opinion  has  been  indulged  bj  many,  with  more  or  less  modification. 

Dr.  Rush's  view  was  more  comprehensive.  He  regarded  the  organ 
as  a  diverticulum,  not  simply  to  the  stomach,  but  to  the  whole  system, 
when  the  circulation  is  greatly  excited,  as  in  passion,  or  in  violent  mus- 
cular eftbrts,  at  which  times  there  is  danger  of  sanguineous  congestion 
in  different  organs;  and  in  support  of  this  view,  he  invoked  its  spongy 
nature ;  the  frequency  of  its  distension ;  the  large  quantity  of  blood 
distributed  to  it ;  its  vicinity  to  the  centre  of  the  circulation ;  and  the 
sensation  referred  to  it,  in  running^aughing,  &c.  M.  Broussais'  has 
still  farther  extended  the  notion  of  i|&verticula.  He  affirms,  that  they 
always  exist  in  the  vicinity  of  organs,  whose  functions  are  manifestly 
intermittent.  In  the  foetus,  the  blood  does  not  circulate  through  the 
lungs  as  when  respiration  has  been  established:  hence,  diverticula  are 
necessary:  these  are  the  thymus  and  thyroid  glands.  The  kidneys  do 
not  act  in  utcro ;  hence  the  use  of  the  supra-renal  capsules  as  diver- 
ticula. At  birth,  these  organs  are  either  wholly  obliterated,  if  the 
organs  to  which  they  previously  served  as  diverticula  have  continuous 
functions ;  or  they  are  partly  obliterated,  if  the  functions  be  intermit- 
tent. Thus,  the  spleen  continues  as  a  diverticulum  to  the  stomach, 
because  its  functions  are  intermittent  through  life;  and  the  thj^mus 
disappears  when  respiration  is  established:  the  liver  and  the  portal 
system  he  regards  as  a  reservoir  for  the  reception  of  blood  in  cases  of 
impediment  to  the  circulation  in  different  parts  of  the  body. 

These  notions  are  entirely  hypothetical.  We  shall  see,  hereafter, 
that  our  ignorance  of  the  offices  of  the  spleen,  thymus,  &c.,  is  great ; 
and  we  have  already  shown,  that  much  more  probable  uses  can  be 
assigned  to  the  portal  system.  The  insufficiency  of  M.  BrouSsais's  doc- 
trine of  diverticula  is  strikingly  evidenced  by  the  fact,  that  whilst  the 
thymus  gland  disappears  gradually  in  the  progress  of  age,  the  thyroid 
remains,  as  well  as  the  supra-renal  capsules.^ 

The  nature  of  the  circulation  in  the  brain,  as  well  as  the  advantages 
of  the  tortuous  arrangement  of  the  carotids,  which  convey  a  great  por- 
tion of  the  blood  to  it,  has  been  referred  to  before.^  From  the  mode  in 
which  its  vessels — arterial  and  venous — are  distributed  to  it,  a  uniform 
supply  of  blood  is  secured;  and  it  has  been  presumed,  that  this  uni- 
formity exists  to  such  a  degree,  that  no  augmented  quantity  of  blood 

'  Commentaires  des  Propositions  de  Pathologie,  &c.,  Paris,  1829;  or  translation,  p. 
214,  Philad.,1832. 

^  Adelon,  Phvsiologie  de  I'llomme,  torn.  iii.  328,  2de  Odit.,  Paris,  1829. 
»  VoL  i.  p.  1U7. 


4:4:2  CIRCULATION. 

can  exist  in  it  so  as  to  exert  undue  pressure  on  the  cerebral  neurine. 
Resting  chiellj  on  the  recorded  results  of  certain  experiments  by  Dr. 
Ivellie/  of  Leith,  many  modern  physiologists  and  therapeutists  have 
maintained,  that  the  quantity  of  blood  in  the  cranium  never  varies; 
and  that  the  brain  is  incompressible.  Under  this  notion,  Dr.  Clutter- 
buck^  affirmed,  that  no  additional  quantity  of  blood  can  be  admitted 
into  the  vessels  of  the  brain,  the  cavity  of  the  skull  being  already  filled 
by  its  contents.  "A  plethoric  state  or  overfulness  of  the  cerebral  ves- 
sels altogether,  though  often  talked  of,  can  have  no  real  existence;  nor 
on  the  other  hand  can  the  quantity  of  blood  ^Yithin  the  vessels  of  the 
brain  be  diminished ;  no  abstraction  of  blood,  therefore,  whether  it  be 
from  the  arm,  or  other  part  of  the  general  system,  or  from  the  jugular 
veins  (and  still  less  from  the  temporal  arteries),  can  have  any  effect  on 
the  bloodvessels  of  the  brain,  so  as  to  lessen  the  absolute  quantity  of 
blood  contained  in  them."  Similar  views  were  maintained  by  Monro 
Secundus,^  Dr.  Abercrombie," — and  it  is  affirmed  by  Dr.  J.  Hughes 
Bennett  to  be  still  the  doctrine  of  "the  Edinburgh  school,"' — and  they 
seemed  to  be  supported  by  the  experiments  of  Dr.  Kellie,  who  inferred 
that,  "in  animals  bled  to  death,  whilst  all  the  other  organs  of  the  body 
are  nearly  emptied  of  blood,  the  vessels  of  the  brain  contain  the  usual 
quantit}^;  but  that  if,  previous  to'bleeding  an  animal,  a  hole  be  made 
in  its  cranium,  and  the  brain  be  thus  exposed,  equally  with  other  or- 
gans, to  atmospheric  pressure,  its  vessels,  like  those  of  other  parts  of 
the  body,  will  be  emptied  as  the  animal  bleeds  to  death."  It  was  im- 
portant to  establish  the  truth  or  inaccuracy  of  these  views — influencing, 
as  they  were  calculated  to  do,  and  have  done,  in  so  essential  a  manner, 
the  therapeutics  of  encephalic  affections;  and  this  has  been  conclusively 
accomplished  by  Dr.  Burrows.^  The  experiments  of  Dr.  Kellie  were 
repeated  by  him,  but  with  opiMsite  results;  and  he  concludes,  that  it  is 
not  a  fallacy,  as  some  suppose,  that  bleeding  diminishes  the  actual  quan- 
tity of  blood  in  the  cerebral  vessels ; — that  by  it  we  not  only  diminish 
the  momentum  of  the  blood  in  the  cerebral  arteries  and  the  Cjuautity 
supplied  to  the  brain  in  a  given  time,  but  actually  diminish  the  amount 
of  blood  in  these  vessels.  "Whether," — he  remarks — "the  vacated 
place  is  replaced  by  serum  or  resiliency  of  the  cerebral  substance 
under  diminished  pressure,  is  a  question  into  which  I  will  not  enter." 

Dr.  Burrows  farther  investigated,  whether  position  can  affect  the 
quantity  of  blood  in  the  vessels  of  the  encephalon, — the  opinion  of  Dr. 
Kellie  from  the  results  of  his  experiments  having  been  in  the  negative. 
Two  full  grown  rabbits  were  killed  by  hydrocyanic  acid,  and  whilst 
their  hearts  still  pulsated,  one  was  suspended  by  the  ears;  the  other  by 
the  hind  legs.  In  this  manner,  they  were  left  for  twenty-four  hours; 
and  before  they  were  taken  down  for  examination,  a  tight  ligature  was 
placed  around  the  throat  of  each,  to  prevent,  as  effectually  as  possible, 

'  Medico-Cliirurgical  Transactions  of  Edinburgh,  i.  2. 

2  Art.  Apoplexy,  Cyclopsedia  of  Practical  Sledicine,  American  edit.,  by  the  author, 
Philad.,  1844. 

*  Observations  on  the  Structure  and  Functions  of  the  Nervous  System,  Edinb.,  1783. 

*  Pathological  and  Practical  Researches  on  Diseases  of  the  Brain  and  the  Spinal 
Cord,  Edinb.,  183(!,  or  Amer.  edit.,  Philad. 

*  Lectures  on  Clinical  Medicine,  p.  143. 

6  On  Disorders  of  the  Cerebral  Circulation,  Amer.  edit.,  Philad.,  1848. 


VELOCITY   OF   THE   CIRCULATION — ERECTILE   TISSUES,      443 

any  farther  flow  of  blood  to  or  from  the  head,  after  they  were  removed 
from  their  respective  positions.  The  contrast  in  the  appearance  of 
the  two  animals  was  striking.  The  one  presented  a  most  complete 
state  of  antemia  of  the  internal  as  well  as  the  external  parts  of  the 
cranium ;  the  other  a  most  intense  hyperemia  or  congestion  of  the 
same  parts;  and  these  opposite  conditions  induced  solely  by  posture, 
and  the  gravitation  of  the  blood.  Like  results  were  obtained  expe- 
rimentally under  the  direction  of  Professor  Donders.  A  portion  of  the 
skull  of  a  rabbit  was  removed,  the  corresponding  piece  of  the  dura 
mater  cut  out,  an  accurately  fitting  portion  of  a  watch-glass  let  into  the 
opening,  and  the  junction  made  air  tight  with  gum.  When  by  com- 
pressing the  nose  and  mouth  respiration  was  interrupted,  within  ten 
seconds  the  increased  redness  of  the  pia  mater  could  be  seen  with  the 
naked  eye.  This  condition  was  made  still  more  evident  by  the  micro- 
scope; and  some  minutes  always  elapsed  before  the  hyperaimia  again 
diminished.  A  dependent  position  of  the  head  also  increased  the  hy- 
pera3mia;  whilst  rapid  abstraction  of  blood  very  distinctly  diminished 
the  diameter  of  the  vessels.' 

The  erectile  tissues  offer  a  variety  in  the  circulation,  which  requires 
some  comment.  Examples  of  these  occur  in  the  corpora  cavernosa  of 
the  penis  and  clitoris;  and  in  the  nipple.  They  appear,  according  to 
Gerber,^  to  consist  of  a  plexus  or  rete  of  varicose  veins  enclosed  in  a 
fibrous  envelope,  with  relatively  minute  interspaces,  which  are  occu- 
])ied  and  traversed  in  all  directions  by  arteries,  nerves,  contractile 
fibres,  and  by  elastic,  fibrous  and  areolar  tissue.  The  fibrous  enve- 
lope, and  trabeculge,  according  to  Kolliker,-^  contain  a  considerable 
amount  of  unstriped  muscular  fibre. 

Of  the  particular  arrangement  of  vessels  in  the  corpora  cavernosa 
of  the  generative  organs  mention  will  be  made  hereafter:  the  mode  of 
termination  of  the  arteries  in  the  erectile  tissues  has  not  been  suffi- 
ciently studied,  nor  are  views  uniform  in  regard  to  their  mode  of 
action;  some  being  of  opinion,  that  they  aft'ord  examples  of  vital  ex- 
pansibility ;  but  as  before  remarked  (page  420),  excitation  is  fii'st 
induced  in  the  nerves  of  the  part — generally  through  the  influence  of 
the  brain — and  the  turgescence  of  vessels  is  a  consequence.  Kcilliker 
maintains,  that  the  office  of  the  muscular  fibres,  which  pass  in  every 
direction  amongst  the  dilated  veins  is  to  keep  them  compressed  in  the 
intervals  of  erection;  and  that  the  excitant  influence  to  erection, 
which  is  exerted  on  the  nervous  system,  either  directly  or  tlirough 
the  influence  of  the  brain,  instead  of  causing  contraction  produces 
relaxation  of  the  fibres,  so  as  to  admit  of  free  distension  of  the  cavern- 
ous vessels.  It  is  not  easy  to  see,  however,  how  the  nerve  power  sent 
to  a  muscle  can  cause  it  to  become  relaxed. 

The  arrangement  of  the  portal  system  of  the  liver  is  also  peculiar, 
and  has  been  given  already  (p.  354). 

'  Cited  in  Brit,  and  For.  Med.-Chir.  Rev.,  April,  1855,  p.  352. 

*  Elements  of  General  Anatomy,  by  Gulliver,  p.  298,  Lond.,  1842. 

*  Mikroskopisclie  Anatomie,  2ter  Bd.  S.  414,  Leipz.,  1854 ;  or  Sydenliam  Society's 
edition  of  his  Manual  of  Human  Histology,  or  Amer.  edit,  of  the  same  by  Dr.  Da 
Costa,  p.  U37,  Philad.,  1854. 


d-i-i  CIRCULATION. 

g.  The  Pulse. 

"We  Lave  had  occasion,  more  than  once,- to  refer  to  the  subject  of  the 
pulse,  or  to  the  beat  felt  by  the  finger  when  applied  over  any  of  the 
larger  arteries.  Opinions  have  varied  essentially  regarding  its  cause. 
AVhilst  most  physiologists  have  believed  it  to  be  owing  to  distension 
of  the  arteries,  caused  by  each  contraction  of  the  left  ventricle;  some 
have  admitted  a  systole  and  diastole  of  the  vessel  itself;  others,  as 
Bichat  and  Weitbrecht,^  have  thought  that  it  is  owing  to  the  locomo- 
tion of  the  artery ;  others,  that  the  impulse  of  the  heart's  contraction 
is  transmitted  through  the  fluid  blood,  as  through  a  solid  body ;  and 
others,  as  Dr.  Young^  and  Dr.  Parry,^  that  it  is  owing  to  the  sudden 
rush  forward  of  the  blood  in  the  artery  without  distension. 

Bichat  was  one  of  the  first,  who  was  disposed  to  doubt,  whether  the 
dilatation  of  the  artery,  which  was  almost  universally  admitted,  really 
existed;  or  if  it  did,  whether  it  was  sufiicieut  to  explain  the  phenome- 
non; and,  since  his  time,  numerous  experiments  have  been  made  by 
Dr.  Parry,  the  result  of  which  satisfied  him,  that  not  the  smallest  dila- 
tation can  be  detected  in  the  larger  arteries,  when  they  are  laid  bare 
during  life ;  nor  does  he  believe,  that  there  is  such  a  degree  of  loco- 
motion of  the  vessel  as  can  account  for  the  eft'ect  produced  upon  the 
finger.  He  ascribes  the  pulse  to  "  impulse  of  distension  from  the  sys- 
tole of  the  left  ventricle,  given  by  the  blood,  as  it  passes  through  any 
part  of  an  artery  contracted  within  its  natural  diameter."  Dr.  Bos- 
tock''  appears  to  coincide  with  Dr.  Parry,  if  we  understand  him  rightly, 
or  at  all.  "  According  to  this  doctrine,"  he  remarks,  "  we  must  regard 
the  artery  as  an  elastic  and  distensible  tube,  which  is  at  all  times  filled, 
although  with  the  contained  fluid  not  in  an  equally  condensed  state, 
and  that  the  effect  produced  upon  the  finger  depends  upon  the  amount 
of  this  condensation,  or  upon  the  pressure  which  it  exercises  upon  the 
vessel,  as  determined  by  the  degree  in  which  it  is  capable  of  being 
compressed.  Where  there  is  no  resistance  to  the  flow  of  the  blood 
along  the  arteries,  there  is  no  variation,  it  is  conceived,  in  their  dia- 
meter, and  it  is  only  the  pressure  of  the  finger  or  some  other  substance 
against  the  side  of  an  artery  that  produces  its  pulse." 

Most  of  the  theories  of  the  pulse  take  the  contractility  of  the  artery 
too  little  into  account.  In  pathology,  where  we  have  an  opportunity 
for  observing  the  pulse  in  various  phases,  we  meet  with  sensations, 
communicated  to  the  finger,  which  it  is  difficult  to  explain  upon  any 
theory,  except  that  of  the  compound  action  of  the  heart  and  arteries. 
The  impulse  is  obviously  that  of  the  heart,  and  although  the  fact  of 
distension  escaped  the  observation  of  Bichat,  Parry,  Weitbrecht,  La- 
mure,  Dollinger,  Rudolphi,*  Jager,^  and  others,  we  ought  not  to  con- 

'  Comment.  Acad.  Imper.  Scient.  Petropol.  ad  An.  1734  and  1735,  Petrop.,  1740. 

*  Croonian  Lectures,  in  Pliilos.  Transact,  for  1809,  part  i. 

3  An  Experimental  Inquiry  into  the  Nature,  Causes,  and  Varieties  of  the  Arterial 
Pulse,  by  Caleb  Hillier  Parry,  London,  1816;  also,  Additional  Experiments  on  the 
Arteries  of  Warm-blooded  Animals,  &c.,  by  Charles  Henry  Parry,  M.  D.,  &c.,  Loudon, 
1819. 

*  Physiology,  3d  edit.,  p.  246,  Lond.,  1836. 

s  Grundris's  der  Physiologie,  2ter  Band.  2te  Abtheil.,  s.  301,  Berlin,  1828. 
''  Tractatus  Anatomico-physiologicus  de  Arteriarum  Pulsu.,  Virceb.,  1830. 


PULSE.  445 

elude,  that  it  does  not  occur.  It  is,  indeed,  difficult  for  us  to  believe, 
that  such  an  impulse  can  be  communicated  to  a  fluid  filling  an  elastic 
vessel  without  pulsator}^  distension  supervening.  In  opposition,  too, 
to  the  negative  observations  of  Bichat  and  Parr}^,  we  have  the  positive 
averment  of  Dr.  Hastings,  and  of  Poiseuille/  Oesterreicher,  Segalas, 
and  Wedemeyer,  that  the  alternate  contraction  and  dilatation  of  the 
larger  arteries  were  clearly  seen.^  M.  Flourens  encircled  a  large 
artery  with  a  thin  elastic  metallic  ring  cleft  at  one  point.  At  the  mo- 
ment of  pulsation  the  cleft  part  became  perceptibly  widened.^ 

The  pulsations  of  the  different  arteries  are  pretty  nearly  sj'nchronous 
with  that  of  the  left  ventricle.  Those  of  the  vessels  near  the  heart 
may  be  regarded  as  almost  wholly  so;  but  an  appreciable  interval  exists 
in  the  pulsations  of  the  more  remote. 

We  have  remarked,  that  the  arterial  system  is  manifestly  more  or 
less  affected  by  the  nerves  distributed  to  it ;  that  it  may  be  stimulated 
by  irritants,  applied  to  the  great  nervous  centres,  or  to  the  nerves  pass- 
ing to  it ;  and  this  is,  doubtless,  the  cause  of  many  of  the  modifications 
of  arterial  tension,  noticed  in  disease.  Inflammation  cannot  affect  a 
part  of  the  system,  for  any  length  of  time,  without  both  heart  and 
arteries  participating,  and  affording  unequivocal  evidence  of  it.  This, 
however,  is  a  subject  that  belongs  more  especially  to  pathology. 

The  ordinary  number  of  pulsations,  per  minute,  in  the  healthy  adult 
male,  is  from  seventy  to  seventy-five;  but  this  varies  greatly  according 
to  temperament,  habit  of  life,  position, — whether  lying,  sitting,  or  stand- 
ing, kc.  Dr.  Guy,''  from  numerous  observations,  found  the  pulse,  in 
healthy  males,  of  the  mean  age  of  27  years,  in  a  state  of  rest,  79  when 
standing;  70,  sitting,  and  67,  lying;  the  difference  between  standing 
and  sitting  being  9  beats;  between  sitting  and  lying,  3  beats;  and  be- 
tween standing  and  lying,  12  beats.  When  all  exceptions  to  the  general 
rule  were  excluded,  the  numbers  were; — standing,  81;  sitting,  71; 
lying,  66; — the  difference  between  standing  and  sitting  being  10  beats; 
between  sitting  and  lying,  5  beats ;  and  between  standing  and  lying, 
15  beats.  The  effect,  produced,  upon  the  pulse  by  change  of  posture. 
Dr.  Guy  ascribes  to  muscular  contraction,  whetlier  employed  to  change 
the  position  of  the  bodj^,  or  to  maintain  it  in  the  same  position.  In 
children,  the  difference  between  the  pulse  in  the  sitting  and  lying  pos- 
ture is  often  very  marked.  In  a  boy,  six  years  of  age,  observed  by 
the  author,  it  amounted  to  fifteen  beats ;  and  Dr.  Evanson^  states,  that 
he  has  often  found  the  pulse — which  at  night  (during  sleep)  was  80, 
full  and  steady — up  to  100  or  even  120  during  the  day,  small  and  hur- 
ried,— and  this  in  children  six  or  seven  years  of  age,  and  in  perfect 
health. 

In  some  individuals  in  health,  the  number  of  beats  is  singularly  few. 

'  Repertoire  generale  d'Anatomle,  &c.,  par  Brescliet,  1829,  torn.  vi.  and  vii.,  and 
Magendie's  Journal  de  Physiol.,  viii.  and  ix, 

^  For  a  mode  of  estimating  the  arterial  distension,  see  Poiseuille,  in  Magendie's 
Journal  de  Physiologic,  ix.  44,  and  Jules  Herison's  description  of  an  instrument — 
Splii/ginometer — which  makes  the  action  of  the  arteries  apparent  to  the  eye. 

'^  Kirkes  and  Paget,  Manual  of  Physiology,  2d  Amer.  edit.,  p.  98,  Philad.,  1853. 

*  Guy's  Hospital  Reports,  No.  vi.,  April,  1838,  x>-  92. 

^  Practical  Treatise  on  the  Management  and  Diseases  of  Children,  by  Messrs.  Evan- 
son  and  Maunsell:  Amer.  edit.,  by  Dr.  Condie,  p.  19,  Philad.,  1843. 


446 


CIRCULATION". 


The  pulse  of  a  person  known  to  the  author  was  on  the  average  thirtj- 
six  per  minute;  and  Lizzari'  affirms,  that  he  knew  a  person  in  whom  it 
was  not  more  than  ten.  It  is  not  improbable,  liowever,  that  in  these 
cases,  obscure  beats  may  have  taken  place  intermediately,  and  yet  not 
have  been  detected.  In  a  case  of  pericarditis,  in  which  the  author  felt 
great  interest,  the  pulse  exhibited  a  decided  intermission  every  few  beats, 
yet  the  heart  beat  its  due  number  of  times ;  the  intermission  of  the 
pulse  at  the  wrist  consisting  in  the  loss  of  one  of  the  beats  of  the  heart. 
It  was  not  improbable  but  that  in  this  case  the  contractility  of  the  aorta 
wus  unusually  developed  by  the  inflammatory  condition  of  the  heart; 
and  that  the  flow  of  blood  from  the  ventricle  was  thus  occasionally 
spasmodically  diminished  or  entirely  impeded.  On  the  other  hand,  the 
natural  pulse  is,  at  times,  far  above  the  average, — 100  and  upwards  in 
the  minute.  It  is  affirmed  that  the  pulse  of  Sir  William  Congreve'^ — 
the  inventor  of  the  well-known  Congreve  rockets — when  he  was  in 
apparently  good  health  never  fell  below  one  hundred  and  twenty- 
eight  beats  per  minute.  The  quickest  pulse,  which  Dr.  Elliotson^ 
ever  felt,  was  208,  counted  easily,  he  says,  at  the  heart;  though  not  at 
the  wrist. 

The  pulse  of  the  adult  female  is  usually  from  ten  to  fourteen  beats  in 
a  minute  quicker  than  that  of  the  male.  In  infancy,  it  is  generally 
irregular,  intermitting,  and  always  rapid,  and  it  gradually  becomes 
slower  in  the  progress  of  age.  It  is,  of  course,  impossible  to  arrive  at 
any  accurate  estimate  of  its  comparative  frequency  at  different  pei'iods 
of  life,  but  the  following  average  by  Ileberden,"*  Somniering,  and 
Mliller,*  have  generally  been  received.  They  are  inaccurate,  however, 
in  regard  to  old  age,  more  especially. 


Ages. 

Number  of  beats  per  minute,  according  to 

Ileberdeu. 

Siimmering.        |            Muller. 

In  the  embryo. 
At  birth,  . 
One  month, 
One  year. 
Two  years. 
Three  years,     . 
Seven  years,     . 
Twelve  years,  . 
Puberty,  . 
Adult,      . 
Old  age,   . 

130  to  140 

120 

120  to  108 

108  to    90 

90  to    80 

72 

70 

120 

no 

90 

80 
70 
60 

150 
Do. 

115  to  130 

100  to  115 

90  to  100 

85  to    90 

80  to    85 
70  to    75 
50  to    05 

A  nearer   approximation  is   given  by  Dr.  Guy  in   the  following 

table : — 


'  Raccolta  D'Opusculi  Scientific,  p.  205  ;  and  Good's  Study  of  Medicine,  Physiolo- 
gical I'niern  to  class  iii.  II;ematica.  See  Cases  of  Slowness  of  Pulse,  by  Mr.  Mayo, 
Lond.  Med.  Gaz.,  May  5,  1838,  p.  232. 

2  Adventures  and  Recollections  of  Colonel  Landmann,  late  of  the  Corps  of  Royal 
Engineers,  i.  12,  London,  1852. 

^  Human  Physiology,  p.  215,  London,  1840.  *  Med.  Transact.,  ii.  21. 

*  Handbuch  der  Pliysiologie,  Baly's  translation,  p.  171,  London,  1838. 


PULSE — ACCOEDIXG   TO    AGE   AXD   SEX. 


447 


j               Age.               1  Slaxinuim. 

Minimum. 

Mean. 

Range. 

1   2to  5 

128 

80 

105 

48 

5  to  10 

124 

72 

93 

52 

10  to  15 

120 

68 

88 

52 

15  to  20 

108 

56 

77 

52 

20  to  25 

124 

56 

78 

68 

25  to  30 

100 

53 

74 

47 

30  to  35 

94 

58 

73 

36 

35  to  40 

100 

56 

73 

44 

40  to  45 

104 

50 

75 

54 

45  to  50 

100 

49 

71 

51 

1  50  to  55 

88 

55 

74 

33 

55  to  60 

108 

48 

74 

60 

60  to  65 

100 

54 

72 

46 

65  to  70 

96 

52 

75 

44 

70  to  75 

104 

54 

74 

50 

75  to  80 

94 

50 

72 

44 

80  and  upwards, 

98 

63 

79 

35 

Dr.  Guy^  lays  down  the  following  as  a  near  approximation  to  the 
average  numbers  at  the  several  leacliDg  periods  of  life.  It  must  be 
borne  in  mind,  that,  as  in  all  similar  cases,  such  averages  can  never 
apply  to  special  examples. 

At  birth, 140  Adult  age, 75 

In  infancy, 120  Old  age, 70 

Childhood, 100  Decrepitude,           .         .         .      75 — 80 

Youth, 90 

Researches  by  MM.  Hourmann  and  Dechambre,^do  not  accord  with 
the  estimates  in  respect  to  the  smaller  number  of  pulsations  in  the  acred. 
MM.  Leuret  and  Mitivie  had  suspected  an  error  in  this  matter  from  an 
examination  of  71  of  the  aged  inmates  of  the  Bicetre  and  La  Salpe- 
tri^re.  MM.  Hourmann  and  Dechambre  examined  255  women  be- 
tween the  ages  of  60  and  96,  and  found  the  average  number  of  the 
pulse  to  be  82-29.  M.  Rochoux,^  however,  still  believes— from  the 
results  of  his  own  observations  as  well  as  those  of  others — that,  as  a 
general  rule,  the  frequency  of  the  pulse  diminishes  in  the  progress  of 
age.  The  attention  of  Dr.  Pennock,^  of  Philadelphia,  has  more  recently 
been  directed  to  the  subject ;  and  the  author  has  great  confidence  in 
the  authenticity  of  results  recorded  by  him.  In  170  males,  and  203 
females,  of  the  average  age  of  about  67,  the  average  frequency  of  the 
pulse  was  75.  The  difference  between  the  pulse  of  the  male  and  female 
continues  to  be  well  marked  in  advanced  life.  MM.  Leuret  and  ]\Iitivie 
found  the  average  frequency  in  27  aged  men,  73  ;  and  in  3-1  aged 
women,  79.  The  average  obtained  by  Dr.  Pen  nock  was  72  for  the 
former  ;  78  for  the  latter. 

Dr.  Gorham*  assigns  130  as  the  mean  number  of  the  pulse  from 
five  months  to  two  years  old;  and  107-63  from  two  to  four  years, 
whence  the  number  continues  almost  the  same  up  to  the  tenth  3'ear. 

'  Art.  Pulse,  Cyclop,  of  Anat.  and  Physiol.,  Pt.  xsxi.  p.  183,  Lond.,  May,  1848. 

*  Archiv.  Grenerales  de  Med.  pour  1835. 

^  Art.  Pulse,  in  Diet,  de  Med.,  2de  edit.,  xxv.  619,  Paris,  1842. 

*  Amer.  Journ.  of  the  Medical  Sciences,  July,  1S47,  i>.  68. 

*  Lond.  Med.  Gaz.,  Nov.  25,  1837. 


44:8  CIRCULATION. 

nis  estimates,  however,  are  much  higher  than  those  of  ^l.  Yalleix.^ 
M.  Trousseau,^  from  repeated  observations,  infers,  that  but  little  stress 
ought  to  be  laid  on  the  pulse  in  the  diagnosis  of  disease  in  infants.  lie 
found,  that  daring  the  first  two  weeks,  it  may  vary  from  78  to  150; 
during  the  second  fortnight,  from  120  to  164;  from  one  to  two  months, 
from  96  to  132 ;  two  to  six  months,  100  to  162;  six  to  twelve  months, 
100  to  160;  and  from  twelve  to  twenty-one  months,  96  to  1-10.  From 
the  observations  of  MM.  Billard,  Valleix,  and  others,  it  would  seem, 
that  the  pulse  of  the  fcjetus  at  the  moment  it  is  expelled  from  the  uterus 
often  falls  to  83  in  the  minute,  and,  in  some  minutes  afterwards,  rises 
to  160.  In  the  course  of  the  first  day,  it  falls  again  to  127,  and  con- 
tinues to  diminish  during  the  first  ten  days,  the  average  being  then 
from  87  to  90.  These  are,  however,  only  averages :  the  variations  are 
very  great.  Sex  appeared  to  have  some  influence.  In  infants,  from 
eight  days  to  six  months  old,  the  average  number  of  pulsations  for 
boys  was  131;  for  girls,  134;  from  six  to  twenty-one  months,  the 
average  for  boys  was  113;  for  girls,  126.  The  state  of  sleeping  or 
waking  had  a  greater  influence.  In  infants  from  fifteen  days  to  six 
months  old,  the  average  of  the  pulse  was  140  during  waking;  121 
during  sleep.  He  has  known  it  rise  from  112  to  160  and  180,  when 
the  child  cried  or  struggled.  On  the  whole,  M.  Trousseau  concludes, 
that  the  pulse  of  children  at  the  breast  varies  from  100  to  150.  After 
the  first  two  months,  it  is  a  little  more  frequent  in  females  than  in 
males;  and  is  about  20  higher  in  the  waking  than  in  the  sleeping  state. 

Strange  to  say,  it  may  be  wholly  absent,  without  the  health  seem- 
ing to  be  interfered  with.  A  case  of  the  kind  is  referred  to  by  Prof. 
S.  Jackson,^  as  having  occurred  in  the  mother  of  a  physician  of  Phila- 
delphia. The  pulse  disappeared  during  an  attack  of  acute  rheuma- 
tism, and  could  never  again  be  observed.  Yet  she  was  active  in  body 
and  mind,  and  possessed  unusual  health.  In  no  part  of  the  body 
could  a  pulse  be  detected.  Dr.  Jackson  attended  her  during  a  part  of 
her  last  illness — inflammation  of  the  intestines ;  no  pulse  existed.  She 
died  whilst  he  was  absent  from  the  city,  and  no  examination  of  the 
body  was  made. 

Between  the  number  of  pulsations  and  respirations  there  would  not 
appear  to  be  any  fixed  relation.  In  many  persons  the  ratio  in  health 
is  4  to  l,"*  but  in  disease  it  varies  greatl3\*  Dr.  Elliotson^  alludes  to  a 
case  of  nervous  disease  in  a  female  at  the  time  in  no  danger  whose 
respiration  was  106,  and  pulse  104. 

'  Memoires  de  la  Societe  Medicale  d'Observation  de  Paris,  torn,  ii.,  Paris,  1844. 

*  Jouro.  des  Connaiss.  Med.-Chir.,  .Juillet  &  Aout,  1841 ;  cited  in  Amer.  Journ.  of  the 
Med.  Sciences,  Oct.,  1841,  p.  458,  and  Jan.,  1842,  p.  199. 

'^  The  Principles  of  Medicine,  founded  on  the  Structure  and  Functions  of  the  Animal 
Organism,  p.  492,  Pliilad.,  1832.  A  case  of  complete  disappearance  of  the  beating  of 
the  heart  is  in  Gazette  Medicale,  21  Nov.,  1836  ;  and  analogous  cases  are  given  in 
Parry  on  the  Pulse,  Bath,  1816,  and  in  Medico-Chirurg.  Review,  xix.  285,  and  April, 
1836. 

■•  Quetelet,  Sur  L'Homme,  p.  87 ;  also,  Guy,  Pennock,  &c.,  in  Art.  Pulse,  op.  cit., 
and  Dr.  John  Reid,  art.  Respiration,  ibid.,  pt.  xxxii.  p.  338,  Lond.,  1848. 

-  P.  A.  Jochmanu,  Beobachtungen  iiber  die  KorperwUrme  in  Chronischen  Fieber- 
haften  Krankheiten,  s.  82,  Berlin,  1853. 

s  Human  Physiology,  p.  215,  Lond.,  1835.  See,  also,  Dr.  Ch.  Hooker,  of  New  Haven, 
Conn.,  in  Boston  Medical  and  Surgical  Journal,  for  May  16,  23,  &c.,  1838. 

. 


USES.  449 

Dr.  Knox^  has  made  some  observations  on  the  pulsations  of  the 
heart,  and  on  its  diurnal  revolution  and  excitability,  from  which  he 
infers:  1,  The  velocity  of  the  heart's  action  is  in  a  direct  ratio  with 
the  age  of  the  individual,— being  quickest  in  young  persons,  slowest 
in  the  aged.  There  may  be  exceptions  to  this,  but  they  do  not  affect 
the  general  law.  2.  There  are  no  data  to  determine  the  question  of 
an  average  pulse  for  all  ages.  3.  There  is  a  morning  acceleration  and 
an  evening  retardation  in  the  number  of  the  pulsations  independently 
of  any  stimulation  by  food,  &c.  4.  The  excitability  of  the  heart  un- 
dergoes a  daily  revolution ; — that  is,  food  and  exercise  affect  its  action 
most  in  the  morning  and  during  the  forenoon ;  less  in  the  afternoon, 
and  least  of  all  in  the  evening.  Hence  it  might  be  inferred,  that  the 
pernicious  use  of  spirituous  liquors  must  be  greatly  aggravated  in 
those  who  drink  before  dinner.  5.  Sleep  does  not  farther  affect  the 
heart's  action  than  through  the  cessation  of  all  voluntary  motion,  and 
a  recumbent  position.  (5.  In  weak  persons,  muscular  action  excites 
that  of  the  heart  more  powerfully  than  in  the  strong  and  healthy ;  but 
this  does  not  apply  to  other  stimulants, — Avine  and  spirituous  liquors, 
for  example.  7.  The  effect  of  the  position  of  the  body  in  increasing 
or  diminishing  the  number  of  pulsations  is  solely  attributable  to  the 
muscular  exertion  required  to  maintain  the  body  in  the  sitting  or 
erect  posture ;  the  debility  may  be  measured  by  altering  the  position 
of  the  person  from  a  recumbent  to  a  sitting  or  erect  one.  8.  The  most 
powerful  stimulant  to  the  heart's  action  is  muscular  exertion.  The 
febrile  pulse  never  equals  this.^ 

h.    Uses  of  the  Circulation. 

The  chief  uses  of  the  circulation  are, — to  transmit  to  the  lungs  the 
products  of  absorption,  in  order  that  they  may  be  converted  into  arte- 
rial blood ;  and  to  convey  to  the  organs  such  arterial  blood,  which 
is  not  only  necessary  for  their  vitality,  but  is  the  fluid  by  which  the 
different  processes  of  nutrition,  calorification,  and  secretion  are  effected. 
The  vessels  are  the  mere  carriers  of  pabulum  to  the  tissues ;  the  cells 
of  which  obtain  from  the  blood  the  materials  that  are  necessary  for 
building  up  each  tissue.  It  is  therefore  outside  of  the  vessel,  that 
every  formative  act  is  accomplished.  Mr.  Paget^  properly  animad- 
verts on  the  error  and  confusion,  which  result  from  speaking  of  the 
"action  of  vessels,"  as  if  the  vessels  really  made  and  unmade  the  parts. 

"  We  have  no  knowledge" — he  adds — "of  the  vessels  as  anything 
but  carriers  of  the  materials  of  nutrition  to  and  fro.  These  materials 
ma}'-,  indeed,  undergo  some  change  as  they  pass  through  the  vessels' 
walls;  but  that  change  is  not  an  assuming  of  definite  shape;  the  ves- 
sels only  convey  and  emit  the  'raw  material;'  it  is  made  up  in  the 
parts,  and  in  each  after  its  proper  fashion.  The  real  process  of  forma- 
tion of  tissues  is  altogether  extra-vascular,  even,  sometimes,  very  far 
extra- vascular ;  and  its  tissue  depends  in  all  cases  chiefly,  and  in  some 

'  Edinburgh  Medical  and  Surgical  Journal,  April,  1837. 

^  The  article  on  the  Pulse,  by  Dr.  Guy,  in  Cyclop,  of  Anat.  and  Physiology,  is  an 
excellent  rcsuw'  of  the  whole  subject.  See  also  Berard,  Cours  de  Physiologic,  3ie  livrai- 
son,  p.  101,  Paris,  1855. 

*  Lectures  on  Surgical  Pathology,  Amer.  edit.,  p.  40,  Pliilad.,  1854. 
VOL.  I.— 29 


450  CIRCULATION. 

entirely,  on  the  affinities  (if  we  may  so  call  tliem)  between  tlie  part  to 
be  nourished  and  the  nutritive  fluid." 

It  may  be  remarked  in  conclusion,  that  the  agency  of  the  blood,  as 
the  cause  of  health  or  disease,  has  had  greater  importance  assigned  to 
it  than  it  merits ;  and  that  although  the  blood  may  be  the  medium, 
by  which  the  source  of  disease  is  conveyed  to  other  organs,  we  cannot 
look  to  it  as  the  seat  of  those  taints  that  are  commonly  referred  to  it. 
"  Upon  the  whole,"  says  Dr.  Good,^  "  we  cannot  but  regard  the  blood 
as,  in  many  respects,  the  most  important  fluid  of  the  animal  machine : 
from  it  all  the  solids  are  derived  and  nourished,  and  all  the  other 
fluids  are  secreted ;  and  it  is  hence  the  basis  or  common  pabulum  of 
every  part.  And  as  it  is  the  source  of  general  health,  so  is  it  also  of 
general  disease.  In  inflammation,  it  takes  a  considerable  share,  and 
evinces  a  peculiar  appearance.  The  miasms  of  fevers  and  exanthems 
are  harmless  to  every  part  of  the  system,  and  only  become  mischiev- 
ous when  they  reach  the  blood ;  and  emetic  tartar,  when  introduced 
into  the  jugular  vein,  will  vomit  in  one  or  two  minutes,  although  it 
might  require  perhaps  half  an  hour  if  thrown  into  the  stomach,  and  in 
fact  it  does  not  vomit  till  it  has  reached  the  circulation.  And  the 
same  is  true  of  opium,  jalap,  and  most  of  the  poisons,  animal,  mineral, 
and  vegetable.  If  imperfectly  elaborated,  or  with  a  disproportion  of 
some  of  its  constituent  principles  to  the  rest,  the  whole  system  par- 
takes of  the  evil,  and  a  dysthesis  or  morbid  habit  is  the  certain  conse- 
quence; whence  tabes,  atrophy,  scurvy,  and  various  species  of  gan- 
grene. And  if  it  becomes  once  impregnated  with  a  peculiar  taint,  it 
is  wonderful  to  remark  the  tenacity  with  which  it  retains  it,  though 
often  in  a  state  of  dormancy  and  inactivity  for  years,  or  even  entire 
generations.  For  as  every  germ  and  fibre  of  every  other  part  is 
formed  and  regenerated  from  the  blood,  there  is  no  other  part  of  the 
systera  that  we  can  so  well  look  to  as  the  seat  of  such  taints,  or  the 
predisposing  cause  of  the  disorders  I  am  now  alluding  to  ;  often  cor- 
poreal, as  gout,  struma,  phthisis:  sometimes  mental,  as  madness;  and 
occasionally  both,  as  cretinism." 

This  picture  is  largely  overdrawn.  Setting  aside  the  erroneous 
pathological  notions  that  assign  to  the  blood  what  properly  belongs  to 
cell  life  in  the  system  of  nutrition,  how  can  we  suppose  a  taint  to  con- 
tinue for  years,  or  even  entire  generations,  in  a  fluid  which  is  perpetu- 
ally undergoing  mutation ;  and,  at  any  distant  interval,  cannot  be 
presumed  to  have  one  of  its  quondam  particles  remaining?  Were  all 
hereditary  diseases  derived  from  the  mother,  we  could  better  compre- 
hend this  doctrine  of  taints ;  inasmuch  as,  during  the  whole  of  foetal 
existence,  she  transmits  the  pabulum  for  the  support  of  her  offspring. 
The  child  is,  however,  equally  liable  to  receive  the  taint  from  the 
father,  who  supplies  no  pabulum,  but  merely  a  secretion  from  the 
blood  at  a  fecundating  copulation,  and  from  that  moment  can  exert  no 
influence  on  the  character  of  the  progeny.  The  impulse  to  this  or 
that  organization  or  conformation  must  be  given  from  the  moment  of 
union  of  the  particles,  furnished  by  each  parent  at  a  fecundating  inter- 
course; and  it  is  probable,  that  no  material  influence  is  exerted  sub- 

'  Op.  cit. 


TBANSFUSION   AND   INFUSION.  451 

sequently  even  by  the  motlier,  except  througli  the  pabuhim  she  fur- 
nishes. The  embryo  accomplishes  its  own  construction,  as  independ- 
ently of  the  parents  as  the  chick  in  ovo. 

i.  Transfusion  and  Infusion. 

The  operation  of  Transfusion, — as  well  as  of  Infusion  of  medicinal 
agents, — was  referred  to  in  an  early  part  of  this  chapter,  to  prove  the 
course  of  the  circulation  to  be  from  the  arteries  into  the  veins.  Both 
these  operations  were  suggested  by  the  discovery  of  Harvey.  The 
former,  more  especially,  was  looked  upon  as  a  means  of  curing  all  dis- 
eases, and  of  renovating  the  aged  ad  libitum.  The  cause  of  every 
disease  and  decay  was  presumed  to  reside  in  the  blood,  and,  conse- 
quently, all  that  was  necessary  was  to  remove  the  faulty  fluid,  and 
substitute  pure  blood  obtained  from  a  healthy  animal  in  its  place. 

As  a  therapeutical  agency,  the  history  of  this  operation  does  not' 
belong  to  physiology.  The  detail  of  the  fluctuation  of  opinions  re- 
garding it,  and  its  total  disuse,  are  given  at  some  length  in  the  Histo- 
ries of  Medicine,  to  which  we  must  refer  the  reader.^  It  appears  to 
have  been  first  performed  on  man  in  France  by  Denis  and  Emmerets 
in  1666;  and  in  the  following  year  it  was  practised  in  England  by 
Drs,  Lower  and  King.^  Before  this,  however,  many  experiments  had 
been  made  on  animals.  In  his  "  Diary"  under  the  date  of  the  14th  of 
November,  1666,  Pepys^  has  the  following  entry: — "Dr.  Croone  told 
me,  that  at  the  meeting  of  Gresham  College  to-night,  which,  it  seems, 
they  now  have  every  Wednesday  again,  there  was  a  pretty  experi- 
ment of  the  blood  of  one  dog  let  out,  till  he  died,  into  the  body  of 
another  on  one  side,  while  all  his  own  run  out  on  the  other  side.  The 
first  died  upon  the  place,  and  the  other  very  well,  and  likely  to  do 
well.  This  did  give  occasion  to  many  pretty  wishes,  as  of  the  blood 
of  a  Quaker  to  be  let  into  an  Archbishop,  and  such  like ;  but,  as  Dr. 
Croone  says,  may,  if  it  takes,  be  of  mighty  use  to  man's  health,  for  the 
amending  of  bad  blood  by  borrowing  from  a  better  body." 

There  are  some  interesting  physiological  facts,  connected  with  trans- 
fusion, that  cannot  be  passed  over.  MM.  Prevost  and  Dumas  found 
that  the  vivifying  power  of  the  blood  does  not  reside  so  much  in  the 
serum  as  in  the  red  particles.  An  animal  bled  to  S3mcope  was  not 
revived  by  the  injection  of  water  or  of  pure  serum  at  a  proper  tem- 
perature ;  but  if  blood  of  one  of  the  same  species  was  used,  the  animal 
seemed  to  acquire  fresh  life  at  every  stroke  of  the  piston,  and  was  at 
length  restored. 

The  operation  was  revived  by  Dr.  Blundell,'*  and  by  MM.  Prevost 
and  Dumas;*  the  first  of  whom  employed  it  with  safety,  and  he  thinks 
with  happy  eftects,  in  exhausting  uterine  hemorrhage.     All  these  gen- 

'  K.  Sprengel,  Histoire  de  Medecine,  par  Jourdan,  iv.  120,  Paris,  1815. 

*  J.  P.  Kay,  art.  Transfusion,  Cyclopsedia  of  Practical  Medicine,  Amer.  edit.,  bj 
tlie  author,  iv.,  468,  Philad.,  1845  ;  and  The  Physiology,  &c.  of  Asphyxia,  p.  254, 
Lond.,  1834. 

*  Diary  and  Correspondence  of  Samuel  Pepys,  F.  R.  S.,  by  Lord  Braybrooke,  3d 
edit.,  iii.  336,  London,  1848. 

*  Medico-Chirurgical  Transactions,  ix.  56  ;  and  x.  296  ;  and  Researches,  physiological 
and  pathological,  p.  63,  London,  1825. 

^  Bibliotheque  Uuiverselle,  xvii.  215. 


452  CIRCULATIOX. 

tlemen  remark,  that  it  can  only  be  adopted  with  perfect  safety  in  ani- 
mals of  like  kinds,  or  in  those  the  corpuscles  of  whose  blood  are  of 
similar  configuration.  MM.  Prevost  and  Dumas,  Dieflfenbach,^  and 
Bischoff,^  agree  as  to  the  deadly  influence  of  the  blood  of  the  mam- 
malia Avhen  injected  into  the  veins  of  birds.  This  influence,  according 
to  Miiller,^  is  in  some  way  connected  with  the  fibrin  of  the  blood,  as 
when  blood  deprived  of  fibrin  was  injected  into  the  vessels,  the  animal 
appeared  to  suffer  no  inconvenience. 

The  introduction  of  the  practice  of  infusing  medicinal  agents  into 
the  blood  was  coeval  with  that  of  transfusion.  It  appears  to  have  been 
first  subjected  to  a  philosophical  examination  by  Sir  Christopher  Wren, 
who  practised  it  on  a  malefactor  in  IQb'o.* 

It  is  a  singular  fact,  that  in  cases  of  infusion,  medicinal  substances 
are  found  to  exert  their  specific  actions  upon  certain  parts  of  the  body, 
precisely  in  the  same  manner  as  if  they  had  been  received  into  the  sto- 
mach. Tartar  emetic,  for  example,  vomits,  and  castor  oil  purges  not 
only  as  certainly,  but  with  much  greater  speed;  for,  whilst  the  former, 
as  before  remarked,  requires  to  be  in  the  stomach  for  fifteen  or  twenty 
minutes,  before  vomiting  is  excited,  it  produces  its  effect  in  one  or  two 
minutes,  when  thrown  into  the  veins.  Dr.  E.  Hale,  of  Boston,  has 
published  an  interesting  pamphlet  on  this  subject.^  In  it  he  traces  the 
history  of  the  operation,  detailing  several  interesting  experiments  upon 
animals;  and  one  upon  himself,  which  consisted  in  the  introduction  of 
a  quantity  of  castor  oil  into  the  veins.  In  this  experiment,  he  did  not 
feel  much  inconvenience  immediately  after  the  iujection ;  but  very 
speedily  experienced  an  oily  taste,  which  continued  for  a  length  of 
time,  and  the  medicine  occasioned  much  gastric  and  intestinal  dis- 
turbance, but  did  not  act  as  a  cathartic.  Considerable  difficulty  was 
experienced  in  the  introduction  of  the  oil,  to  wliich  circumstance  M. 
Magendie"  ascribes  Dr.  Hale's  safety;  for  it  is  found,  by  experiments 
on  animals,  that  viscid  fluids,  such  as  oil,  are  unable  to  pass  through 
the  pulmonary  capillaries,  in  consequence  of  which  the  circulation  is 
arrested,  and  death  follows.  Such,  also,  appears  to  have  been  the  result 
of  the  experiments  of  Dr.  Hale  with  })owdered  substances. 

The  injection  of  medicines  into  the  veins  has  been  largely  practised 
at  the  Veterinary  School  of  Copenhagen,  and  with  complete  success — 
the  action  of  the  medicine  being  incomparably  more  speedy,  and  the 
dose  required  much  less.  It  is  rarely  employed  by  the  physician,  ex- 
cept in  experiments  on  animals;  but  it  is  obvious,  that  it  might  be  had 
recourse  to  with  happy  effects,  where  narcotic  and  other  poisons  have 
been  taken,  and  where  the  mechanical  means  for  their  removal  are  not 
at  hand. 

'  Die  Transfusion  des  Blutes,  Berlin,  1828. 

'  Miiller's  Archiy.,  1835;  cited  in  Baly's  translation  of  J.  Miiller's  Handbuch, 
u.  s.  w. 

3  Handbuch  der  Physiol ogie,  Baly's  translation,  i.  141,  London,  1838.  See,  on  the 
different  efl'ects  of  transfusion  of  arterial  and  venous  blood  on  animals,  Bischoif,  in  Miil- 
ler's Archiv.,  Heft  iv.  1838,  cited  in  Brit,  and  For.  Med.  Rev.,  April,  1839,  p.  548. 

*  Chelius,  System  of  Surgery,  translated  by  South,  Ampr.edit.,iii.  62tj,  Pliilad.,  1847. 

*  Boylston  Medical  Prize  Dissertations  for  the  years  1819  and  1821,  p.  100,  Boston, 
1821. 

6  Precis,  &c.,  ii.  430. 


IN"   ANIMALS. 


453 


4.    CIRCULATORY  APPARATUS  IN  ANIMALS. 

In  concluding  tliis  subject,  a  brief  allusion  to  the  circulatory  appa- 
ratus of  other  parts  of  the  animal  kingdom  may  be  interesting  and 
instructive. 

In  the  mammalia  in  general,  the  inner  structure  of  the  heart  is  the 
same  as  in  man;  but  its  situation  differs  materially;  and  in  some  of 
them,  as  in  the  stag  and  pig,  two  small  flat  bones,  called  hones  of  the 
hearty  exist,  where  the  aorta  arises  from  the  left  ventricle.  In  the 
amphibious  mammalia  and  the  cetacea,  it  has  been  supposed,  that  the 
foramen  ovale  in  the  septum  between  the  auricles  is  open  as  in  the 
human  foetus,  to  allow  them  to  pass  a  considerable  time  under  water 
without  breathing;  but  the  observations  of  Blumenbach,  Cuvier,  and 
others  seem  to  show,  that  it  is  almost  always  closed.  Sir  Everard  Home 
found  it  open  in  the  sea  otter,  in  two  instances;  but  these  are  regarded 
by  naturalists  as  exceptions  to  the  general  rule.  In  several  of  the  web- 
footed  mammalia  and  cetacea,  as  in  the  common  otter,  sea  otter,  and 
dolphin,  particular  vessels  are  always  greatly  enlarged  and  tortuous; — 
a  structure  which  has  been  chiefly  noticed  in  the  vena  cava  inferior,  and 
is  supposed  to  serve  the  purpose  of  a  diverticulum,  whilst  the  animal 
is  under  water;  or  to  receive  a  part  of  the  returning  blood,  and  retain 
it  until  respiration  can  be  resumed. 

In  hirds^  the  structure  of  the  heart  universally  possesses  a  singular 
peculiarity.  Instead  of  the  right  ventricle  having  a  membranous  valve, 
as  in  the  left,  and  as  in  all  the  mammalia,  it  is  provided  with  a  strong, 
tense,  and  nearly  triangular  muscle,  which  aids  in  the  propulsion  of 
the  blood  from  the  right  side  of  the  heart  into  the  lungs.  Tliis  is  pre- 
sumed to  be  necessary,  in  consequence  of  their  lungs  not  admitting  of 
expansion  like  those  of  the  mammalia,  and  of  their  being  connected 
with  numerous  air-cells. 

The  heart  of  reptiles  or  amphibia  in  general  con- 
sists either  of  only  one  ventricle,  or  of  two,  which 
freely  communicate,  so  as  to  constitute  essentially 
but  one.  The  number  of  auricles  always  corre- 
sponds with  that  of  the  ventricles.  That  the  cavi- 
ties— auricular  and  ventricular — are,  however, 
single,  although  apparently  double,  is  confirmed 
by  the  fact,  that,  in  all,  there  is  only  a  single 
artery  proceeding  from  the  heart,  which  serves 
both  for  the  pulmonic  and  systemic  circulations. 
After  this  vessel  has  left  the  heart,  it  divides  into 
1  two  branches,  by  one  of  which  a  part  only  of  the 
blood  is  conveyed  to  the  lungs,  whilst  the  other 
proceeds  to  different  parts  of  the  body.  Those 
two  portions  are  united  in  the  heart,  and  after 
being  mixed  together  are  sent  again  through  the 
great  artery.  In  these  animals,  therefore,  aeration 
is  less  extensive  than  in  the  higher;  and  we  can 
thus  understand  many  of  their  peculiarities; — 

how,  for  example,  the  circulation  may  continue,  when  the  animal  is  so 
situate  as  to  be  incapable,  for  a  time,  of  respiration;  as  well  as  the  great 


Fig.  126. 


Circulation  in  the  Frog. 


454 


CIRCULATION. 


Circulation  in  Fishes 


Fig.  128. 


Fig-  127.  resistance  to  ordinary  deranging  influences, 

bj  which  they  are  characterized.     Fig.  126 
represents  the  circulatory  apparatus  of  the 
frog;  in  which  E  is  the  ventricle  and  D  the 
\\Jl'(      //^^'^s  ^^^l^     auricle.     From  the  former  arises  the  aorta  F, 
^V  ({       W  _   .'';'/u/      which  soon  divides  into  two  trunks.     These, 
after  sending  branches  to  the  head  and  neck, 
turn  downwards  (O  and  P),  and  unite  in  the 
single  trunk  A.    This  vessel  sends  arteries  to 
the  body  and  limbs,  which  ultimately  termi- 
nate in  veins,  and  unite  to  form  the  vena  cava 
C.     From  each  of  the  trunks  into  which  the 
aorta  bifurcates  at  its  origin  arise  the  arteries 
F.     These  are  distributed  to  the  lungs,  and 
communicate  with  the  pulmonary  veins,  which 
return  the  blood  to  the  auricle,  D,  where  it 
becomes  mixed  with  the  blood  of  the  systemic 
circulation.  In  the  tadpole  state, the  circulation 
is  branchial,  as  in  fishes.    The  heart  then  sends 
the  whole  of  its  blood  to  the  hranchice  or  gills,  and  it  is  returned  by 
veins  following  the  course  of  the  dotted  lines  M  and  N  (Fig.  126),  which 
unite  to  form  the  descending  aorta.     As  the  lunofs 
undergo  their  developement, small  arterial  branches 
arise  from  the  aorta  and  are  distributed  to  those 
organs;  and  in  proportion  as  these  arteries  enlarge, 
the  original  branchial  arteries  diminish,  until  ulti- 
mately they  are  obliterated,  and  the  blood  flows 
wholly  through  the  enlarged  lateral  trunks,  O  and 
P,  which,  by  their  union,  form  the  descending  aorta. 
In  Jishes,  the  heart  is  extremely  small,  in  propor- 
tion to  the  body;  and  its  structure  is  simple;  con- 
sisting of  a  single  auricle  and  ventricle,  D  and  E 
(Fig.  127).    From  the  ventricle  E  an  arterial  trunk 
arises,  which,  in  most  fishes,  is  expanded  into  a 
kind  of  bulb,  F,  as  it  leaves  the  heart,  and  proceeds 
straight  forward  to  the  hranchice  or  giUs^  G  and  H. 
From  these,  the  blood  passes  into  a  large  artery,  A, 
analogous  to  the  aorta,  which  proceeds  along  the 
spine,  and  conveys  the  blood  to  the  various  parts 
of  the  system;  and,  by  the  vena  cava,  C,  the  blood 
is  returned  to  the  auricle.    This  is,  consequently,  a 
case  of  single  circulation. 

Insects  appear  to  be  devoid  of  bloodvessels. 
Cuvier  examined  all  the  organs  in  them,  which,  in 
red-blooded  animals,  are  most  vascular,  without 
discovering  the  least  appearance  of  a  bloodvessel, 
although  extremel}^  minute  ramifications  of  the 
trachea  were  obvious  in  every  part.  Insects,  how- 
ever, both  in  their  perfect  and  larve  state,  have  a 
membranous  tube  running  along  the  back,  in  which  alternate  dilatations 
and  contractions  are  perceptible,  and  which  has  been  considered  as  their 


Interior  uf  the  Leech. 

a,  a.  Respiratory  cells, 
ft,  6.  Two  large  arteries. 
c,  c.  Mucous  glands,  d,  d. 
Glands  connected  with  the 
testicles,  e,  e.  Testicles. 
/.  Penis,    g.  Uterus. 


KUTRITION.  455 

heart ;  but  it  is  closed  at  both  ends,  and  no  vessels  can  be  perceived 
originating  from  it.  To  this  the  innumerable  ramifications  of  the  trachea 
convey  the  air,  and  thus,  as  Cuvier  has  remarked,  "le  sang  ne  pouvant 
aller  chercher  I'air,  c'est  I'air  qui  va  chercher  le  sang"  ("the  blood  not 
being  able  to  go  in  search  of  the  air — the  air  seeks  the  blood").  Carus, 
however,  discovered  a  continuous  circulation  through  arteries  and  veins 
in  a  few  of  the  perfect  insects,  and  especially  in  some  larves.  Lastly : 
in  many  genera  of  the  class  vermes,  particularly  amongst  molluscous 
animals,  there  is  a  manifest  heart,  which  is  sometimes  of  a  singular 
structure.  Some  of  the  bivalves — it  is  affirmed — have  as  many  as  four 
auricles;  whilst  many  animals, — as  the  leech  and  Lumhricus  vmrivus, — 
have  no  heart ;  but  circulating  vessels  exist,  in  which  contraction  and 
dilatation  are  perceptible. 

The  marginal  figure  (Fig.  128),  of  the  interior  of  a  leech,  given  by 
Sir  Everard  Home,  exhibits  the  mode  of  circulation  and  respiration  in 
that  animal.  There  is  no  heart,  but  a  large  vessel  exists  on  each  side. 
The  water  is  received,  through  openings  in  the  belly,  into  the  cells  or 
respiratory  organs,  and  passes  out  through  the  same. 


CHAPTER  Y. 

NUTRITION. 

The  investigation  of  the  phenomena  of  the  circulation  has  exhibited 
the  mode  in  which  arterial  blood  is  distributed  over  the  body  in  minute 
vessels,  not  appreciable  by  the  naked  eye,  and  often  not  even  with  the 
microscope,  and  so  numerous,  that  it  is  impossible  for  the  finest-pointed 
instrument  to  be  forced  through  the  skin  without  penetrating  one,  and 
perhaps  several.  It  has  been  seen,  likewise,  that  in  the  capillary  system 
of  vessels,  this  arterial  blood  is  changed  into  venous ;  and  it  was  ob- 
served, that  in  the  same  system,  parts  are  deposited  or  separated  from 
the  blood,  and  certain  phenomena  occur,  into  the  nature  of  which  we 
have  now  to  inquire;  beginning  with  those  of  nutrition,  which  comprise 
the  incessant  changes  that  are  taking  place  in  the  body,  both  of  absorp- 
tion and  deposition  for  the  decomposition  and  renovation  of  each  organ. 
Nutrition  is  well  defined  by  M.  Adelon^  as  the  action,  by  which  every 
part  of  the  body,  on  the  one  hand,  appropriates  or  assimilates  to  itself 
a  portion  of  the  blood  distributed  to  it;  and,  on  the  other,  yields  to  the 
absorbing  vessels  a  portion  of  the  materials  that  previously  composed 
it.  The  precise  character  of  the  apparatus,  by  which  this  important 
function  is  accomplished,  we  have  no  exact  means  of  knowing.  All 
admit  that  the  old  matter  must  be  taken  up  by  absorbents,  and  the  new 
be  deposited  by  arteries,  or  by  vessels  continuous  with  them.  As  the 
precise  arrangement  of  these  minute  vessels  is  not  perceptible  by  the 
eye,  even  when  aided  by  powerful  instruments,  their  arrangement  has 
given  rise  to  controversy.  Whilst  some  have  imagined  lateral  pores 
in  the  capillaries,  for  the  transudation  of  nutritive  deposits;  others  have 
presumed,  that  inconceivably  small  vessels  are  given  oft"  from  the  capil- 

'  Physiologie  de  rHomme,  torn.  iii.  p.  359,  2de  edit.,  Paris,  1829. 


456  KUTRITION. 

lary  system,  which  constitute  a  distinct  order,  and  whose  function  is  to 
exhale  the  nutritive  substance, — an  idea,  which,  as  has  been  said  else- 
where, has  been  revived  by  M.  Bourger3^  Hence,  they  have  been 
termed  exhalanis  or  nutritive  exhaJants ;  but  the  anatomical  and  physio- 
logical student  must  bear  in  mind,  that  whenever  the  term  is  used  by 
writers,  they  do  not  always  pledge  themselves  to  the  existence  of  any 
distinct  set  of  vessels,  but  merely  mean  the  minute  vessel,  whatever 
may  be  its  nature,  which  is  the  agent  of  nutrition,  and  conveys  the 
pabulum  to  the  different  tissues. 

In  investigating  the  ph3^siology  of  nutrition,  two  antagonistic  pro- 
cesses demand  attention;  1st.  Decomposition^  by  which  the  tissue  yields 
to  the  absorbing  vessels  a  portion  of  its  constituents ;  and  2dly.  Com- 
position^ by  which  it  assimilates  a  part  of  the  arterial  blood  that  enters 
it,  and  supplies  the  loss  it  had  sustained  by  the  previous  act  of  decom- 
position. The  former  of  these  actions  obviously  belongs  to  the  function 
of  absorption ;  but  its  consideration  was  deferred,  in  consequence  of  its 
close  application  to  the  function  we  are  about  to  investigate.  It  com- 
prises what  is  meant  by  interstitial^  organic,  or  decomposing  absorption, 
and  does  not  require  many  comments,  after  the  long  investigation  of 
the  general  phenomena  of  absorption  into  which  we  entered.  The 
conclusion  then  arrived  at,  was, — that  the  chyliferous  and  lymphatic 
vessels  form  chjde  and  lymph,  respectively,  refusing  the  admission  of 
most  other  substances ; — but  that  they  and  the  veins  admit  every  liquid 
which  possesses  the  necessary  tenuity ;  and  that  whilst  all  the  absorp- 
tions,— which  require  the  substance  acted  upon  to  be  decomposed  and 
transformed, — are  eflected  by  the  chyliferous  and  lymphatic  vessels, 
those  that  demand  no  alteration  are  chiefly  accomplished  through  the 
coats  of  the  veins  by  imbibition.  It  is  easy,  then,  to  deduce  the  agents 
to  which  we  refer  the  absorption  of  decomposition.  As  it  is  exerted 
on  solids,  and  as  these  cannot  pass  through  the  coats  of  the  vessel  in 
their  solid  condition,  it  follows  that  other  ao-ents  than  the  veins  must 
accomplish  the  process;  and,  again,  as  we  never  find  in  the  lymphatic 
vessels  any  thing  but  lymph,  and  have  ever}^  reason  to  believe,  that 
an  action  of  selection  is  exerted  at  their  extremities,  similar  to  that  of 
the  chyliferous  vessels  on  the  heterogeneous  substances  exposed  to  them, 
we  naturally  look  to  the  lymphatics  as  the  main,  if  not  the  sole,  organs 
concerned  in  the  absorption  of  solids. 

It  appears  manifest  that  the  different  tissues  are  endowed  with  a  vital 
attractive  and  elective  force,  which  they  exert  upon  the  blood; — that 
each  tissue  attracts  only  those  materials  of  which  it  is  itself  composed; 
and  thus,  that  the  whole  function  of  nutrition  is  an  affair  of  elective 
affinity;  yet  this  cannot  be  the  force  that  presides  over  the  original 
formation  of  the  tissues  in  the  embryo.  An  attraction  cannot  be  ex- 
erted by  parts  not  yet  in  existence.  To  account  for  this,  it  has  been 
imagined,  that  a  peculiar  force  is  destined  to  preside  over  formation  and 
nutrition,  and  various  names  have  been  assigned  to  it.  B}''  most  of  the 
ancients  it  was  termed  facuUas  formatrix,  nutrix,  auctrix ;  by  Van  Hel- 
mout,'  Bias  alleiativam;  and  by  Bacon, ^ //'iOi'ws  assimilationis.     It  is  the 

'  Opera,  pars  i.  ^  Novum  Orgauum,  lib.  ii.  aplior.  48. 


AGENTS   OF   NUTRITION.  457 

facuJtas  vegetativa  of  Harvey/  the  anima  vegetativa  of  Stahl;^  the  jmis- 
sance  da  moule  interieur  of  Buffou;'  the  vis  essentialis  of  C.  F.  Wolff  ;■• 
and  the  Bildungstrieb  or  nisiis  formativus  oi  JMnvaQwhsich  and  most 
German  writers.*  This  force  is  meant,  when  writers  speak  of  genn 
force,  2^l(istic  force,  force  of  nutrition,  force  of  formation,  and  force  of  vege- 
tation. AVhatever  difference  there  may  be  in  the  terms  selected,  all 
appear  to  regard  it  as  charged  with  maintaining,  for  a  certain  length 
of  time,  living  bodies  and  all  their  parts,  in  the  possession  of  their  due 
composition,  organization,  and  vital  properties;  and  of  putting  them 
in  a  condition,  during  a  certain  period  of  their  existence,  to  produce 
beings  of  the  same  kind  as  themselves.  It  is  obvious,  however,  that 
none  of  these  terms  elucidate  the  intricate  phenomena  of  nutrition, 
and  none  express  more  than — that  living  bodies  possess  a  vital  force^ 
under  the  action  of  which,  formation  and  nutrition  are  accomplished. 

The  important — indispensable — actions  that  constitute  nutrition 
occur  in  the  tissues  supplied  by  the  intermediate  or  capillary  system 
of  vessels;  but  not  in  those  vessels  themselves.  Their  function — as 
before  remarked — is  to  convey  to  the  system  of  nutrition  the  pabulum 
from  which  the  tissues  are  formed;  but  tlie  formation  of  the  tissues  takes 
place  on  the  outside  of  the  vessel;  and  the  organic  cells  are  the  imme- 
diate agents.  It  is  not,  however,  the  whole  of  the  circulating  fluid  that 
constitutes  such  pabulum.  The  blood  corpuscles — excepting  in  a  single 
case,  menstruation — are  not  found  outside  the  vessels  in  the  exercise 
of  the  healthy  functions.  The  liquor  sanguinis  alone  transudes,  and  is 
the  material  on  which  the  nucleated  cell  exerts  its  plastic  power." 

Under  the  idea  that  all  the  vessels  of  the  capillary  system  are 
possessed  of  coats,  it  is  not  so  easy  to  comprehend  how  either  nutri- 
tion or  secretion  can  be  accomplished.  Were  we  to  adopt  the  opinion, 
before  referred  to,  that  many  of  the  vessels  of  the  capillary  system 
consist  of  merabraneless  or  coatless  tubes,  it  would  be  more  readily 
understood,  that  by  the  elective  and  attractive  forces  possessed  by  the 
tissues  and  exerted  by  them  on  the  blood,  materials  may  be  obtained 
from  that  fluid  as  it  passes  through  the  intermediate  system  of  vessels, 
which  may  be  inservient  to  the  nutrition  of  the  tissues  bathed  by  it. 
The  mode  in  which  the  blood  is  distributed  through  the  tissues  may 
be  likened  to  the  distribution  of  the  water  of  a  river  through  a 
marsh,  which  conveys  to  the  animal  and  vegetable  bodies  that  flourish 
in  it  the  materials  for  their  nutrition.  To  adopt  the  language  of  an 
intelligent  and  philosophical  writer,^  "In  every  part  of  the  body,  in. 
the  brain,  the  heart,  the  lung,  the  muscle,  the  membrane,  the  bone, 
each  tissue  attracts  only  those  constituents  of  which  it  is  itself  com- 
posed. Thus,  the  common  current,  rich  in  all  the  proximate  constituents 
of  the  tissues,  flows  out  to  each.     As  the  current  approaches  the  tissue, 

'  De  Generatione  Animaliiim,  Lond.,  1G51,  p.  170. 

^  Theoria  Medica  Vera.  Hal.,  1708.  '  Histoire  Naturelle,  torn.  ii. 

*  De  Generatione,  Hal.,  1759. 

^  Comment.  Societ.  Getting.,  torn.  viii.  ;  and  Institutionos  Pliysiologic?e,  §  31,  Got 
ting.,  1798. 

^  Mulder,  The  Chemistry  of  Vegetable  and  x\nimal  Physiology,  translated  by  From- 
berg,  p.  597,  Edinburgh  and  London,  1849.  See,  also,  on  this  subject,  Paget,  Surgical 
Pathology,  Anier.  edit.,  p.  140,  Philad.,  1854. 

'  The  Philosophy  of  Health,  by  Dr.  Southwood  Smith,  vol.  i.  p.  405,  London,  1835. 


458  NUTRITION. 

the  particles  appropriate  to  the  tissue  feel  its  attractive  force,  obey  it, 
quit  the  stream,  mingle  with  the  substance  of  the  tissue,  become  iden- 
tified with  it,  and  are  changed  into  its  own  true  and  proper  nature. 
Meantime,  the  particles  which  are  not  appropriate  to  that  particular 
tissue,  not  being  attracted  by  it,  do  not  quit  the  current,  but,  passing 
on,  are  borne  by  other  capillaries  to  other  tissues,  to  which  they  are 
appropriate,  and  by  which  they  are  apprehended  and  assimilated. 
When  it  has  given  to  the  tissues  the  constituents  with  which  it 
abounded,  and  received  from  them  particles  no  longer  useful,  and 
which  would  become  noxious,  the  blood  flows  into  the  veins,  to  be  re- 
turned by  the  pulmonic  heart  to  the  lung,  where,  parting  with  the  use- 
less and  noxious  matter  it  has  accumulated,  and  replenished  with  new 
proximate  principles,  it  returns  to  the  systemic  heart,  by  which  it  is 
again  sent  back  to  the  tissues." 

Particles  of  blood  are  seen  to  quit  the  current  and  mingle  with  the 
tissues;  particles  are  seen  to  quit  the  tissues,  and  mingle  with  the  cur- 
rent; but  allthat  we  can  see,  as  Dr.  Smith  has  remarked,  with  the  best 
aid  we  can  get,  does  but  bring  us  to  the  confines  of  grand  operations, 
of  which  we  are  altogether  ignorant.  It  is  not  necessary,  however,  for 
the  nutrition  of  certain  parts,  that  they  should  receive  capillary  vessels. 
There  are  tissues,  commonly  termed  extra-vascular,  in  the  substance  of 
which  neither  injection  nor  the  microscope  has  exhibited  the  existence 
of  bloodvessels,  and  which  would  seem  to  derive  their  nourishment  by 
imbibition  from  blood  flowing  in  the  vessels  of  adjacent  tissues.  To 
these  belong  the  crystalline  body,  epidermis  and  epithelium,  hair,  nails, 
enamel  of  the  teeth,  &c.,  &c. 

We  have  said  that  the  main,  if  not  the  sole,  agents  of  the  absorption 
of  solids  are  the  lymphatics.  Almost  all  admit,  that  they  receive  the 
products  of  the  absorption  of  solids ;  but  all  do  not  admit,  that  the 
action  of  taking  up  solid  parts  is  accomplished  immediately  by  the 
absorbents.  They  who  think,  that  a  kind  of  spongy  tissue  or  "  paren- 
chyma" exists  at  the  radicles  of  the  absorbent  vessels,  believe  that 
this  sponge  possesses  a  vital  action  of  absorption,  when  bodies,  possess- 
ing the  requisite  constitution  and  consistence,  are  put  in  contact  with 
it ;  but  they  maintain,  that  the  solid  parts  are  broken  down  by  the  same 
agents — the  extreme  arteries — which  secreted  them,  and  that,  when 
reduced  to  the  proper  fluid  condition,  they  are  imbibed  by  the  paren- 
chyma, and  conveyed  into  the  lymphatics.  But  if  the  existence  of  this 
sponge  were  demonstrated,  the  above  explanation  would  scarcely  be 
admissible,  for  it  could  not  be  conceived  to  do  more  than  imbibe;  it 
could  not  break  down  solids,  and  reduce  them  to  lymph — the  only  fluid 
which,  as  we  have  seen,  is  ever  met  with  in  lymphatics.  Its  existence 
is,  however,  altogether  supposititious.  Besides,  the  arrangement  has  not 
been  invoked  in  favour  of  thecli3diferous  vessels,  which  are  so  analogous 
in  their  organization  and  functions  to  the  lymphatics.  It  has  not  been 
contended,  that  the  arteries  of  the  intestinal  canal  form  the  chyle  from 
the  alimentary  matters  in  the  small  intestine,  and  that  the  office  of  the 
chyliferous  vessels  is  restricted  to  the  reception  of  this  chyle,  imbibed 
and  brought  in  contact  with  their  radicles  by  the  ideal  sponge  or 
parenchyma. 

We  have  before  shown,  that  there  is  every  reason  for  the  belief,  that 


AGENTS   OF   NUTRITION".  459 

a  vital  action  of  selection  and  elaboration  exists  at  the  very  origin  of 
the  chyliferous  vessels ;  and  the  same  may  be  inferred  of  the  lymphatics. 
The  great  difficulty  has  been  to  understand  how  either  exhaling  artery 
or  absorbing  lymphatic  can  reduce  the  solid  matter — of  bone,  for  ex- 
ample— to  the  constitution  and  consistence  requisite  for  entering  the 
lymphatics;  but  we  might  conceive,  that  the  latter  as  readily  as  the 
former,  by  virtue  of  its  vital  properties — for  the  operation  must  be 
admitted  by  all  to  be  vital — and  by  means  of  its  contained  fluid,  might 
soften  the  solid  so  as  to  admit  of  its  being  received  into  the  vessel.  We 
should  still,  however,  have  to  explain  the  mysterious  operation  by 
which  those  absorbents  are  enabled  to  reduce  to  their  elements,  bone, 
muscle,  tendon,  &c.,  and  to  recompose  them  into  the  form  of  lymph. 
Dr.  Bostock'  fancifully  suggests,  that  the  first  step  in  this  series  of 
operations  is  the  death  of  the  part ;  by  which  expression  he  means,  that 
it  is  no  longer  under  the  influence  of  arterial  action.  "It  therefore 
ceases  to  receive  the  supply  of  matter  which  is  essential  to  the  support 
of  all  vital  parts,  and  the  process  of  decomposition  necessarily  com- 
mences." The  whole  of  his  remarks  on  this  subject  are  eminently 
gratuitous,  and  appear  to  be  suggested  by  an  extreme  unwillingness  to 
ascribe  the  process  to  any  thing  but  physical  caiises.  If  there  be,  how- 
ever, any  one  phenomenon  of  the  animal  economy,  which  is  more  mani- 
festly referable  to  vital  action  than  another,  it  is  the  function  of  nutri- 
tion, both  as  regards  the  absorption  of  parts  already  deposited,  and 
the  exhalation  of  new.  We  know  that  the  blood  contains  most  of  the 
principles  that  are  necessary  for  the  nutrition  of  organs,  and  that  it 
must  contain  the  elements  of  all.  Fibrin,  albumen,  fat,  salts,  &c., 
exist  in  it,  and  these  are  deposited,  as  the  blood  traverses  the  tissues; 
but  why  one  of  these  should  be  selected  by  one  set  of  vessels,  and  an- 
other by  another  set,  and  in  what  manner  the  elements  of  those,  not 
already  formed  in  the  blood,  are  brought  together,  is  nnknown  to  us. 

Blood  has  been  'designated  as  "liquid  flesh," — chair  coulante^ — but 
something  more  than  simple  transudation  through  vessels  is  necessary 
to  form  it  into  flesh,  and  to  give  it  the  compound  organization  of  fibrin, 
gelatin,  osmazome,  &c. — in  the  form  of  muscular  fibre  and  areolar 
membrane — as  we  observe  in  the  muscle.  Nothing,  perhaps,  has  more 
clearly  exhibited  the  want  of  knowledge  on  this  subject  than  the  fol- 
lowing vague  attempt  at  solving  the  mystery  by  one  of  the  most  dis- 
tinguished physiologists  of  the  age.  "  Some  immediate  principles,  that 
enter  into  the  composition  of  the  organs  or  of  the  fluids,  are  not  found 
in  the  blood, — such  as  gelatin,  uric  acid,  &c.  They  are  consequently 
formed  at  the  expense  of  other  principles,  in  the  parenchyma  of  the 
organs,  and  by  a  chemical  action,  the  nature  of  which  is  unknown  to 
us,  but  which  is  not  the  less  real,  and  must  necessarily  have  the  effect 
of  developing  heat  and  electricity." 

The  views  of  recent  histologists  have  approximated  us  more  to  a 
true  knowledge  of  this  mysterious  action.  They  have  not  been  con- 
tent with  endeavouring  to  reduce  the  different  organized  textures  to 
primary  fibres  and  filaments,  but,  by  the  aid  of  the  microscope,  have 
attempted  to  discover  the  particular  arrangement  and  mode  of  forma- 

'  System  of  Physiology,  edit.  cit.,p.  625. 


460  NUTRITION. 

tion  of  the  constituent  corpuscles.  The  discovery  of  that  valuable 
instrument  gave  the  impulse ;  and  very  soon  the  scientific  world  was 
presented  with  the  results  obtained  by  numerous  observers.  These 
observations  have  been,  fi-om  time  to  time,  continued  until  the  present 
da}'.  It  is,  however,  to  be  regretted,  that,  until  recently,  our  informa- 
tion, derived  from  this  source,  was  not  as  accurate  as  was  desirable. 
From  different  quarters,  the  most  discordant  statements  were  presented, 
exhibiting  clearly,  either  that  the  narrators  employed  instruments  of 
very  different  powers,  or  that  they  were  blinded,  or  had  the  vision 
depraved,  by  preconceived  theories  or  hj^potheses. 

One  of  the  very  first  effects  of  the  discovery  of  the  microscope  was 
the  detection  by  Leeuenhoek,^  of  a  globular  structure  of  the  primi- 
tive tissues  of  the  body,  an  announcement  which  gave  rise  to  much 
controversy,  and  engaged  the  attention  particularly  of  Prochaska,* 
Foutana,^  Sir  Everard  Home,  Mr.  Bauer,  the  brothers  Wenzel,"*  M. 
Milne  Edwards,  MM.  Prevost  and  Dumas,*  Dutrochet,  Hodgkin,** 
Raspail,  and  others.''  The  observations  and  experiments  of  Dr.  Ed- 
wards, more  especially,  occasioned  at  the  time  much  interesting  specu- 
lation and  inquiry.  They  may  perhaps  be  taken 
Fig.  129.  as  the  foundation  on  which  the  believers  in  the 

globular  structure  of  later  years  rested  their  opi- 
nions. His  views  were  first  published  in  1828, 
in  a  communication,  entitled  '■'' Memoire  sur  la 
Stnicture  elementaire  des  ^5?-wic2):>awa;  Tissues  Or- 
ganiques  des  Animanx  f^  and  in  a  second  article 
in  the  Annales  des  Sciences  Naturelles^  for  Decem- 
ber, 1826,  entitled  ^^ Recherches  ■microscopiques  sur 
la  Structure  intime  des  Tissues  Or  ganiques  des  Ani- 
mauxy  He  examined  all  the  principal  textures 
of  the  body,  the  areolar  tissue,  membranes,  tea- 
,    ^.  dons,  muscular  fibre,  nervous  tissue,  skin,  coats 

Arcoliir  Xissu6  . 

of  the  bloodvessels,  &c.  When  the  areolar  tissue 
was  viewed  through  a  powerful  lens,  it  seemed  to  consist  of  cylinders; 
but,  by  using  still  higher  magnifying  powers,  these  cylinders  were 
found  to  be  formed  of  rows  of  globules  of  the  same  size,  that  is,  about 
the  ^  JQj5th  or  gfj'o^jth  of  an  inch  in  diameter  (Fig.  129);  separated  from 
each  other,  and  lying  in  various  directions;  crossing  and  interlacing; 
some  of  the  rows  straight;  others  bent,  and  some  twisted,  forming 
irregular  layers  united  by  a  kind  of  network.  The  membranes,  which 
consist  of  areolar  tissue,  were  found  to  present  exactly  the  same  kind 
of  arrangement.  The  muscular  fibre,  when  examined  in  like  manner, 
was  found  to  be  formed  of  globules,  also  ggoo^^  P^^^  of  ^^  ^^^*^^^  ^'^ 
diameter.  Here,  however,  the  rows  of  globules  are  always  parallel. 
The  fibres  uev^er  intersect  each  other  like  those  of  areolar  tissue,  and 

'  Opera  Omnia,  Lugdun.  Batav.,  1722.         ^  j>q  Structure  Nervorum,  Viiul.,lT79. 

"  Sur  les  Poisons,  ii.  18.  ''  De  Structura  Cerebri,  Tubing.,  1S12. 

*  Bibliotheque  Universelle  des  Sciences  et  Arts,  t.  xvii. 

^  In  Drs.  Hodgkin's  and  Fisher's  translation  of  W.  Edwards,  Sur  les  Agens  Phy- 
siques, Loud.,  1832. 

'  Klencke,  Ueber  das  Physiolodsche  uud  Pathologische  Leben  der  Mikroskopischen 
Zellen,  .Jena,  1844. 


AGENTS   OF   NUTRITION". 


461 


Fiff.  130. 


Muscular  Tissue. 


Fig.  131. 


this  is  the  only  discenuble  difference, — the  form  and  size  of  the  glo- 
bules being  alike.  The  size  of  the  globules,  and  the  linear  arrange- 
ment they  assume,  seemed  to  be  the  same  in  all  animals  that  possess  a 
muscular  structure.     (Fig.  130.) 

The  nervous  structure  had,  by  almost  all  observers,  been  esteemed 
globular.  The  examination  of  M.  Edwards  yielded 
similar  results.-'  It  seemed  to  be  composed  of  lines  of 
globules  of  the  same  size  as  those  that  form  the  areolar 
membrane  and  muscles;  but  holding  an  intermediate 
place  as  to  the  regularity  of  their  arrangement,  and 
having  a  fatty  matter  interposed  between  the  rows. 
In  regard  to  the  size  of  the  globules,  however,  M.  Ed- 
wards difi'ered  materially  from  an  accurate  and  expe- 
rienced microscopic  observer,  Mr.  Bauer,^  who  asserted 
that  the  cerebral  globules  are  of  various  sizes.  (Fig. 
181.)  From  the  results  of  his  own  diversified  ob- 
servations M.  Edwards  concluded,  that  "spherical 
corpuscles,  of  the  diameter  of  g^gth  of  a  millimetre, 
constitute  by  their  aggregation  all  the  organic  tex- 
tures, whatever  may  be  the  properties,  in  other  re- 
spects, of  those  parts,  and  the  functions  for  which  they  are  destined." 

The  harmony  and  simplicity,  which  would  thus  seem  to  reign 
through  the  structures  of  the  animal  body,  attracted  great  attention  to 
the  labours  of  M.  Edwards.  The  vegetable  king- 
dom was  subjected  to  equal  scrutiny;  and — what 
seemed  still  more  astounding — it  was  affirmed, 
that  the  microscope  proved  it  also  to  be  consti- 
tuted of  globules  precisely  like  those  of  the  ani- 
mal, and  of  the  same  magnitude,  gg'^^th  of  an 
inch  in  diameter;  hence,  it  was  assumed,  that  all 
organized  bodies  possess  the  same  elementary 
structure,  and  of  necessity,  that  the  animal  and 
the  vegetable  are  readily  convertible  into  each 
other  under  favourable  circumstances,  and  differ 
only  in  the  greater  or  less  complexity  of  their 
organization.  Independently  of  all  other  objec- 
tions, however,  the  animal  differs,  as  we  have 
seen,  from  the  vegetable,  in  composition;  and  this  difference  must 
exist  not  only  in  the  whole,  but  in  its  parts;  so  that,  even  were  it  de- 
monstrated that  the  globules  of  the  beings  of  the  two  kingdoms  are 
alike  in  size,  it  would  by  no  means  follow  that  they  should  be  identical 
in  intimate  composition. 

The  discordance,  which  we  have  deplored,  is  strikingly  applicable 
to  the  case  before  us.  The  appearance  of  the  memoir  of  Dr.  Edwards 
excited  the  attention  of  M.  Dutrochet,  and  in  the  following  year  his 
'■''  Recherclies'^  on  the  subject  were  published,  in  which  he  asserts,  that 
the  globules,  which  compose  the  different  structures  of  invertebrated 

'  See,  also,  Calori,  in  Bulletino  delle  Scienze  Medich.  di  Bologna,  Sett.,  1836,  p.  152. 
^  Philosoph.  Transact,  for  1818 ;  and  Sir  E.  Home,  Lectures   on  Comparative  Ana- 
tomy, vol.  iii.  lect.  3,  Lond.,  1823. 


Xervous  Tissue. 


462  NUTRITION. 

animals,  are  considerably  larger  than  those  of  the  vertebrated ;  that 
the  former  appear  to  consist  of  cells,  containing  other  globules  still 
smaller ;  and  hence  he  infers,  that  the  globules  of  vertebrated  animals 
are  likewise  cellular,  and  contain  series  of  still  smaller  globules.  Dr. 
Edwards,  in  his  experiments,  found,  that  the  globules  of  the  nervous 
tissue,  whether  examined  in  the  brain,  in  the  spinal  cord,  ganglia,  or 
nerves,  have  the  same  shape  and  diameter,  and  that  no  difference  in 
them  can  be  distinguished  from  whatever  animal  the  tissue  is  taken. 
M.  Dutrochet,  on  the  other  hand,  considers,  with  Sir  Everard  Home, 
and  the  brothers  Wenzel,  that  the  globules  of  the  brain  are  cellules 
of  extreme  minuteness,  containing  a  medullary  or  nervous  substance, 
which  is  capable  of  becoming  concrete  by  the  action  of  heat  and  acids. 
This  structure,  he  remarks,  is  strikingly  evidenced  in 
Fig.  132.  certain  molluscous  animals ;  and  he  instances  the  small 
pulpy  nucleus,  which  forms  the  cerebral  hemisphere  of 
Umax  rufus^  and  helix  pomatia,  and  is  composed  of 
globular,  agglomerated  cellules,  on  the  parietes  of 
which  a  considerable  number  of  globular  or  ovoid  cor- 
puscles are  perceptible.  (Fig.  132.) 
Cellules  of  Brain.  M.  Dutrochet,  again,  did  not  find  the  structure  of 
the  nerves  to  correspond  with  that  of  the  brain.  He 
asserted,  that  the  elementary  fibres,  which  enter  into  their  composi- 
tion, do  not  consist  simply  of  rows  of  globules,  according  to  the  opi- 
nion of  M.  Edwards  and  others,  but  that  they  are  cylinders  of  a 
diaphanous  substance,  the  surface  of  which  is  studded  with  globular 
corpuscles ;  and  that,  as  these  cover  the  whole  surface  of  the  cylinder, 
we  are  led  to  believe  that  they  are  in  the  interior  also.  After  detail- 
ing this  difference  of  structure  between  the  brain  and  the  nerves,  the 
former  consisting  chiefly  of  nervous  corpuscles,  the  latter  chiefly  of 
cylinders  or  fibres,  M.  Dutrochet  announced  the  hypothesis,  which  ex- 
hibits too  many  indications  of  having  been  formed  prior  to  his  micro- 
scopic investigations, — that  these  cerebral  corpuscles  are  destined  for 
the  production  of  the  nerve  power,  and  that  the  nervous  fibres  are 
tubes,  filled  with  a  peculiar  fluid,  by  the  agency  of  which  nervimoiion 
is  effected.  For  further  developements  of  the  views  of  M.  Dutrochet, 
the  reader  is  referred  to  the  work  itself,  which  exhibits  all  the  author's 
ingenuity  and  enthusiasm,  but  can  scarcely  be  considered  historical. 

The  beautiful  superstructure  of  M.  Edwards,  and  the  ingenuity  of 
M.  Dutrochet,  were,  however,  most  fatally  assailed  by  subsequent  ex- 
periments of  Dr.  Hodgkin  with  a  microscope  of  unusual  power.  The 
globular  structure  of  the  animal  tissues,  so  often  asserted,  and  appa- 
rently so  clearly  and  satisfactorily  established  by  M.  Edwards,  was, 
we  are  told  by  Dr.  Hodgkin,^  a  mere  deception ;  and  the  most  minute 
parts  of  the  areolar  membrane,  muscles,  and  nerves,  were  again  re- 
ferred to  the  striated  or  fibrous  arrangement.  A  part  of  the  discre- 
pancy between  MM.  Edwards  and  Dutrochet  may  be  explained  by  the 
fact  of  the  former  using  an  instrument  of  greater  magnifying  power 
than  the  latter,  who  employed  the  simple  microscope  only ;  and  it  was 
observed,  that  when  the  former  used  an  ordinary  lens,  the  arrangement 

'  Op.  citat.,  p.  46G. 


AGENCY   OF   CELLS   IN  NUTRITION.  463 

of  a  tissue  appeared  cylindrical,  wliich,  witli  tlie  compound  microscope, 
was  distinctly  globular.  The  discordance  between  Messrs.  Edwards 
and  Hodgkin  was  reconcilable  with  more  difficulty.  On  the  whole 
subject,  indeed,  minds  were  kept  in  a  state  of  doubt,  and  the  rational 
physiologist  waited  for  ulterior  developements.  MM.  Prevost  and 
Dumas,  and  M.  Edwards,  farther  affirmed,  that  all  the  proximate  prin- 
ciples— albumen,  fibrin,  gelatin,  &c., — assume  a  globular  form,  when- 
ever they  change  from  the  fluid  to  the  solid  state,  whatever  may  be 
the  cause  producing  such  conversion.  M.  EaspaiP — a  wayward  genius, 
who  has  quitted  the  sober  pursuit  of  science,  for  the  uncertainty  and 
turmoil  of  politics,  from  which  he  has  suffered  greatly — ranged  him- 
self among  those  who  considered,  that  the  ultimate  structure  of  all 
organic  textures  is  vesicular,  and  that  the  organic  molecule,  in  its 
simplest  form,  is  an  imperforate  vesicle,  endowed  with  the  faculty  of 
inspiring  gaseous  and  liquid  substances,  and  of  expiring  again  such  of 
their  elements  as  it  cannot  assimilate ; — properties,  which  he  conceived 
it  to  possess  under  the  influence  of  vitality.  His  views  contain,  per- 
haps, the  germ  of  those  that  follow,  and  that  have  since  occupied  so 
much  the  minds  of  observers. 

The  microscopical  researches  of  Schwann  and  Schleiden^  led  them 
to  affirm,  that  the  new-forming  tissues  of  vegeta- 
bles originate  from  a  liquid  gum  or  vegetable 
mucus,  and  those  of  animals  probably  from  the 
liquor  sanguinis,  after  transudation  from  the  ca- 
pillary vessels.  This  matrix^  in  a  state  fully  pre- 
pared for  the  formation  of  the  tissue,  is  termed  by 
them  intercellular  substance  and  cytohlastema.  In  the 
first  instance,  it  exhibits  minute  granular  points, 

which  grow  and  become  more  regular  and  defined 

from  the  agglomeration  of  minuter  granules  around    Primary  Organic  Cell, 

the  larger,  constituting  nuclei  or  cytohlasts  or  cell-       showing  the  germinal 

germs,  and  having,  when  fully  formed,  and  in  fact       Nucleolus."  ^"^'    ^° 

formed   before   them,   one    or    more    well-defined 

bodies  within,  called  nucleoli.     From  the  c^^toblasts,  cells — primordial 

or  germinal  cells — are  formed.     A  transparent  vesicle  grows  over  each, 

and  becomes   filled  with   fluid;   this 

gradually   extends   and  becomes    so  Fig.  134. 

large  that  the  cytoblast  appears  like 

a   small  body  within  its  walls,    and        •  ©     0      ^ 

hence  the  cell  is  said  to  be  nucleated. 

The  form  of  the  cells  is  at  first  irre- 

p-nlnr     tliPTi    mnrp    rpo-nlqr     qnrl    thpv      PI""  representing  the  formation  of  a  Nu- 

guiar,  tneu  more  regular,  ana  iney       ^j^^^^  ^^^  ^^  ^  ^^^^  ^^  ^^^  Nucleus,  ac- 
are  alternately  flattened  by  pressure       cording  to  Schieideu's  view, 
against  each  other,  so  as  to  assume 

different  forms  in  different  tissues.  Such  is  the  description  of  Schwann 
and  Schleiden  of  the  vegetable  cells  from  which  all  the  tissues  of 

'  Op.  citat.,  §  126. 

*  Mikroskopische  Untersuchungen  iiber  die  TJebereinstimmuiig  in  der  Struktur  und 
dem  Wachstum  der  Thiere  und  Ptlanzen,  von  Dr.  Th.  Schwann  und  Dr.  Schleiden,  in 
Miiller's  Archiv.,  p.  137,  1838  ;  and  Microscopical  Researches  into  the  Accordance  and 
Growth  of  Animals  and  Plants,  translated  by  Henry  Smith,  Sydenham  Society's  edition, 
London,  1847. 


464 


NUTRITION. 


plants  take  their  origin.  In  like  manner,  the  tissues  of  animals  are 
formed  from  a  fluid,  in  which  nncleoli,  nvclei  or  cytohlasts — and  cells, 
are  successively  developed.  The  globules  of  lymph,  pus,  and  mucus, 
are  cells  with  their  walls  distinct  and  isolated  from  each  other;  horny 
tissues  are  cells  with  distinct  walls,  but  united  into  coherent  tissues ; 
bone,  cartilage,  &c.,  are  formed  of  cells  whose  walls  have  coalesced ; 
areolar  tissue,  tendon,  &c.,  are  cells  which  have  split  into  fibres ;  and 
muscles,  nerves,  and  capillary  vessels  are  cells  whose  walls  and  cavi- 
ties have  coalesced. 

These  cells  seem  to  possess  an  independent  and  limited  life,  which 
has  no  immediate  connexion  with  that  of  the  organism;  the  decompo- 
sition constantly  taking  place  in  the  living  body  being  connected  with 
the  death  of  the  cells  of  which  the  several  parts  are  constructed ;  and 
for  the  reintroduction  of  which  into  the  circulating  fluid,  the  lymphatic 
system  appears  to  be  specially  destined.  By  virtue  of  this  vital  power, 
they  not  only  attract  but  change  the  substances  brought  in  contact 
with  them,  or  have  a  power  of  self-nutrition;  and  that  this  is  probably 
independent  of  the  nervous  system  is  shown  by  an  experiment  of  Dr. 
Sharpey,  in  which  the  reproduction  of  a  portion  of  the  tail  of  a  sala- 
mander took  place,  although  it  was  cut  off  after  the  organ  had  been 
completely  paralyzed  by  dissecting  out  at  its  root  a  portion  of  the 
spinal  cord,  together  with  the  arches  of  the  vertebrae.  To  the  doctrine 
of  cell  formation.  Professor  Goodsir,^  of  Edinburgh,  has,  of  late  years, 

made  several  important  additions. 
Amongst  other  observations,  he 
states,  that  besides  all  organs  and 
tissues  having  their  origin  in  and 
consisting  essentially  of  simple  or 
developed  cells  possessed  of  a  spe- 
cial independent  vitalit}'-,  the  com- 
ponent cells  are  divided  into  nu- 
merous departments,  each  of  which 
consists  of  several  cells  arranged 
round  one  central  or  capital  cell, 
which  latter  is  the  source  whence 
all  the  other  cells  in  its  own  de- 
partment derived  their  origin.  To 
each  of  these  several  central  nu- 
cleated cells  he  gives  the  name 
nutritive  centre  or  germinal  spot. 
Plach  nutritive  centre  possesses 
the  power  of  absorbing  materials 
of  nourishment  from  the  surround- 
ing vessels,  and  of  generating,  by 
means  of  its  nucleus,   successive 


Endogenous  Cell-growth  in  Cells  of  a  Melice- 
rous  Tumour. 

a.  Cells  presenting  nuclei  in  various  stages  of  de-     i  i         n  i        ^„„„^11~. 

velopement  into  a  Sew  generation.    6.  Parent-cell     brOOds  OI  yOUUg  eUClOgenOUS  CClls, 
filled  with  a  new  generation  of  young  cells, -n-hicli 
have  originated  from  the  granules  of  the  nucleus. 


which  from  time  to  time  fill  the 

cavity  of  the  parent  cell,  and,  carry- 

ino-  with  them  its  cell-wall,  pass  ofi'  in  certain  directions,  and  under 


'  Anatomical  and  Pathological  Observations,  p.  1,  Edinb.,  1845. 


AGENCY   OF    CELLS    IN   NUTEITION.  465 

various  forms,  according  to  the  texture  or  organ  of  which  the  parent 
forms  a  part.  There  are  two  kinds  of  nutritive  centres, — those  pecu- 
liar to  the  textures,  and  those  belonging  to  organs.  The  former  are  in 
general  permanent ;  the  latter  peculiar  mostly  to  the  embryonic  state, 
and  ultimately  disappearing;  but  there  is  one  form  in  which  the  nutri- 
tive centres  are  arranged  both  in  healthy  and  morbid  parts,  which  con- 
stitutes what  Mr.  Goodsir  calls  a  germinal  membrane.  It  is  only  met 
with  on  the  free  surface  of  organs  or  parts.  It  is  a  fine  transparent 
membrane,  consisting  of  cells  arranged  at  equal  and  variable  distances 
within  it.  The  centres  of  these  component  cells  are  flattened,  so  that 
their  walls  form  the  membrane  by  cohering  at  their  edges,  and  their 
nuclei  remain  in  its  substance  as  germinal  centres.  One  surface  of  the 
membrane  is  attached  to  that  of  the  organ  or  part,  and  is,  therefore, 
applied  upon  a  more  or  less  richly  vascular  tissue ;  the  other  is  free, 
and  it  is  to  it  only  that  the  developed  or  secondary  cells  of  its  germinal 
spots  are  attached.  These  secondary  cells,  whilst  fjrming,  are  contained 
between  the  two  layers  of  the  germinal  membrane;  but  as  they  become 
developed,  they  carry  forward  the  anterior  laj^er,  and  become  attached 
to  the  free  surface,  whilst  the  nuclei  are  left  in  the  substance  of  the  pos- 
terior layer  in  close  contact  with  the  bloodvessels,  from  which  they 
derive  the  materials  for  the  formation  of  new  cells. 

The  doctrine  of  the  developement  of  all  the  organic  tissues  from 
cells  is  now  embraced  by  almost  all  histological  inquirers;  yet  there 
are  some  who  doubt  it ;  and  others,  who  by  no  means  regard  it  as 
applicable  to  all  the  tissues.  Thus  M.  Mandl'  objects  to  the  term 
cytoblastema  as  applicable  to  the  matrix  or  organizing  material  of  the 
tissues,  because  it  necessarily  involves  the  supposition  that  it  gives 
origin  to  cells.  According  to  him,  the  elements,  that  are  developed  in 
the  blastema — as  he  prefers  to  call  it — do  not  generally  deserve  the 
name  of  cells,  inasmuch  as  they  may  either  liquefy  as  in  the  glands; 
consolidate  as  in  the  amorphous  membranes;  or  become  transformed 
directly  into  fibres,  as  in  the  areolar  tissue.  Mr.  Gulliver,^  too,  has 
inferred  from  his  observations,  that  the  mere  extension  of  the  parietes 
of  cells  is  not  essential  to  the  formation  of  all  tissues,  since  fine  fibres 
or  fibrils  are  found  in  fibrin  that  has  coagulated  even  out  of  the  body. 
He  has  given  several  figures  to  exhibit  the  analogy  of  structure  between 
false  membranes  and  fibrin  coagulated  after  death,  or  after  the  removal 
of  the  blood  from  the  body.  iSchwann,  on  the  other  hand,  lays  down 
the  rule,  which  he  considers  of  universal  application,  that  all  organic 
tissues,  however  different  they  may  be,  have  one  common  principle  of 
developement  as  their  basis,  the  formation  of  cells; — that  is  to  say, 
nature  never  unites  molecules  immediately  into  a  fibre,  tube,  &c. ;  but, 
always,  in  the  first  instance,  forms  a  round  cell;  or  changes,  when  it  is 
requisite,  the  cells  into  the  various  primary  tissues,  as  they  present 
themselves  in  the  adult  state;  but  "how,"  says  Mr.  Gulliver,^  "  is  the 
origin  of  the  fibrils,  which  I  have  depicted  in  so  many  varieties  of 
fibrin,  to  be  reconciled  with  this  doctrine  ?  and  what  is  tlie  proof  that 

'  Manuel  d'Anatomie  Generale,  p.  549,  Paris,  1843. 

^  Appendix  to  Gerber's  Anatomy,  Atlas,  p.  60,  and  Figs.  244-6,  Lond.,  1842. 

^  Lond.  and  Edinburgh  Philosoph.  Magazine,  Oct.,  1842. 

VOL.  I. — yu 


466  NUTRITION, 

these  fibrils  may  not  be  the  primordial  fibres  of  animal  textures?  I 
could  never  see  any  satisfactory  evidence,  that  the  fibrils  of  fibrin  are 
changed  cells ;  and,  indeed,  in  many  cases,  the  fibrils  are  formed  so 
quickly  after  coagulation,  that  their  production,  according  to  the  views 
of  the  eminent  physiologist  just  quoted  [Schwann],  would  hardly  seem 
possible.  Nor  have  I  been  able  to  see,  that  these  fibrils  arise  from  the 
interior  of  the  blood-disks,  like  certain  fibres  delineated  in  the  last 
interesting  researches  of  Dr.  Barry."  Mr.  T.  Wharton  Jones,^  also, 
has  considered  the  notion  entertained  by  Dr.  Barry,^that  a  fibre  exists 
in  the  interior  of  the  blood  corpuscles,  and  that  these  fibres,  after  their 
escape  from  them,  constitute  the  fibres  which  are  formed  by  the  con- 
solidation of  the  fibrin  of  the  liquor  sanguinis,  to  be  erroneous.  He 
regards  the  appearance  as  altogether  illusive.  Dr.  Carpenter,^  in  re- 
marking on  Mr.  Gulliver's  figures,  all  of  which,  as  he  properly  observes, 
clearly  show,  that  a  small  portion  of  coagulated  fibrin  contains  a  far 
larger  number  of  fibres  than  we  can  imagine  to  be  contained  in  the 
number  of  blood-disks  that  would  fill  the  same  space,  states,  that  he 
has  discovered  a  very  interesting  example  of  a  membrane  composed 
almost  entirely  of  matted  fibres,  which  so  strongly  resembles  the  deline- 
ations of  fibrous  coagula  given  by  Mr.  Gulliver,  that  he  cannot  but 
believe  in  the  identity  of  the  process  by  which  they  are  produced. 
This  is  the  membrane  enclosing  the  white  of  the  egg,  and  forming  the 
animal  basis  of  the  shell.  If  the  shell  be  treated  with  dilute  acid,  a 
tough  membrane  remains,  exactly  resembling  that  which  lines  it;  and 
if  the  hen  has  not  been  supplied  with  lime,  there  is  no  difierence 
between  the  two  membranes  even  without  the  action  of  acid  on  the 
outer  one.  Each  of  them  consists  of  numerous  laminasof  most  beauti- 
fully matted  fibres  intermixed  with  round  bodies  exactly  resembling 
exudation  cells.  It  is  in  the  interstices  of  these  fibres,  that  the  calca- 
reous particles  are  deposited,  which  give  density  to  the  shell.  These 
membranes,  according  to  Dr.  Carpenter,  are  formed  around  the  albu- 
men, which  is  deposited  on  the  surface  of  tlie  ovary  during  its  passage 
along;  the  oviduct,  from  the  interior  of  which  the  fibrinous  exudation 
must  take  ])lace. 

It  is  clear,  then,  that  this  doctrine  of  the  origin  of  all  the  tissues  from 
cells  cannot  be  considered  established."  Nor  can  ideas  be  esteemed 
more  fixed  in  regard  to  the  character  of  the  matrix  or  blastema.  M. 
MandP  afl&rms  that  we  know  not  whether  it  is  the  albumen  or  fibrin  of 
the  blood.  Others,  and  perhaps  the  majority  of  the  present  day,  ascribe 
it  to  fibrin,  between  which,  as  we  have  elsewhere  seen,  and  albumen, 
there  is,  according  to  Alulder,  Liebig,  and  others,  an  almost  itleutity  of 
chemical  composition.  Fibrin  has  been  considered — but,  as  is  remarked 

'  Proceedings  of  tlie  Royal  Society,  No.  56.  ^  phjios.  Trans,  for  1842. 

3  Origin  and  Functions  of  Cells,  in  Brit,  and  For.  Med.  Rev.  for  Jan.,  1843,  p.  277. 
See  alao  The  Cell:  its  Physiology,  Pathology,  and  Philosophy,  by  Waldo  J.  Burnett, 
M.  D.,  in  Transactions  of  the  American  Medical  Association,  vi.  64.5,  Philad.,  1853; 
and  T.  H.  Huxlev  ou  the  Cell  Theory,  in  Brit,  and  For.  Med.-Cliirurg.  Rev.  for  Oct., 
1853,  p.  285. 

*  "Cette  pierre  angulaire  de  la  physiologie  microscopique" — says  a  recent  writer — • 
"  est  done  une  veritable  pomme  de  discorde.  Cela  est  vraiment  douimage  ;  car  cette 
doctrine  est  si  non  convain^ante  du  moins  fort  amusante."  .1.  L.  Braclict,  Physiologie 
Elementaire  de  rilomme,  2de  edit.,  i.  25,  Paris  and  Lyons,  1855. 

*  Op.  cit.,  p.  548. 


AGENCY   OF   CELLS   IN  NUTRITION.  467 

elsewhere,  on  insufficient  grounds — to  possess  higher  properties;  and 
the  change  of  albumen  into  fibrin  has  been  esteemed  the  first  important 
step  in  the  process  of  assimilation.  In  the  chyliferous  vessels,  the  pro- 
portion of  fibrin  increases  as  the  chyle  and  lymph  proceed  onwards  in 
the  vessels;  whilst  that  of  the  albumen  diminishes.  Such,  however,  is 
not  rigorously  the  fact,  for  on  refeiTing  to  the  table  slightly  modified 
from  that  of  Gerber,  which  has  been  given  elsewhere  (p.  227),  it  will 
be  seen,  that  in  the  afferent  lacteals  between  the  intestines  and  mesen- 
teric glands,  the  albumen  has  been  found  in  minimum  quantity;  in  the 
efferent  or  central  lacteals,  from  the  mesenteric  glands  to  the  thoracic 
duct,  in  maximum  quantity ;  and  in  the  thoracic  duct  in  medium  quan- 
tity ;  whilst  the  fibrin  goes  on  progressively  increasing  as  the  chyle 
and  lymph  proceed  onwards.  On  the  other  hand,  the  fat  was  found  to 
diminish  progressively;  so  that  there  appears  to  be  more  probability 
that  the  fibrin  is  formed  from  the  fat,  directly  or  indirectly,  than  from 
the  albumen. 

It  would  seem  not  improbable, — as  before  remarked,' — that  some 
nitrogenized  material  like  pepsin,  or  diastase  in  plants,  is  secreted  from 
the  parietes  of  the  chyliferous  vessels,  which  occasions  a  change  in  the 
constituents  of  the  chyle ;  and  the  view  is  somewhat  confirmed  by  the 
fact  to  which  attention  has  been  drawn  by  Mr.  G.  Ross,^  that  the  con- 
stituents of  fatty  matter,  added  to  those  of  uric  acid,  would  very  nearly 
give  the  atomic  constituents  of  albumen  ;  whence,  as  Dr.  Carpenter^ 
has  remarked,  it  might  be  surmised,  that  when  there  is  a  demand  for 
proteinaceous  compounds  in  the  system,  nitrogenized  matter,  which 
would  otherwise  be  thrown  out  of  the  system,  may  be  united  with  non- 
nitrogenized  cpmpounds  taken  as  food,  in  order  to  supply  its  wants. 
That  there  is  an  essential  physiological  difference,  however,  between 
fibrin  and  albumen,  notwithstanding  their  affirmed  similarity  in  chemi- 
cal composition,  is  shown  by  the  fact,  that  effused  fibrin  has  a  tendency 
to  spontaneous  coagulation,  whilst  albumen  requires  the  agency  of  heat. 
This  difference  in  properties  would  necessarily  induce  the  belief,  that 
the  two  substances  differ  more  perhaps  in  chemical  composition  than 
the  results  of  the  analyses  of  Mulder,  Liebig,  and  others,  would  seem 
to  indicate ;  and  such  appears  to  be  proved  by  those  of  MM.  Dumas 
and  Cahours,  which  have  been  conducted  on  a  very  extensive  scale ; 
and  show,  that  the  proportion  of  carbon  is  seven  per  cent,  less  in  fibrin 
than  in  albumen;  whilst  that  of  nitrogen  is  from  eight  to  nine  per  cent, 
more.  A  correct  idea,  these  gentlemen  think,  may  be  formed  of  the 
elementary  composition  of  fibrin  by  considering  it  a  compound  of 
casein,  albumen,  and  annnonia.'' 

It  lias  been  previously  shown, ^  that  there  is  great  reason  to  doubt, 
that  fibrin  is  the  main  material  employed  in  nutrition;  and  that  argu- 
ments have  been  brought  forward  to  establish,  that  it  is  rather  the 
product  of  a  retrograde  change  of  the  albuminous  matters.  The  com- 
paratively small  quantity  in  which  it  is  present  in  the  liquor  sanguinis 
does  not  favour  the  view,  that  it  alone  is  the  pabulum  for  the  higher 
nutritive  acts. 

A  view  is  entertained  by  many,  that  nothing  but  proteinaceous  com- 

'  Pa-e  22(1.  2  Lancet,  1842-3,  vol.  i.  "  Op.  cit.,  p.  492. 

"  Meu.  E.viiuiiner,  October  14,  1843,  p.  232.  »  Page  49. 


468  NUTRITION. 

pounds  can  serve  for  the  nutrition  of  the  tissues;  and  that  gelatin  is 
not  adapted  for  this  purpose.  Liebig  suggests,  that  it  may  be  inservient 
to  the  nutrition  of  the  gelatinous  tissues;  and  Dr.  Carpenter^  says,  there 
is  no  doubt,  that  it  is  incapable  of  being  applied  to  the  reconstruction 
of  any  but  those  tissues;  and  that  it  seems  questionable,  whether,  even 
in  those,  it  exists  in  a  condition  that  can  rightly  be  termed  organized: 
yet  it  appears  to  the  author,  that  no  doubt  ought  to  be  entertained  on 
the  matter.  The  inconclusiveness  of  the  experiments  made  on  gelatin 
as  an  article  of  food  has  been  animadverted  on  elsewhere  (p.  113). 
Although  not  a  proteinaceous  compound,  it  is  one  that  is  highly  nitro- 
genized.  When  used  as  an  aliment,  it  is  not  capable  of  being  detected 
in  the  chyle  or  blood,  and  hence  must  have  undergone  a  metamorphosis, 
probably  into  an  albuminous  compound;  and  it  is  certainly  as  difficult 
to  comprehend  how,  under  such  circumstances,  gelatin  can  be  inservient 
to  the  nutrition  of  gelatinous  tissues  when  no  gelatin  is  present  in  the 
blood,  as  to  comprehend  that  it  may  be  converted  into  albumen.  How 
gelatinous  aliment,  in  other  words,  is  formed  into  chyle  and  blood  in 
which  gelatin  is  not  discoverable,  and  from  these  again  gelatinous  tissues 
are  re-formed,  is  as  incomprehensible  as  that  any  of  the  proteinaceous 
tissues  should  be  constituted  from  the  same  pabulum ;  or  that  oleagi- 
nous aliments — as  is  admitted  by  some,  who  deu}^  the  same  power  to 
the  gelatinous — should  be  convertible  into  proteinaceous  compounds. 

Such  is  the  state  of  uncertainty  in  wliich  we  are  compelled  to  rest  in 
regard  to  this  important  function.  None  of  the  views  can  be  esteemed 
established.  They  are  in  a  state  of  transition ;  and  all,  perhaps,  that 
we  are  justified  in  deducing  hjqjothetically  is,  that  the  vital  force,  which 
exists  in  the  blastema  furnished  by  tlie  parents  at  a  fecundating  union, 
gives  occasion  to  the  formation  of  cells,  and  that  the  tissues  are  farther 
developed  through  the  agency  of  cell-life^  so  as  to  constitute  most  of 
the  textures  of  which  the  body  is  composed. 

It  is  the  action  of  nutrition,  that  occasions  the  constant  fluctuations 
in  the  weight  and  size  of  the  body,  from  the  earliest  embryo  condition 
till  advanced  life.  The  cause  of  the  growth  of  organs  and  of  the  body 
generally,  as  well  as  of  the  limit  accurately  assigned  to  such  growth, 
according  to  the  animal  or  vegetable  species,  is  dependent  upon  vital 
laws  that  are  unfathomable.  Nor  are  we  able  to  detect  the  precise  mode 
in  which  the  growth  of  paits  is  effected.  It  cannot  be  simple  extension, 
for  the  obvious  reason  that  the  body  and  its  various  compartments 
augment  in  weight  as  well  as  in  dimension.  The  rapidity  with  which 
certain  growths  are  effected  is  astonishing.  The  Bovisia  giganieum  has 
been  known  to  increase,  in  a  single  night,  from  a  mere  point  to  the  size 
of  a  large  gourd,  estimated  to  contain  -18,000,000,000  of  cellules;  and 
supposing  twelve  hours  to  have  been  necessary  for  its  growth,  the  cells 
in  it  must  have  been  produced  at  the  rate  of  4,000,000,000  an  hour,  or 
more  than  6(3,000,000  a  minute, — the  greater  part  of  the  elements  neces- 
sary for  this  astonishing  Ibrmution  being  obtained  from  the  air.'     But 

'  Principles  of  Human  Physiology,  2d  edit.,  p.  47(3,  London,  1844.  In  the  last  edition 
of  his  work  {]>.  tj4.  Philad..  1855)  he  doubts,  wliether  it  can  even  go  to  the  nutrition  of 
the  gelatinous  tissues ;  and  expresses  the  opinion,  doubtless — the  author  thinks — to  be 
equally  abandoned  hereafter,  that  its  alimentary  value  "must  be  limited  to  its  calorific 
power." 

^  Truman,  Food  and  its  InHuence  on  Health  and  Disease,  &c.,  p.  229,  Lond.,  1842. 


NUTRITION.  469 

these  rapid  growths  possess  little  vitality,  and  their  decay  is  almost  as 
rapid  as  their  production.  Analogous  growths — but  not  to  the  like  ex- 
tent— occur  in  the  human  body,  aud  the  same  remark  applies  to  them. 

In  the  large  trees  of  our  forests  we  find  a  fresh  layer  or  ring  added 
each  year  to  the  stem,  until  the  full  period  of  developement ;  and  it  has 
been  supposed  that  the  growth  of  the  animal  body  may  be  effected  in  a 
similar  manner,  both  as  regards  its  soft  and  harder  materials, — that  is, 
by  layers  deposited  externally.  That  the  long  bones  lengthen  at  their 
extremities  is  proved  by  an  experiment  of  Mr.  Hunter.^  Having  ex- 
posed the  tibia  of  a  pig,  he  bored  a  hole  into  each  extremity  of  the 
shaft,  aud  inserted  a  shot.  The  distance  between  the  shots  was  then 
accurately  taken.  Some  months  afterwards,  the  same  bone  was  exa- 
mined, and  the  shots  were  found  at  precisely  their  original  distance 
from  each  other;  but  the  extremities  of  the  bone  had  extended  much 
beyond  their  first  distance  from  them.  The  flat  bones  also  increase  by 
a  deposition  at  their  margins ;  and  the  long  bones  by  a  similar  depo- 
sition at  their  periphery, — additional  circumstances  strongly  exhibiting 
the  analogy  between  the  successive  developement  of  animals  and  vege- 
tables. Exercise  or  rest;  freedom  from,  or  the  existence  of,  pressure, 
produces  augmentation  of  the  size  of  organs,  or  the  contrary;  and  there 
are  certain  medicines,  as  iodine,  which  are  said  to  occasion  emaciation 
of  particular  organs  only — as  of  the  female  mammas.  The  efiect  of 
disease  is  likewise,  in  this  respect,  familiar  and  striking.^ 

The  ancients  had  noticed  the  changes  effected  upon  the  body  by  the 
function  we  are  considering,  and  attempted  to  estimate  the  period  at 
which  a  thorough  conversion  might  be  accomplished,  so  that  not  one 
of  its  quondam  constituents  should  be  present.  By  sortie,  this  was  held 
to  be  seven  years;  by  others,  three.  It  is  hardly  necessar}^  to  say,  that 
in  such  a  calculation  we  have  nothing  but  conjecture  to  guide  us.  The 
nutrition  of  the  body  and  its  parts  varies,  indeed,  according  to  numerous 
circumstances.  It  is  not  the  same  during  the  period  of  growth  as  sub- 
sequently, when  absorption  and  deposition  are  balanced, — so  far,  at 
least,  as  concerns  the  augmentation  of  the  body  in  one  direction.  Par- 
ticular organs  have,  likewise,  their  period  of  developement,  at  which 
time  the  nutrition  of  such  parts  must  necessarily  be  more  active, — 
the  organs  of  generation,  for  example,  at  the  period  of  pubert}^;  the 
enlargement  of  the  mammas  in  the  female;  the  appearance  of  the  beard 
and  the  amplification  of  the  larynx  in  the  male,  &m.  All  these  changes 
occur  after  a  determinate  plan. 

The  activity  of  nutrition  appears  to  be  increased  by  exercise,  at 
least  in  muscular  organs ;  hence  the  well-marked  muscles  of  the  arm 
in  the  prize-fighter,  of  the  legs  in  the  dancer,  &c.  The  muscles  of  the 
male  are,  in  general,  much  more  clearly  defined;  but  the  difference 
between  those  of  the  hard-working  female  and  the  inactive  male  may 
not  be  very  apparent. 

The  most  active  parts  in  their  nutrition  are  the  glands,  muscles,  and 
skin,  whicli  alter  their  character — as  to  size,  colour,  and  consistence — 

'  Observations  on  Ce>rtain  Parts  of  the  Animal  Economy,  with  notes,  by  Prof.  Owen, 
Amer.  edit.,  ]).  321,  Pliihid.,  1840, 

^  The  autlior's  l^eneral  Therajientics  and  Mat.  Med,,  5th  edit,,  Philad,,  1853;  aud  his 
Practice  of  Medicine,  3d  edit,,  Philad,,  1848. 


470 


NUTRITION. 


Tattooed  Head  of  a  New  Zealand  Chief. 


with  great  rapidity ;  whilst  the  tendons,  fibrous  membranes,  bones,  &;c., 
are  much  less  so,  and  are  altered  more  slowly  by  the  efi'ect  of  dis- 
ease.    A  practice,  which  prevails 
Fig.  136.  amongst  certain   professions  and 

people,  would  seem,  at  first  sight, 
to  show  that  the  nutrition  of  the 
skin  cannot  be  energetic.  Sailors 
are  in  the  habit  of  forcing  gun- 
powder through  the  cuticle  with 
a  pointed  instrument,  and  of 
figuring  the  initials  of  their 
names  upon  the  arm  in  this  man- 
ner :  the  particles  of  the  gunpow- 
der are  thus  driven  into  the  cutis 
vera,  and  remain  for  life.  The 
operation  of  tattooing^  or  of  punc- 
turing and  staining  the  skin,  pre- 
vails in  many  parts  of  the  globe, 
and  especially  in  Polynesia,  where 
it  is  looked  upon  as  greatly  orna- 
mental. The  art  is  said  to  be 
carried  to  its  greatest  perfection 
in  the  Washington  or  New  Mar- 
quesas Islands  ;^  where  the  wealthy 
are  often  covered  with  various  de- 
signs from  head  to  foot ;  subjecting  themselves  to  a  most  painful  ope- 
ration for  this  strange  kind  of  personal  decoration.  The  operation 
consists  in  puncturing  the  skin  with  some  rude  instrument,  according 
to  figures  previously  traced  upon  it,  and  rubbing  into  the  punctures 
a  thick  dye,  frequently  composed  of  the  ashes  of  the  plant  that  fur- 
nishes the  colouring  matter.  The  marks,  thus  made,  are  indelible. 
M.  Magendie^  asks: — "How  can  we  reconcile  this  phenomenon  with 
the  renovation,  which,  according  to  authors,"  (and  he  might  have 
added,  according  to  himself,)  "happens  to  the  skin?"  It  does  not 
seem  to  us  to  be  in  any  manner  connected  with  the  nutrition  of  the 
skin.  The  colouring  matter  is  an  extraneous  substance,  which  takes 
no  part  in  the  changes  constantly  going  on  in  the  tissue  in  which  it  is 
embedded;  and  the  circumstance  seems  to  afford  a  negative  argument 
in  flivour  of  venous  absorption.  Had  the  substance  possessed  the 
necessary  tenuity,  it  would  have  entered  the  veins  like  other  colouring 
matters ;  but  the  particles  are  too  gross  for  this,  and  hence  remain  free 
from  all  absorbing  influence. 

Like  the  other  organic  functions,  nutrition  does  not  require  the 
presence  of  a  nervous  system.  The  beautiful  products  of  the  vege- 
table kingdom  sufficiently  demonstrate  that  it  can  be  accom])lished 
witliout  one;  and  in  the  jtrimordial  cell,  from  which  the  new  being  in 
man  and  animals  is  formed,  Ave  may  in  vain  look  for  anj^thing  resem- 
bling a  nervous  system.  Generally  by  those  who  believe  in  the  necessity 
of  a  nervous  system  for  the  execution  of  this  as  well  of  eveTj  other  or- 

'  Lawrenre,  Lectures  on  Physiology,  &c.,  p.  411,  LouJ.,  1S19. 
*  Precis,  &c.,  edit.  cit..  ii.  483. 


SECRETION.  471 

ganic  act,  the  action  of  the  sympathetic  is  invoked  ;  others  have  assigned 
great  influence  to  the  spinal  marrow,  M.  Brown-Sequard/  however, 
found  that  birds  are  able  to  live  for  months  after  the  destruction  of 
the  spinal  cord  from  the  fifth  costal  vertebra  to  its  termination;  and  if 
the  operation  has  been  performed  on  a  young  bird,  it  will  continue  to 
grow  well.  He  succeeded  in  keeping  alive  a  young  cat  from  the  8th 
of  April  until  the  4th  of  July,  after  that  part  of  the  cord,  which  ex- 
tends from  the  11th  or  12th  costal  vertebra  to  the  sacrum  had  been 
destroyed.  Although  paraplegic,  the  palsied  parts  had  grown  in 
length  proportionately  as  much  as  the  sound  parts;  and  they  had  ac- 
quired more  than  double  the  length  which  they  had  at  the  time  of  the 
operation.  The  functions  of  organic  life  appeared  to  be  carried  on 
without  any  apparent  disturbance,  and  the  nutritive  reparation  was  so 
powerful,  that  the  portions  of  the  vertebral  column  which  had  been 
cut  off'  were  reproduced.  In  birds  on  which  the  operation  had  been 
practised  he  found  that  the  secretion  of  quills  and  nails  continued  to 
take  place. 

Yet  although  nutrition  can  be  accomplished  without  a  nervous  sys- 
tem ;  its  intensity  can  be  materially  modified  in  man  and  animals  by 
nervous  influence;  and  in  this  way  we  must  account  for  the  effects 
occasionally  induced  on  tumours  by  the  efforts  of  the  animal  raag- 
netizer,  for  example. 


CHAPTER  VI. 

SECRETION. 

We  have  next  to  describe  an  important  and  multiple  function,  wliich 
also  takes  place  in  the  intermediate  system — in  the  very  tissue  of  our 
organs — and  separates  from  the  blood  the  various  humours.  This  is 
the  function  of  secretion, — a  terra  literally  signifying  separation — and 
which  has  been  applied  both  to  operation  and  product.  Thus,  the 
liver  is  said  to  separate  the  bile  from  the  blood  by  an  action  of  secre- 
tion, and  the  bile  is  said  to  be  a  secretion. 

The  organs  that  execute  the  various  secretory  operations  differ 
greatly  from  each  other.  They  have,  however,  been  grouped  by  ana- 
tomists into  three  classes,  each  of  which  will  require  a  general  notice, 

1,    ANATOMY  OF  THE  SECKETOBY  APPARATUS, 

The  secretory  organs  have  been  divided  into  the  exhalant,  follicular, 
and  glandular. 

The  remarks  made  respecting  the  exlialmd  vessels  under  the  head  of 
Nutrition  render  it  unnecessary  to  allude,  in  this  place,  to  any  of  the 
apocr3q3hal  descriptions  of  them,  especially  as  their  very  existence  is 
supposititious. 

A  simp]e/o///c/e  or  crtjpt  has  the  form  of  an  ampulla  or  vesicle,  and 
is  situate  in  tlie  substance  of  the  skin  and  mucous  membranes;  secret- 
ing a  fluid  for  the  purjDose  of  lubricating  them.     In  the  capillary  ves- 

'  Med.  Examiner,  May,  1S52,  p.  321,  and  August,  1852,  p.  495, 


472  SECRETION. 

sel,  tlie  secreted  fluid  passes  immediately  from  the  bloodvessel,  without 
being  received  iuto  any  excretory  duct;  and,  in  the  simplest  follicle,  there 
is  essentially  no  duct  specially  destined  for  the  excretion  of  the  humour. 
It  is  membranous  and  vascular,  having  an  internal  cavity  into  Avhich 
the  secretion  is  poured ;  and  the  product  is  excreted  upon  the  surface 
beneath  which  it  is  situate,  either  by  a  central  aperture,  or  by  a  very 
short  duct — if  duct  it  can  be  called — generally  termed  a  lacuna.  Many 
of  the  so  called  follicles  are,  however,  more  complicated,  and  consist, 
like  the  Meibomian,  of  various  cul-de-sacs^  with  separate  ducts  which 
open  into  one;  so  that  the  distinction  between  a  compound  follicle  and 
a  gland  is  not  easily  made ;  and  physiologically  no  difference  can  be 
considered  to  exist. 

The  gland  is  of  a  more  complex  structure  than  the  simple  follicle. 
It  consists  of  an  artery  which  conveys  blood  to  it;  of  an  intermediate 
body, — the  gland^  properly  so  called, — and  of  an  excretory  duct  to 
carry  off  the  secreted  fluid,  and  to  pour  it  on  the  surface  of  the  skin 
or  mucous  membrane.  The  bloodvessel,  that  conveys  to  the  gland 
the  material  from  which  the  secretion  has  to  be  effected,  enters  the 
organ, — at  times,  by  various  branches ;  at  others,  by  a  single  trunk ; 
and  ramifies  in  the  tissue  of  4he  gland;  communicating  at  its  extremi- 
ties with  the  origins  of  the  veins  and  indirectly  with  the  excretory 
ducts.  These  ducts  arise  b}^  fine  radicles  at  the  part  w^here  the  arte- 
rial ramifications  terminate;  and  they  unite  to  form  larger  and  less 
numerous  canals,  until  they  end  in  one  large  duct,  as  in  the  pancreas ; 
or  in  several,  as  in  the  lachrymal  gland, — the  duct  generally  leaving 
the  gland  at  the  part  where  the  bloodvessel  enters.  Of  this  there  is  a 
good  exemplification  in  the  kidney. 

The  pavement  and  the  cylinder  epithelium,  as  well  as  all  the  inter- 
mediate forms,  are  met  with  in  the  difterent  glands.  These  are  not 
necessarily  a  continuation  of  the  epithelium  of  the  cutaneous  system; 
on  the  contrary,  that  of  the  latter  is  often  seen  changing  its  form  at  its 
entrance  into  the  gland. 

Besides  the  vessels  above  mentioned,  veins  exist,  which  communicate 
with  the  bloodvessels  that  convey  blood  to  the  gland,  both  for  the  for- 
mation of  the  humour  and  the  nutrition  of  the  organ;  and  which  return 
the  residuary  blood  to  the  heart.  Lymphatic  vessels  are  likewise  there; 
and  nerves, — proceeding  from  the  ganglionic  sj^stem, — form  a  network 
around  the  secreting  arteries,  accompany  them  into  the  interior  of  the 
organ,  and  terminate,  like  them,  invisibly.  Bordeu^  was  of  opinion, 
that  the  glands,  judging  from  the  parotid,  are  largely  supplied  Avith 
nerves.  They  do  not,  however,  all  belong  to  it,  some  merely  crossing 
it  in  their  course  to  other  parts.  Bichat,^  from  the  small  number  sent 
to  the  liver,  was  induced  to  draw  opposite  conclusions  to  those  of 
Bordeu. 

These  mav  be  looked  upon  as  the  great  components  of  the  glandular 
structure.  They  are  bound  together  by  areolar  tissue,  and  have  gene- 
rally an  outer  envelope.  The  intimate  texture  of  these  organs  has  been 
a  topic  of  much  speculation.     It  is  generally  considered,  that  the  final 

'  Sur  les  Glaniles,  in  ffiiivres  Completes,  par  M.  Rieherand,  Paris,  1S18. 
^  Auat.  Gi.neral.,  torn.  ii. 


SECRETORY  APPARATUS. 


473 


ramifications  of  the  arterial  vessels,  with  the  radicles  of  the  veins  and 
excretory  ducts,  and  the  final  ramifications  of  the  lymphatic  vessels 
and  nerves,  form  so  many  small  lobules,  composed  of  minute  granular 
masses.  Such,  indeed  is  the  appearance  the  texture  presents  when 
examined  by  the  naked  eye.  Each  lobule  is  conceived  to  contain  a  final 
ramification  of  the  vessel  or  vessels  that  convey  blood  to  the  organ,  a 
nerve,  a  vein,  a  l3miphatic,  and  an  excretory  duct, — with  areolar  tissue 
binding  them  together.  When  the  organ  has  an  external  membrane, 
it  usually  forms  a  sheath  to  the  various  vessels.  The  lobated  structure 
is  not  equally  apparent  in  all  the  glands.  It  is  well  seen  in  the  pan- 
creas, salivary  and  lachrymal. 

The  precise  mode  in  which  the  vessel,  from  the  blood  of  which  the 
secretion  is  effected,  communicates  with  the  excretory  duct,  does  not 
admit  of  detection.  Professor  Mliller'  maintains,  that  the  glandular 
structure  consists  essentially  of  a  duct  with  a  blind  extremity,  on  whose 
parietes  plexuses  of  bloodvessels  ramify,  from  which  the  secretions  are 
immediately  made, — a  view  which  was  confirmed  by  the  pathological 
appearances,  in  a  case  of  disease  of  the  portal  system  that  fell  under  the 
author's  observation,  and  is  referred  to  hereafter.  The  opinion  of  Mal- 
pighi^  was  similar.  He  affirmed  that  such  glands  as  the  liver  are  com- 
posed of  very  minute -bodies,  called  acini  from  their  resemblance  to  the 
stones  of  grapes; — that  these 

acini  are  hollow  internally,  Fit?.  137. 

and  covered  externally  by 
a  network  of  bloodvessels; 
and  that  these  minute  blood-' 
vessels  pour  into  the  cavities 
of    the    acini   the   secreted 

fluid,  from  which  it    is    sub-     ,;„„,,  composed  of  secretin, 

sequently  taken  up  by  the  I'^t  bloodvessels. 
excretory  ducts.  Euysch,^ 
however,  held,  that  the  acini 
of  Malpighi  are  merely  con- 
voluted vessels,  continuous 
with  the  excretory  ducts. 
In  Malpighi's  view,  the  se- 
cretory organ  is  a  mere 
collection  of  follicles;  in 
Euysch's,  simply  an  exha- 
lant  membrane,  variously 
convoluted.     "The  chief,  if 

not  the  only  difference,"  says  a  popular  writer,^  "between  the  secret- 
ing structure  of  glands  and  that  of  simple  surfaces,  api:)ears  to  consist 
in  the  different  number  and  the  different  arrangement  of  their  capillary 
vessels.     The  actual  secreting  organ  is  in  both  cases  the  same, — capil- 

'  De  Glandular.  Secernent.  Structura  Penition,&c.,  Lips.,  1830;  or  the  English  edit, 
hy  Mr.  SoUv,  Lond.,  1839. 

2  Opera  Omnia,  &c.,  p.  300,  Lugd.  Batav.,  1G87. 

'^  Epist.  Anatom.  qua  respondet  Viro  Clarissimo  Hermann.  Boorhaav.,  p.  45,  Lugd. 
Batav.,  1722. 

••  ISouthwood  Smith,  in  Animal  Physiology,  p.  115;  Library  of  Useful  Knowledge, 
Loud.,  1829. 


Plan  of  a  Secreting  Membrane. 

Memhrana  propria  or  basement  membrane,     h.  Epithe- 
nucleated  cells,    c.  La  yer  of  capil- 


Fig.  138. 


Plan  to  show  augmentation  of  Surfiice  by  formation  of 
Processef. 


a,  h,  c.  As  in  preceding  figure. 
■  subdivided  processes. 


d.  Simple,  and  e,  /,  branched 


474 


SECRETION. 


lary  bloodvessel;   and  it  is  uncertain  whether  either  its  peculiar  ar- 
rangement, or  greater  extent  in  glandular  texture,  is  productive  of 

any  other  effect  than  that  of 
Fig-  139.  furnishing  the  largest  quan- 

tity of  bloodvessels  within 
the  smallest  space.  Thus 
convoluted  and  packed  up, 
secreting  organ  may  be  pro- 
cured to  any  amount  that 
may  be  required,  without 
the  inconvenience  of  bulk 
and  weight." 

It  is  manifest,  that  the  sim- 
plest form  of  the  secretory 
apparatus  consists  of  simple 
capillary  vessel,  and  animal 
membrane;  and  that  the 
follicles  and  glands  are 
structures  of  a  more  com- 
plex organization,  but  still 
essentially  identical ;  —  all 
perhaps — as  will  be  seen 
presently — executing  their 
functions  by  means  of  cell 
agency.  Or,  to  use  the 
views  and  lansjuagje  of  the 
day,  every  secreting  organ 
possesses,  as  essential  parts 
of  its  structure,  a  simple  and 
apparently  anhistous  or  tex- 
tureless  membrane,  called 
pnmay-y  or  haseTiient  mem- 
bnvie ;  cells  and  hlondvessels; 
and  by  some,  all  the  various 
modes  in  which  these  three 
structural  elements  are  ar- 
ranged have  been  classed 
under  one  or  other  of  two 
principal  divisions — mem- 
branes,  and  (jlands} 
Some  of  the  glands,  as  the  lacteal  and  salivary,  are  granular  in  their 
arrangement;  others,  as  the  spermatic  and  urinary,  consist  of  convo- 
luted tubes;  but  all  may  be  regarded  as  a  prolongation  of  the  skin ; 
and  the  essential  difference  between  the  various  secretory  organs  is  in 
the  extent  occasionally  of  e version  but  generally  of  inversion  and  con- 
volution of  the  secretory  membrane.  This  is  well  represented  in  the 
marginal  figures.^     The   morphology  of  the  secretory  apparatus  has 

'  Kirkes  and  Paget,  Manual  of  Physiology,  Amer.  edit.,  p.  23S,  Philad.,  1P40. 
*  Quain's  Human  Anatomy  by  Quain  and  Sharpey,  Amer.  edit,  by  Leidy,  ii.  99, 
riiilad.,  1849. 


Plans  of  extension  of  Secreting  Membrane,  by  inversion 
or  recession  in  form  of  cavities. 

A.  Simple  glands,  viz.,  g,  straight  tube,  h,  sac,  i,  coiled 
tube.  B.  JIultilocular  crypts,  k,  oftubular  form,  Z,  saccular. 
c.  Racemose  or  vesicular  compound  glands,  m.  Entire  gland, 
showing  branched  duct  and  lobular  structure,  n.  A  lobule, 
dotaclied  with  o,  branch  of  duct  proceeding  from  it.  D.  Com- 
pound tubular  gland. 


PHYSIOLOGY   OF   SECRETION.  475 

been  carefully  investigated  ;  but  here — as  elsewhere — we  remain  igno- 
rant of  the  vital  processes  concerned.  "  We  must  not," — says  Liebig^ 
— "  forget  that  anatomy  alone,  from  the  days  of  Aristotle  to  Leenen- 
hoek's  time,  has  thrown  but  a  partial  light  upon  the  laws  of  the  phe- 
nomena of  life.  As  a  knowledge  of  the  apparatus  of  distillation  does 
not  instruct  us  alone  concerning  its  uses ;  so  in  many  processes,  as  in 
distillation,  he  who  understands  the  nature  of  fire,  the  laws  of  the  dif- 
fusion of  heat,  and  of  evaporation,  the  construction  of  the  still,  and  the 
products  of  distillation, — knows  infinitely  more  of  the  process  of  dis- 
tillation than  the  smith  himself  who  made  the  apparatus.  Each  new 
discovery  in  anatomy  has  added  acuteness,  exactitude,  and  extent  to  its 
descriptions;  unwearied  investigation  has  almost  penetrated  to  the 
inmost  cell,  from  whence  a  new  road  of  inquiry  must  be  opened." 

2.    FUYSIOLOGY  OF  SECRETION. 

The  uncertainty  which  has  rested  on  the  intimate  structure  of  secret- 
ino-  or2:ans,  and  on  the  mode  in  which  the  different  bloodvessels  com- 
municate  with  the  commencement  of  the  excretory  duct,  has  enveloped 
the  function,  executed  by  those  parts,  in  obscurity.  We  see  the  pan- 
creatic artery  pass  to  the  pancreas;  ramify  in  its  tissues;  become 
capillary,  and  escape  detection;  and  other  vessels  becoming  larger  and 
larger,  and  emptying  themselves  into  vessels  of  greater  magnitude, 
until,  ultimately,  all  the  secreted  humour  is  contained  in  one  large  duct, 
which  passes  onwards,  and  discharges  its  fluid  into  the  small  intestine. 
Yet  if  we  follow  the  pancreatic  artery  as  far  back  as  the  eye  can  carry 
us,  even  when  aided  by  glasses  of  considerable  magnifying  power,  or  if 
we  trace  back  the  pancreatic  duct,  we  fiiul,  in  the  former  vessel,  always 
arterial  blood,  and  in  the  latter,  always  pancreatic  fluid.  It  must,  con- 
sequently, be  between  the  part  at  which  the  artery  ceases  to  be  visible, 
and  at  which  the  pancreatic  duct  becomes  so,  that  secretion  is  effected. 

Conjecture,  in  the  absence  of  positive  knowledge,  has  been  busy,  at  all 
times,  in  attempting  to  explain  the  mysterious  agency  by  which  such 
various  humours  are  separated  from  the  same  fluid;  and,  according  as 
chemical,  or  mechanical,  or  exclusively  vital  doctrines  have  prevailed 
in  physiology,  the  function  has  been  referred  to  one  or  other  of  those 
agencies.  The  general  belief  amongst  the  physiologists  of  the  sixteenth 
and  seventeenth  centuries  was,  that  each  gland  possesses  a  peculiar 
kind  of  fermentation,  which  assimilates  to  its  own  nature  the  blood 
passing  through  it.  Tlie  notion  of  fermentation  was,  indeed,  applied 
to  most  of  the  vital  phenomena.  It  is  now  totally  abandoned,  owing 
to  its  being  purely  imaginary,  and  inconsistent  with  all  our  ideas  of  the 
vital  operations.  When  tliis  notion  had  passed  av/ay,  and  the  fashion 
of  accounting  for  physiological  phenomena  on  mechanical  principles 
took  its  ])lace,  the  o|)inion  ju'evailed,  that  the  secretions  are  eflected 
through  the  glands  as  through  filters.  To  admit  of  this  mechanical 
result,  it  was  maintained,  that  all  the  secreted  fluids  exist  ready  formed 
in  the  blood,  and  that,  wdien  they  arrive  at  the  different  secretory 
organs,  they  pass  through,  and  are  received  by,  the  excretory  ducts. 


184o 


Chemistry  and  Physics  iu  relation  to  Physiology  and  Pathology,  p.  105,  Loud., 


476  SECRETION". 

Des  Cartes'  and  Leibnitz^  were  warm  supporters  of  this  mechanical  doc- 
trine, although  their  views  differed  materially  with  regard  to  the  precise 
nature  of  the  operation.  Des  Cartes  supposed,  that  the  particles  of 
the  various  humours  are  of  different  shapes,  and  that  the  pores  of  the 
glands  have  a  corresponding  figure;  so  that  each  gland  permits  those 
particles  only  to  pass  through  it  which  have  the  shape  of  its  pores. 
Leibnitz,  on  the  other  hand,  likened  the  glands  to  filters,  which  had 
their  pores  saturated  with  their  own  peculiar  substance,  so  that  they 
admitted  it  to  pass  through  them,  and  excluded  all  others, — as  paper, 
saturated  with  oil,  prevents  the  filtration  of  water.  Tlie  mechanical 
doctrine  of  secretion  was  taught  by  IMalpighi  and  Boerhaave,^  and  con- 
tinued to  prevail  until  the  time  of  Haller.  All  the  secretions  were  con- 
ceived to  be  ready  formed  in  the  blood,  and  the  glands  were  loolscd 
upon  as  sieves  or  strainers  to  convey  off  the  appropriate  fluids  or 
humours.  In  this  view  of  the  subject,  all  secretion  was  a  transudation 
througli  the  coats  of  the  vessels, — particles  of  various  sizes  passing 
through  pores  respectively  adapted  for  them."* 

The  mechanical  doctrine  of  transudation,  in  this  shape,  is  founded 
upon  supposititious  data ;  and  the  whole  facts  and  argum^snts  are  so 
manifestly  defective,  that  it  is  now  abandoned.  ]\IM.  ]\fagendie  and 
Fodera  have,  however,  revived  the  mechanical  view  of  late  years ;  but 
under  an  essentially  different  form,  and  one  especially  applicable  to 
the  exhalations.  The  former  gentleman,*  believing  that  many  of 
these  exist  ready  formed  in  the  blood,  thinks  that  the  character  of  the 
exhaled  fluid  is  dependent  upon  the  physical  arrangement  of  the  small 
vessels,  and  his  views  repose  upon  the  following  experiments.  If,  in 
the  dead  body,  Ave  inject  warm  water  into  an  artery  passing  to  a  serous 
membrane,  as  soon  as  the  current  is  established  from  the  artery  to  the 
vein,  a  multitude  of  minute  drops  may  be  observed  ooziug  through  the 
membrane,  which  speedily  evaporate.  If,  again,  a  solution  of  gelatin, 
coloured  with  vermilion,  be  injected  into  the  vessels,  it  will  often  hap- 
pen, that  the  gelatin  is  deposited  around  the  cerebral  convolutions,  and 
in  the  anfractuosities,  without  the  colouring  matter  escaping  from  the 
vessels,  whilst  the  latter  is  spread  over  the  external  and  internal  sur- 
faces of  the  choroid.  If,  again,  linseed  oil,  also  coloured  with  vermi- 
lion, form  the  matter  of  the  injection,  the  oil,  devoid  of  colouring 
matter,  is  deposited  in  the  articulations  which  are  furnished  with  large 
synovial  capsules ;  and  no  transudation  takes  place  at  the  surface  of 
the  brain,  or  in  the  interior  of  the  eye,  M,  Mageudie  asks,  if  these  be 
not  instances  of  true  secretion  taking  place  post  viortem^  and  evidently 
dependent  upon  the  phj^sical  arrangement  of  the  small  vessels ;  and 
whether  it  be  not  highly  probable,  that  the  same  arrangement  must, 
in  part  at  least,  preside  over  exhalation  during  life.  M.  Fodera,*  to 
whose  experiments  on  the  imbibition  of  tissues  we  had  occasion  to 
allude  under  the  head  of  Absorption,  embraces  the  views  of  M.  Ma- 

'  De  Hoinine,  p.  11,  Lugd.  Bat.,  1664,  ^  Haller,  Element,  Physiol,,  vli,  3, 

*  Piwleetiones  Academics,  &c,,  edit.  A.  Haller,  §  253,  Gottlu.,  1740-1743. 

*  Mascagni,  Nova  per  Poros  hiorgauicoa  Secretioiiem  Theoria.,  Rom,,  1793,  torn,  ii, 
^  Precis,  &c,,  edit,  cit.,  ii.  444, 

^  Magendie's  Journal  de  Physiologie,  iii.  35  ;  and  Reclierclies,  &c.,  siir  TAbsori^tion 
et  PExkalatiou,  Pai-is,  1824. 


PHYSIOLOGY   OF   SECRETION.  477 

gendie,  and  so  does  Valentin.^  If  the  vessels  of  a  dead  body,  M. 
Fodcra  remarks,  be  injected,  the  substance  of  the  injection  is  seen 
oozing  through  them ;  and  if  an  artery  and  a  vein  be  exposed  on  a 
living  animal,  a  similar  oozing  through  the  parietes  is  observable. 
This  is  more  manifest  if  the  trunk,  whence  the  artery  originates,  be 
tied, — the  fluid  being  occasionally  bloody.  If  the  jugular  veins  be 
tied,  not  only  does  oedema  occur  in  the  parts  above  the  ligatures,  but 
there  is  an  increase  of  the  salivary  secretion.  It  is  not  necessary  to 
refer  to  the  various  experiments  of  Fodcra  relating  to  this  topic,  or  to 
those  of  Harlan,  Lawrence  and  Coates,  Dutrochet,  Fanst,  Mitchell,  and 
others.  They  are  of  the  same  character  as  those  previously  alluded 
to  when  treating  of  the  imbibition  of  tissues;  for  transudation  is  only 
imbibition  or  soaking  from  within  to  without.  MM.  Magendie  and 
Fodera,  indeed,  conclude,  that  imbibition  is  a  primary  physical  cause 
of  exhalation  as  it  is  of  absorption. 

Another  phj^sical  cause,  adduced  by  M.  Magendie,  is  the  pressure 
experienced  by  the  blood  in  the  circulatory  system,  which,  he  thinks, 
contributes  powerfully  to  cause  the  more  aqueous  part  to  pass  through 
the  coats  of  the  vessels.  If  water  be  forcibly  injected  through  a 
syringe  into  an  artery,  all  the  surfaces,  to  which  the  vessel  is  distri- 
buted, as  well  as  the  larger  branches  and  the  trunk  itself,  exhibit  the 
injected  fluid  oozing  in  greater  abundance  according  to  the  force  ex- 
erted in  the  injection.  He  farther  remarks,  that  if  Avater  be  injected 
into  the  veins  of  an  animal,  in  sufficient  quantity  to  double  or  treble 
the  natural  amount  of  circulating  fluid,  a  considerable  distension  of  the 
circulatory  organs  is  produced,  and  the  pressure  is  largely  augmented. 
If  any  serous  membrane  be  now  examined, — as  the  peritoneum, — a 
watery  fluid  is  observed  issuing  rapidly  from  it,  which  accumulates  in 
the  cavity,  and  produces  a  true  dropsy  under  the  eye  of  the  experi- 
menter; and,  occasionally,  the  colouring  part  of  the  blood  transudes 
at  the  surface  of  certain  organs,  as  the  liver,  spleen,  &c. 

Hamberger,  again,  broached  the  untenable  physical  hypothesis,  that 
each  secreted  humour  is  deposited  in  its  proper  secretory  organ  by 
virtue  of  its  specific  gravity,^ — but  all  these  speculations  proceed  upon 
the  belief,  that  the  exhalations  exist  ready  formed  in  the  blood ;  and 
that,  consequently,  the  act  of  secretion,  so  far  as  concerns  them,  is  one 
of  separation  or  secerning, — not  of  fresh  formation.  That  this  is  the 
case  with  the  more  aqueous  secretions  is  probable,  and  not  impossible 
with  regard  to  the  rest.  Organic  chemistry  is  subject  to  more  diffi- 
culties in  the  way  of  analysis  than  inorganic ;  and  it  can  be  under- 
stood, that  in  a  fluid  so  heterogeneous  as  the  blood  the  discovery  of 
any  distinct  humour  may  be  impracticable.  Of  course,  the  elements 
of  every  fluid,  as  well  as  solid,  must  be  contained  in  it;  and  we  have 
already  seen,  that  not  merely  the  inorganic  elements,  but  the  organic 
or  compounds  of  organization  have  been  detected  in  it  by  the  labours 
of  Chevreul  and  others.  There  are  indeed,  some  singular  facts  con- 
nected with  this  subject.     MM.  Prevost  and  Dumas,^  having  removed 

'  Lelirbudi  der  Pliysiologie  des  Menscheii,  Bd.  1,  s.  601,  Braunscliweig,  1844. 
2  Adelon,  Physiologie  del'Homme,  2de  edit.,  iii.  455,  Paris,  1821). 
^  Anuales  de  Chimie,  torn.  xxii.  and  xxxiii.  90. 


478  SECRETION. 

tlie  kidneys  in  cats  and  clogs,  and  afterwards  analyzed  the  blood, 
found  urea  in  it — the  characteristic  element  of  urine.  This  principle 
was  contained  in  greater  quantity,  the  longer  the  period  that  had. 
elapsed  after  the  operation ;  whilst  it  could  not  be  detected  in  the 
blood,  when  the  kidneys  were  present.  The  experiment  was  soon 
afterwards  repeated  by  MM.  Vauquelin  and  Segalas^  with  the  same 
results.  The  latter  introduced  urea  into  the  veins  of  an  animal  whose 
kidneys  were  untouched;  he  was  unable  to  detect  the  principle  in  the 
blood ;  but  the  urinary  secretion  was  largely  augmented  after  the  in- 
jection ;  whence  he  concludes,  that  urea  is  an  excellent  diuretic.  Sub- 
sequentl}'-,  MM.  Gmelin  and  Tiedemann,  iu  association  with  JNl.  Mits- 
cherlich,^  arrived,  experimentally,  at  the  same  conclusions  as  M^[. 
Prevost  and  Dumas.  The  existence  of  urea  in  the  fluid  ejected  from 
the  stomach  of  the  animal  was  rendered  probable,  but  there  were  no 
traces  of  it  in  the  fteces  or  bile.  The  animal  died  the  day  after  the 
extirpation  of  the  second  kidney.  They  were  totally  unable  to  detect 
either  urea  or  sugar  of  milk  in  the  healthy  blood  of  the  cow. 

These  circumstances  would  favour  the  idea,  that  certain  of  the  se- 
cretions may  be  formed  in  the  blood,  and  may  simply  require  the 
intervention  of  a  secreting  organ  to  separate  them;^  but  the  mode  in 
which  such  separation  is  effected  is  entirely  inexplicable  under  the 
doctrine  of  simple  mechanical  filtration  or  transudation.  It  is  unlike 
any  physical  process  that  can  be  imagined.  The  doctrine  of  filtration 
and  transudation  can  apply  only  to  those  exhalations  iu  which  the 
humour  has  undergone  no  apparent  change ;  and  it  is  obviously  im- 
possible to  specify  these,  in  the  imperfect  state  of  our  means  of  analy- 
sis. In  the  ordinary  aqueous  secretions,  simple  transudation  may 
embrace  the  whole  process;  and,  therefore,  it  is  unnecessary  to  have 
recourse  to  any  other  explanation ;  especially  after  the  experiments 
instituted  by  M.  Magendie,  supported  by  pathological  observations  in 
which  there  has  been  partial  oedema  of  the  legs,  accompanied  by  more 
or  less  complete  obliteration  of  the  veins  of  the  infiltrated  part, — the 
vessels  being  obstructed  by  fibrinous  coagula,  or  compressed  by  cir- 
cumjacent tumours.  Thus,  ascites  or  dropsy  of  the  peritoneum  may 
be  occasioned  by  obstruction  of  the  portal  circulation  in  the  liver,  and 
in  this  way  we  may  account  for  the  frequency  with  which  we  find  a 
union  of  hydropic  and  hepatic  afi:ections  in  the  same  individual.  The 
like  pathological  doctrine,  founded  on  direct  observation,  has  been 
extended  to  phlegmasia  dolens  or  swelled  leg;  an  affection  occurring 
iu  the  puerperal  state,  and  oiten  found  connected  with  obstruction  in 
the  great  veins  that  convey  the  blood  back  from  the  lower  extremity. 
It  may  not,  consequently,  be  wide  of  the  truth — if  not  wholly  accu- 
rate— to  consider  certain  of  the  secretions,  with  Dr.  Billing,''  to  be 
"vital  transudations  from  the  capillaries  into  the  excretory  ducts  of 
the  glands,  by  pores  invisible  to  our  senses,  even  when  aided  by  the 
most  perfect  optical  instruments." 

'  Magendie,  Precis,  &c..  ii.  478. 

2  Tieilemann  and  Treviranus,  Zeitt;clirift  fiir  Physiol.,  B.  v.  Heft  i. ;  cited  in  Brit, 
and  Foreit^n  Med.  Review,  p.  .')y2,  fur  April,  183G. 

3  Dr.  W.  Philip,  in  Lond.  Med.  Gazette  for  March  25th,  1837,  p.  952. 

*  First  Principles  of  Medicine,  Anier.  edit.,  p.   55,  Philad.,  1842;  2d  Anier.  edit., 
Philad.,  1S51. 


THE0KIE9.  479 

The  generality  of  physiologists  have  regarded  the  more  complex 
secretions — the  follicular  and  glandular — as  the  results  of  chemical 
action  ;  and  under  the  view,  that  these  secretions  do  not  exist  ready 
formed  in  the  blood,  and  that  their  elements  alone  are  contained  in 
that  fluid,  it  is  impossible  not  to  admit  that  chemical  agency  must  be 
exerted.  In  support  of  the  chemical  hypothesis,  which  has  appeared 
under  various  forms, — some,  as  Keill,^  presuming  that  the  secretions 
are  formed  in  the  blood,  before  they  arrive  at  the  place  appointed  for 
secretion;  others,  that  the  change  is  effected  in  the  glands  themselves, 
— the  fact  of  the  formation  of  a  number  of  substances  from  a  very  few 
elements,  provided  these  be  united  in  different  proportions,  has  been 
urged.  Take,  for  example,  the  elementary  bodies,  oxygen  and  nitro- 
gen. These,  in  one  proportion,  form  atmospheric  air;  in  another, 
nitrous  oxide ;  in  another,  nitric  oxide ;  in  a  fourth,  hyponitrous  acid ; 
in  a  fifth,  nitrous  acid ;  in  a  sixth,  nitric  acid,  &c.,  compounds  which 
differ  as  much  as  the  various  secretions  differ  from  each  other  and  from 
the  blood.  Many  of  the  compounds  of  organization  likewise  exhibit, 
by  their  elementary  constitution,  that  but  a  slight  change  is  necessary, 
in  order  that  they  may  be  converted  into  each  other.  Dr.  Prout^  has 
exhibited  the  close  alliance  between  three  substances — urea,  lithic 
acid,  and  sugar, — and  has  shown  how  they  may  be  converted  into  each, 
other,  by  the  addition  or  subtraction  of  single  elements  of  their  con- 
stituents. Urea  is  composed  of  two  atoms  of  hj^drogen,  and  one  of 
carbt)n,  oxygen,  and  nitrogen  respectively ;  by  removing  one  of  the 
atoms  of  hydrogen  and  the  atom  of  nitrogen,  it  is  converted  into  sugar; 
by  adding  to  it  an  additional  atom  of  carbon,  into  lithic  or  uric  acid. 
Dr.  Bostock,^ — who  is  disposed  to  push  the  application  of  chemistry  to 
tlie  explanation  of  the  functions  as  far  as  possible, — to  aid  us  in  con- 
ceiving how  a  variety  of  substances  may  be  produced  from  a  single 
compound,  by  the  intervention  of  physical  causes  alone,  supposes  the 
case  of  a  quantity  of  materials  adapted  for  the  vinous  fermentation 
being  allowed  to  flow  from  a  reservoir  through  tubes  of  various  dia- 
meters, and  with  various  degrees  of  velocity.  "If  we  were  to  draw 
oft' portions  of  this  fluid  in  different  parts  of  its  course,  or  from  tubes, 
which  differed  in  their  capacity,  we  should,  in  tlie  first  instance,  obtain 
a  portion  of  uufermented  syrup;  in  the  next,  we  should  have  a  fluid 
in  a  state  of  incipient  fermentation;  in  a  third,  the  complete  vinous 
liquor;  while,  in  a  fourth,  we  might  have  acetous  acid."  Any  expla- 
nation, however,  founded  upon  this  loose  analogy,  is  manifestly  too 
physical.  Dr.  Bostock  admits  this,  for  he  subsequently  remarks,  that 
"  if  we  adopt  the  chemical  theory  of  secretion,  we  must  conceive  of  it 
as  originating  in  the  vital  action  of  the  vessels,  which  enables  them  to 
transmit  the  blood,  or  certain  parts  of  it,  to  the  various  organs  or 
structures  of  the  body,  where  it  is  subjected  to  the  action  of  those  re- 
agents which  are  necessary  to  the  production  of  these  changes.''  The 
admission  of  such  vital  agency,  in  some  shape,  is  indispensable. 

Attempts  have  been  made  to  establish  secretion  as  a  nervous  action 

'  Tentamina  Medico-Physica,  iv. ;  and  Ilaller,  Element.  Physiol. ,  &c.,  lib.  vii. 
sect.  3. 

■^  Me'lico-Chirurg.  Transact.,  viii.  540. 
^  Physiol.,  3d  edit.,  p.  510,  Lond.,  183G. 


480  SECRETION. 

and  numerous  arguments  and  experiments  have  been  brought  forward 
in  support  of  the  position.  That  many  of  the  secretions  are  affected 
by  the  condition  of  the  mind  is  known  to  aU.  The  act  of  crying,  in 
evidence  of  joy  or  sorrow;  the  augmented  secretion  of  the  salivary 
glands  at  the  sight  of  pleasant  food;  of  the  kidney  during  fear  or 
anxiet}^;  and  the  experimental  confirmation,  by  Mr.  Hunter,  of  the 
truth  of  the  common  assertion — that  the  she-ass  gives  milk  no  longer 
than  the  impression  of  the  foal  is  on  Ler  mind, — the  skin  of  the  foal, 
thrown  over  the  back  of  another,  and  frecjuently  brought  near  her, 
being  sufficient  to  renew  the  secretion, — sufficiently  indicate,  that  the 
organs  of  secretion  can  be  influenced  through  the  nervous  system  in 
the  same  manner  as  the  functions  of  nutrition  and  calorification.^ 

The  discovery  of  galvanism  naturally  suggested  it  as  an  important 
agent  in  the  process, — or  rather  that  the  nervous  fluid  strongly  resem- 
bles the  galvanic.  This  conjecture  seems  to  have  been  first  hazarded 
by  Berzelius,  and  Sir  Everard  Home  ;^  and,  about  the  same  time,  an 
experiment  was  made  by  Dr.  Wollaston,^  which,  he  conceived,  threw 
light  on  the  process.  He  took  a  glass  tube,  two  inches  high,  and 
three-quarters  of  an  inch  in  diameter;  and  closed  it  at  one  extremity 
with  a  piece  of  bladder.  He  then  poured  into  the  tube  a  little  water, 
containing  540^^  ^^  ^^^  weight  of  chloride  of  sodium,  moistened  the 
bladder  on  the  outside,  and  placed  it  upon  a  piece  of  silver.  On 
curving  a  zinc  wire  so  that  one  of  its  extremities  touched  the  piece  of 
metal,  and  the  other  dipped  into  the  liquid  to  the  depth  of  an  inch, 
the  outer  surface  of  the  bladder  immediately  indicated  the  presence  of 
pure  soda ;  so  that,  under  this  feeble  electric  influence,  the  chloride  of 
sodium  was  decomposed,  and  the  oxide  of  sodium — soda — passed 
through  the  bladder.  M.  Fodcra'*  performed  a  similar  experiment, 
and  found,  that  whilst  ordinary  transudation  frequently  required  an 
hour  before  it  was  evidenced,  it  was  instantaneously  exhibited  under 
the  galvanic  influence.  On  putting  a  solution  of  cyanuret  of  potassium 
into  the  bladder  of  a  rabbit,  forming  a  communication  with  the  solution 
by  means  of  a  copper  wire;  and  placing  on  the  outside  a  cloth  soaked 
in  a  solution  of  sulphate  of  iron,  to  which  an  iron  wire  was  attached ; 
he  found,  by  bringing  these  wires  into  communication  with  the  gal- 
vanic pile,  that  the  bladder  or  the  cloth  was  suddenly  coloured  blue, 
according  as  the  galvanic  current  set  from  without  to  within,  or  from 
within  to  without; — that  is,  according  as  the  iron  wire  was  made  to 
communicate  with  the  positive  pole,  and  the  copper  wire  with  the 
negative,  or  conversely.  But  it  is  not  necessary,  that  there  should  be 
communication  with  the  galvanic  pile.  If  an  animal  membrane,  as  a 
bladder,  containing  iron  filings,  be  immersed  in  a  solution  of  sulphate 
of  co'pper,  the  sulphuric  acid  will  penetrate  the  membrane  to  reach 
the  iron,  with  which  it  forms  a  sulphate,  and  the  metallic  copper  will 

'  For  examples  of  the  same  kind,  see  Fletcher's  Rudiments  of  Physiology,  part  ii. 
b,  p.  10,  Edinb.,  183();  Biirdafh,  Physiologie,  ii.  s.  w.,  §  522;  Dr.  A.  Combe,  on  Infancy, 
Amer.  edit.,  chap,  v.,  Philad.,  1840;  and  Carpenter,  Principles  of  Human  Physiology, 
Amer.  edit.,  by  Dr.  F.  G.  Smith,  p.  740,  Philad.,  18,55. 

^  Lectures  on  Comp.  Anat.,  iii.  16,  London,  1810;  and  v.  154,  London,  1828. 

3  Philosoph.  Mag.,  xxxiii.  438. 

*  Magendie"s  Journal  de  Physiologie,  iii.  35;  and  Recherches,  &c.,  sur  I'Absorption 
et  I'Exhalation,  Paris,  1824. 


THEORIES   OF   SECRETION".  481 

be  deposited  on  the  lower  surface  of  the  membrane;  the  animal  mem- 
brane, in  such  case,  offering  no  obstacle  to  the  action  of  the  ordinary 
chemical  affinities. 

With  some  of  the  chemical  physiologists,  there  has  been  a  disposition 
to  resolve  secretion  into  a  mere  play  of  electric  affinities.  Thus,  M. 
Donne^  affirms,  that  from  the  whole  cutaneous  surface  an  acid  humour 
is  secreted,  whilst  the  digestive  tube,  except  in  the  stomach,  secretes 
an  alkaline  mucus:  hence,  he  infers,  that  the  external  acid^  and  the 
internal  alkaline  membi^anes  of  the  human  body,  represent  the  two 
poles  of  a  pile,  the  electrical  effects  of  which  are  appreciable  b}^  the 
galvanometer.  On  placing  one  of  the  conductors  of  the  instrument  in 
contact  with  the  mucous  membrane  of  the  mouth,  and  the  other  with 
the  skin,  the  magnetic  needle  deviated  fifteen,  twenty,  and  even  thirty 
degrees,  according  to  its  sensibility ;  and  its  direction  indicated,  that 
the  mucous  or  alkaline  membrane  took  negative,  and  the  cutaneous 
membrane,  positive  electricity.  Pie  further  asserts,  that,  between  the 
acid  stomach  and  tlie  aJkaline  liver,  extremely  powerful  electrical  cur- 
rents are  formed.  These  experiments  do  not,  however,  aid  us  mate- 
rially in  our  solution  of  the  phenomena  of  secretion.  They  exhibit 
merely  electrical  phenomena  depeudent  upon  diffei^ence  of  chemical 
composition.  This  is,  indeed,  corroborated  by  the  experiments  of  M. 
Donne  himself  on  the  secretions  of  vegetables.  He  observed  electrical 
phenomena  of  the  same  kind  in  them;  but,  he  says,  electrical  currents 
in  vegetables  are  not  produced  by  the  acid  or  alkaline  conditions  of 
the  parts  as  in  animals,  the  juice  of  fruits  being  always  more  or  less 
acid.  Experiments  of  M.  Biot,  however,  show,  that  the  juices,  which 
arrive  by  the  pedicle,  are  modified  in  some  part  of  the  fruit,  and  M. 
Donnu  thinks  it  is  perhaps  to  this  difference  in  the  chemical  compo- 
sition of  the  juices  of  the  two  extremities,  that  the  electrical  phenomena 
are  to  be  attributed. 

The  effects  of  the  section  of  the  pneumogastric  nerves  on  the  func- 
tions of  digestion  and  respiration  have  been  given  elsewhere,  at  some 
length.  It  was  then  stated,  that  when  digestion  was  suspended  by  their 
division,  Dr.  Wilson  Philip'^  was  led  to  ascribe  it  to  the  secretion  of  the 
gastric  juice  having  been  arrested;  an  opinion,  which  Sir  B.  Brodie  had 
been  induced  to  form  previously,  from  the  results  of  experiments,  which 
showed  that  the  secretion  of  urine  is  suspended  by  the  removal  or  de- 
struction of  the  brain;  and  that  when  an  animal  is  destroyed  by  arsenic, 
after  the  division  of  the  |:)neumogastric  nerves,  all  the  usual  symptoms 
are  produced,  except  the  peculiar  secretion  from  the  stomach.  ISir  B. 
Brodie  did  not  draw  the  conclusion,  that  the  nervous  influence  is  abso- 
lutely necessary  to  secretion,  but  that  it  is  a  step  in  the  process;  and 
the  experiments  of  M.  Magendie-''  on  the  effect  of  division  of  the  nerve 
of  the  filth  pair  on  the  nutritive  secretion  of;  the  cornea,  confirm  the 
position.  We  have,  indeed,  numerous  evidences,  that  the  nervous  system 
cannot  be  indispensable  to  secretion.  In  all  animals,  this  power  must 
exist;  yet  there  are  some  in  which  no  nervous  system  is  apparent. 
Dr.  Bostock*  has  given  references  to  cases  of  monstrous  or  deformed 

'  Aiinales  de  Cliimie,  &c.,  Ivii.  400  ;  and  .Journal  Hebdomad.,  Fev.,  1834. 
^  London  Medical  Grazette,  March  18  and  March  25,  ]837. 

3  Precis,  &c.,ii.  489.  *  Physiology,  edit,  cit.,  p.  525,  Lend.,  1836. 

VOL.  I. — oi 


482  SECRETioisr. 

foetuses,  born  witli  many  of  their  organs  fully  developed,  yet  in  which 
there  was  apparently  no  nervous  system.  It  may  be  said,  however, 
that,  in  all  these  cases,  a  rudi mental  nervous  system  may  and  must 
have  existed;  but  setting  aside  the  case  of  animals,  secretion  is  equally 
effected  in  the  vegetable,  in  which  there  is  no  nervous  system^  yet  the 
function  is  accomplished  as  perfectly,  and  perhaps  in  as  multiple  a 
manner,  as  in  animals.  It  is  manifest,  therefore,  that  this  is  one  of  the 
vital  actions  occurring  in  the  very  tissue  of  organs,  of  which  we  have 
no  more  knowledge  than  we  have  of  the  nutritive  actions  in  general. 
All  that  we  know  is,  that  in  special  organs  various  humours  are  secreted 
from  the  blood,  some  of  which  can  be  detected  in  that  fluid;  others  not. 

The  doctrine  of  developement  by  cells  was  an  important  step  in  this 
inquiry.  It  has  been  elsewhere  shown  how  cells  are  considered  to  effect 
the  work  of  absorption ;  and  secretion  is  probably  accomplished  in  a 
similar  manner.  It  is  essentially  a  function  of  nucleated  cells, — such 
cells  possessing  a  peculiar  organic  power  by  virtue  of  wdiich  they  can 
draw  into  their  interior  certain  kinds  of  materials,  varying  according 
to  the  nature  of  the  fluid  they  are  destined  to  secrete.''  Some  cells  have 
merely  to  separate  certain  ingredients  from  the  surrounding  medium; 
others  have  to  elaborate  within  themselves  matters  that  do  not  exist  as 
such  in  the  nutritive  medium.  Although  secreting  cells  thus  differ  in 
the  nature  of  the  fluid  which  they  secrete,  their  structure  seems  to  be 
nearly  the  same  in  all  cases, — each  consisting,  like  other  primitive  cells, 
of  a  nucleus,  cell-wall,  and  cavity.  The  nucleus  appears  to  be  both 
the  reproductive  organ  by  which  new  cells  are  generated,  and  the  agent 
for  separating  and  preparing  the  secreted  material.  The  cell-cavity 
seems  chiefly  destined  to  contain  the  secreted  fluid  until  ready  to  be 
discharged;  at  which  time  the  cell,  then  matured,  bursts  and  discharges 
its  contents  into  the  inter-cellular  space  on  which  it  is  situate,  or  upon 
a  free  surface,  as  the  case  may  be. 

The  mode  of  secretion  in  glands,  of  which  Professor  Goodsir  takes 
the  testicle  of  the  squalus  cornuhicus  as  a  type,  appeared  to  him  to  be 
as  follows.  Around  the  extremities  of  the  minute  ducts  of  the  glands 
are  developed  acini  or  primary  nucleated  cells,  each  of  which,  as  it 
increases  in  size,  has  generated,  within  it,  secondary  cells — the  product 
of  its  nucleus.  The  cavity  of  the  parent  cell  does  not  communicate 
with  the  duct  on  which  it  is  situate  until  its  contents  are  fully  matured, 
at  which  time  the  cell-wall  bursts  or  dissolves  away,  and  its  contents 
are  discharged  into  the  duct.  From  this  constant  succession  of  growth 
and  solution  of  cells  it  results,  that  the  whole  parenchyma  of  a  gland 
is  continually  passing  through  stages  of  developement,  maturity'-,  and 
atrophy, — the  rapidity  of  the  process  being  in  proportion  to  the  acti- 
vity of  the  secretion.  There  seems,  consequently,  in  this  view  of  the 
subject,  to  be  no  essentifil  difference  between  the  process  of  secretion, 
and  the  growth  of  a  gland :  the  same  cells  are  the  agents  b}^  which 
both  are  effected.  The  parenchj^ma  of  glands  is  chiefly  made  up  of  a 
mass  of  cells  in  all  stages  of  developement:  as  these  cells  individually 
increase  in  size,  and  so  constitute  their  own  growth  as  well  as  that  of 
the  common  glandular  mass,  they  are  at  the  same  time  elaborating 

'  Professor  Goodsir,  Transactions  of  the  Royal  Society  of  Edinburgli,  1842;  and  Ana- 
tomical and  Pathological  Observations,  Ediulb.,  1845. 


THEORIES.  483 

within  themselves  the  material  of  secretion,  which,  when  matured, 
they  discharge  by  dissolving  away.  There  are  numerous  germinal 
spots  or  centres  in  a  gland,  from  which  acini  or  primary  cells  are  de- 
veloped. The  true  fluid  of  secretion,  in  Mr.  Goodsir's  opinion,  is  not 
the  product  of  the  ])arent  cell  of  the  acinus,  but  of  its  included  mass 
of  secondary  cells,  which  themselves  become  primary  secreting  cells, 
and  form  the  material  of  secretion  in  their  cavities.  In  some  cases, 
these  secondary  cells  pass  out  entire  from  the  parent  cell,  constituting 
a  form  of  secretion  in  which  the  cells  possess  the  power  of  becoming 
more  fully  developed  after  being  discharged  and  cast  into  the  duct  or 
cavity  of  the  gland.  He  considers  growth  and  secretion  to  be  identi- 
cal— the  same  process  under  different  circumstances,— a  view  which 
had  indeed  been  already  embraced  by  others,  and  which  ought  to 
be  universal.  It  must  be  recollected,  that  bloodvessels,  like  absorb- 
ents, are  shut  sacs;  and,  therefore,  the  materials  for  nutrition  and 
secretion  must  pass  either  through  them  in  the  maimer  suggested  by 
Mr.  Goodsir,  or  by  transudation.  Transudation,  however,  would  seem 
to  be  mainly,  if  not  wholly,  applicable  to  tenuous  fluids  only;  whilst 
every  solid  in  the  body  must  l3e  nourished  by  materials  obtained  from 
the  blood.  The  agency  of  cells  in  nutrition  and  secretion  may,  there- 
fore, be  regarded  as  established.  Mr.  Addison^  has  suggested,  that 
these  cells  are  not  developed  in  the  organs  of  nutrition  and  secretion 
at  the  expense  of  materials  supplied  by  the  blood;  that  they  are 
neither  more  nor  less  than  the  colourless  corpuscles  of  the  blood, 
which  elaborate  those  products  whilst  still  floating  in  its  current,  and. 
then  escape  from  the  vessels.  It  is  not  easy,  however,  to  comj^rehend, 
that  corpuscles,  apparently  identical,  should  exist  in  the  blood  charged 
with  the  different  properties  of  separating  bile,  urine,  saliva,  &c.,  irom 
the  fluid;  or  that  they  could  escape  through  the  parietes  of  the  contain- 
ing bloodvessels,  and  then  penetrate  the  parietes  of  the  excretory  ducts 
to  take  their  place — it  has  been  supposed — as  epithelium  cells  on  the 
lining  membrane  of  these  outlets.  Moreover,  as  has  been  shown  else- 
where, there  is  reason  to  believe,  that  the  office  of  the  white  corpuscles 
of  the  blood  is  of  a  different  character.^ 

In  cases  of  vicarious  secretion,  we  have  the  singular  phenomenon  of 
organs  assuming  an  action  for  which  they  were  not  destined.  If  the 
secretion  from  the  kidney,  for  example,  be  arrested,  urine  is  occasion- 
ally found  in  the  ventricles  of  the  brain,  and,  at  other  times,  a  urinous 
fluid  has  been  discharged  by  vomiting  or  by  cutaneous  transpiration  : 
the  secreting  cells  of  those  parts  must,  consequently,  have  assumed  the 
functions  of  the  kidney,  and  to  this  they  were  excited  by  the  presence 
of  urea,  or  the  elements  of  the  urinary  secretion  in  the  blood, — a  fa«;t, 
which  exhibits  the  important  influence  that  the  condition  of  the  blood 
must  exert  on  the  secretions,  and,  indeed,  on  nutrition  in  general.^  It 
is  thus  that  many  of  our  remedial  agents,  alkalies, — the  preparations  of 
iodine,  &c., — produce  their  efl'ects.     They  flrst  enter  the  mass  of  blood, 

'  The  Actual  Process  of  Nutrition  on  tlie  Living  Structure  demonstrated  Ly  tlie 
Microscope,  &c.,  Loud.,  1844.  ^  See  p.  3(!4  of  this  volume. 

"  An  interesting  case  of  vicarious  secretion  of  milk  has  been  recorded  in  liulletino 
delle  Scienze  Mediche,  April,  1839;  cited  in  Brit,  and  For.  Med.  Rev.  for  Jan.  184(i; 
and  another  by  Dr.  S.  W.  Mitchell,  in  Amer.  Journ.  of  the  Med.  Sciences  for  July, 
1855,  which  will  be  noticed  under  Lactation. 


484 


SECRETION. 


and,  by  circulating  in  the  capillary  system,  induce  a  modification  of 
the  function  of  nutrition.  There  are  other  cases,  again,  in  which  the 
condition  of  the  blood  being  natural,  the  cells  of  nutrition  may  assume 
morbid  action.  Of  this  we  have  examples  in  the  ossification  of  organs, 
which,  in  the  healthy  condition,  have  no  bony  constituent;  in  the  de- 
position of  fat  in  cases  of  diseased  ovaria ;  and  in  the  altered  secre- 
tions produced  by  any  source  of  irritation  in  a  secreting  orgau.^ 

In  describing  the  physiology  of  the  difierent  secretions,  one  of  three 
arrangements  has  usually  been  adopted;  either  according  to  the  nature 
of  the  secreting  organ,  the  function  of  the  secreted  fluid,  or  its  chemi- 
cal character.  The  first  of  these  has  been  followed  by  MM.  Bichat 
and  jSfagendie,^  who  have  adopted  a  division  into  exhaled^  follicular, 
and  glandular  secretions.  It  is  the  one  followed  by  M.  Lepelletier, 
except  that  he  substitutes  the  term  j^ersjyiratonj  for  exhaled.  According 
to  the  second,  embraced  by  MM.  Boyer,^  Sabatier,"  and  Adelon,*  they 
are  divided  into  recj-ementilial,  or  such  as  are  taken  up  by  internal  ab- 
sorption and  re-enter  the  circulation;  and  excrementitia I,  or  such  as 
are  evacuated  from  the  body,  and  constitute  the  excretions.  Some 
physiologists  add  a  third, — the  recremento-excrementitial, — in  which  a 
part  of  the  humour  is  absorbed  and  the  remainder  ejected.  Lastly, 
the  division  accoi'ding  to  chemical  character  has  been  followed,  with 
more  or  less  modification,  by  Plenck,^  Richerand,'  Blumenbach,^ 
Young,^  and  Bostock  ;^°  the  last  of  whom  has  eight  classes;  the  aque- 
ous, albuminous,  mucous,  gelatinous,  fihriyious,  oleaginous,  resinous,  and 
saline.  To  all  of  these  classifications  cogent  objections  might  be  made. 
The  one  we  shall  follow  is  the  anatomical, — not  because  it  is  the  most 
perfect,  but  because  it  is  the  course  that  has  been  usually  adopted 
throughout  this  worlc.  Defective,  too,  as  it  is,  it  will  enable  us  to  take 
a  survey  of  every  one  of  the  numerous  secretions  classified  in  the  fol- 
io wins 


TABLE  OF  THE  SECRETIONS. 


I.  Exhalations 

OR 

Simple  Secketioxs. 


A.  Internal. 


B.  External. 

c.  Internal  and 
external. 


1.  Areolar. 

2.  Serous.    \ 


General  and 
vascular. 


3.  Synovial 

4.  Adipous.     \ 

5.  Pigmental. 

6.  Capsular. 

1.  Dermic 

2.  Menstrual. 
Gaseous 


Fat. 
Marrow. 


ic    i^^i"- 

I  Mucous  membranes. 


'  See  Dr.  W.  B.  Carpenter,  art.  Secretion,  in  Cyclop,  of  Anat.  and  Phvsiol.,  iv.  439, 
Lond.,  1852. 

^  Precis  de  Physiologic,  2de  edit.,  ii.  243,  Paris,  1825. 

3  Axiaiomie,  2de  edit.,  i.  8,  Paris,  1803.         *  Traite  Coniplet  d'Anatomie,  Paris,  1791. 

^  Physiologic  de  T Homme,  edit,  cit.,  iii.  438. 

^  The  Chemico-Physiological  Doctrine  of  the  Fluids,  &:c.,  translated  by  Dr.  llooiJer, 
Lond,.,  1797. 

^  Elemeiis  de  Physiologie,  13eme  edit.,  chap,  vi.,  Bnixelles,  1837. 

8  Phvj^iology.  by'EUiotson,  4th  edit.,  Lond.,  1828. 

^  lutioduction  to  Medical  Literature,  p.  104,  Lond.,  1813. 

'0  Physiology,  3d  edit.,  p.  48,  Lond.,  1836. 


EXHALATI02TS. 


485 


II.  Follicular  Secretions. 


1.  Of  mucous  membranes. 


III.  Glandular  Secretions. 


2.  Of 


3.  Of 

f  1.  Of 

2.  Of 

3.  Of 

4.  Of 

5.  Of 

6.  Of 

7.  Of 

8.  Of 


the  skin. 
,  Sebaceous. 

Meibomian. 

Ceruminous. 
,  Preputial. 

Odoriferous, 
the  ovaries, 
the  skin. 

the  lachrymal  gland, 
the  salivary  glands, 
the  pancreas, 
the  liver, 
the  kidneys, 
the  testes. 
the  mammae. 


Gastro-pulmo- 
nary,  genito- 
urinary, &c. 


I.   EXHALATIONS  OR  SIMPLE  SECRETIONS. 

All  tbe  exhalations  take  place  into  the  areolae  and  internal  cavities 
of  the  body, — or  from  the  skin  and  mucous  membranes; — hence  such 
division  into  internal  and  external.  The  former  are  recrementitiaJ.,  the 
latter  recremento-excremerititial.  To  the  class  of  internal  exhalations 
belong:  1.  The  areolar  exhalation.  2.  The  serous  exhalation.  3.  The 
synovial  exhalation.  4.  The  adipous  exhalation.  5.  The  pigmental 
exhalation.  6.  The  exhalation  of  the  areolar  capsules.  To  the  class 
of  external  exhalations  belong:  1.  The  exhalation  of  the  mucous  mem- 
branes. 2.  The  menstrual  exhalation.  The  gaseous  exhalations  may 
be  either  external  or  internal. 

A.    INTERNAL  EXHALATIONS. 

1.  Areolar  Exhalatiori. 

A  brief  view  of  the  nature  of  the  primary  areolar^  cellular,  fihro- 
cellular,  or  connective  membrane  or  tissue  was  given  in  an  early  part  of 
this  work.     As  we  observe  it,  it  is  not  properly  cellular,  but  is  corn- 


Fig.  140. 


Fig.  141. 


Portion  of  Areolar  Tissue  inflnted  and  rlrieil, 
showin;^  the  general  chnraoter  of  its  larger 
meshes  ;  magnified  twenty  diameters. 


Arrangement  of  FiVires  in  Areolar  Tipsue. 
Magnified  135  diamoters. 


486 


SECRETION. 


]iosed  of  a  network  of  fibres,  and  lamellre  formed  by  tbc  adhesion  of 
fibres  laid  side  by  side;  and  these  interw^oven  so  as  to  leave  nninerous 
interstices  and  areola?  amongst  them,  which  have  a  tolerably  free  com- 
munication with  each  other/ 

Two  kinds  of  fibrous  tissue — the  ichite  and  the  yellow — may  be  de- 
tected in  it, — the  white  presenting  itself  in  the  form  of  inelastic  bands, 
the  largest  5,^0^^^  ^^  ^^  moh  in  breadth,  somewhat  wavy  in  their 
direction,  marked  longitudinally  by  numerous  streaks,  and  being  en- 
tirely resolved  into  gelatin  by  long  boiling;  and  the  yellow  existing 
in  the  form  of  long,  single,  elastic,  branched  filaments,  with  a  dark 
decided  border,  and  disposed  to  curl  when  not  put  upon  the  stretch. 
Tiiese  interlace  with  the  others,  but  seem  to  have  no  continuity  of  sub- 
stance with  them.  They  are,  for  the  most  part,  between  the  g  o'oo^^^  ^^^^ 
T(5c)oo^^"^  of  an  inch  in  thickness;  but  are  often  met  with  both  larger 
and  smaller.  It  is  not  much  changed  by  prolonged  boiling;  and 
appears  to  be  mainly  albuminous  in  its  character. 

The  interstices  in  the  areolar  membrane,  wherever  existing,  are  kept 
moist  by  a  serous  fluid,  analogous  to  that  exhaled  from  serous  mem- 
branes, and  which  appears  to  have  the  same  uses, — that  of  facilitating 
the  motion  of  the  lamelke,  or  fibres  on  each  other,  and,  consequently, 


Fi^.  142. 


Fig.  143 


1) 


^^^'xiMm^^^k^  \^M)Mi\l^'i<^. 


White  FiVirous  Tissue,  from  Ligniuent. 
— Magnified  65  diameters. 


Yellow  Fibrous  Tissue,  from  Lisramentum  Nuchae  of 
Calf. — Ma<rnilied  65  diameters. 


of  the  organs  between  which  the  areolar  tissue  is  placed.  When  this 
secretion  collects,  from  the  causes  mentioned  in  the  last  section,  the 
disease  called  oedema  or  anasarca  is  induced. 

2.  Ser OILS  Exhalation — General  and  Vascular. 

a.  General. 

This  is  the  fluid  secreted  by  the  serous  membranes  that  line  the 
various  cavities  of  the  body; — as  the  pleura,  pericardium,  peritoneum, 
arachnoid  coat  of  the  brain,  tunica  vaginalis  testis,  and  the  lining 
membrane  of  the  vessels.     Eudolphi^  asserts,  that  serous  membranes 

'  For  the  histology  of  the  areolar  and  serous  membranes,  see  Todd  and  Bovmian, 
Physiological  Anatomy  and  Physiology  of  Man,  London,  1842 ;  and  Dr.  Brinton,  art. 
Serous  and  Synovial  Membranes,  Pt.  xxxiv.  p.  ,512,  London,  Jan.,  1849. 

^  Grimdriss  der  Pliysiologie,  ^  113,  Berlin,  1821. 


OF   SEROUS   MEMBRANES.  487 

are  incapable  of  inflammation,  are  not  vascular,  and  do  not  secrete ; 
and  that  the  secretions  of  shut  sacs  take  place  from  the  subjacent 
parts,  and  transude  through  the  serous  membrane,  which,  conse- 
quentlv,  in  his  view,  is  a  kind  of  cuticle.  In  a  physiological  con- 
sideration, it  is  not  of  moment  whether  they  resemble  the  cuticle  or 
not;  and  anatomically  the  question  only  concerns  the  layer  that  covers 
the  surface.   • 

Serous  membranes,  as  elsewhere  remarked,  form  shut  sacs,  and  in- 
vest viscera,  whose  free  surfaces  come  in  contact,  or  which  lie  in  cavi- 
ties unattached  to  surrounding  parts.  To  the  law,  that  they  form 
close  or  shut  sacs,  there  is  but  one  exception  in  the  human  subject; 
in  the  opening  of  the  Fallopian  tubes  into  the  cavity  of  the  abdomen. 

They  are  constituted  of  fibro-areolar  tissue  so  interwoven  as  to  con- 
stitute a  membrane, — the  free  surface  covered  with  a  layer  of  flattened 
cells  forming,  in-  most  cases,  a  tessellated  epithelium.  Between  the 
epithelium  and  subserous  areolar  tissue  is  the  pri'tnary  or  basement 
membrane}  The  basement  membrane  and  epithelium  are  concerned 
in  the  secretion  of  the  fluid  by  which  the  free  surface  of  the  membrane 
is  moistened.  The  general  arrangement  of  serous  membranes  has 
been  well  described  by  Professor  (ioodsir.^  A  portion  of  the  human 
pleura  or  peritoneum,  according  to  him,  consists,  from  its  free  surface 
inwards,  of  a  single  layer  of  nucleated  scales;  of  a  germinal  mem- 
brane, aud  of  a  subserous  areolar  texture  intermixed  with  occasional 
elastic  fibres.  The  bloodvessels  of  the  serous  membrane  ramify  in  the 
areolar  texture.  The  germinal  membrane  seldom  shows  the  lines  of 
junction  of  its  component  flattened  cells.  These  appear  elongated  in 
the  form  of  ribands, — their  nuclei  or  the  germinal  spots  of  the  mem- 
brane being  elongated,  expanded  at  one  extremity,  pointed  at  the  other, 
and  somewhat  bent  upon  themselves;  they  are  bright  and  crystalline, 
and  may  or  may  not  contain  smaller  cells  in  their  interior.  If  these 
germinal  centres  be  the  sources  of  all  the  scales  of  the  superficial  layer, 
each  centre  being  the  source  of  the  scales  of  its  own  compartment, 
then  the  matter  necessary  for  the  formation  of  these  during  their  de- 
velopement  must  pass,  he  conceives,  from  the  capillary  vessels  to  each 
of  the  centres,  acted  on  by  forces  whose  centres  of  action  are  the  ger- 
minal spots; — each  of  the  scales,  after  being  detached  from  its  parent 
centre,  deriving  its  nourishment  by  its  own  inherent  powers. 

From  these  membranes  a  fluid  is  exhaled,  which  is  of  an  albuminous 
character,  resembling  gi'eatly  the  serum  of  the  blood,  except  in  con- 
taining less  albumen.  M.  Donnc^  says  it  is  always  alkaline  in  the 
healthy  state.  This  is  owing  to  the  presence  of  carbonate  or  albumi- 
nate of  soda.  It  contains  7  or  8  per  cent,  of  albumen,  and  salts.  In 
health,  this  fluid  never  accumulates  in  the  cavities, — the  absorbents 
taking  it  up  in  proportion  as  it  is  deposited ;  but  if,  from  any  cause, 
the  exhalants  should  pour  out  a  larger  quantity  than  usual,  whilst  the 
absorbents  are  not  proportionably  excited,  accumulation  may  take 
place;  or  the  same  effect  may  ensue  if  the  exhalants  pour  out  no  more 

'  Bowman,  art.  Mucous  Membrane,  Cyclopaedia  of  Anatomy  and  Physiology,  ^.  484, 
April,  1842. 

^  Anatomical  and  Pathological  Observations,  Edinb.,  1845. 
^  Journal  llebdomail.,  Fevrier,  lb34. 


488  SECRETION. 

than  their  usual  quantit}^,  whilst  the  absorbents  do  not  possess  their 
due  activity.  Under  either  circunastance,  we  have  an  accumulation — 
a  dropsy.  The  exhaled  fluid  probably  transudes  through  the  parietes 
of  the  arteries,  and  re-enters  the  circulation  by  imbibition  through  the 
coats  of  the  veins.  If  we  kill  an  animal  and  open  it  immediately 
afterwards,  this  exhalation  appears  in  the  form  of  a  halitus  or  vapour, 
and  the  fluid  is  seen  lubricating  the  free  surface  of  the  membrane. 
This,  indeed,  appears  to  be  its  principal  office ;  by  which  it  favours  the 
motion  of  the  organs  upon  each  other. 

The  serous  exhalations  probably  differ  somewhat  in  each  cavity,  or 
according  to  the  precise  structure  of  tlie  membrane.  The  difference 
between  the  chemical  character  of  the  fluid  of  the  dropsy  of  different 
cavities  would  lead  to  this  belief.  As  a  general  rule,  according  to  Dr. 
Bostock,^  the  fluid  from  the  cavity  of  the  abdomen  contains  the  greatest 
proportion  of  albumen,  and  that  from  the  brain  the  least;  but  many 
exceptions  occur  to  this. 

h.  Vascular. 

A  fluid  is  exhaled  from  the  inner  or  serous  coat  of  tlie  arterial, 
venous,  and  lymphatic  vessels.  It  probably  does  not  differ  much  from 
the  fluid  of  serous  membranes  in  general;  and  its  use,  doubtless,  is  to 
lubricate  the  interior  of  the  vessel,  and  prevent  adhesion  between  it 
and  the  fluid  circulating  within  it. 

3.  Synovial  Exlialation. 

Within  the  articular  capsules,  and  bursge  mucosae, — which  are 
described  under  ^luscular  Motion, — a  fluid  is  secreted,  which  is 
spread  over  the  articular  surfaces  of  bones,  and  facilitates  their  move- 
ments. Dr.  Clopton  Havers^  considered  this  fluid  to  be  secreted  by 
synovial  glands^ — for  such  he  conceived  the  reddish  cellular  masses  to 
be,  that  are  found  in  certain  articulations.  Haller^  strangely  regarded 
the  synovia  as  the  marrow,  which  had  transuded  through  the  spongy 
extremities  of  the  bones ;  but,  since  the  time  of  Bichat,  every  anato- 
mist and  physiologist  has  ascribed  it  to  the  exhalant  action  of  the 
synovial  membrane, — which  strongly  resembles  the  serous  membranes 
in  form,  structure,  and  functions, — whose  folds  constitute  the  projec- 
tions that  Havers  mistook  for  glands.  The  opinion  of  Havers  has, 
however,  been  confirmed  by  Mr.  Kaiuey,'*  It  had  been  believed  by 
man}',  that  the  folds  of  synovial  membrane,  which  form  fringes,  con- 
tain merely  globules  of  fat,  and  are  only  inservient  to  the  mechanical 
office  of  filling  up  spaces  that  would  otherwise  be  left  vacant  during 
the  movements  of  the  joints.  By  a  careful  examination  of  their 
structure,  with  the  aid  of  the  microscope,  Mr.  Eainey  found  a  peculiar 
arrangement  of  vessels  not  at  all  resembling  those  that  secrete  fat,  and 
an  epithelium  of  remarkable  form  and  disposition,  and  characteristic 
of  organs  whose  function  it  is  to  effect  a  special  secretion.     These 

'  Op.  citat.,  p.  485. 

*  De  Ossibus,  serm.  iv.  c.  1  ;  and  Osteologia  Nova,  London,  1691. 
"  Element.  PliysioL,  iv.  11. 

*  Proceedings  of  the  Royal  Society  of  London,  No.  65, 1847. 


OF   THE    SYNOVIAL    MEMBRANE.  489 

fringes  he  traced  not  only  in  the  joints  but  in  the  sheaths  of  tendons, 
and  in  the  bursts — wherever,  indeed,  synovia  is  secreted.  When  Avell 
injected  they  are  seen  under  the  microscope  to  consist  of  a  convolu- 
tion of  bloodvessels  and  an  investing  epithelium,  which,  besides  en- 
closing separately  each  packet  of  convoluted  vessels,  sends  off  from 
each  tubular  sheath  secondary  processes  of  various  shapes  into  which 
no  bloodvessels  enter.  The  lamina  itself  forming  these  folds  and  pro- 
cesses consists  of  a  very  thin  membrane  studded  with  flattish  oval 
cells,  a  little  larger  than  blood  corpuscles,  but  destitute  of  nucleus  or 
nucleolus, — presenting  none  of  the  characters  of  tessellated  epithelium, 
but  corresponding  more  to  what  Mr.  Goodsir  has  termed  "germinal 
membrane."     The  proper  office  of  this  structure  is  to  secrete  synovia. 

The  synovial  membrane  exists  in  all  the  movable  articulations,  and 
in  the  channels  and  sheaths  in  which  the  tendons  play.  The  articular 
capsules  are  shut  sacs;  and  the  generality  of  anatomists  consider  that 
the  membranes  are  reflected  over  the  incrusting  cartilages.  M.  Ma- 
gendie,  however,  affirms,  that  he  has  several  times  satisfied  himself, 
that  they  do  not  pass  beyond  the  circumference  of  the  cartilages. 
From  the  inner  surface  of  these  membranes  the  synovia  is  exhaled  in 
the  same  manner  as  in  other  serous  cavities. 

M.  Margueron^  analyzed  synovia  obtained  from  a  posterior  extremity 
of  the  ox,  and  found  it  consist  of  modified  albumen  presenting  the 
colour,  smell,  taste,  and  elasticity  of  vegetable  gluten,  fibrinous  matter, 
11*86 ;  albumen,  4-52;  chloride  of  sodium,  I'To;  carbonate  of  soda, 
0-71;  phosphate  of  lime,  O'TO;  and  water,  8046.  M.  Donne^  says  it  is 
always  alkaline  in  health ;  but  in  certain  diseases  sometimes  becomes 
acid.  The  synovia  of  a  stall  fed  ox  was  found  by  Frerichs^  to  con- 
sist of 

Water, 969-90 

Solid  constituents,      .........  30"10 

Mncous  matter  with  epithelium,         ......  2'40 

Fat, 0-62 

Albumen  and  extractive  matter,         .         .         .         .         .         .  15*76 

Salts, 11-32 

That  of  an  ox,  which  had  been  pasture-fed  all  the  summer,  con- 
tained 

Water 948-54 

Solid  constituents, 51-46 

Mucous  matter  and  epithelium,           .         .         .         .         .         .  5-60 

Fat, 0-76 

AlVnamen  and  extractive  matter,          ......  35*12 

Salts, 9-98 

4.  Adipous  Exhalation. 

a.  Fat. 

Considerable  diversity  of  opinion  has  prevailed  regarding  the  pre- 
cise organ  for  the  secretion  of  fat.    Ilaller  supposed,  that  the  substance 

'  Annales  de  Chimie,  xiv.  123  ;  and  art.  Synovie,  Diet,  des  Sciences  Mfidicalos,  liv. 
125,  Paris,  1821. 

^  Journal  Hebdomad.,  Fevrier,  1834. 

3  Art.  Synovia,  in  Wagner"s  Handworterbuch  der  Physiologie,  IBte  Lieferung,  s. 
467,  Eraunschweig,  1848. 


490 


SECRETION. 


A  small  cluster  of  Fat-Cells  magnified  150  diameters. 


exists  ready  formed  in  the  blood,  and  simply  transudes  through  the 
pores  of  the  arteries ;  and  Chevreul  and  others  have  given  confirma- 
tion   to    the    opinion,    by 
Fig.  144.  the  circumstance  of  their 

having  met  with  fatty  mat- 
ter in  that  fluid.  Anato- 
mists have,  likewise,  been 
divided  upon  the  subject  of 
the  precise  tissue  into  which 
the  fat  is  deposited;  some 
believing  it  to  be  the  ordi- 
naiy  areolar  tissue,  into 
which  it  is  dropped  by  the 
agency  of  appropriate  ves- 
sels; others,  as  Malpighi^ 
and  Dr.  William  Hunter,^ 
believing  in  the  existence 
of  a  peculiar  adipous  tissue, 
consisting,  according  to  ]\[.  Beclard,'  of  small  bursas  or  membranous 
vesicles,  which  enclose  the  fat,  and  are  found  in  the  areolas  of  the 
tissue.  These  vesicles  are  said  to  var}^  greatly  in  size :  generallj^,  they 
are  round  and  globular ;  and,  in  certain  subjects,  receive  very  appa- 
rent vessels.  They  form  so  many  small  sacs  without  apertures,  in  the 
interior  of  which  are  filaments  arranged  like  septa.     In  fatty  subjects, 

these  adipous  vesicles 
are  very  perceptible, 
being  attached  to  the 
areolar  tissue  and  neigh- 
bouring parts  by  a  vas- 
cular pedicle. 

Thefatoriginatesfrora 
fat-cells,  which  are  usu- 
ally of  a  spherical  or 
spheroidal  shape,  but 
sometimes,  when  closely 
pressed  together  without 
the  intervention  of  any 
intercellular  substance, 
they  become  polyhedral. 
The  adipous  tissue  is 
a  membrane  of  extreme 
tenuity,  which  forms 
the  vesicle  that  includes 
Bloodvessels  of  Fat  Vesicles.  the  fat.    The  membrane 

1.  Minute  flattened  fat  lobule,  in  which  the  vessels  only  are  re-  j^g       homOO'CneOUS       and 
presented.     3.  Terminal  artery.     4.  Primitive  vein.     5.  Fat  vesicle,  °  , 

of  one  border  of  the  lobule,  separately  represented.     Magnified  100  transparent,     abOUt     the 
diameters. — 2.  P?/7»  of  the  arrangement  of  capillaries  on  the  exterior  .         .i       n         •       i    tt  •    l 

of  the  vesicle-s,  more  highly  magnified.  2  0  0  0  0 '■^-' ^"^ '^^^  inCll  tUlCK, 


Fiff.  145. 


i 


'  De  Omento,  Pinguedine,  et  Adiposis  Ductibus,  in  Oper.,  London,  16S7. 

2  Medical  Observations  and  Inquiries,  vol.  ii.,  London,  1777. 

3  Art.  Adipeux,  in  Dictionnaire  de  Medecine,  torn.  i.  ;  and  Elements  of  General  An- 
atomy, translated  by  Togno,  p.  128,  PLilad.,  1830. 


OF   THE    ADIPOUS    MEMBRANE.  491 

and  is  moistened  by  a  Avaterj  fluid,  for  which  it  has  a  greater  attrac- 
tion than  the  fat  it  contains.  Each  vesicle  is  from  the  gfloth  to  the 
g^gth  of  an  inch  in  diameter.  When  the  fat  vesicles  exist  in  any  num- 
ber, their  arrangement  is  generally  lobular,  with  an  investment  of 
areolar  tissue,  which  favours  motion,  and  the  distribution  of  the  blood- 
vessels. These  enter  the  interlobular  clefts,  ramify  through  their  inte- 
rior as  a  solid  capillary  network,  occupy  the  angles  formed  by  con- 
tiguous sides  of  the  vesicles,  and  anastomose  with  one  another  at  the 
points  where  these  angles  meet. 

M.  RaspaiP  affirms,  that  there  is  the  most  striking  analogy  between 
the  nature  of  the  adipous  granules  and  that  of  the  amylaceous  grains. 
As  in  the  case  of  fecula,  each  adipous  granule  is  composed  of  at  least 
one  integument,  and  an  enclosed  substance,  both  of  which  are  as  slightly 
nitrogenized  as  fecula;  and  both  fecula  and  fat  are  equally  inservient 
to  the  nutrition  of  the  organs  of  developement :  whenever  there  is  excess 
of  life  and  activity,  the  fat  is  seen  to  disappear,  and  whenever  there  is 
rest,  it  accumulates  in  its  reservoirs.  If  a  portion  of  fat  be  examined, 
it  is  found  to  consist  of  an  outer  vesicle  with  strong  membranous  pari- 
etes,  containing  small  adipous  masses  readily  separable  from  each 
other,  each  invested  with  a  similar,  but  slighter,  vesicular  membrane; 
and  these,  again,  contain  others  still  more  minute,  until  ultimately  we 
come  to  the  vesicles  that  invest  the  adipous  granules  themselves.  Each 
of  these  masses  adheres,  at  some  point  of  its  surface,  to  the  inner  surface 
of  the  vesicle  that  encloses  it,  by  a  hilum  in  the  same  manner  as  the 
grain  of  fecula.  All  the  vesicles,  but  especially  the  outermost  and 
strongest,  have  a  reddish  vascular  network  on  their  surface,  the  vessels 
of  which  augment  in  size  as  they  approach  the  part  where  the  vesicle 
is  adherent,  and  there  open  into  one  of  the  vessels  of  the  larger  vesicle 
that  encloses  them. 

The  arrangement  of  this  tissue,  as  well  as  the  quantity  of  fat,  varies 
in  different  parts  of  the  body.  It  is  always  found  in  the  orbit,  on  the 
sole  of  the  foot,  and  at  the  pulps  of  the  lingers  and  toes.  The  subcu- 
taneous areolar  tissue,  and  that  covering  the  heart,  kidnej^s,  &c.,  also 
generall}^  contain  it;  but  it  is  never  met  with  in  deposit  in  the  eyelids, 
scrotum,  or  within  the  cranium. 

Fat  is  exhaled  by  the  secretory  vessels  in  a  fluid  state;  but  after  it 
is  deposited,  it  becomes  more  or  less  solid.  According  to  the  researches 
of  MM.  ChevreuP  and  Braconnot,  human  fat  is  almost  always  of  a  yel- 
low colour;  inodorous,  and  composed  of  two  portions; — the  one  fluid, 
and  the  other  concrete,  which  are  themselves  composed,  but  in  different 
proportions,  of  two  immediate  principles,  to  which  the  former  chemist 
gave  the  names  elain  or  oJein^  and  stearin.  Subsequently,  the  organic 
elements  of  fat  were  considered  to  be  stearin^  margarin^  and  olein ;  the 
two  former,  which  are  solid  when  separate,  being  dissolved  in  the  latter 
at  the  ordinary  temperature  of  the  body.  Chemistry  has,  however, 
shown,  that  the  fat  contained  in  the  cells  of  the  adipous  tissue  is  com- 
posed of  a  base  of  a  sweetish  taste,  thence  termed  ghjcerin^  itself  an 
oxide  of  glyceryl,  with  stearic;  margaric,  and  oleic  acids, — stearin  being 

'  Cliimie  Organique,  p.  183,  Paris,  1833. 

^  Recherch.es  Chimiques  sur  les  Corps  Gras,  &c.,  Paris,  1823. 


492  SECRETION. 

esteemed  a  bi-stearate  of  gl3^ccrin ;  and  olein  or  elain  an  oleate  of  gly- 
cerin.    These  proximate  principles  are  sometimes  seen  spontaneously 
separated  within  the  human  fat  vesicle.     The  stearin  collects  in  the 
form  of  a  small  star  on  the  inner  surface  of  the 
Fig-  146.  membrane,  as  in  the  marginal  figure  at  2,  2,  2, 

^g^^  the  elain  occupying  the  remainder  of  the  vesi- 

/C^y^^^     a      cle,  except  where  there  is  an  unusually  small 

p^^^^^P\. 2     quantity  of  fat,  when  a  little  aqueous  fluid  is 

J^^^^^S!  seen  interposed  between  the  elain  and  the  cell- 

^  — ^    fflj^^^  membrane. 

^^/-  ^  It  is  probable,  that  chemical  analysis  would 

Fat  Vesicles  from  an  Ema-    exhibit  the  fat  to  vary  in  different  parts  of  the 

ciated  Subject.  body,  as  its  Sensible   properties   are  different. 

1, 1.  coii-raembrane.  2,2,2.    Sir  Evcrard  Homc,' on  loose  analogies  and  in- 

Solid  portion  collected  as  a  star-  ,       .  ,      ,  ^  t  °t  .     . 

like  mass,  with  theeiain  in  con-  conclusivc  argumcuts,  has  advauccd  the  opinion, 
J'hTceu.'^'"'  "' '"''  ''"^  ^^"°^  that  it  is  more  than  probable,  that  fat  is  formed 
in  the  lower  portion  of  the  intestines;  and 
thence  is  carried,  through  the  medium  of  the  circulating  blood,  to  be 
deposited  in  almost  every  part  of  the  body.  "  When  there  is  a  great 
demand  for  it,  as  in  youth,  for  carrying  on  growth,  it  is  laid  imme- 
diately under  the  skin,  or  in  the  neighbourhood  of  the  abdomen. 
When  not  likely  to  be  wanted,  as  in  old  age,  it  is  deposited  in  the  in- 
terstices of  muscular  fibres,  to  make  up  in  bulk  for  the  wasting  of  these 
organs.  M.  de  Blainville^  held  the  opinion,  that  fat  is  derived  from 
venous  blood,  and  that  it  is  exhaled  through  the  coats  of  the  vessels. 
This  opinion  he  founds  on  the  mode  in  which  the  fat  is  distributed  in 
the  omenta  along  the  course  of  the  veins;  and  he  affirms,  that  he  has 
seen  it  flow  out  of  the  jugular  vein  in  a  dead  elephant.  But  this  last 
fact,  as  M.  Lepelletier-'  has  judiciously  remarked,  proves  nothing  more 
than  that  fat — taken  up  by  the  absorbents  from  the  vesicles  in  which 
it  had  been  deposited  by  the  exhalants — had  been  conveyed  into  the 
venous  blood  with  other  absorbed  matters.  It  in  no  wise  shows,  that 
the  venous  blood  is  the  pabulum  of  the  secretion,  or  that  the  veins  ac- 
com]ilish  it. 

The  purposes  served  by  the  fat  are  both  general  and  heal.  The 
great  general  use  is,  by  some  physiologists,  conceived  to  be, — to  serve 
as  a  provision  in  cases  of  wasting  indisposition;  when  the  digestive 
function  is  incapacitated  for  performing  its  due  office,  and  emaciation 
is  the  consequence.  In  favour  of  this  view,  the  rapidity  with  which 
fat  disap})ears  after  slight  abstinence  has  been  urged,  as  well  as  the 
facts,  connected  with  the  torpidity  of  animals,  which  are  always  found 
to  diminish  in  weight  during  this  state.  Professor  jSIangili,  of  Pa  via, 
procured  two  marmots  from  the  Alps,  on  the  1st  of  December.  The 
larger  weighed  25  Milanese  ounces;  the  smaller  only  22|th;  on  the  8d 
of  January,  the  larger  had  lost  f  ths  of  an  ounce,  and  the  smaller  J  "jths. 
On  the  5th  of  February,  the  larger  weighed  only  22|:  the  smaller  21. 
Dr.  Monro  kept  a  hedgehog  from  the  month  of  November  to  the 

'  Lect.  on  Comp.  Anat.,  i.  468,  LoncL,  1814,  and  vol.  vi.  Lond.,  1828  ;  aud  Pliilos. 
Transact.,  1S21,  p.  34. 

^  De  rOrganisation  des  Animanx,  &c.,  Paris,  1825. 

^  Plijsiologie  Medicale  et  Philosopliique,  ii.  4iJ6,  Paris,  1832. 


OF   THE   ADIPOUS    MEMBRANE.  493 

month  of  March  following,  which  lost,  in  the  meanwhile,  a  considera- 
ble portion  of  its  weight.  On  the  25th  of  December,  it  weighed  13 
ounces  and  3  drachms;  on  the  6th  of  February,  11  ounces  and  7 
drachms;  and  on  the  8th  of  Marcli,  11  ounces  and  3  drachms.  The 
loss  was  13  grains  daily .^ 

The  local  uses  of  fat  are  chiefly  of  a  physical  character.  On  the 
sole  of  the  foot  it  diminishes  the  effects  of  pressure,  and.  serves  the 
same  office  on  the  nates ;  in  the  orbit  it  forms  a  kind  of  cushion,  on 
which  the  eyeball  moves  with  focility ;  and  when  in  certain  limits  it 
gives  that  rotundity  to  the  frame,  which  we  are  accustomed  to  regard 
as  beauty  of  form.  Dr.  Fletcher,^  indeed,  considers  its  principal  use 
to  be,  to  fill  up  interstices,  and  thus  to  give  a  pleasing  contour  to  the 
body.  In  another  place,  it  is  observed,  that  fatty  substances  are  bad 
conductors  of  caloric;  and  hence  may  tend  to  preserve  the  temperature 
of  the  body  in  cold  seasons ;  a  view  which  is  favoured  by  the  fact,  that 
many  of  the  Arctic  animals  are  largely  supplied  with  fat  beneath  the 
common  integuments;  and  it  has  been  affirmed,  that  fat  people  gene- 
rall}'  suffer  less  than  lean  from  the  cold  of  winter. 

It  is  obviously  impracticable  to  estimate  accurately  the  total  quan- 
tity of  fat  in  the  body.  It  has  been  supposed  that,  in  an  adult  male 
of  moderate  size,  it  forms  2'oth  of  the  whole  weight;  but  it  is  doubtful 
whether  we  ought  to  regard  this  as  even  an  approximation, — the  data 
being  so  inadequate.  In  some  cases  of  polysarcia  or  obesity,  the  bulk 
of  the  body  has  been  enormous.  That  of  a  girl  is  detailed,  who  weighed 
256  pounds,  when  only  four  years  old.^  A  girl,  said  to  be  onl}^  tea 
years  old,  called  the  "  Ohio  giantess,"  was  exhibited  in  Philadelphia, 
in  the  year  ISl-l,  who  was  said  to  Aveigh  265  pounds;  and  in  March, 
1817,  an  Ohio  girl,  twelve  years  of  age — perhaps  the  same — was  ex- 
hibited, who  weighed  330  pounds.  The  Lowell  Advertiser,  of  Sep- 
tember, 1844,  states,  that  a  coloured  girl,  aged  fourteen,  a  native  of 
Nassau,  New  York,  died  in  that  city,  weiglyng  500  pounds.  A  man 
of  the  name  of  Bright,  at  Maiden,  England,  weighed  728  pounds;  and 
the  celebrated  Daniel  Lambert,  of  Leicester,  England,  weighed  739 
pounds  a  little  before  his  death,  which  occurred  in  the  fortieth  year  of 
his  age."  The  circumference  of  his  body  was  three  yards  and  four 
inches ;  and  of  his  leg  one  yard  and  one  inch.  His  coffin  was  six 
feet  four  inches  long;  four  feet  four  inches  wide;  and  two  feet  four 
inches  deep.  A  Kentuckian,  of  the  name  of  Pritchard,  who  exhibited 
himself  in  Cincinnati,  in  1834,  weighed  five  hundred  and  fifty  pounds. 
The  "  Canadian  giant," — as  he  was  called — whom  Dr.  Gross*  saw  in 
Philadelphia,  in  1829,  weighed  six  hundred  and  eighteen  pounds.  lie 
was  six  feet  four  inches  in  height,  and  the  circumference  of  each  leg 
around  the  calf  was  nearly  three  feet.  The  deposition  of  fat  was  con- 
fined chiefly  to  the  abdomen  and  lower  limbs, — the  thorax,  shoulders, 
and  arms  being  little  larger  than  in  other  persons.  The  public  Jour- 
nals of  this  country*"  have  recorded  the  death  of  a  Mr.  Cornelius,  who 

'  Fleming,  Pliilosophy  of  Zoology,  ii.  59,  Ediub.,  1822. 

^  Rudiments  of  Physiology,  part  iii.,  by  Dr.  Lewius,  p.  71,  Edinb.,  1837. 

^  Philos.  Transact.,  No.  1^5. 

*  (iood's  Study  of  Medicine,  Class  vi.  Ord.  1,  Gen.  1,  Sp.  1. 

"  Elements  of  Pathological  Anatomy.  2(1  edit.,  p.  202,  Philad.,  1845. 

«  Philadelphia  Public  Ledger,  October  4,  1841. 


494:  SECRETION. 

weighed  720  pounds;  and  in  the  year  1854,  a  woman  was  exhibited 
in  Philadelphia,  who  was  said  to  weigh  7G4  pounds;  and  another  800 
pounds.  Dr.  Elliotson^  says  he  saw  a  female  child,  but  a  year  old, 
which  weighed  sixty  pounds.  She  had  begun  to  grow  fat  at  the  end 
of  the  third  month. 

In  these  cases,  the  specific  gravity  of  the  body  may  be  much  less 
than  that  of  water.  It  is  said,  that  some  time  ago  there  was  a  fat 
lighterman,  on  the  river  Thames,  "  who  had  fallen  overboard  repeat- 
edly, without  any  farther  inconvenience  than  that  of  a  good  ducking; 
since  though  he  knew  nothing  wdiatever  of  the  art  of  swimming,  he 
always  continued  to  flounder  about  like  a  firkin  of  butter,  till  he  was 
picked  up."^ 

In  some  of  the  varieties  of  the  human  family  singular  adipous  de- 
posits are  met  with.  In  the  Bosjesman  female  vast  masses  of  fat  accu- 
mulate on  the  buttocks,  which  give  them  the  most  extravagant  appear- 
ance. The  projection  of  the  posterior  part  of  the  body,  in  one  sub- 
ject,'according  to  Sir  John  Barrow,^  measured  five  inches  and  a  half 
from  a  line  touching  the  spine.  "  This  protuberance,"  he  remarks, 
"consisted  of  fat,  and  when  the  woman  walked  had  the  most  ridicu- 
lous appearance  imaginable,  every  step  being  accompanied  with  a 
quivering  and  tremulous  motion,  as  if  two  masses  of  jelly  were  attached 
behind."  The  "Hottentot  Venus,"  who  had  several  projections,  mea- 
sured more  than  nineteen  inches  around  the  haunches;  and  the  pro- 
jection of  the  hips  exceeded  (U  inches.  Dr.  Somerville''  found  on 
dissection,  that  the  size  of  the  buttocks  arose  from  a  vast  mass  of  fat, 
interposed  between  the  integuments  and  muscles,  which  equalled  four 
fingers'  breadth  in  thickness.  It  is  singular  that,  according  to  the 
statement  of  this  female,  which  is  corroborated  by  the  testimony'  of 
Sir  John  Barrow,  the  deposition  does  not  take  place  till  the  first  i>reg- 
nancy.  Pallas'  has  described  a  variety  of  sheep — ovis  stentopyga  or 
"fat  buttocked" — which  is  reared  in  immense  flocks  by  the  pastoral 
tribes  of  Asia.  In  it,  a  large  mass  of  fat  covers  the  nates  and  occu- 
pies the  place  of  the  tail.  The  protuberance  is  smooth  beneath,  and 
resembles  a  double  hemisphere,  when  viewed  behind, — the  os  coccygis 
or  rump-bone  being  perceptible  to  the  touch  in  the  notch  between  the 
two.  They  consist  merely  of  fat;  and,  when  very  large,  shake  in 
walking  like  the  buttocks  of  the  female  Bosjesman.  Mr.  Lawrence^ 
remarks,  that  there  are  herds  of  sheep  in  Persia,  Syria,  Palestine,  and 
some  parts  of  Africa,  in  which  the  tail  is  not  wanting  as  in  ovis  stea- 
topyrja^  but  retains  its  usual  length,  and  becomes  loaded  with  fat. 

According  to  Liebig,^  the  abnormous  condition,  which  causes  an 
undue  deposition  of  fat  in  the  animal  body,  depends  on  a  dispropor- 
tion between  the  quantity  of  carbon  in  the  food,  and  that  of  the  oxy- 
gen absorbed  by  the  skin  and  lungs.     In  the  normal  condition,  the 

'  Human  Physiology,  London,  1841,  P.  i.  331. 

2  Fletcher,  Kudimeiits  of  Physiology,  by  Dr.  Lewins,  pt.  3,  p.  71,  Edinb.,  1837. 

3  Travels  into  tlie  interior  of  Southern  Africa,  p.  281,  London,  1801. 

*  Medico-Chirurgieal  Transactions,  vii.  157. 

*  Spicilea;ia  Zoologica,  fasc.  xi.  p.  63.  Also,  Erman,  Travels  in  Siberia,  Amer.  edit., 
Philad.,  1850. 

•>  Lectures  on  Physiology,  Zoology,  &c.,  p.  427,  London,  1819. 

^  Animal  Chemistry,  Webster's  edit.,  p.  85,  Cambridge,  Mass.,  1842. 


OF   THE    ADIPOUS    MEMBRANE.  495 

quanti'ty  of  carbon  given  out  is  exactly  equal  to  that  which  is  taken 
in  the  food,  and  the  body  experiences  no  increase  of  weight  from  the 
accumulation  of  substances  containing  much  carbon  and  no  nitrogen ; 
but  if  the  supply  of  highly  carbonized  food  be  increased,  then  the 
normal  state  can  only  be  preserved  by  exercise  and  labour,  through 
which  the  waste  of  the  body  is  increased,  and  the  supply  of  oxygen 
accumulated  in  the  same  proportion.  The  production  of  fat,  Liebig 
maintains,  is  always  a  consequence  of  a  deficient  supply  of  oxygen ; 
for  oxygen  is  absolutely  indispensable  for  the  dissipation  of  the  excess 
of  carbon  in  the  food.  "This  excess  of  carbon,  deposited  in  the  form 
of  fat,  is  never  seen  in  the  Bedouin  or  in  the  Arab  of  the  desert,  who 
exhibits  with  pride  to  the  traveller  his  lean,  muscular,  sinewy  limbs, 
altogether  free  from  fat;  but  in  prisons  and  jails  it  appears  as  a  pufh- 
ness  in  the  inmates,  fed,  as  they  are,  on  a  poor  and  scanty  diet:  it 
appears  in  the  sedentary  females  of  oriental  countries  ;  and  is  produced 
under  the  well-known  conditions  of  fattening  of  domestic  animals." 

In  accordance,  too,  with  his  views  of  animal  temperature,  already 
referred  to,  Liebig  considers  that  in  the  formation  of  fat  there  is  a  new 
source  of  heat.  The  oxygen  set  free  in  the  action  is  given  out  in 
combination  with  carbon  and  hydrogen;  and  whether  this  carbon  and 
hydrogen  proceed  from  the  substance  that  yields  the  oxygen,  or  from 
other  compounds,  still  there  must  have  been  generated  by  the  forma- 
tion of  carbonic  acid  or  water  as  much  heat  as  if  an  equal  weight  of 
carbon  or  hydrogen  had  been  burned  in  air  or  in  oxygen  gas. 

Whether  the  view  of  Liebig  be  admitted  or  not,  it  is  certain  that  the 
circumstances,  which  favour  obesity,  are  absence  of  activity  and  ex- 
citement of  all  kinds ;  hence,  for  the  purpose  of  fattening  animals  in 
rural  economy,  they  are  kept  in  entire  darkness,  to  deprive  them  of 
the  stimulus  of  light,  and  encourage  sleep  and  muscular  inactivity. 
Castration — by  abolishing  one  kind  of  excitability — and  the  time  of 
life  at  which  the  generative  functions  cease  to  be  exerted,  especially 
in  the  female,  are  favourable  to  the  same  result, 

h.  Marrow. 

A  fluid,  essentially  resembling  fat,  is  found  in  the  cavity  of  long 
bones,  in  the  spongy  tissue  of  short  bones,  and  in  the  areohe  of  bones 
of  every  kind.  This  is  the  marrow — -medulla  ossium.  The  secretory 
organ  is  the  very  delicate  membrane,  which  is  perceptible  in  the  inte- 
rior of  the  long  bones,  lining  the  medullary  cavity,  and  sending  pro- 
longations into  the  compact  substance,  and  others  internally,  which 
form  septa  and  spaces  for  the  reception  of  the  marrow.  The  cells, 
thus  formed,  are  distinct  from  each  other.  From  the  observations  of 
Mr.  Howship,'  it  would  seem  probable,  that  the  oil  of  bones  is  depo- 
sited in  longitudinal  canals,  that  pass  through  the  solid  substance  of 
the  bone,  and  through  which  its  vessels  are  transmitted.  This  oil  of 
hones  is  the  marrow  of  the  compact  structure,  the  latter  term  being 
generally  restricted  to  the  secretion  when  contained  in  the  cavities  of 
long  bones ;  that  which  exists  in  the  spongy  substance  being  termed, 
by  some  writers,  the  medullary  juice.     The  medullary  membrane,  called 

'  Medico-Cliirurg.  Trans.,  vii.  393. 


496  SECRETION. 

also  tlie  internal  periostenm,  consists  chiefly  of  bloodvessels  ramifying 
on  an  extremely  delicate  areolar  tissue,  in  which  nerves  may  likewise 
be  traced. 

Marrow  is  seen  in  two  forms,  one  yellow  and  the  other  red.  The 
former  which  is  found  principally  in  the  long  bones,  is  a  semifluid 
substance,  and  was  examined  by  Berzelius  as  obtained  from  the  hume- 
rus of  an  ox.  He  found  it  to  consist  of  the  following  constituents: — 
pure  adipous  matter,  96;  skins  and  bloodvessels,  1;  albumen,  gelatin, 
extractive,  peculiar  matter,  and  water,  3,  The  latter  is  found  in  the 
processes,  and  in  flat  and  short  bones ;  in  the  bodies  of  the  vertebrae, 
basis  cranii,  sternum,  &c.  That  of  the  diploe  was  examined  by  Ber- 
zelius, and  found  to  contain  75.0  water,  and  25-0  solid  matters — as 
albumen,  fibrin,  extractive  and  salts.' 

The  marrow  is  one  of  the  corporeal  components,  of  whose  use  we 
can  scarcely  offer  a  plausible  conjecture.  It  has  been  supposed  to 
render  the  bones  less  brittle ;  but  this  is  not  correct,  as  those  of  the 
fcetus,  which  contain  little  or  no  marrow,  are  less  so  than  those  of  the 
adult;  whilst  those  of  old  persons,  in  whom  the  medullary  cavity  is 
large,  are  more  brittle  than  those  of  the  adult.  It  is  possible  that  it 
may  be  placed  in  the  cavities  of  bones, — which  would  otherwise  be  so 
many  vacant  spaces, — to  serve  the  general  purposes  of  flit,  when 
required  by  the  system.  The  other  hypotheses  that  have  been  enter- 
tained on  the  subject  are  not  deserving  of  notice. 

5.  Pigmental  Exhalation. 

The  nature  of  the  exhalation,  which  constitutes  the  colouring  matter 
of  the  skin,  will  engage  attention,  when  treating  of  the  skin  under  the 
Sexse  of  Touch.  It  is  presumed  to  be  exhaled  by  the  vessels  of  the 
skin,  and  to  be  deposited  beneath  the  cuticle,  so  as'  to  communicate  the 
colours  that  characterize  the  different  races.  Such  is  regarded  as  the 
secretory  arrangement  by  most  anatomists  and  physiologists ;  but  M. 
Gaultier,^  whose  researches  into  the  intimate  constitution  of  the  skin 
have  gained  him  much  celebrity,  is  of  opinion,  that  it  is  furnished  by 
the  bulbs  of  the  hair;  and  he  assigns,  as  reasons  for  this  belief,  that 
the  negro,  in  whom  it  is  abundant,  has  short  hair;  that  the  female, 
whose  hair  is  more  beautiful  and  abundant  than  that  of  the  male,  has 
the  fairest  skin;  and  that  when  he  applied  blisters  to  the  skin  of  the 
negro,  he  saw  the  colouring  matter  oozing  from  the  bulbs  and  depo- 
sited at  the  surface  of  the  rete  mucosum.  But  the  views  of  modern 
anatomists  on  the  corpus  mucosum  are  given  elsewhere. 

The  composition  ofl-his  pigment  cannot  be  determined  with  pre- 
cision, owing  to  its  quantity  being  too  small  to  admit  of  examination. 
Chlorine  deprives  it  of  its  black  hue,  and  renders  it  yellow.  A  negro, 
by  keeping  his  foot  for  some  time  in  water  impregnated  with  this  gas, 
deprived  it  of  its  colour,  and  rendered  it  nearly  white;  but  in  a  few 
days  the  black  colour  returned  with  its  former  intensity.    The  experi- 

'  Moser  and  Stralil,  Handbucli  der  Pliysiologischen  and  Patliologischeii  Clieniie,  s. 
334,  Leipz.,  1851. 

2  Rechorcdics  sur  rOrc;auisation  do  la  Peau  de  rHoiiime,  &c.,  Paris.  1S09  and  1811. 


OF   MUCOUS   MEMBRANES — DERMIC.  497 

ment  was  made  with  similar  results  on  the  fingers.  Blumenbach^ 
thought,  that  the  mucous  pigment  was  formed  chiefly  of  carbon ;  and 
the  notion  has  received  favour  with  many. 

The  colour,  according  to  Henle  and  others,  is  owing  to  pigment  cells, 
of  which  the  pigmentum  nigrum  of  the  eye  is  wholly  composed.  On 
the  choroid  coat  they  form  a  kind  of  pavement,  and  have  somewhat  of 
a  polyhedral  shape.  In  the  human  skin,  they  are  scattered  through 
the  ordinary  epidermic  cells,  and  the  colour  of  the  skin  is  determined 
by  that  of  their  contents.  Krause,^  however,  denies  that  the  colour  of 
the  cuticle  of  the  Ethiopian  depends  on  pigment  cells  like  those  of  the 
pigmentum  nigrum.  It  is  oAving  chiefly,  he  says,  to  the  colour  of  the 
proper  nuclei  and  cells  of  the  epidermis.  There  are,  indeed,  some  few 
pigment  cells  mingled  with  the  proper  cells  of  the  middle  and  super- 
ficial layers  of  the  epidermis;  but  they  are  distinguishable  from  those 
of  the  pigmentum  nigrum  by  containing  far  fewer  pigment  granules, 
and  by  having  always  a  dark,  not  a  clear,  nucleus.  The  colour  depends 
especially  on  the  dark  or  almost  black-brown  colour  of  the  nuclei,  whe- 
ther free  in  the  deep  layers  of  epidermis  or  surrounded  by  cells.  They 
have  dark  nucleoli  and  sharp  outlines;  appear  only  very  obscurely 
granular,  and  cannot  be  broken  into  smaller  pigment  granules.  The 
cells  surrounding  them  may  be  seen  in  the  deeper  layers :  they,  also,  are 
uniformly  dark,  although  less  so  than  the  nuclei.  In  the  middle  and 
superficial  layers,  the  nuclei,  as  long  as  they  can  be  seen,  are  still  dark; 
the  cells  are  much  paler,  but  brownish  and  darker  than  in  the  corre- 
sponding layers  in  uncoloured  persons. 

Pigment  granules  are  amongst  the  most  minute  structures  of  the 
body,  being  not  more  than  2000 o^^^  of  an  inch  in  their  largest  diame- 
ter, and  about  one-fourth  as  much  in  thickness. 

The  uses  of  the  pigment  of  the  skin — as  well  as  of  that  which  lines 
the  choroid  coat  of  the  eye,  the  posterior  surface  of  the  iris,  and  the 
ciliary  processes — are  detailed  in  other  places. 

6,  Capsular  Exhalation. 
Under  this  term,  M.  Adelon^  has  included  different  recrementitial 
secretions  effected  within  the  organs  of  sense,  or  in  parenchymatous 
structures, — as  the  aqueous,  crystalline,  and  vitreous  humours  of  the 
eye,  and  the  liquor  of  Cotugno,  all  of  which  have  ali-eady  engaged 
attention ;  the  exhalation  of  a  kind  of  albuminous,  reddish,  or  whitish 
fluid  into  the  interior  of  the  lymphatic  ganglions,  and  into  the  organs, 
called  by  M.  Chaussier,  glandiform  ganglions^  and  by  M.  Beclard,  san- 
guineous ganglions; — namely,  the  thymus,  thyroid,  supra-renal  capsules, 
and  spleen.  We  know  but  little,  however,  of  the  fluids  formed  in  these 
parts;  and  of  their  uses  we  are,  in  the  main,  ignorant. 

B.    EXTERNAL  EXHALATIONS. 

1.  Exltalations  of  the  Shin  and  Mucous  Membranes — Dermic. 
The  mucous  membranes,  like  the  skin,  which  they  so  strongly  re- 
semble in  their  structure,  functions,  and  diseases,  exhale  a  similar  tran- 

'  Instit.  Physiol.,  §  274;  and  Elliotson's  translation,  4th  edit.,  Lond.,  1828. 
^  Art.  Haut,  in  Wagner's  Handworterlnich  der  I'hjsiologie,  7te  Lief.,  S.  108,  Braun- 
schwoit;,  1S44.  ^  Physiologic  de  I'llomme,  2de  edit.,  toni.  iii.  483,  Paris,  1829. 

VOL.  I.— 32 


498  SECRETION. 

spiratory  fluid.  This  lias  not  been  subjected  to  chemical  examination. 
It  is,  indeed,  almost  impracticable  to  separate  it  from  the  follicular 
secretions  of  the  same  membrane;  and  from  the  extraneous  substances 
almost  always  in  contact  with  it.  It  is,  probably,  however,  similar  to 
the  fluid  of  the  cutaneous  and  pulmonary  depurations,  both  in  character 
and  use. 

The  pulmonary  transpiration,  to  which  allusion  has  so  often  been 
made,  bears  a  striking  analogy  to  the  cutaneous.  Sir  B.  Brodie  and 
M.  Magendie,  from  the  examination  of  cases  of  fistulous  opening  into 
the  trachea,  deny  that  it  comes  from  the  lungs,  believing  it  to  be  formed 
by  the  moist  .mucous  lining  of  the  nose,  throat,  &c.;  but  this  view  has 
been  disproved  by  Paoli  and  Regnoli,  in  the  case  of  a  young  female, 
whose  trachea  had  been  opened,  and  in  whom,  at  the  temperature  of 
39°  Fahr.,  watery  vapour  was  distinctly  expired,  through  the  cauula. 
Mojon'  strangely  supposes  the  vapour  of  the  breath  to  be  a  watery 
fluid  secreted  by  the  thyroid  gland,  and  suspended  in  the  respired  air, 
its  volatilit}^  being  caused  by  the  presence  of  caloric.  At  one  time,  it 
was  universally  believed  to  be  owing  to  the  combustion  of  the  hydrogen 
and  carbon  given  oft"  from  the  lungs;  but  we  have  elsewhere  shown, 
that  no  such  combustion  occurs  there;  and  besides,  the  exhalation  takes 
place  when  gases  containing  no  oxygen  are  respired  by  animals.  It  is 
now  almost  universally  admitted  to  be  exhaled  into  the  air-cells  of  the 
lungs  from  the  pulmonary  artery  chiefly ;  but  partly  from  the  bron- 
chial arteries  distributed  to  the  mucous  membrane  of  the  air-passages.' 
Much  of  the  vapour,  Dr.  Prout  conceives,  is  deriv'ed  fz'om  the  chyle  in 
its  passage  through  the  lungs;  and  tlius,  he  considers,  the  weak  and 
delicate  albumen  of  the  chyle  is  converted  into  the  strong  and  perfect 
albumen  of  the  blood. 

The  air  of  expiration,  according  to  Valentin^  and  Brunner  appears 
saturated  with  it,  so  that,  as  they  have  remarked,  the  quantity  of  vapour 
exhaled  may  be  estimated  by  subtracting  the  quantity  contained  in  the 
atmospheric  air  expired  from  the  quantity,  which,  at  the  same  barometric 
pressure,  would  saturate  the  same  atmospheric  air  at  the  temperature 
of  99"5° — the  general  temperature  of  the  air  of  expiration.  On  the 
other  hand,  if  the  quantity  of  watery  vapour  in  the  expired  air  be  esti- 
mated, the  quantity  of  the  air  itself  may  thence  be  accurately  deter- 
mined— being  as  much  as  that  quantity  of  water}^  vapour  would  satu- 
rate at  the  ascertained  temperature  and  barometric  pressure.  It  has 
not  been  established,  however,  that  the  expired  air  is  saturated  with 
moisture." 

Sundry  interesting  experiments  have  been  made  on  this  exhalation 
by  Magendie,  Milne  Edwards,  Breschet,  and  others.  If  water  be  in- 
jected into  the  pulmonary  arterj^,  it  passes  into  the  air-cells  in  mj^riads 
of  almost  imperceptible  drops,  and  mixes  with  the  air  contained  in 
them.     M.  Magendie*  found,  that  its  quantity  might  be  augmented  at 

'  Leggi  Fisiologiclie,  &c.,  translated  by  Skene,  p.  76,  Lond.,  1827. 

*  Sir  B.  Brodie,  riiilosojjhical  Transactious  for  lc?12,  and  Plijsioloyical  Researches,  p. 
19,  Lond.,  1851. 

^  Lehrbuch  der  Physiologic  des  Menschen,  i.  547,  Braunschweig,  1844. 

*  Dr.  John  Reid,  art.  Rusj^iration,  Cyclop,  of  Auat.  and  Phys.,  pt.  xxxii.  p.  345, 
Lond-,  Aug.,  1848.  =  Precis,  &c.,  ii.  346. 


OF  MUCOUS  MEMBRANES  —  PULMONARY.         499 

pleasure  on  living  animals,  by  injecting  distilled  water,  at  a  tempera- 
ture approaching  that  of  the  body,  into  the  venous  system.  He  injected 
into  the  veins  of  a  small  dog  a  considerable  amount  of  water.  The 
animal  was  at  first  in  a  state  of  real  plethora — the  vessels  being  so 
much  distended  that  it  could  scarcely  move;  but  in  a  few  minutes  the 
respiration  became  manifestly  huiTied,  and  a  large  quantity  of  fluid 
was  discharged  from  the  mouth,  the  source  of  which  appeared  evidently 
to  be  the  pulmonary  transpiration  greatly  augmented. 

But  not  only  is  the  aqueous  portion  of  the  blood  exhaled  in  this 
manner,  experiment  shows,  that  many  substances  introduced  into  the 
veins  by  absorption,  or  by  direct  injection,  issue  from  the  lungs.  Weak 
alcohol,  a  solution  of  camphor,  ether,  and  other  odorous  substances, 
when  thrown  into  the  cavity  of  the  peritoneum  or  elsewhere,  were 
found,  by  M.  Magendie,  to  be  speedily  absorbed  by  the  veins,  and  con- 
veyed to  the  lungs,  where  they  transuded  into  the  bronchial  cells,  and 
were  recognised  in  the  expired  air  by  their  smell.  Phosphorus,  when 
injected,  exhibited  this  transmission  in  a  singular  and  evident  manner. 
M.  Magendie,^  on  the  suggestion  of  M.  Armand  de  Montgarny,  "a 
young  physician,"  he  remarks,  "of  much  merit,"  now  no  more,  in- 
jected into  the  crural  vein  of  a  dog  half  an  ounce  of  oil,  in  which 
phosphorus  had  been  dissolved:  scarcely  had  he  finished  the  injection, 
before  the  animal  sent  through  the  nostrils  clouds  of  a  thick  white 
vapour,  which  was  phosphoric  acid.  When  the  experiment  was  made 
in  the  dark,  these  clouds  were  luminous.  M.  Tiedemann^  injected  a 
drachm  of  the  expressed  juice  of  garlic  into  a  vein  of  the  thigh  of  a 
middle-sized  dog;  in  the  space  of  three  seconds  the  breath  smelt  strongly 
of  garlic.  When  spirit  of  wine  was  injected,  the  exhaled  vapour  was, 
recognised  when  the  injection  was  scarcely  over. 

MM.  Breschet  and  Milne  Edwards^  made  several  experiments  for 
the  purpose  of  discovering  why  the  pulmonary  transpiration  expels  so 
promptly  the  different  gases  and  liquid  substances  received  into  the 
blood.  Considering  propei'ly,  that  exhalation  differs  only  from  absorp- 
tion in  taking  place  in  an  inverse  direction,  these  gentlemen  conjec- 
tured, that  it  ouglit  to  be  accelerated  by  every  force,  that  would  attract 
the  fluids  from  within  to  witliout;  and  such  a  force  they  conceive  inspi- 
ration to  be,  which,  in  their  view,  solicits  the  fluids  of  the  economy  to. 
the  lungs,  in  the  same  mechanical  manner  as  it  occasions  the  entrance 
of  air  into  the  air-cells.  In  support  of  this  view  they  adduce  the  fol- 
lowing experiments.  To  the  trachea  of  a  dog  a  pipe,  communicating 
with  a  bellows,  was  adapted,  and  the  thorax  was  largely  opened.. 
Natural  respiration  was  immediately  suspended;  but  artificial  respira- 
tion was  kept  up  by  means  of  the  bellows.  The  surface  of  the  air-cells^ 
was,  in  this  way,  constantly  subjected  to  the  same  pressui'e,  there 
being  no  longer  diminislied  pressure  during  inspiration,  as  when  the 
thorax  is  sound,  and  the  animal  breathing  naturally.  Six  grains  of" 
camphorated  spirit  were  now  injected  into  the  peritoneum;  and,  at  the 
same  time,  a  similar  quantity  in  another  dog,  whose  respiration  wasv 

'  Precis,  &o.,  ii.  348. 

^  Tiedemanii  and  Trcviranns,  Zeitschrift  ftir  Pliysiologie,  Band.  v.  II.  ii. ;  cited  ini. 
British  and  Foreign  Medical  Review,  i.  241,  Lond.,  1836.  * 

^  Recherches  Experinientales  sur  rExhalation  Puluioiiaire,  Paris,  1S2(). 


500  SECRETION. 

natural.  In  tlie  course  of  from  three  to  six  minutes,  the  odorous  sub- 
stance was  detected  in  the  puhnonarj  transpiration  of  the  latter;  but 
in  the  other  it  was  never  manifested.  They  now  exposed  in  the  first 
animal  a  part  of  the  muscles  of  the  abdomen,  and  applied  a  cupping- 
glass  to  it;  when  the  smell  of  the  camphor  speedily  appeared  at  the 
cupped  surface.  Their  conclusion  was,  that  the  pulmonary  surface, 
having  ceased  to  be  subjected  to  the  suction  force  of  the  chest  during 
inspiration,  exhalation  was  arrested,  whilst  that  of  the  skin  was  deve- 
loped as  soon  as  an  action  of  aspiration  was  exerted  upon  it  by  the 
cupping-glass. 

Into  the  crural  veins  of  two  dogs, — one  of  which  breathed  naturally, 
and  the  other  was  circumstanced  as  in  the  last  experiment, — they 
injected  essential  oil  of  turpentine.  In  the  first  of  these,  the  substance 
was  soon  apparent  in  the  pulmonary  transpiration;  and,  on  opening 
the  body,  it  was  discovered,  that  the  turpentine  had  impregnated  the 
lung  and  pleura  much  more  strongly  than  the  other  tissues.  In  the 
other  animal,  on  the  contrary,  the  odour  of  the  turpentine  was  scarcely 
apparent  in  the  vapour  of  the  lungs;  and  on  dissection,  it  was  not  found 
in  greater  quantity  in  the  lungs  than  in  other  tissues; — in  the  pleura, 
for  instance,  than  in  the  peritoneum. 

From  the  results  of  these  experiments,  MM.  Breschet  and  Edwards 
conckide,  that  each  inspiratory  movement  constitutes  a  kind  of  suction, 
which  attracts  the  blood  to  the  lungs ;  and  causes  the  ejection  of  the 
liquid  and  gaseous  substances  which  are  mingled  with  that  fluid, 
through  the  pulmonary  surface,  more  than  through  the  other  exhalant 
surfaces  of  the  body.  In  their  experiments,  these  gentlemen  did  not 
find,  that  exhalation  was  effected  with  equal  readiness  in  every  part 
of  the  surface,  when  the  cupping-glass  was  applied  in  the  mode  that 
has  been  mentioned.  The  skin  of  the  thigh,  for  example,  did  not  indi- 
cate the  odour  of  camphorated  alcohol  as  did  that  of  the  region  of  the 
stomach. 

The  chemical  composition  of  the  pulmonary  transpiration  appears 
to  be  water,  holding  in  solution,  perhaps,  some  saline  and  albuminous 
matter;  but  our  information  on  this  subject,  derived  from  the  chemist, 
is  not  precise.  M.  Collard  de  Martigny's'  experiments  make  it  consist, 
in  1000  parts, — of  water  907,  carbonic  acid  90;  animal  matter — the 
nature  of  which  he  was  unable  to  determine — o.  M.  Chaussier  found, 
that  by  keeping  a  portion  of  it  in  a  close  vessel  exposed  to  an  elevated 
temperature,  a  very  evident  putrid  odour  was  exhaled  on  opening  the 
vessel.  This  could  only  have  arisen  from  the  existence  of  nitrogeuized 
matter  in  it. 

The  pulmonary  transpiration  being  liable  to  all  the  modifications 
which  affect  the  cutaneous,  it  is  not  surprising,  that  we  should  meet 
with  so  much  discordance  in  the  estimates  of  diiTerent  individuals,  re- 
garding its  quantity  in  a  given  time.  Ilales^  valued  it  at  20  ounces  in 
the  twenty -four  hours:  Sanctorius,^  Alenzies,"  and  Dr.  AVilliam  Wood,* 

'  Magendie's  Journal  de  Pliysiologie,  x.  111. 

^  Statical  Essays,  ii.  322,  Lond.,  1767.  ^  Medicina  Statica,  Aplior.  v. 

*  Dissertation  on  Respiration,  p.  54,  Edinb.,  1796. 

*  Essay  on  the  Structure,  &c.,  of  the  Skin,  Edinb.,  1832. 


MENSTRUAL  —  GASEOUS.  501 

at  6  ounces;  Mr.  Abernetliy'  at  9  ounces;  MM.  Lavoisier  and  Scguin^ 
at  17|  ounces  poids  de  marc;  Dr.  Thomson^  at  19  ounces,  Dr.  Dulton 
at  from  1  pound  8|  ounces,^  to  20|  ounces  avoirdupois,^  Dr.  Carpen- 
ter^ at  from  16  to  20  ounces,  and  Kirkes  and  Paget^  at  from  6  to  27 
ounces.  The  uses  it  serves  in  the  animal  economy  are  identical  with 
those  of  the  cutaneous  transpiration.  It  is  essentially  depuratory. 
Experiments,  some  of  which  have  been  detailed,  have  sufficiently  shown, 
that  volatile  substances  introduced  in  any  way  into  the  circulatory 
sy^item,  if  not  adapted  for  the  formation  of  arterial  blood,  are  rapidly 
exhaled  into  the  bronchial  tubes.  Independently,  therefore,  of  the 
lungs  being  the  great  organs  of  respiration,  they  play  a  most  important 
part  in  the  economy,  by  throwing  oil"  those  substances,  that  might  be 
injurious,  if  retained. 

2.  Menstrual  Exhalation. 

The  secretion  of  the  menstrual  fluid,  which  is  mainly  a  sanguineous 
exhalation  from  the  vessels  of  the  uterus,  will  fall  more  appropriately 
under  consideration  when  treating  of  the  functions  of  reproduction. 

3.   Gaseous  Exlialation. 

The  secretion  of  air  from  the  bloodvessels  is  not  so  manifest  as  in 
the  case  of  the  exhalations  thus  far  considered;  but  if  we  regard,  with 
many,  the  separation  of  carbonic  acid  from  the  blood  as  a  secretion,  it 
is  one  of  the  most  extensive  and  important  in  the  animal  economy. 
Gases  are  perpetually  received  into  the  vessels  of  the  lungs,  and  to  a 
certain  degree  elsewhere,  whilst  under  the  function  of  Respiration  it 
has  been  seen,  that  carbonic  acid  is  constantly  exhaled.  Moreover,  in 
the  swim-bladders  of  fishes  an  unequivocal  case  of  gaseous  secretion 
is  presented;  for  many  of  these  have  no  communication  whatever,  by 
duct  or  otherwise,  with  any  outlet  of  the  body.  In  the  order  Pharyn- 
gognatJu  of  Miiller,  which  includes  the  fiimily  of  the  saury  pike  and 
others ;  in  Anacanthini,  including  the  cod  and  plaice ;  in  Acantlwjjteri, 
including  the  perch,  gurnard,  mullet,  mackerel,  and  others ;  in  the 
Pleciognathi  of  Cuvier,  including  the  globe  fish  ;  and  in  Lopliohranclm 
of  the  same  naturalist,  which  includes  the  sea  horse  and  pipe  fish, — a 
characteristic  is  the  possession  of  a  swim  bladder  without  an  air  duct. 
In  these  cases,  there  can  be  no  question  of  the  secretion  of  air;  and 
accordingly  such  a  secretion  has  been  admitted  by  physiologists.^  It 
may  account  for  the  copious  developement  of  air  in  the  intestinal  canal, 
as  has  been  suggested  elsewhere  ;^  and  for  the  production  of  many  of 
the  pneumatoses,  which  are  so  difficult  of  explanation  under  any  other 

'  Surgical  and  Physiol.  Essays,  p.  141,  Loud.,  1793. 

2  Mini,  de  la  Societe  Royale  de  Medecine,  pour  1782-3;  Annal.  de  Cliimie,  v.  264; 
and  Mem.  de  I'Acad.  des  Sciences,  pour  1789. 

^  System  of  Chemistry,  vol.  iv.  "  Manchester-  Memoirs,  2d  series,  ii.  29. 

^  Ibid.,  vol.  V.  ^  Human  Physiology,  §  549,  Loud.,  1842. 

'  Manual  of  Physiology,  2d  Amer.  edit.,  p.  139,  Philad.,  1853. 

*  John  Hunter,  Observations  on  Certain  Parts  of  the  Animal  Economy,  with  Notes 
by  Prof.  Owen,  Amer.  edit.,  p.  127,  Philad.,  1840.  J.  Vogel,  The  Pathological  Anato- 
my of  the  Human  Body,  by  Dr.  Day,  ]).  31,  London,  1847;  and  Prof.  Owen,  Lectures 
on  the  Comparative  Anatomy  and  Physiology  of  the  Vertebrate  Animals,  p.  272,  Lond., 
184(1. 

**  Page  185. 


502  SECRETION. 

view.     The  last  subject  lias,  however,  received  the  author's  attention 
in  another  work.^ 

II.   FOLLICULAR  SECRETIONS. 

Follicular  secretions  are  effected  from  the  skin  or  the  mucous  mem- 
branes. Thej  may  be  divided  into  two  great  classes; — 1st,  the  follicu- 
lar secretions  of  mucous  membranes ;  and  2dly,  i\\Q  follicular  secretions  of 
the  skin. 

1.  Follicular  Secretion  of  Mucous  Membranes. 

Tlie  whole  extent  of  the  mucous  membranes  lining  the  alimentary 
canal,  air-passages,  and  urinary  and  genital  organs,  is  the  seat  of  a 
secretion,  the  product  of  which  has  received,  in  the  abstract,  the  name 
of  mucus ;  although  it  differs  somewhat  according  to  the  situation  and 
character  of  the  particular  follicles  whence  it  proceeds.  Still,  essen- 
tially, the  structure,  functions,  and  products  of  all  mucous  membranes 
are  the  same.^  Such  is  the  general  sentiment.  M.  Donne,^  however, 
ranges  the  different  mucous  membranes  in  three  great  divisions — ac- 
cording to  their  microscopical  characters,  the  chemical  reaction  of 
their  mucus,  and  the  structure  of  the  epithelium.  His  first  division 
comprises  those  membranes  that  are  analogous  to  the  skin, — in  other 
words,  that  secrete  an  acid  fluid,  which  contains,  under  the  form  of  pel- 
licles, or  scales,  the  product  of  the  desquamation  of  the  epidermis. 
They  are,  in  reality,  reflections  of  the  outer  skin,  and  in  no  respect 
deserve  the  name  of  mucous  membranes.  The  vaginal  mucous  mem- 
brane is  one  of  these,  being  a  mere  reflection  of  the  outer  skin,  and 
possessing  its  principal  properties.  It  secretes  a  mucus,  which  is 
always  acid;  strongly  reddening  litmus  paper,  and  filled  with  soft, 
flattened  lamellie,  or  rather  cells,  like  the  epidermic  vesicles  of  the 
skin.  In  regard  to  its  physiological  properties,  this  membrane,  like 
the  skin,  is  endowed  with  exquisite  sensibility ;  it  is  scarcely  ever  the 
seat  of  hemorrhage,  and  ulcerates  less  readily  than  raucous  membranes 
properly  so  called.  The  membranes  with  acid  mucus  and  epidermic 
vesicles  never,  he  says,  exhibit  any  epidermic  cells.  The  second  divi- 
sion comprises  the  "  true  raucous  membranes."  They  differ  from  the 
skin  in  every  respect, — both  by  the  nature  of  their  epithelium,  and 
the  chemical  reaction  of  their  secretion,  which  is  always  alkaline.  It 
is  viscid,  and,  instead  of  exhibiting  under  the  microscope  the  epidermic 
lamelkie  or  cellules,  mentioned  above,  it  presents  only  mucous  globules, 
whose  structure,  properties,  and  origin  are  entirely  different.  These 
membranes,  of  which  the  bronchial  raucous  membrane  may  be  taken 
as  the  type,  ulcerate  readily;  are  the  seat  of  hemorrhages,  and  do  not 
possess  tactile  sensibility  like  the  skin.  To  these  belong  the  vibratile 
organs  or  cilia. 

These  two  orders  of  membranes,  according  to  M.  Donne,  are  found 
approximated,  and  almost  confounded,  although  still  preserving  their 
distinct  characters,  in  the  vagina  and  neck  of  the  uterus, — the  one 
secreting  a  creamy,  not  ropy,  always  acid  mucus;  and  presenting, 

'  Practice  of  Medicine,  3d  edit.,  i.  172,  Pliilad.,  1848. 
^  See  Mucous  Membranes,  under  the  Sense  of  Touch. 
'^  Cours  de  Microscopie,  p.  143,  Paris,  1844. 


FOLLICULAE,    OF   MUCOUS   MEMBEANES.  503 

under  tlae  microscope,  large  epidermic  cellules;  tlie  other  furnisliing  a 
glairy,  ropy  mucus,  constantly  alkaline,  and  containing  mucous  glo- 
bules much  smaller  than  epidermic  cells,  and  of  a  structure  and  com- 
position wholly  different.  The  third  division  comprises  a  class  inter- 
mediate between  the  two  others,  constituted  by  parts  which  participate 
in  the  organization  of  skin  and  mucous  membranes,  through  surfaces 
which  have  not  yet  entirely  lost  the  qualities  of  the  external  mem- 
brane, and  already  possess  some  of  those  of  the  internal  or  true  mu- 
cous membranes.  Such  are  the  orifices  where  the  skin  does  not  ter- 
minate suddenly,  but  becomes  gradually  transformed  into  mucous 
membrane,  as  at  the  mouth,  nose,  anus,  &c.  These  parts  secrete  a 
mucus,  which  M.  Donne  terms  mixed:  in  this  are  found  combined  the 
characters  of  the  two  already  mentioned,  with  a  predominance  of  the 
one  or  the  other,  according  as  the  properties  of  the  skin,  or  those  of 
the  mucous  membranes,  prevail.  The  mucus  of  the  mouth  he  regards 
as  an  example  of  the  intermediate  species.^ 

In  the  history  of  the  different  functions,  in  which  certain  of  the 
mucous  membranes  are  concerned,  the  uses  of  the  secretion  have  been 
detailed;  and  in  those  functions,  that  will  hereafter  have  to  engage 
attention,  in  which  other  mucous  membranes  are  concerned,  its  uses 
will  fall  more  conveniently  under  notice.  But  few  points  will,  there- 
fore, require  explanation  at  present. 

The  mucus  secreted  by  the  nasal  follicles  seems  alone  to  have  been 
subjected  to  chemical  analysis.  MM.  Fourcroy  and  Vauquelin^  found 
it  composed  of  the  same  ingredients  as  tears.  According  to  the  analy- 
sis of  Berzelius,^  its  contents  are  as  follows : — water,  933'7  ;  mucin 
o3"3 ;  chlorides  of  potassium  and  sodium,  5"6 ;  lactate  of  soda  with 
animal  matter,  3"0 ;  soda,  0*9  ;  albumen  and  animal  matter,  soluble  in 
water,  but  insoluble  in  alcohol,  with  a  trace  of  phosphate  of  soda,  3*5. 
Dr.  G.  O.  Eees''  considers  mucus  to  be  a  compound  of  albumen  in  a 
state  of  close  combination  with  alkaline  salts,  and  probably  free  alkali; 
and  he  affirms,  that  the  artificial  compound  formed  by  the  addition  of 
alkalies  and  neutral  salts  to  albuminous  matter  is  essentially  the  same 
as  mucus. 

According  to  M.  Easpail,^  mucus  is  the  product  of  the  healthy  and 
daily  disorganization  or  wear  and  tear  of  mucous  membranes.  Every 
mucous  membrane,  he  affirms,  exfoliates  in  organized  layers,  and  is 
thrown  off,  more  or  less,  in  this  form ;  but  the  serous  membranes 
either  do  not  exfoliate,  or  their  exfoliation  [excoriation)  is  reduced  to  a 
liquid  state  to  be  again  absorbed  by  the  organs.  When  examined  by 
a  microscope  of  high  magnifying  power,  mucus  presents  here  and 
there,  appearances  of  shreds  similar  to  those  described  by  M.  Kaspail. 
These  have  been  considered  by  recent  histologists  detached  epithelium 
cells,  with  granulated  globular  particles,  which  are  esteemed  to  be 

'  See,  on  the  structure,  relations,  and  offices  of  the  Mucous  Memhrnnos,  Mr.  Bow- 
man, art.  Mucous  Membrane,  in  Cyclop,  of  Anat.  and  Physiol.,  Parts  xxiii.  and  xxiv., 
Lond.,  1842. 

^  Journal  de  Physique,  xxxix.  359. 

^  Medico-Chirurg.  Transactions,  torn.  iii.  ;  also,  Thomson,  Chemistry  of  Animal 
Bodies,  p.  507,  Eilinb.,  1843. 

■•  Cyclop,  of  Anat.  and  Physiol.,  P.  xxiii.  p.  484,  April,  1842. 

*  Ciximie  Organiiiue,  p.  24(J,  and  p.  504,  Paris,  1832. 


504  SECRETION". 

cliaracteristic  of  the  secretion  from  the  surface  of  mucous  membranes.^ 
It  is  never  free  from  ejjithelium  of  the  mucous  membrane  whence  it 
originated;  and,  according  to  Lehmann,^  may  be  said  to  consist  almost 
entirely  of  epithelium,  which  seems  to  be  held  together  only  hj  means 
of  a  pellucid  juice. 

Although  mucus  is  classed  as  a  follicular  secretion,  it  would  seem  to 
be  formed  in  mucous  membranes  in  which  no  follicles  can  be  detected, 
as  in  those  lining  the  frontal  and  other  sinuses  of  the  cranium.  M. 
Mandl,^ — who  first  stated  the  belief  in  the  identity  in  structure  of  the 
globules  of  mucus  and  pus  and  the  red  corpuscles  of  the  blood, — 
describes  mucus  as  composed  of  a  viscid  liquid  in  which  are  swim- 
ming, besides  lamellae  of  epithelium,  special  elements,  which  he  calls 
globules  of  mucus.  These  are  of  two  kinds, — the  one  consisting  of 
mammillated  corpuscles,  0-005  to  0'006  of  a  rnillimHre  in  diameter ;  the 
other,  from  0*01  to  0"02  of  a  millim^re  in  diameter, — the  latter  being 
true  cells,  composed  of  an  envelope  and  a  nucleus. 

The  great  use  of  mucus,  wherever  met  with,  is  to  lubricate  the  sur- 
face on  which  it  is  poured.  Experiments,  however,  by  Oesterlen'' 
have  proved  the  influence  of  the  layer  of  mucus,  which  lines  the 
digestive  canal,  in  retarding  both  the  imbibition  of  fluids  inclosed 
within  the  canal,  and  the  permeation  of  fluids  by  endosmose.  The 
passage  of  fluid  into,  or  through,  the  mucous  membrane  of  the  intes- 
tines was,  in  many  cases,  more  than  twice  as  rapid  when  the  mucus 
had  been  removed  as  when  still  adherent. 

2.  Follicular  Secretion  of  the  /Skin. 

This  is  the  sebaceous  and  micaceous  humour,  observed  in  the  skin 
of  the  cranium,  and  in  that  of  the  pavilion  of  the  ear.  It  is,  also,  the 
humour,  which  occasionally  presents  the  appearance  of  small  worms 
beneath  the  skin  of  the  face,  when  it  is  forced  through  the  external 
aperture  of  the  follicle;  and  when  exposed  to  the  air  causes  the  black 
spots  sometimes  observable  on  the  face. 

The  following  were  found  by  Esenbeck^  to  be  its  constituents  :  fat, 
24-2 ;  osmazome,  with  traces  of  oil,  12'6 ;  watery  extractive  matters, 
11-6;  albumen  and  casein,  24-2;  carbonate  of  lime,  2-1;  phosphate  of 
lime  20'0;  carbonate  of  magnesia,  1*6;  acetate  of  soda,  and  chloride  of 
sodium,  traces. 

The  cutaneous  or  miliary  follicles  or  glands  are  referred  to  elsewhere, 
in  describing  the  anatomy  of  the  common  integument.  At  times,  they 
are  simple  crypts,  formed  merely  by  an  inversion  of  the  common  inte- 
gument ;  at  others,  more  complicated  but  still  a  like  inversion ;  and 
they  usually  open  into  channels  by  which  the  hairs  issue.   (Fig.  147,  2.) 

In  certain  parts  of  the  skin,  they  are  more  numerous  than  in  others. 
!Mr.  Eainey  was  unable  to  detect  them  in  the  palms  of  the  hands  and 

'  For  the  different  forms  of  mucus,  see  Donne,  op.  cit.,  p.  145. 

2  Lehrbueli  der  Fhysiologisclien  Cliemie,  ii.  3(51,  Leipz.,  1850  ;  or  Amer.  edit,  of  Dr. 
Day's  translation  by  Dr.  R.  E.  Rogers,  ii.  85,  Philad.,  1S55. 

'  Manuel  d'Anatomie  Generale,  p.  478,  Paris,  1843. 

^  Beitrilse  zur  Plivsioloifie  des  Gesuuden  und  Kranken  Organismus,  S.  245,  Jena, 
1-43. 

*  V.  Bruiis,  Lelirbuch  der  Allgemeineu  Anatomic,  S.  353,  Braunscliweig,  1841. 


FOLLICULAE,    OF   THE   SKIN. 


605 


soles  of  the  feet.  Fig-  147. 

Their  appearance 
ill  the  axilla  of 
the  negro  has 
been  described 
by  Professor  Hor- 
ner.' Their  gran- 
ular or  composite 
character  in  the 
axilla,  he  thinks, 
is  sufficiently  evi- 
dent ;  but  the 
point  is  yet  to  be 
settled,  whether 
their  excretory 
ducts  have  the 
tortuous  arrange- 
ment of  those  of 
the  ceruminous 
glands,  o  r  whether 
they  be  branched 
and  racemose,  like 
those  of  the  sali- 
vary. Mr.  Has- 
salP  afiirms,  that 
they  are  similar 
in  organization  to 
the  sudoriparous 
glands,  but  much 
larger. 

The  secretion 
from  the  dift'erent 
cutaneous  folli- 
cles differs,  pro- 
bably, according 
to  the  different 
character  and  ar- 
rangement of  ani- 
mal  membrane 
from  which  the 
cells  that  form 
it  are  developed. 
There  is,  certain- 
ly, a  marked  dif- 
ference between 
the  fluids  secreted 
in  the  axilla, 
groin,  prepuce,  feet,  &c.,  each  appearing  to  have  its  characteristic  odour; 


Sebaceous  or  Oil  Glands  and  Ceruminous  Glands. 

1.  S'^cfion  of  skin,  magnified  three  diameters.  2,  2.  Hairs.  3,  3.  Superfi- 
cial sebaceous  glauds.  1,  1.  Larger  and  deeper-seated  glands  by  which  the 
cerumen  appears  to  be  secreted.  3.  A  ceruminous  ghmd  m,ore  largely  mag- 
nified, formed  of  convoluted  tube  1,  forming  excretory  duct  2.  3.  A  small 
vessel,  and  its  branches.  3.  A  hair  from  meatus  auditorius,  perforating  epi- 
dermis at  3,  and  at  4,  contained  within  its  double  follicle,  o,  5.  1,  1.  Seba- 
ceous follicles  of  hair  with  their  excretory  ducts. 

Fis.  14S. 


Cutaneous  Follicles  or  Glands  of  tho  Axilla,  magnified  one-third. 


'  American  Journal  of  the  Medical  Sciences,  for  January,  1846,  p.  13. 

*  The  Micro.scopic  Anatomy  of  the  Iluman  Body,  Part  xiii.  p.  42tj,  Lond.,  1848. 


506 


SECRETION". 


although  a  part  of  this  may  be  owing  to  changes  occurring  in  the  mat- 
ter of  secretion  by  retention  in  parts  to  which  the  free  access  of  air  is 
prevented.  The  cutaneous  or  miliary  glands,  depicted  by  Dr.  Horner, 
are  considered  by  him  to  be  the  glandulce  odoriferoe.  of  the  axilla.  Id 
many  animals  odorous  secretions  of  a  similar  character  are  formed  by 
special  organs;  but  whether  the  scent  peculiar  to  animals  and  to  races 
is  thus  secreted  is  canvassed  elsewhere,  and  must  be  regarded  as  some- 
what unsettled. 

The  cerumen  is  a  follicular  secretion,  as  well  as  the  whitish,  odorous 
and  fatty  matter — smegma — which  forms  under  the  prepuce  of  the  male, 
and  in  the  external  parts  of  the  female,  where  cleanliness  is  disregarded. 
The  Jiumour  of  Meihomius  is  also  follicular,  as  well  as  that  of  the  carun- 
cula  lacrymalis,  of  the  crypts  around  the  base  of  the  nipple,  &c. 
The  use  of  these  secretions  is  to  favour  the  functions  of  the  parts 

over  which  they  are  distributed. 
Fig.  149.  That  which  is  secreted  from  the 

skin  is  spread  over  the  epider- 
mis, hair,  &c.,  giving  suppleness 
and  elasticity  to  the  parts ;  ren- 
dering the  surface  smooth  and 
polished,  and  thus  obviating  the 
evils  of  abrasion  that  might 
otherwise  arise.  It  is  also  con- 
ceived, that  its  unctuous  nature 
may  render  the  parts  less  per- 
meable to  humidity. 

In  the  ducts  of  the  sebaceous 
follicles,  a  parasite  was  discover- 
ed by  M.  Simon,  of  Berlin ;' 
which  has  been  minutely  de- 
scribed by  Mr.  Erasmus  Wil- 

Entozoa  from  the  Sebaceous  Follicles.  SOn,^  ProfcSSOr  Yogel,'    McSSrS. 

Tocld  and  Bowman,^  and  Pro- 
fessor Owen.*     It  is  the  ylca?-ws 
folUculorum  of  Simon,  Demodex 
foUicuhrum  of  Owen,  and  Steatozoon.  follicuhrum  of  Mr.  Wilson.     By 
him  two  chief  varieties  of  the  adult  animal  are  depicted.     These  are 
mainly  distinguished  by  their  length — the  one  measuring  from  the 
yi^th  to  the  -^\t\  the  other  from  the  yjj^th  to  the  y^^th  of  an  inch. 

The  marginal  figure  represents  them  as  found  by  Messrs.  Todd  and 
Bowman  in  a  sebaceous  follicle  of  the  scalp.  They  do  not  appear  to 
be  of  any  physiological  or  pathological  importance. 

*  Miiller's  Archiv.,  s.  218,  1842. 

2  On  Diseases  of  tlie  Skin,  2d  Amer.  edit.,  p.  424,  Philad.,  1847  ;  and  in  Pliiloso- 
pliical  Transactions  for  1844. 

*  The  Pathological  Anatomy  of  the  Human  Body ;  translated  by  Dr.  Day,  p.  453, 
Lond.,  1847. 

*  The  Physiological  Anatomy  and  Physiology  of  Man,  p.  42.5,  Lond.,  1845. 

*  Lectures  on  the  Comparative  Anatomy  and  Physiology  of  the  Inveilebrate  Animals, 
p.  251,  Loud.,  1843. 


a.  Two  seen  in  their  ordinary  position  in  the  orifice 
of  one  of  the  sebaceous  follicles  of  the  scalp,  b.  Short 
variety,    c.  Long  variety. 


TEANSPIRATORY,    OF   THE   SKIN.  507 

3.  Secretion  of  the  Ovaries. 

The  secretion  of  the  ovaria — the  formation  of  ova — is  accomplished 
in  the  follicles  of  De  Graaf.  They  are  devoid  of  outlet ;  and  the  secre- 
tion has  to  make  its  way  to  the  surface  of  the  ovary  and  be  discharged, 
— the  Fallopian  tube  receiving  it,  and  acting  as  an  excretory  duct. 
The  mode  in  which  this  is  accomplished  falls  more  appropriately 
under  consideration,  when  the  functions  of  Eeproduction  are  inves- 
tigated. 

III.   GLAXDULAK  SECRETIONS. 

The  glandular  secretions  are  seven  in  number;  the  transpiration, 
tears,  saliva,  pancreatic  juice,  bile,  urine,  sperm,  and  milk. 

1.  Transpiratory  Secretion  of  the  Skin. 

A  transparent  fluid  is  constantly  exhoaled  from  the  skin,  which  is 
generally  invisible  in  consequence  of  its  being  converted  into  vapour 
as  soon  as  it  reaches  the  surface ;  but,  at  other  times,  owing  to  augmen- 
tation of  the  secretion,  or  to  the  air  being  loaded  with  humidity,  it  is 
apparent  on  the  surface  of  the  body.  When  invisible,  it  is  called  in- 
sensible transpiration  or  perspiration ;  when  perceptible,  siceat.  In  the 
state  of  health,  according  to  M.  Thenard,^  this  fluid  reddens  litmus 
paper;  yet  the  taste  is  rather  saline — resembling  that  of  common  salt 
— than  acid.  AVagner,^  indeed,  affirms  that  it  generally  shows  alka- 
line reaction ;  and,  at  other  times,  does  not  affect  vegetable  blues ;  but 
the  sweat  of  many  parts  of  the  body, — the  armpits  for  example, — is 
said  always  to  react  like  an  alkali.  Allusion  has  already  been  made 
to  the  views  of  M.  Doniic,'^  who  considers,  that  the  external,  and  the 
internal  alkaline  membranes  of  the  human  body  represent  the  two  poles 
of  a  pile,  the  electrical  effects  of  which  are  appreciable  by  the  galva- 
nometer. 

The  smell  of  the  perspiration  is  peculiar,  and  when  concentrated, 
and  especially  when  subjected  to  distillation,  becomes  almost  insup- 
portable. The  fluid  is  composed,  according  to  M.  Thcnard,  of  much 
water,  a  small  quantity  of  acetic  acid,  chloride  of  sodium,  and  perhaps 
of  potassium,  a  very  little  eartliy  phosphate,  a  trace  of  oxide  of  iron, 
and  an  inappreciable  quantity  of  animal  matter.  Berzelius'*  regards  it 
as  water  holding  in  solution  chlorides  of  potassium  and  sodium,  lactic 
acid,  lactate  of  soda,  and  a  little  animal  matter;  Anselmino,''  as  con- 
sisting of  a  solution  of  osmazome,  chlorides  of  sodium  and  calcium, 
acetic  acid,  and  an  alkaline  acetate,  salivary  matter,  sulphates  of  soda 
and  potassa,  and  calcareous  salts,  with  mucus,  albumen,  sebaceous 
humour,  and  gelatin  in  variable  proportions;  and  M.  EaspaiP  looks 
upon  it  as  an  acid  product  of  the  disorganization  of  the  skin.  The 
solid  constituents,  according  to  Simon, ^  are  a  mixture  of  salts  and  ex- 

'  Trait*',  de  Cliimie,  torn.  iii. 

2  Elements  of  Physiology,  by  R.  Willis,  §  204,  Loud.,  1842. 

*  Journal  Hebdomad.,  Fevrier,  1834. 

*  Medico-Chir.  Trans.,  iii.  256. 

*  Lepelletier,  Physiologie  M'  dicale  et  Pliilosopliique,  ii.  452,  Paris,  1832. 
^  Chimie  Organique,  p.  505,  Paris,  1832. 

'  Animal  Chemistry,  Sydenham  Society's  edit.,  ii.  101,  Lond.,  1846. 


508 


SECRETION. 


Fi£j.  150. 


tractive  matters,  of  wliicli  tlie  latter  preponderate:  the  principal  ingre- 
dient of  the  salts  is  chloride  of  sodium.  From 
what  he  admits  to  be  superficial  and  merely 
qualitative  investigations,  he  considers  he  has 
established  the  existence  in  normal  sweat,  of 
— First.  Substances  soluble  in  ether ;  traces 
of  fat,  sometimes  including  butyric  acid. 
Secondbj.  Substances  soluble  in  alcohol ;  al- 
cohol extract;  free  lactic  or  acetic  acid ;  chlo- 
ride of  sodium ;  lactates  and  acetates  of  po- 
tassa  and  soda;  lactate  or  chlorohydrate  of 
ammonia.  Thirdly.  Substances  soluble  in 
water ;  water  extract ;  phosphate  of  lime, 
and  occasionally  an  alkaline  sulphate ;  and, 
fourtldy.  Substances  insoluble  in  water;  de- 
squamated epithelium;  and — after  the  re- 
moval of  the  free  lactic  acid  by  alcohol — 
phosphate  of  lime  with  a  little  peroxide  of 
iron.  In  the  solid  matter  urea  was  detected 
by  Landerer,^  and  also  by  M.  Favre,^ — whose 
researches  are  more  complete  and  exact  than 
any  perhaps  that  had  been  before  under- 
taken. He  found  the  constituents  of  hum;in 
sweat  to  be  as  follows:  chloride  of  sodium, 
2"2305 ;  chloride  of  potassium,  0"2i37;  alka- 
line sulphates,  0'0115;  phosphoric  acid,  traces; 
earthy  phosphate,  traces;  calcareous  salts, 
traces;  alkaline  albuminate,  0-0050;  epithe- 
lium, lactates  of  potassa,  traces;  and  soda, 
O-ain  ;  hydrotates,^  1-5623  ;  urea,  0-0428  ;  fat, 
0-0136;  water,  995-5733.  Schottin,'' however, 
was  unable  to  detect  either  urea  or  ammonia 
in  the  matter  of  perspiration. 

After  evaporation  upon  a  clean  glass  plal ;.', 
fragments  of  epidermic  cells  are  generally  ob- 
served in  it,  and  crystals  are  left  behind,  which 
are  those  of  its  contained  salts.  With  great 
care  to  avoid  admixture,  Krause^  collected  a 
small  quantity  of  pure  cutaneous  perspiration 
from  the  palm  of  the  hand,  where  there  are  no 
sebaceous  follicles.  The  fluid  yielded,  with 
boiling  ether,  some  small  globules  of  oil  and 
crystals  of  margarin.     It  was  acid,  but  alter 

twenty -four  hours  became  alkaline  by  the  developement  of  ammonia. 

'  Gr.  0.  Rees,  art.  Sweat,  Cyclopedia  of  Anatomy  and  Physiology,  pt.  xxxvii.  p.  844, 
Lond.,  October,  1849. 

2  Comptes  Rendiis,  xxxv.  721  ;  Arcliives  Uenerales  de  Med.,  Juillet,  1853  ;  and  Bec- 
querel  and  Rodier,  Traite  de  Cliimie  Pathologique,  p.  525,  Paris,  1854. 

3  M.  Favre  affirms  that  he  discovered  a  new  nitrogenous  acid  in  the  sweat,  which 
he  calls  the  hydrotic  or  sudoric. 

*  Canstatt,  Ibid.,  S.  120. 

^  Art.  llaut,  in  Wagner's  Handworterbuch  der  Physiologie,  7te  Lieferung,  S.  108. 


Vertical  Section  of  the  Skin  of. 
the  Sole. 
a.  Cuticle;  the  deep  layers  (rete 
mucosum)  more  coloured  than  the 
upper,  and  their  particles  rounded; 
the  superficial  layers  more  and 
more  scaly.  6.  Papillary  struc- 
ture, c.  Cutis,  d.  Sweat-gland, 
lying  in  a  cavity  on  the  deep  sur- 
face of  the  skin,  and  Imbedded  in 
globules  of  fat.  Its  duct  is  seen 
passing  to  the  surface.  Magnified 
40  diameters. 


TRANSPIEATOEY,    OF   THE   SKIN". 


509 


In  another  experiment,  lie  found,  that  the  tissue  of  the  epidermis  con- 
tains a  fatty  substance  independently  of  the  fatty  matter  secreted  on  its 
surfice. 

In  a  memoir  presented  to  the  Academic  Royale  des  Sciences  of  Paris, 
MM.  Breschet  and  Koussel  de  Vauzeme  first  clearly  showed,  that  there 
exists  in  the  skin  an  apparatus  for  the  secretion  of  the  sweat,  consisting 
of  a  glandular  parenchyma,  which  secretes  the  liquid,  and  of  ducts, 
which  pour  it  on  the  surface  of  the  body.  These  ducts  are  arranged 
spirally,  and  open  very  obliquely  under  the  scale  of  the  epidermis.  To 
this  apparatus  they  applied  the  epithet  ^^  diajmogenous  f^  and  called  the 
ducts  ^^sudoriferous  or  hidrophorousP^ 

Each  sudoriparous  gland  consists  of  a  coil  or  excretory  duct  sur- 
rounded by  bloodvessels,  and  imbedded  in  fat  vesicles.  Thence  the 
duct  passes  in  the  manner  represented  in  the  marginal  figure,  towards 
the  surface,  and  opens  on  the  epidermis  by  an  oblique  valve-like  aper- 
ture. The  excretory  duct  is  lined  by  epithelium,  which  is  a  prolonga- 
tion of  the  epidermis.  These  glands  are  numerously  distributed;  but 
especially  so  in  the  palms  of  the  hand,  and  soles  of  the  foot.     In  the 


Fig.  151. 


Fiff.  152. 


Vertical  Section  of  Epiderniit!,  from  Palm  of 
the  Hand. 

a.  Outer  portion,  composed  of  flattened  scales. 
h.  Inner  portion,  consisting  of  nucleated  cells. 
c.  Tortuous  perspiratory  tube,  cut  across  by  the 
section  higher  up. — Magnified  lOJ  diameters. 


Surface  of  the  Skin  of  the  Palm,  showing  the 
Riilf^es,  Furrows,  Cross-grooves,  and  Orifices 
of  the  Sweat-ducts. 

The  scaly  texture  of  the  cuticle  is  indicated  by  the 
irregular  lines  on  the  surface. — Magnified  20  diame- 
ters. 


former  situation  they  amount,  according  to  Professor  Krause,^  to  2736 
in  every  square  inch ;  and  in  the  latter,  to  2685.     Mr.  K.  AVilson^ 


'  Op.  cit.,  s.  131. 

2  Bresobet,  Nouvelles  Reclierches  sur  la  Structure  de  la  Peau,  Paris,  1835. 

"'  Healthy  Skin,  p.  42,  Lond.,  1845  ;  or  Auicr.  edit.,  p.  OS,  PLilad.,  1854. 


510  SECRETION. 

counted  the  perspiratory  pores  on  the  palm  of  the  hand,  and  found 
3528  in  a  square  inch;  and  each  of  these  pores  being  the  aperture  of  a 
little  tube  of  about  a  quarter  of  an  inch  long,  it  follows,  that  in  a  square 
inch  of  skin,  on  the  palm  of  the  hand,  there  exists  a  length  of  tube  equal 
to  882  inches,  or  73|  feet.  To  obtain  an  estimate  of  the  length  of  tube 
of  the  perspiratory  system  of  the  whole  surface  of  the  body,  he  thinks 
that  2800  might  be  taken  as  a  fair  average  of  the  number  of  pores  in 
the  square  inch;  and  700,  consequentlj^,  of  the  number  of  inches  in 
length.  "Now  the  number  of  square  inches  of  surface  in  a  man  of 
ordinary  height  and  bulk  is  2500 ;  the  number  of  pores,  therefore, 
7,000,000,  and  the  number  of  inches  of  perspiratory  tube,  1,750,000; 
that  is,  li5,83o  feet  or  48,600  yards,  or  nearly  28  miles!" 

Numerous  experiments  have  been  instituted  for  the  purpose  of  dis- 
covering the  quantity  of  transpiration  in  a  given  time.  Of  these,  the 
earliest  were  by  Sanctorius, — for  which  he  is  more  celebrated  than  for 
any  of  his  other  labours, — after  whom  the  cutaneous  transpiration  was 
called  Perspirahile  Sanctorianiirn}  For  thirty  years,  this  indefatigable 
experimentalist  weighed  daily,  with  the  greatest  care,  his  solid  and 
liquid  ingesta  and  egesta,  and  his  body,  with  the  view  of  deducing  the 
loss  sustained  by  the  cutaneous  and  pulmonary  exhalations.  He  found, 
that  every  twenty-four  hours  his  body  returned  to  the  same  weight, 
and  that  he  lost  the  whole  of  the  ingesta ; — five-eighths  by  transpira- 
tion, and  three-eighths  by  the  ordinary  excretions.  For  eight  pounds 
of  ingesta  there  were  only  three  pounds  of  sensible  egesta,  which  con- 
sisted of  forty-four  ounces  of  urine,  and  four  of  feces.  It  is  lamentable 
to  reflect,  that  so  much  time  Avas  occupied  in  the  attainment  of  such 
insignificant  results.  The  self-devotion  of  Sanctorius  gave  occasion, 
however,  to  the  institution  of  numerous  experiments  of  the  same  kind ; 
as  well  as  to  discover  the  variations  in  the  exhalation,  according  to 
age,  climate,  &c.  The  results  of  these  have  been  collected  by  Ilaller,^ 
but  they  afford  little  instruction ;  especially  as  they  were  directed  to 
the  transpiration  in  general,  without  affording  any  data  from  v/hich  to 
calculate  the  proportion  exhaled  from  the  lungs  compared  with  that 
constantly  given  off  by  the  cutaneous  surface.  Bye,^  who  dwelt  in 
Cork,  lat.  51°  54',  found,  in  the  three  winter  months — December,  Janu- 
ary, and  February — that  the  quantity  of  urine  was  3937  ounces;  of 
perspiration,  4797;  in  the  spring  months — March,  April,  and  ^lay — 
the  urine  amounted  to  3558  ;  the  perspiration  to  5405 ;  in  the  summer 
months — June,  July,  and  August — the  former  amounted  to  3352 ;  the 
latter  to  5719;  and  in  the  three  autumnal  months — September,  October, 
and  November — the  quantity  of  urine  was  3369;  of  perspiration,  4471. 
The  daily  average  estimate  in  ounces  was  as  follows: — 

Urine.  Perspiration. 

Winter 42,^5  53 

Spring, 40  60 

yummer,      .........     37  63 

Autumn,      .........     37  50 

Thus  making  the  avei'age  daily  excretion  of  urine,  throughout  the 

'  Ars  Sanctorii  de  Statica  Medicina,  cum  Comment.  Martini  Lister,  Lugd.  Bat.,  1711. 

2  Elem.  Physiol.,  xii.  2,  10. 

'  Rogers  on  Epidem.  Diseases,  Appendix,  Dubl.,  1734. 


TRAXSPIRATORY,    OF   THE   SKIN.  511 

year,  to  be  a  little  more  than  39  ounces;  and  of  the  transpiration,  56 
ounces.  Keill/  on  the  other  hand,  makes  the  average  daily  perspira- 
tion, 31  ounces;  that  of  the  urine,  38;  the  weight  of  the  feeces  being 
5  ounces,  and  of  the  solid  and  liquid  ingesta,  75.  His  experiments 
were  made  at  Northampton,  England,  lat.  52°  11'.  Bryan  liobinson^ 
found,  as  the  result  of  his  observations  in  Ireland,  that  the  ratio  of  the 
perspiration  to  urine  was,  in  summer,  5  to  3;  in  winter,  2  to  3;  whilst 
in  April,  May,  October,  November,  and  December,  they  were  nearly 
equal.  In  youth,  the  ratio  of  the  perspiration  to  urine  was  1340  to 
1000;  in  the  aged,  967  to  1000.  Hartmann,  when  the  solid  and  liquid 
ingesta  amounted  to  80  ounces,  found  the  urine  discharged  28  ounces; 
the  fasces,  6  or  7  ounces;  and  the  perspirable  matter,  -15  or  46  ounces. 
De  Gorter,^  in  Holland,  when  the  ingesta  were  91  ounces,  found  the 
perspiration  amount  to  49  ounces;  the  urine  to  36;  and  the  fasces  to  8. 
Dodart^  asserts,  that,  in  France,  the  ratio  of  the  perspiration  to  the  fasces 
is  as  7  to  1 ;  and  the  whole  ,egesta  15  to  12  or  10.  The  average  per- 
spiration in  the  twenty-four  hours,  he  estimates  at  33  ounces  and  two 
drachms;  and  Sauvages,  in  the  south  of  France,  found,  that  when  the 
ingesta  were  60  ounces  in  the  day,  the  transpiration  amounted  to  33 
ounces;  the  urine  to  22  ;  and  the  faeces  to  5.  But  most  of  these  esti- 
mates were  obtained  in  the  cooler  climates, — the  ^Wegiones  loreales,''^ — 
as  Ilaller-'  has,  not  very  happily,  termed  them. 

According  to  Lining,^  whose  experiments  were  made  in  South  Caro- 
lina, lat.  32°  47',  the  perspiration  exceeded  the  urine  in  the  warm 
months;  but  in  the  cold,  the  latter  had  the  preponderance.  The  fol- 
lowing table,  quoted  by  Haller,  gives  the  average  daily  proportion  of 
urine  and  perspiration,  for  each  month  of  the  year,  in  ounces. 

Urine.         Perspiration. 

December, 70-81  42-55 

January, 72-43  39-97 

February, 77-86  37*45 

March, 70-59  43-23 

April,             59-17  47-72 

May,                56-15  58-11 

June,               52-90  71-39 

July,               43-77  86-41 

August, 55-41  70-91 

September, 40-60      ^      77-09 

October, 47-67  40-78 

November, 63-16  40-97 

After  the  period  at  which  Haller  wrote,  no  experiments  of  any 
moment  were  made  for  appreciating  the  transpiration.  Whenever 
trials  were  instituted,  the  exhalation  from  both  the  skin  and  lungs  was 
included  in  the  result,  and  no  satisfactory  means  were  adopted  for 
separating  them,  until  MM.  Lavoisier  and  Scguin^  made  their  cele- 
brated experiments.  M.  Seguin  enclosed  himself  in  a  bag  of  gummed 
taffeta,  which  was  tied  above  the  head,  and  had  an  aperture  the  edges 

'  Tentamina  Medico-Phys.,  Appendix,  Lond.,  1718. 

^  Dissertation  on  tlie  Food  and  Discharges  of  Human  Bodies,  Dublin,  1748. 

"  De  Perspiratione  Insensibili,  Lugd.  Bat.,  1736. 

*  Memoir,  de  I'Acad.  des  Sciences,  ii.  276.  ^  Op.  cit. 

^  Philos.  Transact,  for  1743  and  1745. 

'  Memoir,  de  I'Acad.  des  Sciences  de  Paris,  Paris,  1777  and  1790. 


512  SECRETION". 

of  which  were  fixed  firound  the  mouth  by  a  mixture  of  turpentine  and 
pitch.  By  means  of  this  arrangement,  the  puhnonary  transpiration, 
alone  escaped  into  the  air.  To  estimate  its  quantity,  it  was  merely 
necessary  for  M.  Seguin  to  weigh  himself  in  the  sac  by  a  very  delicate 
balance,  at  the  commencement  and  termination  of  the  experiment, 
By  repeating  it  out  of  the  sac,  he  determined  the  total  quantity  of 
transpired  fluid;  so  that,  by  deducting  from  this  the  quantity  of  fluid 
exhaled  from  the  lungs,  he  obtained  the  amount  of  cutaneous  tran- 
spiration. He,  moreover,  kept  an  account  of  the  food  which  he  took; 
of  the  solid  and  liquid  egesta;  and,  as  far  as  he  was  able,  of  every  cir 
cumstance  that  could  influence  the  transpiration. 

The  results — as  applicable  to  Paris,  at  which  MM.  Lavoisier  and 
Seguin  arrived,  by  a  series  of  well-devised  and  well-conducted  experi- 
ments— were  the  following: — First.  Whatever  may  be  the  quantity  of 
food  taken,  or  the  variations  in  the  state  of  the  atmosphere,  the  same 
individual,  after  having  increased  in  weight  by  the  whole  quantity  of 
nourishment  taken,  returns  daily,  after  the  lapse  of  twenty-four  hours, 
to  nearly  the  same  weight  as  the  day  before ; — provided  he  is  in  good 
health;  his  digestion  perfect ;  not  fattening  nor  growing;  and  avoids 
all  kinds  of  excess.  Secondly.  If,  when  all  other  circumstances  are 
identical,  the  amount  of  food  varies;  or  if — the  amount  of  food  being 
the  same — the  efl'ects  of  transpiration  differ,  the  quantity  of  the  excre- 
ments augments  or  diminishes,  so  that  every  day  at  the  same  hour  we 
return  nearly  to  the  same  weight ;  proving,  that  when  digestion  goes 
on  well,  the  causes,  that  concur  in  the  loss  or  excretion  of  the  food 
taken  in,  afford  each  other  mutual  assistance, — in  the  state  of  health 
one  charging  itself  with  what  the  other  is  unable  to  accomplish. 
Thirdly.  Defective  digestion  is  one  of  the  most  direct  causes  of  dimi- 
nution of  transpiration.  Fourthly.  When  digestion  goes  on  well,  and 
the  other  causes  are  equal,  the  quantity  of  food  has  but  little  eft'cet  on 
the  transpiration.  M.  Seguin  affirms,  that  he  has  very  frequently  taken 
at  dmner  two  pounds  and  a  half  of  solid  and  liquid  food;  and  at  other 
times  four  pounds;  yet  the  results  in  the  two  cases  differed  but  little, — 
provided  only  the  quantity  of  fluid  did  not  vary  materially  in  the  two 
cases.  Fifthly.  Immediately  after  dinner,  the  transpiration  is  at  its 
minimum.  Sixthly.  When  all  other  circumstances  are  equal,  the  loss 
of  weight  induced  by  insensible  transpiration  is  at  its  maximum  during 
digestion.  The  increase  of  transpiration  during  digestion  compared 
with  the  loss  sustained  when  fasting,  is,  on  an  average,  2f^  grains  per 
minute.  Seventhly.  AVhen  circumstances  are  most  favourable,  the 
greatest  loss  of  weight  caused  by  insensible  transpiration  was,  accord- 
ing to  their  observations,  82  grains  per  minute;  consequently,  8  ounces, 
2  drachms  and  48  grains  poids  de  marc,  per  hour;  and  5  pounds  in 
twenty-four  hours,  under  the  calculation,  that  the  loss  is  alike  at  all 
hours  of  the  day,  which  is  not,  however,  the  fact.  '  Eighthly.  When  all 
the  accessory  circumstances  are  least  favourable,  provided  only  that 
digestion  is  properly  accomplished,  the  smallest  loss  of  weight  is  11 
grains  per  minute;  consequently,  1  ounce,  1  drachm  and  12  grains  per 
hour;  and  1  pound,  11  ounces  and  4  drachms  in  the  twenty -four  hours. 
Nirdlily.  Immediately  after  eating,  the  loss  of  weight  caused  by  the 
insensible  perspiration  is  10^  grains  per  minute  during  the  time  at 


i 


TRANSPIRATORY,    OF   THE   SKIN.  513 

•whicli  all  tlie  extraneous  causes  are  most  unfavourable  to  transpiration; 
and  ISi'g  grains  per  minute  wlien  these  causes  are  most  favourable,  and 
the  internal  causes  are  alike.  "These  differences,"  says  M.  Seguin,  "in 
the  transpiration  after  a  meal,  according  as  the  causes  influencing  it  are 
more  or  less  favourable,  are  not  in  the  same  ratio  with  the  differences 
observed  at  any  other  time  when  the  other  circumstances  are  equal; 
but  we  know  not  how  to  account  for  the  phenomenon."  Terdhhj.  The 
cutaneous  transpiration  is  immediately  dependent  both  on  the  solvent 
virtue  of  the  circumambient  air,  and  the  power  possessed  by  the  ex- 
halants  of  conveying  the  perspirable  fluid  as  far  as  the  surface  of  the 
skin.  Eleventhly.  From  the  average  of  all  the  experiments  it  seems, 
that  the  loss  of  weight  caused  by  the  insensible  transpiration  is  18 
grains  per  minute;  and  that,  of  these  18  grains,  11,  on  the  average, 
belong  to  the  cutaneous  transpiration,  7  to  the  pulmonary.  Twelfthly. 
The  pulmonary  transpiration,  compared  with  the  volume  of  the  lungs, 
is  much  more  considerable  than  the  cutaneous,  compared  with  that  of 
the  surface  of  the  skin.  Thirteenthly.  AVhen  all  other  circumstances 
are  equal,  the  pulmonary  transpiration  is  nearly  the  same  before  and 
immediately  after  a  meal;  and  if,  on  an  average,  it  is  11  \  grains  per 
minute  before  dinner,  it  is  VI ^^  grains  after  dinner.  Lastly.  All  in- 
trinsic circumstances  being  equal,  the  weight  of  the  solid  excrements 
is  least  during  winter. 

Although  these  results  are  probably  fairly  deduced  from  the  experi- 
ments ;  and  the  experiments  themselves  almost  as  well  conceived  as 
the  subject  admits  of,  we  cannot  regard  the  estimates  as  more  than 
approximations.  Independently  of  the  fact,  that  the  envelope  of  taffeta 
must  necessarily  have  retarded  the  exhalation,  by  shutting  off'  the  air, 
and  causing  more  to  pass  off  by  pulmonary  transpiration,  the  perspi- 
ration must  incessantly  vary,  according  to  circumstances  within  and 
without  the  system :  some  individuals,  too,  perspire  more  readily  than 
others ;  and  the  amount  exhaled  is  dependent,  as  we  have  seen,  upon 
climate  and  season, — and  likewise  upon  the  quantity  of  fluid  received 
into  the  digestive  organs. 

From  these  and  other  causes,  Bichat  was  led  to  observe,  that  the 
endeavour  to  determine  the  quantity  of  the  cutaneous  transpiration  is 
as  vain  as  to  endeavour  to  specify  what  quantity  of  water  is  evapo- 
rated every  hour  on  a  fire,  the  intensity  of  which  is  varying  every 
instant.  To  attempt,  however,  the  solution  of  the  problem,  experi- 
ments were  undertaken  by  Cruikshank,'  and  by  Abernethy.  Their 
plan  consisted  in  confining  the  hand,  for  an  hour,  in  an  air-tight  glass 
jar,  and  collecting  the  transpired  moisture.  Mr.  Abernethy,  having 
weighed  the  fluid  collected  in  the  glass,  multiplied  its  quantity  by 
88J,  the  number  of  times  he  conceived  the  surface  of  the  hand  and 
wrist  to  be  contained  in  the  wdiole  cutaneous  surface.  This  gave  2J 
pounds,  as  the  amount  exhaled  from  the  skin  in  the  twenty  four  hours, 
on  the  supposition,  that  the  whole  surface  perspires  to  an  equal  ex- 
tent. These  experiments  have  been  repeated  by  Dr.  William  Wood,'' 
of  Newport,  England,  with  some  modifications.     He  pasted  around  the 

'  Experiments  on  the  Insensible  Perspiration,  p.  5,  Lond.,  1795. 
^  An  Essay  on  the  Structure  and  Functions  of  the  Skin,  &€.,  Edinb.,  1832. 
VOL.  I. — 33 


514 


SECRETION, 


mouth  of  a  jar  one  extremity  of  a  bladder  the  ends  of  whicli  were  cut 
away,  and  the  hand  being  passed  through  the  bLadder  into  the  jar,  the 
other  extremity  was  bound  to  the  wrist  with  a  ligature,  not  so  tight, 
however,  as  to  interfere,  in  any  degree,  with  the  circulation.  The 
exact  weight  of  the  jar  and  bladder  had  previously  been  ascertained. 
During  the  experiment,  cold  water  was  applied  to  the  outer  surface  of 
the  jar,  to  cause  the  deposition  of  the  fluid  accumulated  within.  The 
result  of  his  experiments  was  as  follows : — 


:p. 

Time  of  day. 

Temperature  in 

Piilse  per 

Fluid  collected  in 

apartment. 

minute. 

an  hour. 

1 

Noon. 

66° 

84 

32  grs. 

2 

Do. 

.    ,     66 

78 

32 

3 

Do. 

66 

78 

26 

4 

Do. 

61 

84 

32 

5 

9  P.M. 

62 

80 

26 

6 

Do. 

62 

75 

23 

Mean 


63-8 


79-8 


28-5 


The  next  thing  was  to  estimate  the  proportion,  which  the  surface  of 
the  hand  and  wrist  bears  to  the  whole  surface  of  the  body.  Mr.  Aber- 
nethy  reckoned  it  as  1  to  38J,  and  Mr.  Cruikshank  as  1  to  60!  Dr. 
Wood  does  not  adopt  the  estimate  of  either.  He  thinks,  however, 
that  the  estimate  of  the  former  as  regards  the  surface  of  the  hand  and 
wrist,  which  he  makes  seventy  square  inches,  is  near  the  truth,  having 
found  it  correspond  both  with  his  own  measurements  and  the  reports 
of  glovers.  Mr.  Abernethy's  estimate  of  the  superficial  area  of  the 
whole  body — 2700  square  inches,  or  above  eighteen  square  feet,  he 
regards  as  too  high.  Perhaps  the  most  general  opinion  is,  that  it 
amounts  to  sixteen  square  feet,  or  2304  square  inches ;  but  Haller  did 
not  think  it  exceeded  thirteen  square  feet,  or  2160  square  inches.  Dr. 
Wood  adopts  the  former  of  these  estimates,  and  is  disposed  to  think, 
that  the  proportion  of  the  surface  of  the  hand  and  fingers,  taken  to  the 
extremity  of  the  bones  of  the  arm,  does  not  fall  short  of  1  to  2,  which 
if  we  adopt  the  ratio  of  the  quantity,  he  found  transpired  per  hour, 
gives,  for  the  whole  body,  about  forty-five  ounces,  or  nearly  four 
pounds  troy  in  the  twenty -four  hours.  This  is  considerably  above  the 
result  of  the  experiments  of  either  S^guiu  or  Abernethy ;  yet,  on  re- 
viewing the  experiments,  Dr.  Wood  is  not  disposed  to  think  it  far 
from  the  truth. 

Dr.  Dalton,  of  Manchester,  undertook  a  series  of  experiments  similar 
to  those  of  Sanctorius,  Keill,  Hartmann  and  Dodart.'  The  first  he 
made  upon  himself  in  the  month  of  March,  for  fourteen  days  in  suc- 
cession. The  aggregate  of  the  articles  of  food  consumed  in  this  time 
was  as  follows, — bread,  168  ounces  avoirdupois;  oaten  cake,  79  ounces; 
oatmeal,  12  ounces;  butcher's  meat,  5-1 J  ounces;  potatoes,  130  ounces; 
pastry,  55  ounces;  cheese,  32  ounces: — Total  of  solid  food,  525|  ounces; 
averaging  38  ounces  daily: — of  milk,  435 J  ounces;  beer,  230  ounces; 
tea,  76  ounces; — Total  of  liquid  food,  741|,  averaging  53  ounces  of 
fluid  daily.  The  daily  consumption  was,  consequently,  91  ounces ;  or 
nearly  six  pounds.     During  the  same  period,  the  total  quantity  of 


■  Manchester  Memoirs,  vol.  v. 


TRANSPIRATOEY,    OF   THE   SKIN.  515 

urine  passed  was  680  ounces;  of  faeces,  68  ounces — the  daily  average 
being, — of  urine,  48  J  ounces;  of  faeces,  5  ounces:  making  53  J  ounces. 
If  we  subtract  these  egesta  from  the  ingesta,  there  will  remain  37| 
ounces,  which  must  have  been  exhaled  by  the  cutaneous  and  pulmo- 
nary transpirations,  on  the  supposition  that  the  weight  of  the  body 
remained  stationary.  To  test  the  influence  of  difference  of  seasons, 
Dr.  Dalton  resumed  his  investigations  in  the  month  of  June  of  the 
same  year.  The  results  were  as  might  have  been  anticipated, — a  less 
consumption  of  solids  and  a  greater  of  fluids;  a  diminution  in  the 
evacuations  and  an  increase  in  the  insensible  perspiration.  The  ave- 
rage of  solids  consumed  per  day  was  84  ounces ;  of  fluids,  56  ounces; — 
total,  90  ounces;  the  daily  average  of  the  evacuations — urine,  42 
ounces;  faeces,  4J, — leaving  a  balance  of  nearly  44  ounces  for  the 
daily  loss  by  perspiration,  or  one-sixth  more  than  during  the  cooler 
season.  He  next  varied  the  process,  with  the  view  of  obtaining  the 
quantity  of  perspiration,  and  the  circumstances  attendant  upon  it  more 
directly.  He  procured  a  weighing  beam,  that  would  turn  with  one 
ounce.  Dividing  the  day  into  periods  of  four  hours  in  the  forenoon, 
four  or  five  in  the  afternoon,  and  nine  in  the  night — or  from  ten  o'clock 
at  night  to  seven  in  the  morning — he  endeavoured  to  find  the  perspi- 
ration corresponding  to  these  periods  respectively.  He  weighed  him- 
self directly  after  breakfast,  and  again  before  dinner,  observing  neither 
to  take,  nor  part  with,  any  thing  in  the  interval,  except  what  was  lost 
by  perspiration.  The  difference  in  weight  indicated  such  loss.  The 
same  course  was  followed  in  the  afternoon  and  night.  This  train  of 
experiments  was  continued  for  three  weeks  in  November.  The  mean 
hourly  losses  by  transpiration  were; — in  the  morning,  1'8  ounce  avoir- 
dupois;— afternoon,  1-67  ounce;  night,  1-5.  During  twelve  days  of 
this  period  he  kept  an  account  of  urine  corresponding  in  time  with 
perspiration.  The  ratio  was  as  46  to  33.  From  the  whole  of  his  in- 
vestigations on  this  subject.  Dr.  Dalton  concludes; — that  of  six  pounds 
of  aliment  taken  in  the  day,  there  appears  to  be  nearly  one  pound  of 
carbon  and  nitrogen  together;  the  remaining  five  pounds  are  chiefly 
water,  which  seems  necessary  as  a  vehicle  to  introduce  the  other  two 
elements  into  the  circulation,  and  also  to  supply  the  lungs  and  mem- 
branes with  moisture; — that  very  nearly  the  whole  quantity  of  food 
enters  the  circulation,  for  the  fasces  constitute  only  y'gth  part,  and  of 
these  a  part — bile — must  have  been  secreted; — tliat  one  great  portion 
is  thrown  off'  by  the  kidneys,  namely,  about  half  of  the  whole  Aveight 
taken,  but  probably  more  or  less  according  to  climate,  season,  &c, ; — 
that  another  great  portion  is  thrown  oft'  by  means  of  insensible  per- 
spiration, which  may  be  subdivided  into  two  parts,  one  of  which 
passes  oft'  by  the  skin — amounting  to  one-sixth  part,  and  the  other 
five-sixths  are  discharged  from  the  lungs  in  the  form  of  carbonic  acid, 
and  water  or  aqueous  vapour. 

M.  Edwards'  instituted  experiments  with  the  view  of  illustrating 
the  eft'ect  produced  upon  cutaneous  transpiration  by  various  circum- 
stances to  which  the  body  is  subjected,  flis  first  trials  were  made  on 
cold-blooded  animals,  in  which   the  cutaneous  transpiration  can  be 

'  Sur  rinfluence  des  Agens  Physiques,  Paris,  1822 ;  or  translation  by  Hodgkiu  and 
Fisher,  Loud.,  1832. 


516  SECRETION, 

readily  separated  from  the  pulmonary,  owing  to  the  length  of  time 
they  are  capable  of  living  without  respiring.  All  that  was  necessary 
was  to  weigh  the  animal  before  and  after  the  experiment,  and  to  make 
allowance  for  the  ingesta  and  egesta.  In  this  way  he  discovered,  that 
the  body  loses  successively  less  and  less  in  equal  portions  of  time; — 
that  the  transpiration  proceeds  more  rapidly  in  dry  than  in  moist  air; 
in  the  extreme  states  nearly  in  the  proportion  of  10  to  1 ; — that  tem- 
perature has,  also,  considerable  influence, — the  transpiration  at  6S°  of 
Fahrenheit,  being  twice  as  much ;  and  at  10-i°,  seven  times  as  much  as 
at  82°,  He  likewise  found,  that  frogs  transpire,  whilst  they  are  in 
water,  as  is  shown  by  the  diminution  they  experience  while  immersed 
in  that  fluid,  and  by  the  appearance  of  the  water  itself,  which  becomes 
perceptibly  impregnated  with  the  matter  excreted  by  the  skin.  In 
warm-blooded  animals,  as  in  the  cold-blooded,  the  transpiration  became 
less  and  less  in  proportion  to  the  quantity  of  fluid  evaporated  from 
the  body ;  and  he  observed  the  same  difference  between  the  eflects  of 
moist  and  dry  air,  as  between  a  high  and  a  low  temperature.  The 
effects  of  these  agents  were  essentially  the  same  on  man  as  on  animals. 
He  found,  that  the  transpiration  was  more  copious  during  the  early 
than  the  latter  part  of  the  day,  and  after  taking  food;  and,  on  the 
whole,  it  appeared  to  be  increased  during  sleep. 

Whenever  the  fluid,  which  constitutes  the  insensible  transpiration, 
does  not  evaporate,  owing  to  causes  referred  to  at  the  commencement 
of  this  article,  it  appears  on  the  surface  in  the  form  o'l  sensible  per sjnr a- 
tion  or  sweat.  It  has  been  supposed  by  some  physiologists,  that  the 
insensible  and  sensible  perspirations  are  two  distinct  functions.  Such 
appears  to  be  the  opinion  of  Haller,  and  of  M.  Edwards,  who  regards 
the  former  as  a  physical  evaporation^ — the  latter  as  a  vital  transudation 
or  secretion;  but  no  sufficient  reason  seems  to  exist,  why  we  should 
not  regard  them  as  different  degrees  of  the  same  function.  It  has  been 
maintained,  indeed,  by  Mr.  Eainey,^  as  the  results  of  careful  histolo- 
gical inquir}^,  that  there  are  no  glands  but  the  sudoriparous  in  the 
integument  of  the  hands  and  feet,  and  hence  it  is  inferred  by  him,  that 
these  glands  furnish  the  oily  or  sebaceous  matter  with  which  these 
parts  are  anointed;  and  in  place  of  regarding  the  sweat  as  an  increase 
of  the  insensible  perspiration,  he  esteems  it  an  increased  secretion  of 
glands,  which,  in  their  less  active  state,  secrete  sebaceous  matter,  and, 
in  their  more  active,  the  fluid  of  transpiration. 

It  has  been  affirmed,  that  the  sweat  is  generally  less  charged  with 
carbonic  acid  than  the  vapour  of  transpiration;  and  that  it  is  richer  in 
salts,  which  are  deposited  on  the  skin,  and  are  sometimes  seen  in  the 
form  of  white  flocculi;  but  our  knowledge  on  this  matter  is  vague. 
There  can  be  no  doubt,  however,  that  a  large  portion  of  the  transpira- 
tion— pulmonary  and  cutaneous — consists  of  the  fluid  of  evaporation, — 
the  smaller  portion,  which  is  the  true  matter  of  perspiration,  being  the 
secretion  of  sudoriferous  glands.  To  establish  the  amount  of  the 
fluids  of  evaporation  and  secretion,  Krause^  endeavoured  both  to  num- 

'  Proceerlincrs  of  the  Royal  Medical  and  Chirurgical  Society,  June  22,  1849,  and 
London  Med.  Gaz.,  .July  20,  1849. 

^  Art.  Haut,  in  Wagner's  Handworterbuch  der  Physiologic,  7te  Lieferung,  S.  108, 
Braunschweig,  1844. 


TRANSPIRATOKY,   OF   THE   SKIN.  617 

ber  and  measure  these  glands.  On  an  average,  lie  says,  in  each  super- 
ficial square  inch  of  the  body  there  are  1000  orifices  and  glands  of  ^th 
of  a  line  in  diameter;  the  greatest  and  least  numbers  in  this  space 
being,  in  the  palm,  2736;  in  the  sole,  2685;  in  the  cheek,  548  ;  in  the 
neck,  back,  and  nates,  417.  The  whole  number,  excluding  the  axilla, 
in  which  they  are  peculiarly  large  and  thickset,  is  estimated  at  about 
2,381,248.  Adopting  these  numbers,  and  supposing  each  gland  to  be 
occupied  by  a  column  of  fluid  presenting  at  the  orifice  a  hemispherical 
surface  g'gth  of  a  line  in  diameter — the  size,  which  Krause  found  by 
admeasurement  of  some  drops  in  a  warm  and  moist,  but  not  sweating 
skin — the  whole  of  the  glands  would  present  an  evaporating  surface 
of  7896  square  inches.  Krause,  therefore,  considers  it  probable — ac- 
cording to  ascertained  laws  of  evaporation,  and  experiments  instituted 
for  the  purpose — that  only  a  portion  of  the  fluid  discharged  by  cuta- 
neous transpiration  is  furnished  by  these  glands;  inasmuch  as  there 
could  not  be  more  than  3365  grains  evaporated  in  the  twenty-four 
hours  from  such  a  surface  under  ftivourable  circumstances,  whereas 
the  experiments  of  MM.  Lavoisier  and  Seguin — as  has  been  shown — 
gave  an  average  of  11  grains  per  minute,  or  15,840  grains  in  the 
twenty-four  hours, — leaving  12,475  grains  to  be  accounted  for  proba- 
bly by  evaporation.  But  these  are,  of  course,  mere  approximations 
to  the  truth. 

Careful  examinations  have  been  made  by  Valentin'  on  his  own  per- 
son, in  regard  to  the  amount  of  both  cutaneous  and  pulmonary  tran- 
spiration. Taking  three  days  of  ordinary  life  in  September,  weighing 
himself  naked  fifteen  times  a  day,  and  all  his  ingesta  and  sensible  ex- 
cretions, he  found  the  averages  of  three  days  to  be: — nutritive  matter 
taken,  45325*5  grains;  excrement,  2956*3  grains;  urine,  22439*3  grains; 
perspiration,  19327*4  grains.  The  ingesta  being  as  1,  the  excrement 
was  '065,  the  urine,  *503 ;  and  the  perspiration,  *422.  There  were  dif- 
ferences, however,  in  the  days ; — in  the  first,  the  proportion  of  the  in- 
gesta to  the  excretions  was  as  1*097  to  1 ;  in  the  second,  as  1*028  to  1 ; 
in  the  third,  as  1  to  1*090.  The  hourl}^  amount  of  transpiration  was 
occasionally  4|  times  as  much  as  at  others ;  the  greatest  dift'erence 
being  caused  by  whatever  excited  sweating,  or  perceptible  moisture  of 
the  skin.  For  instance,  on  the  same  day,  the  hourly  amount,  after 
taking  two  cups  of  coffee,  and  during  gentle  perspiration,  was  1213*65 
grains;  in  the  forenoon,  in  pretty  active  exercise  and  sweating,  1402*75 
grains;  and  in  the  evening,  during  copious  sweating  from  exercise, 
2056*85  grains;  but  whilst  writing  quietly  in  the  forenoon  of  the  same 
day  it  fell  to  858*7  grains,  and  three  or  four  hours  after  dinner,  it  was 
only  509*95  grains.  Nothing  influenced  the  transpiration  so  much  as 
rest  and  bodily  exertion.  Even  when  the  latter  did  not  produce 
manifest  sweating,  the  effect  was  considerable.  After  eating,  also, 
transpiration  was  generally  increased,  and  its  minimum  was  observed 
during  fasting,  and  whilst  at  rest  in  a  cool  temperature.  During  the 
night  and  in  sleep,  the  transpiration  was  diminished;  but  not  more 
than  in  rest  during  the  day.  Mental  exertion  had  no  obvious  in- 
fluence. 

'  Lelirbucli  der  Pliysiologie  des  Mensclieii,  B.  i.  S.  582;  and  Krause,  op.  cit.,  S.  140. 


518  SECRETIO^r, 

Particular  parts  of  the  body  perspire  more  freely,  and  sweat  more 
readily  than  others.  The  forehead,  armpits,  groins,  hands,  feet,  &c., 
exhibit  evidences  of  this  most  frequently ;  some  of  them  perhaps,  owing 
to  the  fluid,  when  exhaled,  not  evaporating  readily, — the  contact  of 
air  being  impeded.  It  is  presumed,  likewise,  that  the  sweat  has  not 
every  where  the  same  composition.  Its  odour  certainly  varies  in  dif- 
ferent parts.  In  the  armpits  and  feet  it  is  generally  considered  to  be 
more  acid;  but  M.  Donne^  affirms,  that  there,  as  well  as  around  the 
genital  organs  and  between  the  toes,  and  wherever  it  is  most  odorous, 
it  is  alkaline,  restoring  the  blue  of  litmus  paper  which  had  been  pre- 
viously reddened  by  an  acid.  He  properly  suggests,  however,  that 
this  may  be  owing  to  admixture  with  the  secretion  of  the  follicles. 
In  the  violent  sweats  that  accompany  acute  rheumatism,  its  acidity 
always  attracts  attention ;  and  in  the  groins,  its  odour  is  strong  and 
rank.  It  diifers  greatly,  too,  in  individuals,  and  especially  in  races. 
In  the  red-haired,  it  is  said  to  be  unusually  strong;  and  in  the  negro, 
during  the  heat  of  summer,  alliaceous  and  overwhelming.  By  clean- 
liness, the  red-haired  can  obviate  the  unpleasant  effect  in  a  great  mea- 
sure by  preventing  undue  accumulation  in  the  axillae,  groins,  &c. ;  but 
no  ablution  can  remove  the  odour  of  the  negro,  although  cleanliness 
detracts  from  its  intensity.  Each  race  appears  to  have  its  characteristic 
odour :  and,  according  to  Humboldt,  the  Peruvian  Indian,  whose  smell 
is  highly  developed  by  education,  can  distinguish  the  European,  Ame- 
rican Indian,  and  negro,  in  the  middle  of  the  night,  by  this  sense  alone. 
Certain  anatomists  and  physiologists — as  has  been  seen  (p.  556) — have 
doubted,  whether  this  special  odorous  matter  of  the  skin  belongs  pro- 
perly to  the  perspiration,  and  have  presumed  it  to  be  the  product  of 
special  organs.  This  is,  however,  by  no  rneans  established ;  and  the 
experiments  of  M.  Thenard,  as  well  as  the  facts  just  mentioned,  would 
rather  seem  to  show,  that  the  matter  of  sweat  itself  has,  within  it,  the 
peculiar  odour.  Simon,^  too,  affirms,  that  on  evaporating  his  own 
sweat,  the  peculiar  smell  of  the  axilla  was  observed,  and  an  odour  of 
ammonia  was  developed :  and  allusion  has  been  made  to  the  recent 
view  of  Mr.  Rainey,  that  the  same  glands  may  in  one  condition  of 
activity  furnish  the  matter  of  transpiration,  and  in  another  the  ordinary 
secretion  of  sebaceous  follicles.  The  fact  of  the  dog  tracing  its  mas- 
ter to  an  immense  distance,  and  discovering  him  in  a  crowd,  has  in- 
duced a  belief,  that  the  scent  may  be  distinct  from  the  sweat;  but  the 
supposition  is  not  necessary,  if  we  admit  the  matter  of  perspiration  to 
be  itself  odorous.  There  can  be  no  doubt,  however,  that  certain 
odorous  secretions  are  formed  by  cutaneous  follicles. 

The  singular  fact  has  been  stated,  that  by  mixing  fresh  blood  with 
one-third  or  one-half  its  bulk  of  strong  sulphuric  acid,  and  stirring  the 
mixture  with  a  glass  rod,  a  peculiar  odour  is  evolved,  which  ditfers  in 
the  blood  of  man  and  animals,  and  in  the  blood  of  the  two  sexes. 
This  odour  resembles  that  of  the  cutaneous  perspiration  of  the  animal. 
"  They  have  hereby  pretended  to  determine,"  says  a  modern  medico- 
legal writer,^  "  whether  any  given  specimen  of  blood  had  belonged  to 

'  Cours  de  Microscopie,  p.  207,  Paris,  1844. 

*  Animal  C'hemi.stry,  Sydenham  Society's  edition,  ii.  102.  Lond.,  184(). 

'^  Taylor,  Medical  Jurisprudence,  Amer.  edit.,  by  Dr.  Griffith,  p.  275,  Philad.,  1845. 


TRANSPIKATORY,    OF   THE   SKIIT.  519 

a  man,  a  woman,  a  horse,  sheep,  or  fish.  Others  pretend,  that  they 
have  been  able  to  identify  the  blood  of  frogs  and  fleas!"  The  first 
person  who  directed  attention  to  this  point  was  M,  Barruel  ;^  who  was 
of  opinion  that  a  knowledge  of  the  fact  might  be  important  in  a 
medico-legal  relation,  with  the  view  of  determining  the  source  of  spots 
of  blood  on  linen  for  example;  but  even  admitting  the  fact,  as  stated 
by  MM.  Barruel,  Devergie,^  and  others,  it  is  obvious,  that  so  much 
must  depend  upon  the  power  of  olfactory  discrimination  of  the  ob- 
server, that  the  evidence  in  any  doubtful  case  could  scarcely  be 
deserving  of  much  weight.  Mr.  Taylor,  indeed,  affirms,  that  there  is 
probably  not  one  individual  among  a  thousand,  whose  sense  of  smell 
could  be  so  acute  as  to  allow  him  to  state,  with  undeniable  certainty, 
from  what  animal  the  unknown  blood  had  really  been  taken. 

Besides  the  causes  before  referred  to,  the  quantity  of  perspiration 
is  greatly  augmented  by  running  or  violent  exertion  of  any  kind ;  es- 
pecially if  the  temperature  of  the  air  be  elevated.  The  amount  will 
vary,  however,  according  to  the  cjuantity  of  moisture  already  present 
in  the  air.  If  it  be  slight,  a  large  quantity  will  pass  off  in  the  form  of 
insensible  perspiration ;  if  the  hygrometric  conditioa  be  high,  less  will 
be  exhaled  in  the  insensible  form,  and  more  in  the  sensible.  Experi- 
ments were  made  by  Dr.  Southwood  Smith,^  on  eight  of  the  workmen, 
employed  at  the  Phoenix  Gas  Works  in  drawing  and  charging  the 
retorts  and  making  up  the  fires.  They  were  weighed  in  their  clothes 
immediately  before  they  began,  and  after  they  had  finished  their 
labour ;  and  in  the  interval  between  the  first  and  second  weighings 
they  were  not  permitted  to  take  any  solids  or  liquids ;  nor  to  pass 
urine  or  fajces.  Two  men  on  a  bright  clear  day  worked  in  an  unusu- 
ally hot  place  for  70  minutes ;  the  loss  of  weight  of  one  of  them  was 
4  lbs.  1-i  oz.;  and  of  the  other  5  lbs.  2  oz. 

Warm  fluids  favour  perspiration  greatly;  hence  their  use,  alone  or 
combined  with  sudorifics,  when  this  class  of  medicines  is  indicated. 
M.  Magendie"  conceives,  that  being  readily  absorbed  they  are  readily 
exhaled.  This  may  be  true ;  but  the  perspiration  breaks  out  too 
rapidly  to  admit  of  this  explanation.  When  ice-cold  drinks  are  taken 
in  hot  weather,  the  cutaneous  transpiration  is  instantaneously  excited. 
The  effect,  consequently,  must  be  produced  by  the  refrigerant  influ- 
ence of  the  cold  medium  on  the  lining  membrane  of  the  stomach, — 
this  influence  being  propagated,  by  sympathy,  to  every  part  of  the 
capillary  system.  The  same  explanation  is  applicable  to  warm  drinks; 
but  the  hot  exert  a  sympathetic  efl'ect  on  the  skin  by  virtue  of  their 
stimulant  action  on  the  mucous  membrane. 

With  regard  to  the  uses  of  the  insensible  transpiration,  it  has  been 
supposed  to  preserve  the  surface  supple,  and  thus  favour  the  exercise 
of  touch ;  and  also,  by  undergoing  evaporation,  to  aid  in  the  refrigera- 
tion of  the  body.  It  is  probable,  however,  that  these  are  secondary 
uses  under  ordinary  circumstances ;  and  that  the  great  office  performed 
by  it  is  to  remove  a  certain  quantity  of  fluid  from  the  blood:  hence 
it  has  been  properly  termed  the  cutaneous  de'imralion.     In  this  respect, 

'  Annales  d'Hygiene,  i.  267. 

*  Medecine  Legale,  2de  edit.,  iii.  761,  Paris,  1S40. 

»  Philosophy  of  Health,  11.  391-396.  *  Precis  de  Physiologie,  2de  edit.,  ii.  455. 


520  SECRETION 

it  bears  a  striking  analogy  to  the  urine,  wliicli  is  the  only  other  depu- 
ratory  secretion,  with  the  exception  of  the  piihiionary  transpiration, 
which  we  shall  find  essentially  resembles  the  cutaneous.  Being  depu- 
ratory,  it  has  been  conceived,  that  any  interruption  to  transpiration 
must  be  followed  by  serious  consequences ;  accordingl}'  most  diseases 
have,  from  time  to  time,  been  ascribed  to  this  cause.  There  is,  how- 
ever, so  great  a  compensation  existing  between  the  urinary  and  cuta- 
neous depurations,  that  if  one  be  augmented,  the  other  is  decreased, — 
and  conversely.  Besides,  it  is  well  known,  that  disease  is  more  apt  to 
be  induced  by  partial  and  irregular  application  of  cold  than  by  frigo- 
rific  influences  of  a  more  general  character.  The  Eussian  vapour- 
bath  exemplifies  this;  the  bather  frequently  passing  with  impunity 
from  a  temperature  of  130°  into  cold  water.  The  morbific  effect — in 
these  cases  of  fancied  check  given  to  perspiration — is  derangement  of 
the  apjtaratus  engaged  in  the  important  functions  of  nutrition,  calori- 
fication, and  secretion,  and  the  extension  of  this  derangement  to  every 
part  of  the  organism. 

As  the  sensible  transpiration  or  stoeat  is  probably  only  the  insensible 
perspiration  in  increased  quantity,  with  the  addition  of  saline,  and 
other  matters  that  are  not  evaporable,  its  uses  demand  no  special 
notice. 

2.  Secretion  of  the  Lachrymal  Gland. 

The  lachrymal  apparatus,  being  a  part  of  that  accessory  to  vision, 
is  described  under  another  head. 

The  tears,  as  we  meet  with  them,  are  not  simply  the  secretion  of  the 
lachrymal  gland,  but  of  the  conjunctiva,  and  occasionally  of  the  carun- 
cula  lacrymalis  and  follicles  of  Meibomius.  ~  It  has  been  presumed, 
too,  by  several  modern  ophthalmologists — by  Wardrop,  Eosas,  Jhng- 
ken,  for  example — that  a  portion  of  them — Eognetta'  says  the  prin- 
cipal portion — consists  of  the  aqueous  humour,  which  passes  through 
the  cornea  by  endosmose ;  but  although  such  endosmose  mat/  exist,  it 
can  assuredly  furnish  but  little  towards  the  composition  of  the  tears.^ 
They  have  a  saline  taste ;  mix  freely  with  water ;  and,  owing  to  the 
presence  of  free  soda,  communicate  a  green  tint  to  blue  infusion  of 
violets.  Their  chief  salts  are  chloride  of  sodium,  and  phosphate  of 
soda.  According  to  MM.  Fourcroy  and  Vauquelin,^  the  animal  matter 
of  the  tears  is  mucus ;  but  it  is  presumed,  by  some,  to  be  albumen  or 
an  analogous  principle — dacryolin.  They  found  them  to  consist  of 
water,  mucus,  chloride  of  sodium,  soda,  phosphate  of  lime  and  phos- 
phate of  soda.     The  following  is  the  result  of  analyses  by  Professor 

Frerichs:^ — 

I.  II. 

Water, 99-06  98-70 

Solid  constituents, 0-94  1-30 

^  

Epithelium, 0-14  0-32 

Albumen, 0-08  0-10 

Chloride  of  Sodium — Alkaline  Phosphates,  Earthy- 
Phosphates,  Mucus,  Fat,  ....  0-72  0-88 

'  Traite  Philosophique  et  Clinique  d'Ophthalmologie,  p.  705,  Paris,  1844, 
2  Frerichs,  Art.  Thriinensecretion,  in  Wagner's  Handwiirterbuch  der  Physiologie,  19te 
Lieferung,  S.  621,  Braunschweig,  1848. 
*  Journal  de  Physique,  xxxix.  256.  ^  Op.  cit.,  S.  618. 


OF   THE   SALIVARY   GLANDS. 


521 


When  tears  are  examined  with  the  microscope,  globules  of  mucus, 
and  debris  of  the  epidermis  are  seen  in  them. 

This  secretion  is  more  influenced  by  the  emotions  than  any  other ; 
and  hence  it  is  concerned  in  the  expressions  of  lively  joy  or  sorrow, 
especially  the  latter. 

3.  Secretion  of  the  Salivary  Glands. 

The  salivary  apparatus  has  likewise  engaged  attention  elsewhere.  It 
consists  of  a  -parotid  gland  on  each  side,  situate  in  front  of  the  ear,  and 
])ehiud  the  neck  and  ramus  of  the  jaw;  a  submaxillarrj,  beneath  the 
body  of  the  bone;  a  sublingual^  situ- 
ate immediately  beneath  the  tongue ; 
— and  an  intralingual  or  lingual^ 
seated  at  the  inferior  surface  of  the 
tongue ; — the  parotids  and  submax- 
illary glands  having  each  but  one 
excretory  duct, — the  sublingual  se- 
veral.-^ The  racemose  granular  struc- 
ture of  the  salivary  glands  in  man 
greatly  resembles  that  of  the  mam- 
mary glands.  The  marginal  figure 
exhibits  their  structure  in  the  sheep. 
All  these  glands  pour  their  respect- 
ive fluids  into  the  mouth,  where  it 
collects,  and  becomes  mixed  with 
the  exhalation  of  the  mucous  mem- 
brane of  the  mouth,  and  the  secre- 
tion from  its  follicles.  It  is  this 
mixed  fluid  that  has  generally  been 
analyzed  by  the  chemist.  When 
collected  without  the  action  of  suck- 
ing, it  is  of  a  specific  gravity  varying  from  1*004  to  1*009 ;  accord- 
ing to  Mitscherlich,  from  l-b061  to  1-0088.  In  the  dog,  Prof.  Ber- 
nard^ found  that  of  the  parotid  to  be  from  1"0036  to  1*0011,  whilst 
Jacubowitsch  noted  it  in  the  same  animal  from  1*0010  to  1*0017.  In 
the  horse,  Lehmann^  found  it  to  be  from  1*0051  to  1*0071.  It  is  trans- 
lucent ;  slightly  opaque ;  very  frothy ;  and  ultimately  deposits  a  ne- 
bulous sediment.  Even  in  the  purest  saliva  there  are  always  found 
)nixed  a  few  epithelial  cells,  derived  from  the  mucous  lining  of  the 
mouth,  or  from  the  excretory  ducts  of  the  secreting  glands.  It  usually 
contains  free  alkali :  in  rare  cases,  during  meals.  Professor  Schultz,* 
of  Berlin,  found  it  acid;  and  during  fasting,  it  is  occasionally  neutral. 
iMitscherlich,^  indeed,  affirms,  that  it  is  acid  whilst  fasting ;  but  becomes 
alkaline  during  eating, — the  alkaline  character  disappearing,  at  times, 

'  Page  77. 

2  Gazette  Med.,  1853,  No.  7, 11,  22  and  23  ;  and  Scherer,  in  Canstatt's  Jaliresbericht, 
1853,  S.  118. 

*  Lehrbuch  der  Physiologisclien  Chemie,  ii.  14,  Leipz.,  1850 ;  or  Amer.  edit,  of  Dr. 
Day's  translation  by  Dr.  R.  E.  Rogers,  i.  415,  Philad.,  1855. 

■•  Becker's  Wissenschaftliclie  Annalen,  B.  ii.  H.  i.  §  32,  1835. 

^  Rullier  and  Raige-Delorme,  art.  Digestion,  Diet,  de  Medecine,  2de  edit.,  x.  300, 
Paris,  1835. 


Lobules  of  the  Parotid  Gland,  in  the  Em- 
bryo of  the  Sheep. 


522 


SECRETION" 


witli  tlie  first  moutliful  of  food.  The  average  amount  of  the  secretion 
in  the  twenty-four  hours  has  not  been  considered  to  exceed  four 
ounces.  Messrs.  Bidder  and  Schmidt/  however,  estimate  the  probable 
amount  for  an  adult  at  140  kilogramme  or  between  three  and  four 
pounds  in  the  twenty-four  hours. 

According  to  Berzelius,^  its  constituents  are — water,  992'2  ;  peculiar 
animal  matter,  2*9 ;  mucus,  I'-i ;  chlorides  of  potassium  and  sodium, 
1'7  ;  lactate  of  soda,  and  animal  matter,  0"9  ;  soda,  0*2.  Di's.  Bostock^ 
and  Thomas  Thomson"  think  that  the  "mucus"  of  Berzelius  resembles 
coagulated  albumen  in  its  properties.  In  the  tartar  of  the  teeth, 
which  seems  to  be  a  sediment  from  the  saliva,  Berzelius  found  79 
parts  of  earthy  phosphate;  12*5  of  undecomposed  mucus;  1  part  of  a 
matter  peculiar  to  the  saliva,  and  7'8  of  an  animal  matter  soluble  in 
chlorohydric  acid.  This  animal  matter,  according  to  the  microscopic 
experiments  of  M.  Raspail,*  is  composed  of  deciduous  fragments  from 
the  mucous  membrane  of  the  cavity  of  the  mouth;  and  he  considers, 

that  the  saliva  is  nothing  more  than  an 
albuminous  solution,  mixed  with  different 
salts,  that  are  capable  of  modifying  more 
or  less  its  solubility  in  water,  and  of  shreds 
or  layers  of  tissue.  MM.  Leuret  and  Las- 
saigne*^  analyzed p?<?-e  saliva,  obtained  from 
an  individual  labouring  under  salivary 
fistula,  and  found  it  to  contain, — water, 
mucus,  traces  of  albumen,  soda,  chloride 
of  potassium,  chloride  of  sodium,  carbon- 
ate and  phosphate  of  lime;  and  Messrs, 
Tiedemann  and  Gmelin^  affirm, — and  their 
analvsis  agrees  pretty  closely  with  that  of  Van  Setten^ — that  it  has 
only  one  or  two  hundredths  of  solid  matter,  which  are  composed  of  a 
peculiar  substance,  called  salivary  matter  or  pff/al in,  osmazome,  mucus, 
perhaps  albumen,  a  little  fat  containing  phosi^horus,  and  the  insoluble 
salts — phosphate  and  carbonate  of  lime.  Besides  these,  they  detected 
the  following  soluble  salts; — acetate,  carbonate,  phosphate,  sulphate, 
sulphocyanate  of  potassa;  and  chloride  of  potassium.  Treviranus' 
thought  that  the  saliva  contains  a  peculiar  acid,  probably  combined 
with  an  alkali;  but  its  chemical  properties  resemble  the  sulpho-cj^anic 
acid  so  greatly,  that  according  to  Kastner'°  they  may  be  taken  for 
each  other. 

As  the  result  of  numerous  analyses.  Dr.  Wright"  gives  the  follow- 
ing constituents  of  healthy  saliva; — water,  988-1;  ptyalin,  1'8 ;  fatty 

'  Die  Verclauungssiifte  und  der  Stoffwechsel,  S.  13,  Mitau  aud  Leipzig,  1852. 

2  Medico-Chirurgical  Transactions,  iii.  242. 

3  Physiol.,  ed.  cit.,  p.  487.  ■•  System  of  Chemistry,  vol.  iv. 
*  Nouveau  Systeme  de  Chimie  Organiqiie,  p.  454. 

^  Recherches,  &c.,  sur  la  Digestion,  p.  33,  Paris,  1826. 

'  Recherches,  &c.,  sur  la  Digestion,  par  Jourdan,  Paris,  1827. 

8  De  Saliva  ejusque  Vi  et  Utilitate,  Groning.,  1837;  cited  in  Brit,  and  For.  Med. 
Rev.,  Jan.,  1839^  p.  236. 

9  Biologie,  Band.  iv.  §  330. 

'"  Ficinns,  art.   Speichel,   in   Pierer's  Anat.   Ph^'siol.   Real   Worterbuch,   vii.    634, 
Altenb.,  1827. 
"  London  Lancet,  Mar,,  1842. 


Distribution  of  Capillaries  around  the 
follicles  of  Parotid  Gland. 


OF   THE   SALIVAEY   GLANDS.  523 

acid,  '05;  chlorides  of  sodium  and  potassium,  14;  albumen  witli  soda, 
0"9;  phosphate  of  lime,  0-6;  albuminate  of  soda,  "OS;  lactates  of  po- 
tassa  and  soda,  '07;  sulphocyanide  of  potassium,  •09;  soda,  '05;  mucus 
with  ptjalin,  2"6.  It  has  also  been  carefully  analyzed  by  Enderlin,^ 
who  concludes  that,  like  the  blood,  it  contains  no  lactate,  carbonate, 
or  acetate;  but  its  alkaline  reaction  is  owing  to  the  tribasic  phosphate 
of  soda,  which  serves  also  as  a  solvent  of  the  mucus  and  protein  com- 
pounds. The  analysis  of  the  ashes  obtained  from  a  very  large  quan- 
tity afforded,  in  100  parts : — 

Tribasic  phosphate  of  soda,     .         .         .         .    '     .         .         .  28*122 

Chlorides  of  sodium  and  potassium,        .....  61*93 

Siilphate  of  soda,    .........  2*315 

Phosphate  of  lime,  "j 

"  magnesia,  >■        ......         .  5*509 

"  iron,  J 

Still  more  recently,  human  saliva  has  been  analyzed  by  Jacubowitsch'^ 
and  found  to  be  composed  as  follows : — 

Water, 999*16 

Fixed  residue,    ..........  4*84 

Epithelium,        ..........  1*62 

Organic  matters,         .........  1*34 

Sulphocyanide  of  potassium,      .......  0*06 

Salts, 1*82 

The  salts  consisted  of  phosphate  of  soda,  0"91:;  lime,  0"03;  magnesia, 
O'Ol;  chlorides  of  potassium  and  sodium,  0*81.^ 

M.  Lassaignc^  examined  the  secretion  from  the  parotid  gland;  and 
that  from  the  submaxillary  of  the  same  animal.  Both  were  transparent 
fluids,  and  possessed  a  slight  alkaline  reaction.  That  of  the  submax- 
illary was  more  viscid,  and  similar  to  mucus  in  consistence.  The  fol- 
lowing was  the  quantitative  analysis  of  the  two.  That  of  the  parotid 
of  the  cow  contained  water,  990*74;  mucus  and  soluble  organic 
matters,  0*1:4;  alkaline  carbonates,  3'38 ;  alkaline  chlorides,  2'S5 ; 
alkaline  phosphates,  2"49;  phosphate  of  lime,  0*10.  That  of  the  sub- 
maxillary contained  water,  991'14;  mucus,  1"73;  soluble  animal  mat- 
ters, 1'80;  alkaline  carbonates,  0*10;  alkaline  chlorides,  5*02;  alkaline 
phosphate,  O'lo;  phosphate  of  lime,  O'OB.* 

Messrs,  Tiedemann  and  Gmelin,  and  M,  Donne,"  found  the  saliva 
invariably  alkaline,  when  the  functions  of  the  stomach  were  well 
executed.  The  last  gentleman  considered  acidity  of  the  saliva  a 
diagnostic  symptom  of  gastritis;  and  Dr,  Eobt.  Thomson^  observed 
the  acid  reaction  in  all  cases  of  inflammation  of  the  mucous  and  serous 

'  Annalen  der  Chemie  und  Pharmacie,  Marz.,  1844. 

2  De  Saliva,  Dissert,  inaugur,  Med.  Univers.  Dorpatens.  ;  cited  by  Scherer,  in  Can- 
statt  and  Eisenmaun's  .Jahresbericlit  iiber  die  Forstchritte  der  Biologie  im  Jahre  1848, 
Erlang.,  1849, 

^  Gr,  Owen  Rees,  Art,  Saliva,  in  Cyclop,  of  Anat.  and  Physiol.,  iv,  415,  Lond,,  1852. 

'•  Journal  de  Chimie  Medicale,  p.  393 ;  and  Scherer,  in  Canstatt's  Jahresbericht,  S. 
106,  1852, 

^  See  on  the  whole  subject  of  the  Saliva,  Bidder  &  Schmidt,  Die  Verdauungssafte 
u.  s.  w,  S,  1,  Mitau  und  Leipzic,  1852. 

**  Archives  Ui  uerales,  Mai  &  Juin,  1835  ;  and  Histoire  Physiologique  et  Pathologique 
de  la  Salive,  Paris,  1836. 

'  Ilecords  of  General  Science,  Dec,  1836. 


524  SECRETION 

membranes.  With  the  view  of  testing  these  points,  Mr.  Laycock* 
instituted  numerous  experiments,  and  tabulated  the  results  of  no  less 
than  567  observations.  His  deductions  do  not  accord  with  those  of 
M.  Donne.  They  are  as  follows : — 1.  The  saliva  may  be  acid  witliout 
apparent  disease  of  the  stomach,  and  when  the  person  is  in  good  health. 
2.  It  is  alkaline  during  difl'erent  degrees  of  gastric  derangement,  as 
indicated  by  the  tongue.  3.  It  may  be  alkaline,  acid  and  neutral, 
when  the  gastric  phenomena  are  the  same;  and,  consequently,  acidity 
of  the  saliva  is  not  a  diagnostic  mark  of  gastric  derangement ;  and, 
lastly,  in  general  it  is  alkaline  in  the  morning,  and  acid  in  the  evening. 
In  a  more  recent  work  M.  Donne^  accounts  for  the  varying  testimony 
of  different  observers  in  regard  to  the  chemical  reaction  of  the  saliva, 
by  the  greater  or  less  proportion  of  the  mucus  of  the  mouth  contained 
in  the  specimens  subjected  to  examination.  In  the  normal  state,  he 
affirms,  it  is  alkaline;  but  the  mucus  secreted  by  the  mucous  mem- 
brane of  the  mouth  being  acid,  the  mixed  fluid,  to  which  the  name 
saliva  is  given,  must  necessarily  vary  according  to  the  proportion  of 
each. 

When  saliva  is  examined  by  the  microscope,  it  presents,  besides  a 
considerable  number  of  lamelhe  of  epithelium,  globules  in  variable 
quantity,  which,  according  to  M.  Mandl,^  proceed  partly  from  the  mu- 
ciparous glands  of  the  mouth,  and  partly  from  the  salivary  glands. 
They  cannot,  however,  be  distinguished  from  each  other. 

As  the  salivary  secretion  forms  a  part  in  the  processes  preparatory 
to  stomachal  digestion,  its  uses  have  been  detailed  in  the  first  volume 
of  this  work,  to  which  the  reader  is  referred.  The  view  of  MM.  Ber- 
nard and  Barreswil,  and  of  Mialhe,  that  the  saliva  contains  an  active 
principle,  analogous  in  its  physical  and  chemical  characters  to  diastase, 
as  well  as* its  action  on  amylaceous  substances,  is  there  described. 

A  soft,  whitish  or  yellowish  matter,  of  greater  or  less  thickness,  is 
constantly  deposited  on  the  teeth,  which,  unless  attention  is  paid,  ac- 
cumulates, and  sometimes  adheres  to  them  with  great  force,  constitut- 
ing hard  and  dry  concretions,  known — as  already  remarked — under 
the  name  of  tartar  or  tartar  of  the  teeth.  Different  views  have  existed 
in  regard  to  its  origin.  Some  have  supposed  it  to  be  a  secretion,  others 
a  deposition  from  the  saliva,  which  is  the  most  probable  opinion ;  and 
others  that  it  is  an  exhalation  from  the  capillary  vessels,  to  which  the 
mucous  membi'ane  of  diseased  gums  is  liable.  It  has  been  affirmed 
by  ]\r.  Mandl**  to  be  a  collection  of  calcareous  skeletons  of  infusoria, 
agglutinated  by  means  of  dried  mucus. 

4.  Secretion  of  the  Pancreas. 

The  -pancreas  or  sweetbread,  (Fig-  1^5,  A,  t,  ?',)  secretes  a  juice  or  hu- 
mour called  succus  j^ci^^creaticus,  2)ancreatic  juice.  Its  texture  resembles 
that  of  the  salivary  glands ;  and  hence  it  has  been  called  by  some  the 
abdominal  salivary  gland.     It  is  situate  transversel}' in  the  abdomen; 

'  Lond.  Med.  Gazette,  Oct.  7,  1S37.  See,  for  a  detailed  account  of  tlie  saliva,  Dr.  S. 
Wright,  op.  cit. 

2  Cours  de  Microscopie,  p.  208,  Paris,  1844. 

^  Manuel  d'Anatomie  Generale,  p.  488,  Paris,  1843. 

*  Gazette  des  Hopitaux,  8  Aoiit,  1843,  p.  3tJ3. 


OF   THE   PANCREAS. 


525 


behind  tlie  stomach  ;  towards  the  concavit}^  of  the  duodenum ;  is  about 
six  inches  in  length,  and  between  three  and  four  ounces  in  weight. 
From  the  results  of 


SIX  examinations, 
Dr.  Gross'  gives  the 
following  as  its  mean 
weight  and  dimen- 
sions : — Weight  2|- 
ounces;  length,  7 
inches;  breadth  at 
the  body  and  splenic 
extremity,  16 J  lines; 
breadth  at  the  neck, 
12  lines;  at  the  head, 
2  inches  and  8  lines; 
thickness  at  the 
body,  neck,  and 
splenic  extremity,  4 
lines ;  thickness  at 
the  head,  8  lines. 
M.  Becourt  found 
the  average  length 


Fig.  155. 


In  this  figure,  which  is  altered  from  Tiedemann, the  Liver  and 
Stomach  are  turned  up  to  show  the  Duodenum,  the  Pancreas, 
and  the  Spleen. 

I.  The  under  surface  of  the  liver,     .cr.  Gall-bladder.    /.  The  common 


f\P  tliir+tT-  fnr/-v  +rk  \^a  ^^le-duct,  formed  by  the  union  of  a  duct  from  the  gall-bladder,  called 
Ol  iniliy-lWO  lO  Oe  the  cystic  duct,  and  of  the  hepatic  duct  coming  from  the  liver,  o.  The 
cardiac  end  of  the  stomach,  where  the  oesophagus  enters,  s.  Under 
surface  of  the  stomach,  p.  Pyloric  end  of  stomach,  d.  DuDdenum. 
h.  Head  of  pancreas  ;  (,  tail ;  and  i,  body  of  that  gland.  The  sub.stance 
of  the  pancreas  is  removed  in  front,  to  show  the  pancreatic  duct  (e)  and 
its  branches,  r.  The  spleen,  v.  The  hilus,  at  which  the  bloodvessels 
enter.  c.  Crura  of  diaphragm.  71.  Superior  mesenteric  artery,  a. 
Aorta. 


8  inches;  and  the 
weight  between  3 
and  4  ounces.^  It 
is  of  a  reddish-white 
colour,  and  firm  con- 
sistence. Its  excretory  ducts  terminate  in  one, — called  duct  of  Wir- 
sung, — which  opens  into  the  duodenum,  at  times  separately  from  the 
ductus  communis  choledochus,  but  close  to  it;  at  others,  confounded 
with,  or  opening  into,  it.^  In  the  rabbit  it  opens  several  inches — 35 
centimetres — below  it.  According  to  M.  Beraud-*  there  are  at  all 
times  two  pancreatic  ducts — the  larger  that  already  mentioned;  the 
smaller  proceeding  from  the  summit  of  the  head  of  the  gland,  and 
opening  into  the  duodenum  above  the  choledoch  duct  in  man.  This 
fact — he  says — has  been  demonstrated  by  his  own  researches,  as  well 
as  by  those  of  M.Bernard,  and  is  seen  in  the  preparations  in  the 
museum  of  the  ^'•Ecole  de  Iledecine,^^  made  by  MM.  Verneuil,  Boulard, 
Fano  and  himself. 

The  amount  of  fluid  secreted  by  the  pancreas  does  not  seem  to  be 
considerable.  M.  Magendie,  in  his  experiments,  was  struck  with  the 
small  quantity  discharged.  Frequently,  scarcely  a  drop  issued  in  half 
an  hour;  and,  occasionally,  a  much  longer  time  elapsed.  Nor  did  he 
find  that  the  flow,  according  to  common  opinion,  and  to  probability, 
was  more  rapid  whilst  digestion  was  going  on.     It  will  be  readily 

*  Elements  of  Pathological  Anatomy,  ii.  357,  Boston,  1839. 

*  Recherches  sur  le  Pancroas,  ses   Fonctions  et  ses  Alterations  Organiques,  Tliese 
Strasbourg,  1830,  cited  by  Mondiere,  Archives  (K'norales  de  Medecine,  Mai,  1836. 

*  Magendie,  Precis  Jib  mentaire,  i.  462;  and  .J.  P.  Mondiere,  op.  cit. 

*  Manuel  de  Physiologie  de  rHomrae,  p.  173,  Paris,  1853. 


526  SECRETION 

understood,  therefore,  that  it  cannot  be  an  easy  task  to  collect  it.  De 
Graaf^  affirms,  that  he  succeeded,  by  introducing  into  the  intestinal 
end  of  the  excretory  duct  a  small  quill,  terminating  in  a  phial  fixed 
under  the  belly  of  the  animal.  M.  Magendie^  states,  that  he  tried  this 
plan  several  times,  but  without  success;  and  he  believes  it  to  be  im- 
practicable. The  plan  he  adopts  is  to  expose  the  intestinal  orifice  of 
the  duct;  to  wipe  the  surrounding  mucous  membrane  with  a  fine  cloth, 
and  as  soon  as  a  drop  of  the  fluid  oozes  to  suck  it  up  by  means  of  a 
"pipette  or  small  glass  tube.  In  this  way,  he  collected  a  few  drops,  but 
never  sufficient  to  undertake  a  satisfactory  analysis.  Messrs.  Tiede- 
mann  and  Gmelin^  made  an  incision  into  the  abdomen;  drew  out  the 
duodenum,  and  a  part  of  the  pancreas;  and,  opening  the  excretory  duct, 
inserted  a  tube  into  it;  and  a  similar  plan  was  adopted  successfully 
on  a  horse  by  MM.  Leuret  and  Lassaigne.''  M.  Bernard's  plan  is  to 
make  an  incision  into  the  right  hypochondrium,  draw  out  the  duode- 
num with  a  part  of  the  pancreas,  pass  a  double  ligature  around  the 
duct,  and  fix  into  it  a  silver  tube,  the  extremity  of  which,  outside  the 
abdomen,  is  attached  to  a  small  India-rubber  bag,  into  which  the  fluid 
flows  in  large  pearl-shaped  drops.-' 

The  difficulty  experienced  in  collecting  any  quantity  is  a  probable 
cause  of  some  of  the  discrepancy  amongst  observers,  regarding  its  sen- 
sible and  chemical  properties.  Certain  of  the  older  physiologists  affirm 
that  it  is  acidulous  and  saline;  others,  that  it  is  alkaline.**  The  majority 
of  those  of  the  present  day  compare  it  with  saliva,  and  affirm  it  to  be 
inodorous,  insipid,  viscid,  limpid,  and  of  a  bluish  white  colour.  The 
latest  experimenters  by  no  means  agree  with  each  other.  According 
to  ]\L  Magendie,  it  is  of  a  slightly  yellowish  hue,  saline  taste,  devoid  of 
smell,  occasionally  alkaline,  and  partly  coagulable  by  heat.  MM. 
Leuret  and  Lassaigne  found  that  of  the  horse — of  which  they  obtained 
three  ounces, — to  be  alkaline,  and  composed  of  991  parts  of  water  in 
1000;  an  animal  matter,  soluble  in  alcohol;  another,  soluble  in  water; 
traces  of  albumen  and  mucus;  free  soda;  chloride  of  sodium;  chloride 
of  potassium;  and  phosphate  of  lime.  In  their  view,  consequently,  the 
pancreatic  juice  strongly  resembles  saliva.  Messrs.  Tiedemann  and 
Gmelin  succeeded  in  obtaining  upwards  of  two  drachms  of  the  juice 
in  four  hours;  and,  in  100  parts,  found  from  five  to  eight  of  solid  parts. 
These  consisted  of  osmazome;  a  matter  which  became  red  by  chlorine; 
another  analogous  to  casein,  and  probably  associated  with  salivary 
matter ;  much  albumen ;  a  little  free  acid,  probably  acetic ;  acetate, 
phosphate,  and  sulphate  of  soda,  with  a  little  potassa;  chloride  of  potas- 
sium, and  carbonate  and  phosphate  of  lime; — so  that,  according  to  these 
gentlemen,  the  pancreatic  juice  differs  from  saliva  in  containing  a 
little  free  acid,  whilst  saliva  is  alkaline;  much  albumen,  and  matter 
resembling  casein ;  but  little  mucus  and  salivary  matter,  and  no  sulpho- 
cyanate  of  potassa.     In  an  examination  by  M.  Bloudlot'  of  three  or 

'  Tract,  de  Pancreat.,  Ludg.  Bat.,  17(31;  and  Haller,  Elem.  PlijsioL,  lib.  xxii.  sect. 
S.  Bern.,  17<J4. 

*  Precis,  iic,  ii.  462.  '  Recherclies,  kc,  i.  41.  ■•  Ibid.,  p.  49. 

*  Beraud,  op.  cit.,  p.  173,  Paris,  1853. 

^  Haller,  op.  cit.  ;  and  Seller,  art.  Pancreas,  Pierer's  Anat.  Physiol.  Real  Worterb., 
Band  vi.  100,  Altenb.,  1825. 

^  Traite  Analytique  de  la  Digestion,  p.  124,  Paris,  1844. 


OF   THE   LIVEE.  527 

four  grammes  of  fluid,  obtained  from  the  duct  of  a  large  dog,  lie  found 
no  evidences  of  albumen,  when  he  passed  an  electric  current  through 
it.     lie,  also,  holds  it  to  be  of  the  same  nature  as  saliva. 

The  following  is  the  result  of  a  recent  analysis :  water,  94:*28 ;  pan- 
creatin, — a  matter  coagulable  by  heat  ;^  mucus ;  carbonate  of  soda ; 
chlorides  of  sodium  and  potassium;  and  phosphate  of  lime,  8*72;  total, 
lOO'OO.  The  pancreatin  gives  to  the  pancreatic  secretion  its  special 
properties.^ 

The  precise  use  of  the  pancreatic  juice  in  digestion — as  we  have 
previously  seen — is  not  determined,  Brunner^  removed  almost  the 
whole  pancreas  from  dogs,  and  tied  and  cut  away  portions  of  the  duct ; 
yet  they  lived  apparently  as  well  as  ever.  The  secretion,  therefore, 
cannot  be  indispensable.  Its  main  uses  seem  to  be  to  favour  the  ab- 
sorption of  oleaginous  matters. 

5.  Secretion  of  the  Liver. 

The  biliary  secretion  is,  also,  a  digestive  fluid,  and  has  been  treated 
of  in  the  appropriate  place.  The  mode,  liowever,  in  which  the  process 
is  efi'ected,  has  not  yet  been  investigated.  The  apparatus  consists  of 
the  liver^  which  accomplishes  the  formation  of  the  fluid  ;  the  hepatic 
duct — the  excretory  channel,  by  which  the  bile  is  discharged;  the  gall- 
bladder^  in  which  a  portion  of  the  bile  is  retained  for  a  time;  the  cystic 
duct — the  excretory  channel  of  the  gall-bladder  ;  and  the  ductus  com- 
munis choledochus  or  choledoch  duct,  formed  by  the  union  of  the  hepatic 
and  cystic  ducts,  which  conveys  the  bile  immediately  into  the  duo- 
denum. 

The  Uver  is  the  largest  gland  in  the  body ;  situate  in  the  abdomen 
beneath  the  diaphragm,  above  the  stomach,  the  arch  of  the  colon,  and 
the  duodenum;  filling  the  whole  of  the  right  hypochondrium,  and  more 
or  less  of  the  epigastrium,  and  fixed  in  its  situation  by  duplicatures  of 
the  peritoneum,  called  ligaments  of  the  liver.  The  weight  of  the  human 
organ  is  generally,  in  the  adult,  about  three  or  four  pounds.  Some 
make  the  average  about  five  pounds;  but  this  is  a  large  estimate.  Of 
60  male  livers  weighed,  Dr.  John  Reid''  found  the  average  weight  to 
be  52  oz,  12^  dr.;  and  of  25  female,  45  oz.  3 J  dr.  In  disease,  how- 
ever, it  sometimes  weighs  twenty  or  twenty-five  pounds;  and,  at  other 
times,  not  as  many  ounces.  Its  shape  is  irregular,  and  it  is  divided 
into  three  chief  lobes,  the  rigid,  left,  and  lobulus  Spigelii.  Its  upper 
convex  surface  every  where  touches  the  arch  of  the  diaphragm.  The 
lower  concave  surface  corresponds  to  the  stomach,  colon,  and  right 
kidney.  On  the  latter  surface,  two  fissures  are  observable, — the  one 
passing  from  before  to  behind,  and  lodging  the  umbilical  vein  in  the 
foetus — called  horizontal  sulcus  or  fissure,  great  fissure  or  fossa  umhilica- 
lis ;  the  other  cutting  the  last  at  right  angles,  and  running  from  right 
to  left,  by  which  difl'erent  nerves  and  vessels  proceed  to  and  from  the 
liver,  and  coWQd.  principal  fissure,  or  sulcus  transversus. 

'  Beraud,  op.  cit.,  p.  179. 

2  Robin  et  Verdeil,  Traite  de  Chimie  Anatomique,  &c.,  iii.  345,  Paris,  1S53. 

*  Experimentanova  circa  Pancreas,  Amstel.,  1683  ;  and  J.  T.  Mondiere,  op.  cit. 

*  Lond.  and  Edinb.  Monthly  Journ.  of  Med.  Science,  April,  1843,  p.  323. 


528  SEGRETIOX 

The  liver  itself  is  composed  of  the  following  anatomical  elements: 
1.  The  hepatic  artery^  a  branch  of  the  coeliac,  which  ramifies  minutely 
through  the  substance  of  the  organ.  The  minuter  branches  of  this 
vessel  are  arranged  somewhat  like  the  hairs  in  a  painter's  brush,  and 
have  hence  been  called  p)^nicilli  of  the  liver.  Mr.  Kiernan^  believes, 
that  the  blood,  which  enters  the  liver  by  the  hepatic  artery,  fulfils  three 
functions: — it  nourishes  the  organ;  supplies  the  excretory  ducts  with 
mucus;  and,  having  fulfilled  these  objects,  becomes  venous;  enters  the 
branches  of  the  portal  veins,  and  not  the  radicles  of  the  hepatic,  as 
usually  supposed,  and  as  still  maintained  by  J.  Miiller  and  others;  and 
contributes  to  the  secretion  of  bile.  2.  The  vena  porta,  which,  we  have 
elsewhere  seen,  is  the  common  trunk  of  the  veins  of  the  digestive 
organs  and  spleen.  It  divides  like  an  artery,  its  branches  accompanying 
those  of  the  hepatic  artery.  Where  it  lies  in  the  transverse  fissure,  it 
is  of  great  size,  and  has  hence  been  called  sinus  vence  portce. 

The  possession  of  two  vascular  systems,  containing  blood,  is  peculiar, 
perhaps,  to  the  liver,  and  has  been  the  cause  of  difi:erence  of  opinion, 
with  regard  to  the  precise  fluid — arterial  or  venous — from  which  the 
bile  is  derived.  According  to  Mr.  Kiernan,  the  portal  vein  fulfils  two 
functions:  it  carries  the  blood  from  the  hepatic  artery,  and  the  mixed 
blood  to  the  coats  of  the  excretory  ducts.  It  has  been  called  vena  arte- 
riosa,  because  it  ramifies  like  an  artery,  and  conveys  blood  for  secretion: 
but,  as  Mr.  Kiernan  has  observed,  it  is  an  arterial  vein,  in  another  sense, 
as  it  is  a  vein  to  the  hepatic  artery,  and  an  artery  to  the  hepatic  vein. 
3.  The  excretory  ducts  or  biliary  ducts.  These  are  presumed  to  arise 
from  acini,  communicating,  according  to  some,  with  the  extremities  of 
the  vena  porta;  according  to  others,  with  radicles  of  the  hepatic  artery; 
whilst  others  have  considered,  that  the  radicles  of  the  hepatic  ducts 
have  blind  extremities,  and  that  the  capillary  bloodvessels,  which  secrete 
the  bile,  ramify  on  them.  This  last  arrangement  of  the  biliary  appa- 
ratus was  well  shown  in  an  interesting  case,  which  fell  under  the  care 
of  Professor  Hall,  in  the  Baltimore  Infirmary,  and  was  examined  after 
death  in  the  author's  presence.  The  particulars  have  been  detailed, 
with  some  interesting  remarks,  by  Professor  Geddings.^  In  this  case, 
in  consequence  of  cancerous  matter  obstructing  the  ductus  communis 
choledochus,  the  whole  excretory  apparatus  of  the  liver  was  enor- 
mously distended ;  the  common  duct  was  dilated  to  the  size  of  the 
middle  finger:  at  the  point  where  the  two  branches  that  form  the  hepa- 
tic duct  emerge  from  the  gland,  they  were  large  enough  to  receive  the 
tip  of  the  middle  finger ;  and  as  they  were  proportionally  dilated  to 
their  radicles  in  the  intimate  tissue  of  the  liver,  their  termination  in  a 
blind  extremity  was  clearly  exhibited.  These  blind  extremities  were 
closely  clustered  together,  and  the  ducts,  proceeding  from  them,  were 
seen  to  converge,  and  terminate  in  the  main  trunk  for  the  correspond- 
ing lobe.  At  their  commencement,  the  excretory  ducts  are  termed  pori 
hiliarii.  These  ultimately  form  two  or  three  large  trunks,  which  issue 
from  the  liver  by  the  transverse  fissure,  and  end  in  the  hepatic  duct.  4. 
Lymphatic  vessels.    5,  Nerves,  in  small  number,  o?mpared  with  the  size 

'  Philosophical  Transactions  for  1<S33,  p.  711. 

2  North  American  Arcliives  of  Medical  and  Surgical  Science,  for  June,  1835,  p.  157. 


OF   THE   LIVER. 


529 


Fig.  156. 


m^ 


of  the  organ,  some  proceeding  from  the  eighth  pair;  but  the  majority 
from  the  solar  plexus,  which  follow  the  course  and  divisions  of  the 
hepatic  artery.  6.  Supra-hepatic  veins  or  vence  cavce  hepaiicce^  which 
arise  in  the  liver  by  imperceptible  radicles,  communicating,  according 
to  common  belief,  with  the  final  ramifications  of  both  the  hepatic  artery 
and  vena  portje;  according  to  Mr.  Kiernan  occupying  the  centre  of  the 
lobules,  and  hence  termed  iniralohnlar  veins — venuUe  intralohulares  seu 
centrales.  They  return  the  superfluous  blood,  carried  to  the  liver  by 
these  vessels,  by  means  of  two  or  three  trunks,  and  six  or  seven 
branches,  which  open  into  the  vena  cava  inferior.  These  veins  gene- 
rally pass,  in  a  convergent  manner,  towards  the  posterior  margin  of  the 
liver,  and  cross  the  divisions  of  the  vena  portse  at  right  angles.  7.  The 
remains  of  the  umbilical  vein,  wdiich,  in  the  foetus,  enters  at  the  hori- 
zontal fissure.  This  vein,  after  respiration  is  established,  becomes  con- 
verted into  a  ligamentous  substance,  called,  from  its  shape,  ligamentuin 
rotiindnm  or  round  ligament.  It  is  difficult  to  describe  the  parenchyma 
or  substance  formed  by  these  anatomical  elements;  and  although  the 
term  liver-coloured  is  used  in  common  parlance,  it  is  not  easy  to  say 
what  are  the  ideas  attached  to  it. 

The  views  of  Mr.  Kiernan  in  regard  to  the  intimate  structure  of  the 
liver,  which  have  been  embraced  by  so 
many  anatomists,  may  be  understood  by 
the  accompanying  illustrations,  taken 
from  his  communications  on  the  sub- 
ject. The  acini,  to  which  allusion  has 
been  made,  are  termed  by  him  lohules. 
Fig.  156,  1,  exhibits  some  of  the  cells 
of  which  the  lobules  are  composed,  seen 
under  a  magnifying  power  of  200  dia- 
meters. 2,  represents  a  longitudinal  section  of  a  lobule  with  ramifi- 
cations of  the  hepatic  vein:  and  Fig.  157,  the  connexion  of  the  lobules 
with  the  same  vein ; — the  centre  of  each 
being  occupied  by  a  venous  twig — or 
intralobular  vein.  Fig.  158  represents 
the  lobules  as  seen  on  the  surface  of  the 
liver  when  divided  transversely.  In 
this,  2,  exhibits  the  interlobular  spaces; 
3,  interlobular  fissures;  4,  intralobular 
veins  occupying  the  centres  of  the  lo- 
bules; and  5,  smaller  veins  terminating 
in  the  central  veins.  Fig.  159  is  a  simi- 
lar section  of  three  lobules,  showing  the 
arrangement  of  the  two  principal  sys- 
tems of  bloodvessels;  1,  1,  intralobular 
veins;  and  2,  2,  interlobular  plexus 
formed  by  branches  of  the  vena  porta.  Fig.  160  represents  a  horizontal 
section  of  two  superficial  lobules,  showing  the  interlobular  plexus  of 
hiliary  ducts:  1,  1,  intralobular  veins;  2,  2,  trunks  of  biliary  ducts,  pro- 
ceeding from  the  plexus  which  traverses  the  lobules ;  8,  interlobular 
tissue;  and  4,  parenchyma  of  the  lobules.  The  interlobular  biliary 
ducts  ramify  upon  the  capsular  surface  of  the  lobules;  and  then  enter 
VOL.  I. — 34 


Lobules  of  Liver. 


Fig.  157. 


Connexion  of  Lobules  of  Liver  with  He- 
patic Vein. 

1.  Hepatic  vein.    2,  2,  2.  Lobules,  each  con- 
taining an  intralobular  or  hepatic  twig. 


)30 


SECRETION 


their  substance  and  are  supposed  to  subdivirle  into  minute  branches, 
"which  by  anastomoses  with  each  other  form  the  reticulated  plexus  de- 
picted in  Fig.  160,  called  by  Mr.  Kiernan  the  lobular  biliary  plexus. 


Fi!?.  158. 


Fig.  159. 


Transverse  Section  of  Lobules  of  the  Liver. 


Horizontal  Section  of  three  Superficial  Loliules, 
showing  the  two  principal  Systems  of  Blood- 
vessels. 


"iJ«i..''5*v;^H>v>^ 


•,^',«v^ 


■!■■ 


'Mb 


It  is  from  this  arrangement  of  the  bloodvessels  and  biliary  ducts, 
that  Mr.  Kiernan  infers  that  bile  must  be  secreted  from  the  portal 
vessels; — the  intralobular  ramifications  of  the  hepatic  veins  conveying 
back  to  the  heart  the  blood  which  has  been  inservient  to  the  secretion. 

The  views  of  Mr.  Kiernan  have 
Fig.  160.  been  generally  adopted  by  ana- 

.^2  2       ..  tomists.      Wagner,      however, 

whilst  he  resjards  the  beautiful 
figures  and  descriptions  of  Mr. 
Kiernan  as  the  best  he  has  seen, 
asserts,  that  they  very  certainly 
also  include  many  mistakes; 
Avhilst  Krause  "combats  the 
views  of  Kiernan.  holding  them 
to  be  hypothetical;'''  and  E.  H. 
Weber-^and  Krukenberg  oppose 
them.  The  chief  point,  accord- 
ing to  Mr.  Paget,  in  which  these 
gentlemen  difter  from  Mr. 
Kiernan,  is  in  denying  that  the  component  parts  of  the  liver  are  ar- 
ranged in  lobules.  They,  with  Henle  and  Mr.  Bowman,  describe  the 
capillary  networks  as  solid, — that  is  as  extending  uniformly  through 
the  liver.  They,  also,  deny  the  existence  of  fibro-cellular  partitions 
dividing  the  liver  into  lobules  as  maintained  by  Mr.  Kiernan  and  J. 
Miiller;^  and  even  the  existence  of  more  fibro-areolar  tissue  than  serves 
to  invest  the  larger  vessels,  &c.,  of  the  organ.     They  likewise  deny 

'  Wagner,  Elements  of  Phvsioloev,  by  R.  Willis,  §  195,  Loud.,  1842. 
2  Miiller's  Arcliiv.,  1844,  Heft  3  and  4.  =»  Ibid. 


.j^^ 


Horizontal    Section    of    two    Superficial    Lobules, 
showing  Interlobular  Plexus  of  Biliary  Ducts. 


OF   THE   LIVER. 


531 


that  there  are  an}^  such  interlobuLar  veins  and  fissures  as  Mr.  Kiernan 
describes,  and  state,  that  the  smaller  branches  of  these  veins  commu- 
nicate by  branches  only  just  larger,  if  at  all  larger,  than  capillaries.' 


Fig.  161. 


Fig.  162. 


.<^^ 


\j:j: 


A  small  portion  of  a  Lobulo  highly  magnified. 

The  secreting  cells  are  seen  witbin  the  tubes,  and  in 
the  interspaces  of  the  latter  the  fibrous  tissue  is  repre- 
sented. 


Portion  of  a  Biliar}'  Tube,  from    a  fresh 
Human  Liver,  very  highly  magnified. 
The  secreting  cells  may  be  noticed  to  he 

polygonal  from  mutual  pressure. 


Histologically  considered,  the  liver  may  be  regarded  as  consisting 
^  of    ramifications    of    excretory 


Fig.  163. 


ducts,  surrounded  by  bloodves- 
sels, which  aftbrd  the  materials 
for  secretion, — and  of  cells  which 
elaborate  it,  but  as  respects  the 
precise  arrangement  of  the  cells 


Fig.  164. 


■^^^  -i 


Transverse  section  of  a  Lobule  of  the  Human 
Liver, 

Showing  the  reticular  arrangomont  of  its  parenchy- 
ma, with  some  of  the  branches  of  the  hepatic  vein  in 
the  centre,  and  those  of  the  portal  vein  at  the  peri- 
pliery. 


Hepatic  Cells  gorged  with  Fat. 
a.  Atrophied  nucleus,    b.  Adipose  globules. 


anatomists  are  not  wholly  in  ac- 
cordance. Dr.  Leidy^  affirms, 
that  they  line  the  inner  surface 
of  the  tubuli  that  form  the  biliary 
plexus  of  Kiernan  ;  that  they  are 
irregularly  angular  or  of  a  poly- 
gonal shape,  owing  to  their  pressing  upon  each  other ;  and  contain  a 
fine  granular  matter,  oil  giotjules,  a  granular  nucleus  and  transparent 
nucleolus, — the  oil  globules,  under  special  circumstances  of  diet  and 

'  See,  on  all  this  subject,  Professor  Tlieile,  art.  Leber,  Wagner's  ILindworterbuch 
der  Fhysiologie,  9te  Lieferung,  S.  308,  Braunschweig,  1845. 

^  American  Journal  of  tlie  Medical  Sciences,  p.  1,  Jan.,  184S  ;  and  Quain's  edition  of 
Quain  and  Sharpey's  Human  Anatomy,  ii.  487,  Philad.,  1849. 


582 


SECRETION" 


disease,  experiencins;  considerable  increase.     Dr.  C.  Hand  field  Joues^ 
lias,  however,  maintained,  that  the  raiiiitications  of  the  hepatic  ducts 


Fi£T.  165. 


i%k»tu 


Minute  Portal  and  Hepatic  Veins  and  Capillaries. 
a,  a.  Twigs  of  the  portal  vein.    d.  Twig  of  the  hepatic  vein.     b.  latermediate  capillaries. 


Fig.  166. 


Diagram  of  the  arrangement  of  the  cellular  parenchyma, 
5,  6,  of  the  human  liver,  with  reference  to  tlie  radicle.s  of 
the  interlobular  ducts,  <i,  a,  and  the  vascular  .spaces,  t',  c. 


do  not  enter  the  lobules  as 
affirmed  by  Mr.  Kiernan,  but 
are  confined  to  the  interlo- 
bular spaces, — the  substance 
of  the  lobules  being  composed 
of  secreting  parenchyma  and 
bloodvessels ;  and  that  the  ac- 
tion of  the  liver  seems  to  con- 
sist in  the  transmission  of  the 
bile,  as  it  is  formed,  from  cell 
to  cell,  until  it  arrives  in  the 
neighbourhood  of  the  excre- 
tory ducts  by  which  it  is  ab- 
sorbed.^ 

A  similar  view  is  embraced 
by  Kulliker,^  and  in  the  last 
edition  of  his  work  Dr.  Car- 
penter'' states,  that  whilst  in 


'  Philopopliical  Transactions,  Pt.  i.,  for  1849.     See,  also,  Ibid.,  for  1846  and  18r)3. 

*  C.  L.  J.  Backer,  De  Structura  tiuhtiliori  Hepatis  Sani  et  Morbosi,  p.  19,  Traiect.  ad 
Rhemm.,  1845. 

^  Jlikroskopiscbe  Anatomie,  ii.   221,  Leipzie,   1852 ;  and  Anier.  translation  of  his 
Human  Histology,  by  Dr.  Da  Costa,  p.  535,  I'liilad.,  1854. 

*  Principles  of  Human  Physiology,  p.  372,  note,  Philad.,  1855. 


OF   THE    LIVER. 


533 


former  editions  he  had  embraced  the  view  of  the  histology  of  the  liver 
laid  down  by  Retzius,  Leidy,  and  others,  farther  inquiry  had  satisfied 
him  that  "the  view  of  the  compound  nature  of  the  hepatic  structure, 
which  Dr.  C.  Handheld  Jones  was  the  first  to  propound,  and  which  har- 
monizes with  Prof.  Kollilver's  account  of  its  structure  is  really  the  cor- 
rect one:" — "this  view,"  he  adds,  "being  strikingly  confirmed  and 
illustrated  by  the  parallel  order  of  anatomical  and  physiological  facts 
presented  by  the  vascular  glands.'" 

Perhaps  the  best  mode,  according  to  Dr.  Budd,^  to  get  a  general 
idea  of  the  structure  of  the  liver  is  to  examine  under  the  microscope, 
— first^  a  thin  slice  of  liver,  in  which  the  portal  and  hepatic  veins 
are  thoroughly  injected;  and  secondly^ — a  small  particle  taken  from 
the  lobular  substance  of  a  fresh  liver,  in  which  the  bloodvessels  are 
empty,  as  in  an  animal  killed  by  bleeding.  Figure  165,  from  a  speci- 
men by  Mr.  Bowman,  represents,  on  a  magnified  scale,  a  small  branch 


Lobules  of  the  Liver  magnified. 

n,  n,  n.  Minute  twig's  of  tlift  portal  vein,  h,  b,  h.  Capillaries  imme<liately  springing  from  tliein,  and 
serving  vritli  them  to  mark  the  outline  of  the  lobules,  d,  d,  d.  Capillaries  in  the  centre  of  the  lobules,  in- 
jected through  the  hepatic  vein.  e.  e.  Places  at  which  the  size  injected  into  the  portal  vein  has  met  that 
injected  into  the  hepatic  vein,  so  that  all  tlie  intermediate  capillaries  are  coloured  and  conspicuous.  I,  I. 
Centres  of  lobules  info  whloU  the  injection  has  not  passed  through  the  hepatic  vein. 

of  the  hepatic  vein,  two  or  three  branches  of  the  portal  vein,  and  the 
intermediate  capillaries.     The  capillaries  appear  to  have  nearly  the 

'  For  recent  views  of  the  liistology  of  tlie  liver  differing  from  those  of  Kiilliker  and 
C.  Handfield  Jones,  see  Proceedings  of  the  Royal  Society,  June,  1855  ;  and  Brit,  and  For. 
Med.-Chir.  Rev.,  Oct.,  1855,  p.  528.  He  considers  that  the  cells  of  the  ducts  stand  in 
relation  to  the  hepatic  cells  as  the  columnar  epithelium  lining  the  stomach  tubes  does 
to  tlie  secretory  cells  at  the  bottom  of  them. 

^  Ou  Diseases  of  the  Liver,  2d  Amer.  edit.,  p.  120,  Philad.,  1853. 


534: 


secretio:n' 


same  relation  to  the  branches  of  the  portal  vein  as  they  have  to  those 
of  the  hepatic.  It  is  difficult  to  tell,  from  this  specimen,  which  branch 
is  portal  and  whicli  hepatic, — the  smaller  branches  of  both  being,  as  it 
were,  hairy  -with  capillaries  springing  directly  from  them  on  every 
side,  and  forming  a  close  and  continuous  network.  Dr.  Budd  thinks, 
that  the  injected  preparations  of  Mr.  Bowman  show  clearly,  that  the 
opinion  of  Malpighi,  Kierhan,  Miiller,  and  others,  that  the  lobules  are 
isolated  from  each  other,  each  being  invested  by  a  layer  of  areolar  tis- 
sue, is  erroneous;  and  that  the  lobules  are  not  distinct,  isolated  bodies, 
but  merely  small  masses,  tolerably  defined  by  the  ultimate  twigs  of  the 
portal  vein,  and  the  injected  or  uninjected  capillaries  immediately  con- 
tiguous to  them.  The  lobules,  according  to  Dr.  Budd,  appear  only  as 
distinct  isolated  bodies  when  seen  by  too  low  a  magnifying  power  to 
clearly  distinguish  the  capillaries.  The  real  nature  of  the  lobules,  and 
the  manner  in  which  they  are  formed,  will  perhaps  be  better  under- 
stood, he  thinks,  by  reference  to  the  illustration,  (Fig.  167,)  for  which 
he  expresses  his  indebtedness  to  Mr.  Bowman.  It  represents,  on  a 
magnified  scale,  six  lobules  of  the  liver,  and  was  made  from  a  drawing 
under  the  microscope  of  a  section  of  the  liver  of  a  cat,  partially  injected 
through  the  portal  vein,  and  also  through  the  hepatic. 

Mr.  Kiernau  has  deduced  interesting  patliological  inferences  from 
the  anatomical  arrangement  of  the  liver  which  he  conceives  to  exist; 


Fie?.  168. 


Fig.  169. 


First  Stage  of  Hepatic  Venous  Congestion.         Second  Stage  of  Hepatic  Venous  Congestion. 

thus,  he  consider^  that  the  lobules  may  be  congested  by  accumulation 
of  blood  in  the  hepatic  or  in  the  portal  venous  sj^stem ;  which  may  be 
detected  by  a  minute  inspection  of  the  lobules.  The  precise  causes  of 
this  are  referred  to  in  another  work.^  The  accompanying  illustrations 
will  be  sufficient  here.  Fig.  168  represents  the  lobules  in  the  first 
stage  of  what  he  terms  hepatic  venous  congestion  or  congestion  of  the 
terminations  of  the  hepatic  vein :  2,  the  interlobular  spaces  and  fis- 
sures. In  Fig.  169,  the  lobules  are  in  the  second  stage  of  congestion. 
B  and  C,  the  interlobular  spaces ;  D,  congested  intralobular  or  hepatic 
veins;  I,  congested  patches  extending  to  the  circumference  of  the 


Practice  of  Medicine,  3d  edit.,  vol.  ii.  chap.  3,  Philad.,  1S48. 


OF   THE   LIVER. 


535 


Fig.  170. 


Portal  Venous  Congestion. 

B.  Interlobular  spaces  and  fissures, 
lobular   veins.     D.    Ansemic    portions. 

getited  x>ortions. 


C.  Intra- 

E.  Con- 


lobules;  F,  nncongested  portions.  Iii  Fig.  170,  the  lobules  are  in  a 
state  of  iJorUd  venous  congestion;  not  a  common  occurrence.  It  lias 
been  seen  by  Mr.  Kiernan  in  children  only. 

The  view  of  Mr.  Kiernan  has 
been  held  to  explain  also  the  diver- 
sity of  the  statement  of  anatomists 
as  to  the  relative  position  of  the 
o-ed  and  yellow  substances,  which 
have  been  considered  to  compose 
the  liver :  the  red  is  the  congested 
portion  of  the  lobules,  whilst  the 
yellow  is  the  non-congested  portion 
in  which  the  biliary  plexus  appears 
more  or  less  distinctly. 

The  liver  has  two  coats; — the 
outer,  derived  from  the  peritoneum, 
which  is  very  thin,  transparent, 
easily  lacerable,  and  vascular,  and 
is  the  seat  of  the  secretion  effected 
by  serous  membranes  in  general. 
It  docs  not  cover  the  posterior  part, 
or  the  excavation  for  the  gall-blad- 
der, the  vena  cava,  or  the  fissures  in  the  concave  surface  of  the  liver. 
The  inner  coat  is  the  proper  membrane  of  the  liver.  It  is  thin,^  but 
not  easily  torn,  and  covers  not  only  every  part  of  the  surface  of  the 
liver,  but  the  large  vessels 
that  are  proper  to  the  organ. 
The  condensed  areolar  sub- 
stance,—  which  unites  the 
sinus  of  the  vena  porta  and 
its  two  great  branches,  the 
hepatic  artery,  common  bili- 
ary duct,  lymphatic  glands, 
lymphatic  vessels,  and  nerves 
in  the  transverse  fossa  or  fis- 
sure of  the  liver, — was  de- 
scribed by  Glisson  as  a  cap- 
sule ;  and  hence  has  been 
called  capsule  of  Glisson.  It 
connects  the  various  anato- 
mical elements  of  the  liver 
together. 

The  (jall-hl adder  is  a  small 
membranous  pouch  of  a  py- 
riform  shape,  situate  at  the 
inferior  and  concave  surface 
of  the  liver  to  which  it  is 
attached;  and  above  thy  co- 
lon and  duodenum.  A  quan- 
tity of  bile  is  usually  found  in  it.  It  is  not  met  with  in  all  animals*, 
is  wanting  in  the  elephant,  horse,  stag,  camel,  rhinoceros,  and  goat ; 


Fig.  171. 


The  three  coats  of  Gall-bladtler  separated  from  each 
other. 

1.  External  or  peritoneal  coat.  2.  Areolar  coat  ■«-ith  its 
vessels  injected.  3.  SIucuus  coat  covered  with  wrinkles. 
■t,  4.  Valves,  formed  by  tliis  coat  in  the  neck  of  gall-bladder. 
5,  ;j.  Orifices  of  mucous  follicles  at  this  point. 


536 


SECRETION 


Fig.  172. 


Gall-bladder  distended  with  Air,  and  with  its  Vessels 
injected. 

1.  Cystic  arterr.  2.  Branches  of  it  which  supply  the 
peritoneal  coat  of  the  liver.  3.  Branch  of  the  hepatic  ar- 
tery which  goes  to  gall-bladder.  4.  Lymphatics  of  gall- 
bladder. 


in  certain  of  the  cetacea ;  in  some  birds,  as  the  ostrich,  pigeon,  and 
parrot;  and  is  occasionally  so  in  man.     Xo   traces  of  it  are  met  with 

in  the  invertebrata.  It  may 
be  looked  upon  as  a  dilata- 
tion of  the  gall -ducts,  and 
adapted  for  the  reception 
and  retention  of  bile.  Its 
largest  yjart  or  fundus  is 
turned  forwards:  and,  when 
filled,  frequently  projects 
beyond  the  anterior  margin 
of  the  liver.  Its  narrowest 
portion,  cervix  or  neck,  is 
turned  backwards,  and  ter- 
minates in  the  cystic  duct. 
Externally,  it  is  partly  co- 
vered by  the  peritoneum, 
which  attaches  it  to  the 
liver,  and  to  which  it  is,  moreover,  adherent  by  areolar  tissue  and  ves- 
sels. Internally,  it  is  rugous;  the  folds  being  reticulated,  and  appear- 
ing somewhat  like  the  cells  of  a  honeycomb. 

Anatomists  have  differed  with  regard  to  the  number  of  coats  proper 
to  the  gall-bladder.  Some  have  described  two  only  ; — the  peritoneal 
and  mucous;  others  have  added  an  intermediate  areolar  coat;  whilst 
others  have  reckoned  four; — a  peritoneal, — a  thin  stratum  of  muscular 
fibres  passing  in  different  directions,  and  of  a  pale  colour, — an  areolar 
coat,  in  which  a  number  of  bloodvessels  is  situate,  and  an  internal 
mucous  coat.  The  existence  of  the  muscular  coat  has  been  denied  by 
perhaps  the  generality  of  anatomists;  but  there  is  reason  for  believing 
in  its  existence.  Kcilliker^  affirms,  that  there  is,  between  its  peritoneal 
covering  and  the  abundant  subserous  connective  tissue,  a  delicate  layer 
of  muscles,  whose  fibre  cells  take  more  particularly  a  longitudinal  and 
a  transverse  direction  and  present  only  indistinct  nuclei.  Amussat 
saw  muscular  fibres  distinctly  in  a  gall-bladder  dilated  by  calculi;  and 
Dr.  Monro  (Tertius),^  Professor  of  Anatomy  in  the  University  of  Edin- 
burgh, asserts,  that  he  has  seen  it  contract,  in  a  living  animal,  for  half 
an  hour,  under  mechanical  irritation,  and  assume  the  shape  of  an  hour- 
glass. The  mucous  coat  forms  the  rugge  to  which  we  have  already 
alluded.  In  the  neck,  and  beginning  of  the  cystic  duct,  there  are  from 
three  to  seven — sometimes  twelve — semilunar  duplicatures,  which  re- 
tard the  flow  of  au}^  fluids  inwards  or  outwards.  These  are  sometimes 
arranged  spirally,  so  as  to  f(jrm  a  kind  of  valve,  according  to  M. 
Amussat.^ 

On  the  inner  surface  of  the  gall-bladder,  especially  near  its  neck, 
numerous  follicles  exist,  the  secretion  from  which  is  said  to  fill  the 
gall-bladder,  when  that  of  the  bile  has  been  interrupted  by  disease,  as 
in  yellow-fever,  scirrhus  of  the  liver,  &c.     The  hepatic  duct  is  the  coin- 


'  Miki'oskopiselie  Anatomie,  ii.  230,  Leipzig,  1852 ;  and  Amer.  edit,  by  Dr.  Da  Costa, 
p.  538,  Philad.,  1854. 

*  Elements  of  the  Anatomy  of  the  Human  Body,  Edinb.,  1825. 
^  Mageudie,  Precis,  &c,,  ii.  4li4. 


OF   THE   LIVER.  537 

mon  trunk  of  all  the  excretory  vessels  of  tLe  liver ;  and  makes  its 
exit  from  that  organ  by  the  transverse  fissure.  It  is  an  inch  and  a 
half  in  length,  and  about  the  diameter  of  an  ordinary  writing-quill. 
It  is  joined,  at  a  very  acute  angle,  by  the  duct  from  the  gall  bladder — 
q/stic  dud — to  form  the  ductus  communis  choledochus.  The  cystic 
duct  is  about  the  same  length  as  the  hepatic.  The  ductus  communis 
choledochus  is  about  three,  or  three  and  a  half  inches  long.  It  descends 
behind  the  right  extremity  of  the  pancreas,  through  its  substance; 
passes  for  an  inch  obliquely  between  the  coats  of  the  duodenum,  dimi- 
nishing in  diameter;  and  ultimately  terminates  by  a  yet  more  con- 
tracted orifice  on  the  inner  surface  of  the  intestine,  at  the  distance  of 
three  or  four  inches  from  the  stomach.  The  structure  of  all  these 
ducts  is  the  same.  The  external  coat  is  thick,  dense,  strong,  and  gene- 
rally supposed  to  be  of  an  areolar  character ;  the  inner  is  a  mucous 
membrane,  like  that  which  lines  the  gall-bladder.  A  fibrous  and  a 
mucous  layer,  according  to  Kolliker,^  can  be  readily  distinguished  in 
the  ductus  communis  choledochus  and  the  cystic  duct;  the  mucous 
layer  containing  a  few  muscular  fibre-cells;  but,  on  the  whole,  so 
sparingly,  that  these  ducts  cannot — he  considers — be  said  to  possess 
any  special  muscular  coat. 

The  secretion  of  bile  is  probably  effected  like  that  of  other  glandular 
organs;  modified,  of  course,  by  the  peculiar  structure  of  the  liver. 
We  have  seen,  that  the  organ  differs  from  every  other  secretory  appa- 
ratus, in  having  two  kinds  of  blood  distributed  to  it ; — arterial  by  the 
hepatic  artery ;  and  venous  by  the  vena  porta.  A  question  has  con- 
sequently arisen — from  which  of  these  is  the  bile  formed?  Anato- 
mical inspection  does  not  positively  settle  the  question;  for  whilst — 
as  has  been  seen — it  is  maintained  by  Muller  and  others,  that  the  ulti- 
mate termination  of  the  capillaries  is  in  the  hepatic  veins;  others, 
with  Kiernan,  believe  that  they  communicate  with  the  portal  system; 
and  if  this  arrangement  were  demonstrated,  we  should  be  compelled 
to  ascribe  the  secretion  to  the  mixed  blood,  which  flows  in  the  inter- 
lobular veins.  But  this  point  of  hepatic  histology  is  not  determined. 
Argument  is  all  that  can  be  adduced  on  one  side  or  the  other.  The 
most  common  and  the  oldest  opinion  is,  that  the  bile  is  separated  from 
the  blood  of  the  vena  porta ;  and  the  chief  reasons  brought  forward 
in  favour  of  the  belief,  are  the  following:  First.  The  blood  of  the  por- 
tal sj^stem  is  better  adapted  than  arterial  blood  for  the  formation  of 
bile,  on  account  of  its  having,  like  all  venous  blood,  more  carbon  and 
hydrogen,  which  are  necessary  for  the  production  of  a  humour  as  fat 
and  oily  as  the  bile;  and,  as  the  experiments  of  Schultz^  and  others 
have  proved,  that  portal  blood  contains  more  fat  than  that  of  other 
veins  and  arteries,  it  has  been  imagined,  by  some,  that  the  blood,  in 
crossing  the  omentum,  becomes  loaded  with  fat.  Secondly.  The  vena 
porta  ramifies  in  the  liver  after  the  manner  of  an  artery,  and  evidently 
communicates  with  the  secretory  ves-sels  of  the  bile,  lliirdlij.  It  is 
larger  than  the  hepatic  artery ;  and  more  in  proportion  to  the  size  of 
the  liver;  the  hepatic  artery  seeming  to  be  merely  for  the  nutrition  of 
the  liver,  as  the  bronchial  artery  is  for  that  of  the  lung. 

'  Op.  cit. 

^  Rust's  Magazine,  B.  xliv. ;  or  Gazette  Medicale,  Aug.  15,  1835. 


538  SECRETIOX 

In  answer  to  these  positions,  it  has  been  argned.  First.  That  there 
seems  to  be  no  more  reason  why  the  bile  should  be  formed  from  venous 
blood  than  other  fatty  and  oleaginous  humours, — marrow  and  f;it  for 
example, — which  are  derived  from  arterial  blood.  It  is  asked,  too, 
whether,  in  point  of  fact,  the  blood  of  the  vena  porta  is  more  rich  in 
carbon  and  hydrogen?  and  whether  there  be  a  closer  chemical  relation 
between  bile  and  tlie  blood  of  the  vena  porta,  than  between  fat  and. 
arterial  blood  ?  Tlie  notion  of  the  absorption  of  fat  from  the  omentum, 
it  is  properly  urged,  is  totally  gratuitous.  Secondly.  The  vena  porta 
does  not  exist  in  the  invertebrated  animals;  and  yet,  in  a  number  of 
them,  there  is  an  hepatic  apparatus,  and  a  secretion  of  bile.  TJiirdly. 
Admitting  that  the  vena  porta  is  distributed  to  the  liver  after  the 
manner  of  an  artery ;  is  it  clear,  it  has  been  asked,  that  it  is  inservient 
to  the  biliary  secretion?  Fourthly.  If  the  vena  porta  be  more  in  pro- 
portion to  the  size  of  the  liver  than  the  hepatic  artery,  the  latter  ap- 
pears to  bear  a  better  ratio  to  the  quantity  of  bile  secreted:  and, 
Lastly.  It  is  clear,  as  has  been  shown  in  another  place,  that  the  liver 
has  other  important  functions  connected  with  the  portal  system,  as  the 
admixture  of  heterogeneous  liquids  absorbed  from  the  intestinal  canal, 
and  their  assimilation. 

In  the  absence  of  accurate  knowledge  derived  from  direct  experi- 
ment, physiologists  have  usually  embraced  one  or  other  of  these  exclu- 
sive views.  The  generality,  as  we  have  remarked,  assign  the  function 
tt5  the  vena  porta.  Bichat,  J.  Miiller,  and  others,  ascribe  it  to  the 
hepatic  artery.  M.  Broussais^  thinks  it  probable,  that  the  blood  of  the 
vena  porta  is  not  foreign  to  the  formation  of  bile,  since  it  is  confounded 
with  that  of  the  hepatic  artery  in  the  parenchyma  of  the  liver;  "but 
to  say  with  the  older  writers,  that  the  bile  can  only  be  formed  from 
venous  blood,  is,  in  our  opinion,"  he  remarks,  "to  advance  too  bold  a 
position,  since  the  hepatic  arteries  send  branches  to  each  of  the  gland- 
ular acini,  that  compose  the  liver."  M.  Magendie  likewise  concludes, 
that  nothing  militates  against  tlie  idea  of  both  kinds  of  blood  partici- 
pating in  the  secretion;  and  that  it  is  supported  by  anatomy,  as  injec- 
tions prove,  that  all  the  vessels  of  the  liver, — arterial,  venous,  lymphatic, 
and  excretory, — communicate  with  each  other.  Mr.  Kiernan,  as  we 
have  seen,  considers  that  the  blood  of  the  hepatic  artery,  after  having 
nourished  the  liver,  is  inservient  to  the  secretion,  but  not  until  it  has 
become  venous,  and  entered  the  portal  veins.  He, — with  all  those  that 
coincide  v/ith  him  in  the  morphological  arrangement  of  the  liver, — 
denies  that  there  is  any  communication  between  the  ducts  and  blood- 
vessels; and  asserts,  that  if  injections  pass  between  them,  it  is  owing 
to  the  rupture  of  the  coats  of  the  vessels.  Experiments  on  pigeons, 
by  M.  Simon,^  of  Metz,  showed,  that  when  the  hepatic  artery  was  tied, 
the  secretion  of  bile  continued,  but  that  if  the  portal  and  hepatic  veins 
were  tied,  no  trace  of  bile  was  subsequently  found  in  the  liver.  It 
would  thence  appear,  that  in  these  animals  the  secretion  of  bile  takes 
place  from  venous  blood.  But  inferences  from  the  ligature  of  those 
vessels  have  been  very  discordant.    In  two  cases,  in  which  ]Mr.  Phillips 

'  Traite  de  Phj'siologie,  &:c.,  translation  by  Drs.  Bell  and  La  Roche,  3d  edit.,  p.  45(5, 
Philad..  1832. 

^  Edinburgh  Medical  and  Surgical  Journal,  xc.  229. 


OF   THE   LIVEE.  539 

tied  the  hepatic  artery,  the  secretion  of  bile  was  uiiinterru]:)tecl,  jct  the 
same  thing  was  observed  in  three  other  cases,  in  which  the  ligature  was 
applied  to  the  trunk  of  the  vena  porta. 

The  view,  that  ascribes  the  bile  to  the  hepatic  artery,  has  always 
appeared  to  the  author  the  most  probable.  It  has  all  analogy  in  its 
favour.  There  has  been  no  disputed  origin  as  regards  the  other  secre- 
tions, excepting,  of  late,  in  the  case  of  the  urinary.  All  proceed  from 
arterial  blood  ;  and  function  sufficient,  we  have  seen,  can  be  assigned 
to  the  portal  system,  without  conceiving  it  to  be  concerned  in  the 
formation  of  bile.  We  have,  moreover,  morbid  cases,  which  would 
seem  to  show  that  bile  can  be  formed  from  the  blood  of  the  hepatic 
artery.  Mr.  Abernethy^  met  with  an  instance,  in  which  the  trunk  of 
the  vena  porta  terminated  in  the  vena  cava;  yet  bile  was  found  in  the 
biliary  ducts.  A  similar  case  is  given  by  Mr.  Lawrence  f  and  Professor 
Monro^  details  a  case  communicated  to  him  by  the  late  Mr,  Wilson,  then 
of  the  Windmill  Street  School,  in  which  there  was  reason  to  suppose, 
that  the  greater  part  of  the  bile  had  been  derived  from  the  hepatic 
artery.  The  patient,  a  female,  thirteen  years  old,  died  from  the  effects 
of  an  injury  of  the  head.  On  dissection,  Mr.  Wilson  found  a  large 
swelling  at  the  root  of  the  mesentery,  consisting  of  several  absorbent 
glands  in  a  scrofulous  state.  Upon  cutting  into  the  mass,  he  acci- 
dentally observed  a  large  vein  passing  directly  from  it  into  the  vena 
cava  inferior,  which,  on  dissection,  proved  to  be  the  vena  porta;  and 
on  tracing  the  vessels  entering  into  it,  one  proved  to  be  the  inferior 
mesenteric  vein:  and  another,  which  came  directly  to  meet  it,  from 
behind  the  stomach,  proved  to  be  a  branch  of  the  splenic  vein,  but 
somewhat  larger,  which  ran  upwards  by  the  side  of  the  vena  cava  in- 
ferior, and  entered  that  vein  immediately  before  it  passes  behind  the 
liver.  Mr.  Wilson  traced  the  branches  of  the  trunk  of  the  vessel  cor- 
responding to  the  vena  porta  sufliciently  far  in  the  mesentery  and 
mesocolon  to  be  convinced,  that  it  was  the  only  vessel  that  returned 
the  blood  from  the  small  intestines,  and  from  the  c^cum  and  colon  of 
the  large  intestines.  lie  could  trace  no  vein  passing  into  the  liver  at 
the  cavity  of  the  porta ;  but  a  small  one  descended  from  the  little 
epiploon,  and  soon  joined  one  of  the  larger  branches  of  the  splenic 
vein.  The  hepatic  artery  came  off  in  a  distinct  trunk  from  the  aorta, 
and  ran  directly  to  the  liver.  It  was  much  larger  than  usual.  The 
greater  size  of  the  hepatic  artery,  in  this  case,  would  favour  the  idea, 
that  the  arterial  blood  had  to  execute  some  office,  that  ordinarily  be- 
longs to  the  vena  porta.  Was  this  the  formation  of  bile?  The  case 
seems,  too,  to  show,  that  bile  can  be  formed  from  the  blood  of  the 
hepatic  artery. 

Professor  Gintrac"  has  published  a  case  in  which  there  was  ossifica- 
tion with  obliteration  of  the  vena  porta.  The  patient  died  of  ascites. 
The  liver  was  pale  or  whitish,  and  irregularly  wrinkled  or  mammil- 
lated  on  its  surface.  The  gall-bladder  contained  a  medium  quantity  of 
thickish  yellow  bile.    The  biliary  ducts  were  normal.    The  vena  porta 

'  PhiLisopliical  Transactions,  vol.  Ixxxiii. 

2  Medico-Cliirurgical  Transactions,  iv.  174. 

^  Elements  of  Anatomy,  Edinliurizli,  1825. 

*  Citetl  iu  American  .Journal  of  tlie  Medical  Sciences,  Oct.,  1844,  p.  47u. 


540  SECRETION" 

above  the  junction  of  the  splenic  and  superior  mesenteric  veins  was 
completely  filled  bj  an  old  clot,  which  adhered  to  the  inner  membrane. 
The  clot  was  solid,  and  of  a  deepish  black  colour.  At  the  same  part 
of  the  vein  several  osseous  plates  were  observed  many  lines  in  diame- 
ter, which  were  situate  between  the  inner  and  middle  coats  of  the  vein, 
without  having  much  adherence  to  either.  All  the  abdominal  veins  that 
ended  in  these  vessels  were  gorged  with  blood,  and  varicose.  Professor 
Gintrac  ascribed  the  ascites  to  the  obliteration  and  ossification  of  the 
vena  porta,  and  he  considered  the  case  to  prove,  that  although  oblite- 
ration of  that  vessel  probably  modified  the  secretion  of  bile,  it  did  not 
prevent  it  altogether;  but  interfered  materially  with  the  nutrition  of  the 
liver.  Hence,  he  inferred,  that  the  blood  of  the  vena  porta  contributes 
to  the  nutrition  of  the  liver;  but  is  not  indispensable  to  the  secretion 
of  bile. 

In  Professor  HaH's  patient,*  the  vena  porta  and  its  bifurcation  were 
completely  filled  with  encephaloid  matter,  so  that  no  blood  could  pass 
through  it  to  the  liver;  the  secretion  of  bile  could  not,  consequently, 
have  been  etYected  through  its  agency.  It  lias  been  presumed,  however, 
that,  in  such  cases,  portal  blood  might  still  enter  the  liver  through  the 
extensive  anastomoses,  which  Professor  Ketzius,^  of  Stockholm,  found 
to  exist  between  the  abdominal  veins.  That  gentleman  observed,  when 
he  tied  the  vena  porta  near  the  liver,  and  threw  a  coloured  injection 
into  the  portion  below  the  ligature,  that  branches  were  filled,  some  of 
which,  proceeding  from  the  duodenum,  terminated  in  the  vena  cava ; 
whilst  others,  arising  from  the  colon,  terminated  in  the  left  emulgent 
vein.  In  subsequent  investigations,  he  observed  an  extensive  plexus  of 
minute  veins  ramifying  in  the  areolar  tissue  on  the  outer  surface  of  the 
peritoneum,  part  of  which  was  connected  with  the  vena  porta,  whilst 
the  other  terminated  in  the  system  of  the  vena  cava.  In  a  successful 
injection,  these  veins  were  seen  anastomosing  very  freely  in  the  pos- 
terior part  of  the  abdomen,  with  the  colic  veins,  as  well  as  with  those 
of  the  kidneys,  pelvis,  and  even  the  vena  cava.  The  arrangement, 
pointed  out  by  Retzius,  accounts  for  the  mode  in  which  the  blood  of 
the  abdominal  venous  system  reaches  the  cava,  when  the  vena  porta  is 
obliterated  from  any  cause;  and  it  shows  the  possibility  of  portal  blood 
reaching  the  liver  so  as  to  be  inservient  to  the  biliary  secretion,  but 
does  not,  we  think,  exhibit  the  prohabi lily . 

Since  then,  cases  of  obliteration  of  the  vena  porta  have  been  re- 
corded, in  which  the  nutrition  of  the  liver  was  materially  impaired,  so 
that  the  organ  had  become  atrophied,  whilst  the  secretion  of  bile  per- 
sisted. Such  a  case  is  given  by  M.  Eaikem,^  of  Brussels.  In  this,  the 
vein  was  entirely  obliterated  by  clots  of  blood  intimately  adherent  to 
its  inner  surface.  The  liver  was  smaller  than  usual;  the  gall-bladder 
contained  a  large  quantity  of  serous  bile  of  a  yellowish  and  orange 
colour,  and  the  cystic  and  hepatic  ducts  were  filled  with  it.  The  trunk 
of  the  hepatic  artery  was  three  lines  in  diameter,  and  contained  no  clots 

'  Page  528. 

2  Ais  Berilttelse  af  Setterblad,  1S35,  S.  9 ;  cited  in  Zeitschrift  fiir  die  Gesammte 
Heilkiuide,  Feb.,  1837,  S.  251. 

^  ]\leiiioires  de  I'Acadi  uiie  Royale  de  Medecine  de  Belsriqne,  torn,  i.,  Bruxelles,  1848; 
translated  in  tlie  Ediub.  Med.  and  iSurg.  Journal,  Ajjnl,  isuU,  p.  350. 


OF   THE   LIVER.  541 

of  blood  ;  and  such  was  the  case  with  the  supra-hepatic  veins.  Whence 
j\f,  Raikem  concludes,  that  in  the  present  state  of  physiological  know- 
ledge, there  are  reasons  sufficiently  conclusive  for  the  opinion,  that  the 
hepatic  artery  is  capable  alone  of  furnishing  to  the  liver  the  materials 
necessary  for  the  secretion  of  bile,  when  the  vena  porta  is  obliterated 
to  so  great  a  degree  as  not  to  allow  the  blood  to  be  conveyed  through 
it  to  the  organ;  and,  he  asks,  as  the  result  of  observations  of  numerous 
pathological  cases,  whether  "it  is  indeed  proved,  as  is  generally  be- 
lieved, that  tlie  hepatic  artery  is  alone  charged  with  the  function  of 
nourishing  the  liver  to  the  exclusion  of  the  portal  vein,"  when  "  we 
observe  that  the  liver  is  atrophied,  in  those  in  whom  the  portal  vein 
has  been  entirely  obliterated  for  a  long  time?"  An  additional  case  of 
the  kind  has  been  detailed  by  Dr.  Craigie.'  In  this,  the  vein  was 
found  completely  filled  and  distended  by  firm,  yet  compressible,  elastic 
matter,  as  if  the  vessel  had  been  injected,  so  that  its  diameter  was  fully 
one  inch.  Of  the  effects  of  this  obliteration,  the  most  remarkable,, 
again,  was  the  atro]ihy  of  the  liver,  which  was  not  more  than  one-third 
of  its  usual  size.  A  small  quantity  of  light  coloured  bile  was  found  in 
the  gall-bladder,  and  during  life  the  fasces  had  ithe  usual  colour.  "M. 
Eaikem,"  says  Dr.  Craigie,  "  has  adverted  to  the  notion  so  much  favoured, 
by  various  physiological  speculators,  that  thediepatic  artery  is  employed 
in  maintaining  the  nutrition  of  the  liver,  while  to  the  portal  vein  be- 
longs the  function  of  conveying  to  the  gland  the  materials  from  which 
bile  is  to  be  prepared;  and,  to  show  its  incompetency,  has  adduced 
several  conclusive  arguments.  It  is  scarcely  possible  to  conceive  a 
stronger  argument  against  it  than  is  furnished  by  the  facts  of  this  case. 
The  portal  vein  was  completely  obstructed,  and  no  blood  must  for  a 
long  time  have  been  conveyed  through  its  branches  into  the  gland. 
The  liver  is  likewise  very  much  reduced  in  size,  not,  indeed,  uniformly 
and  equally  in  all  its  parts,  but  still  so  much  and  so  generally  atrophied,, 
that  it  is  difficult  to  ascribe  the  diminution  and  wasting  of  parts  to  any 
other  cause.  The  two  circumstances,  therefore,  appear  to  stand  in  the 
relation  of  cause  and  effect."  It  is  to  be  regretted  that  the  history  of 
this  case  is  rendered  imperfect  by  the  circumstance,  that  "  the  state  of 
the  hepatic  artery  was  not  ascertained." 

It  would  seem,  then,  that  the  portal  system  is  not  absolutely  neces- 
sary to  the  formation  of  bile;  yet  a  modern  writer^  considers  it  "a  most 
puerile  question"  to  ask  whether  the  secretion  can  be  effected  from 
venous  blood  !  "Had  not,"  he  adds,  "  secretion  been  destined  to  take 
])lace  from  the  blood  of  the  vena  portarum,  nature  would  not  have 
been  at  the  pains  to  distribute,  it  through  the  liver;  the  peculiar  ar- 
rangement is  already  an  answer  to  the  question;  the  end  of  it  is,  as  I 
have  said,  to  economise  arterial  blood."  As  before  remarked,  however, 
a  sufficient  function  can  be  assigned  to  the  portal  system  without  sup- 
posing that  it  has  any  agency  in  the  secretion  of  bile.  Still,  there  is 
nothing  inconsistent  with  the  idea,  that  both  kinds  of  blood  may  be 
iuservient  to  the  secretion.     Mention  has  been  made  elsewhere,  that 

'  Edinb.  Me<l.  and  Surg.  Journal,  April,  1850,  p.  512. 

*  Dr.  R.  Willis,  Loudon  and  Edinb.  Monthly  Journal  of  Med.  Sciences,  Sejit.,  1S41, 
p.  628. 


542  SECRETION" 

MM.  Bouchardat  and  Sandras,  having  fed  lierbivorous  animals  on 
farinaceous  substances,  detected  more  dextrin,  grape  sugar,  and  lactic 
acid  in  the  blood  of  the  vena  porta  than  in  that  of  any  other  vessel ; 
and  that  Trortimer  discovered  grape  sugar  in  the  blood  of  the  portal 
vein,  but  not  in  that  of  the  hepatic  veins  of  animals  with  whose  food 
that  substance  had  been  mixed.  Moreover,  MM.  Blondlot'  and-Chossat^ 
found,  that  the  administration  of  non-nitrogenous  articles  of  food,  espe- 
cially of  sugar,  considerably  increased  the  amount  of  bile  secreted. 
On  the  other  hand,  however,  Nasse  found,  that  a  diet  of  animal  food 
induced  a  far  more  abundant  secretion  of  bile  in  the  dog  than  vegeta- 
ble amylaceous  food;  yet  an  abundant  addition  of  fat  to  the  ordinary 
food  of  the  animal  occasioned  a  marked  augmentation  of  the  secretion. 
When  cats,  however,  were  fed  on  pure  fat,  Bidder  and  Schmidt^  found, 
that  they  secreted  no  more  bile  than  if  the}^  had  been  wholly  deprived 
of  food  for  the  same  time.  An  exclusive  fatty  diet  does  not,  therefore, 
affect  the  biliary  secretion.^ 

When  bile  is  once  formed  in  the  tissue  of  the  liver,  it  is  received 
into  the  minute  excretory  radicles,  whence  it  proceeds  along  the  ducts 
until,  from  all  quarters,  it  arrives  at  the  hepatic  duct.  A  difference  of 
sentiment  exists  regarding  the  course  of  the  bile  from  the  liver  and 
gall-bladder  to  the  duodenum.  According  to  some,  it  is  constantly 
passing  along  the  choledoch  duct;  but  the  quantity  is  not  the  same 
during  digestion  as  at  other  times.  In  the  intervals  of  digestion  a  part 
only  of  the  bile  attains  the  duodenum ;  the  remainder  ascends  along 
the  cystic  duct,  and  is  deposited  in  the  gall-bladder.  During  digestion, 
however,  not  only  the  whole  of  the  newly  secreted  bile  arrives  at  the 
duodenum,  but  that  which  had  been  collected  in  the  interval  is  evacu- 
ated into  the  intestine.  In  support  of  this  view  it  is  affirmed,  that  bile 
is  always  met  with  in  the  duodenum  ;  and  that  the  gall-bladder  always 
contains  more  bile  when  abstinence  is  prolonged,  and  is  empty  imme- 
diately after  digestion. 

A  great  difficulty  has  been,  to  explain  how  the  bile  gets  into  the 
gall-bladder ;  and  in  what  manner  it  is  expelled  from  that  reservoir. 
In  many  birds,  reptiles,  and  fishes,  the  hepatic  duct  and  cystic  duct 
open  separately  into  the  duodenum ;  whilst  ducts,  called  hepato-cystic, 
pass  directly  from  the  liver  to  the  gall-bladder.  In  man,  however,  the 
onl}^  visible  route,  by  which  it  can  reach  that  reservoir,  is  by  the 
cystic  duct,  the  direction  of  which  is  retrograde ;  and,  consequently, 
the  bile  in  the  erect  attitude  has  to  ascend  against  gravity.  The  spiral 
valve  of  M.  Amussat  has  been  presumed  to  act  like  the  screw  of  Ar- 
chimedes, and  to  facilitate  the  entrance  of  the  refluent  bile ;  but  this 
appears  to  be  imaginary.  It  is,  indeed,  impossible,  to  see  any  analogy 
between  the  corporeal  and  the  hydraulic  instrument.  The  arrange- 
ment of  the  termination  of  the  choledoch  duct  in  the  duodenum  has 
probably  a  more  positive  influence.  The  embouchure  is  the  narrow- 
est part  of  the  duct ;  the  ratio  of  its  calibre  to  that  of  the  hepatic  duct 

'  Essai  siir  les  Fonctions  du  Foie,  p.  62,  Paris,  1S4G. 

2  Gazette  Medicale  de  Paris,  Oct.,  1843. 

3  Die  Verdauuiigssilfte  und  der  Stoflweclisel,  S.  151,  Mitau  und  Leipzig,  1852. 

'•  Lehmann,  Pliysiological  Chemistry,  translated  from  the  German  by  Dr.  Day  ;  Amer. 
edit,  by  Dr.  R.  E."  Rogers,  i.  472,  Philad.,  1S55. 


OF    THE    LIVER.  543 

naving  been  estimated  at  not  more  than  one  to  six,  and  to  the  calibre 
of  its  own  duct  as  one  to  lifteen.  This  might  render  it  impracticable 
for  the  bile  to  flow  into  the  duodenum  as  promptl}^  as  it  arrives  at  the 
embouchure;  and,  in  this  way  collecting  in  the  duct,  it  might  reflow 
into  the  gall-bladder.  M.  Amussat,  indeed,  affirms,  that  this  can  be 
demonstrated  on  the  dead  body.  By  injecting  water  or  mercury  into 
the  upper  part  of  the  hepatic  duct,  the  injected  liquid  was  found  to 
issue  both  by  the  aperture  into  the  duodenum,  and  by  the  upper  aper- 
ture of  the  cystic  duct  into  the  gall-bladder. 

With  regard  to  the  mode  in  which  the  gall-bladder  empties  itself 
during  digestion,  it  is  probably  by  a  contractile  action.  We  have 
seen,  that  it  has  not  usually  been  admitted  to  possess  a  muscular  "coat, 
but  that  it  is  manifestly  contractile.  The  chyme,  as  it  passes  into  the 
duodenum,  excites  the  orifice  of  the  choledoch  duct;  this  excitement 
is  propagated  along  the  duct  to  the  gall-bladder,  which  contracts ;  but 
according  to  M.  Amussat  does  not  evacuate  its  contents  suddenly ;  for 
the  different  planes  of  the  spiral  valve  are  applied  against  each  other, 
and  only  permit  the  flow  to  take  place  slowly.  This  he  found  was  the 
case  in  the  dead  body,  when  water  was  injected  into  the  gall-bladder, 
and  then  passed  out  through  the  cystic  duct.  Other  phj'siologists 
have  presumed,  that  although  the  bile  is  secreted  in  a  continuous 
manner,  it  only  flows  into  the  duodenum  during  chylification ;  at  other 
times,  the  choledoch  duct  is  contracted,  so  that  tli'e  bile  is  compelled 
to  reflow  through  the  cystic  duct  into  the  gall-bladder;  and  it  is  only 
when  the  gall-bladder  is  filled,  that  it  passes  freely  into  th6  duodenum. 
Independently,  however,  of  other  objections  to  this  view,  vivisections 
have  shown,  that  if  the  orifice  of  the  choledoch  duct  be  exposed,  what- 
ever may  be  the  circumstances  in  which  the  animal  is  placed,  the  bile 
is  seen  issuing  guttaiim  at  the  surface  of  the  intestine.  That  the  flow 
of  bile  from  the  gall-bLadder,  however,  is  dependent  tipon  the  presence 
of  aliment  in  the  intestines,  is  shown  by  the  fact,  that  the  reservoir  is 
almost  always  found  turgid  in  those  who  have  died  from  starvation ; 
the  secretion  formed  at  the  ordinary  slow  rate  having  gradually  accu- 
mulated for  want  of  demand.  This  fact,  it  has  been  properly  remarked, 
is  important  in  juridical  inquiries. 

The  biliary  secretion,  ^vhich  proceeds  immediately  from  the  liver — 
hepatic  hik — ditfers  from  that  obtained  from  the  gall-bladder,- — cystic 
lile.  The  latter  possesses  greater  bitterness ;  is  thicker,  of  a  deeper 
colour ;  and  is  that  which  has  been  usually  analyzed.  It  is  of  a  vel- 
lowish-green  colour;  viscid;  and  slightly  bitter.  It  combines  readily 
with  water  in  all  proportions;  mixes  freel}^  with  oil  or  fat;  and  foams, 
when  stirred,  like  soap}^  water.  It  is,  indeed,  in  common  use  in  the 
same  way  as  soap  for  cleansing  articles  of  dress,  and  especially  for 
taking  out  grease.  Its  chemical  properties  have  been  frequently 
examined;  3^et  much  is  still  needed,  before  we  can  consider  the  ana- 
lysis satisfactory.  Cystic  bile  has  been  generally  supposed  to  have  an 
alkaline  reaction ;  but  M.  Bouisson,  Dr.  Kemp,  and  Von  Gorup-Besa- 
nez,^  and  others  who  examined  it,  state,  that  when  fresh  and  perfectly 
healthy,  it  is  neutral.     The  last  observer  found  it  at  first  neutral ;  but 

'  Untersucliuiigen  liber  Galle,  S.  17,  Erlangen,  1S46. 


54-i  SECRETION 

in  the  early  periods  of  its  decomposition  it  is  apt  to  become  acid,  and 
afterwards  alkaline.     The  effects  of  bile,  however,  on  test  papers  are 
difficult  to  appreciate,  on  account  of  the  yellow  stain  it  gives  them.    It 
has   been   examined   by  Boerhaave,  Verheyen,   Baglivi,    Ilartmann 
Macbride,    Kamsay,    Gaubius,    Cadet,    Fourcroy,    Maclurg,   Thenard 
Berzelius,  Chevreul,  Leuret  and  Lassaigne,  Frommherz  and  Gugert, 
Schultz,  Vogel,  John,  Treviranus,  Tiedemann  and  Gmelin,  Bouisson 
Liebig,  Kemp,  Platner,  Frerichs,  Von  Gorup-Besanez,  Mulder,  Bensch 
Strecker,  &c.,^  &c.     Thenard's^  analysis  of  1100  parts  of  human  bile  is 
as  follows : — water,  1000  ;  albumen,  42  ;  resinous  matter,  41 ;  yellow 
matter,  {cholepyrrhin^  biUj^hcein),  2  to  10 ;  free  soda,  5  or  6 ;  phosphate 
and  sulphate  of  soda,  chloride  of  calcium,  phosphate  of  lime,  and  oxide 
of  iron,  4  or  5.     According  to  M.  Chevallier,  it  contains  also  a  quan- 
tity of  picromel  or  biUn.     Berzelius^  called  in  question  the  correctness 
of  M.  Thenard's  analysis,  and  gave  the  following  : — water,  908*4 ;  bilin, 
80 ;  albumen,  3*0 ;  soda,  4*1 ;  phosphate  of  lime,   0*1 ;  common  salt, 
3"4;  phosphate  of  soda,  with  some  lime,  I'O.     His  analysis  of  ox-gall 
gave,  water,  928'380 ;  solid  constituents,  71'620;  bilin,  50*000;  chlo- 
ride of  sodium,  lactate  of  soda,  and  extractive  matter  soluble  in  alco- 
hol, 4*334;  cholesterin,  *001 ;  mucus,  2*350.     In  a  more  recent  essay"* 
he  gives  the  proportions  in  man  as  follows : — water,  90*44 ;  bilin,  8*00 
mucus  of  the  gall-bladder,   0*30 ;  alkali  associated  with  bilin,  0*41 
chloride  of  sodium ;   alkaline  lactate,   and  extractive  matters,  0*74 
phosphates  and  sulphates  of  soda  and  lime,  0*11.     The  results  of  Dr, 
Davy's*  analysis  of  healthy  bile  were  as  follows : — water,  86*0  ;  resin 
of  bile,  12*5;  albumen,  1*5.     The  experiments  of  Gmelin,  for  which  he 
is  highly  complimented  by  Berzelius,^  although  the  latter  considers, 
that  some  of  the  products  may  have  been  formed  by  the  reaction  of 
elements  upon  each  other — yielded  the  following  results: — an  odorous 
material,   like   musk;  cholesterin;   oleic   acid;  margaric  acid;    choiic 
acid;  resin  of  bile;   taurin  (gallen  asp  a  r  agin);  bilin;   colouring 
matter;  osmazome;  a  substance  which,  when  heated,  had  the  odour 
of  urine;  another  resembling  bird-lime,  gleadin;  alburnen  (?);  mucus 
of  the  gall-bladder;  casein,  or  a  similar  substance;  ptyalin,  or  a  simi- 
lar matter;  bicarbonate  of  soda;  carbonate  of  ammonia;   acetate  of 
soda;  oleate,  margarate,  cholate,  and  phosphate  of  potassa  and  soda; 
chloride  of  sodium,  and  phos}ihate  of  lime.     Cadet''  considered  bile  as 
a  soap  with  a  base  of  soda,  mixed  with  sugar  of  milk, — a  view,  which 
Raspail,^  Demar9ay,®  Liebig  and  others  think,  harmonizes  most  with 
observed  facts.     Every  other  substance  met  with  in  the  bile,  M.  Ras- 
pail  looks  upon  as  accessory.     M.  Deraar9ay  regards  it  as  a  soda  salt; 

'  Lelimann,  Lelirbucli  der  Pliysiologisclien  Clioniie,  ii.  Gl,  Leipzig,  1850  ;  and  Amer. 
edit,  of  Dr.  Day's  translation,  i."458,  Philad.,  IBjI.o. 
^  Mem.  de  la  Societe  d'Arcueil,  i.  38,  Paris,  1807. 
3  Mcdico-Chirurgical  Transactions,  iii.  241. 

*  Art.  Galle,  Handworterbiich  der  Physiologie,  3te  Lieferung,  s.  518,  Braunschweig, 
1842. 

*  Monro's  Elements  of  Anatomy,  i.  579. 

6  Henle,  art.  Galle,  in  Encyclop.  Worterb.  it.  s.  w.  B.  xiii.  S.  126,  Berlin,  1835. 
'  Experiences  sur  la  Bile  des  Hommes,  &c.,  in  Mein.  de  PAcadem.  de  Paris,  1767. 
^  Chimie  Organique,  p.  45],  Paris,  1833. 

^  Annil.  der  Pharmac,  xxvii.,  cited  by  Liebig,  Animal  Chemistry,  Webster's  edit., 
p.  305,  Cambridge,  Mass. 


OF   THE   LIVER. 


545 


and  regards  the  essential  constituents  to  be  an  oily  acid,  wliicli  be 
terms  choleic,  and  soda,  wbicb  exists  in  a  state  of  combination  with  it. 
Again,  it  has  been  analyzed  by  Muratori,^  who  assigns  it  the  follow- 
ing constituents; — water,  832;  peculiar  fatty  matter,  5;  colouring 
matter,  11;  cholesterin  combined  with  soda,  4;  picromel  of  Thenard, 
94*86;  osmazome  (estratto  di  carne)^  2*69;  mucus,  37;  soda,  5*14;  phos- 
phate of  soda,  3'45;  phosphate  of  lime,  3;  and  chloride  of  sodium, 
1'86.  Von  Gorup-Besanez,^  who  found  oxide  of  iron  as  a  common 
constituent  of  the  ashes  of  the  bile,  states,  that  copper  can  generally 
be  detected  in  it  in  health;  and  constantly  in  biliary  calculi. 

One  of  the  most  recent  analyses  of  human  bile  is  given  by  Frerichs.^ 
It  was  obtained  from  healthy  men  killed  by  severe  accidents.  The 
following   is   one    analysis: — 

water,   86*00 ;    solid    constitu-  Fig-  173. 

ents,  14*00  ;  bilate  of  soda  [cho- 
leate  of  soda  ?]  10*22 ;  choles- 
terin, 0*16;  margarin  and  olein, 
0*32;  mucus,  2*66;  chloride  of 
sodium,  0*25;  tribasic  phos- 
phate of  soda,  0*20 ;  basic  phos- 
phate of  lime,  basic  phosphate 
of  magnesia,  0*18 ;  sulphate  of 
lime,  0*02;  peroxide  of  iron, 
traces. 

The  proportion  of  solid  mat- 
ter in  the  bile  is  usually  from 
9  to  12  per  cent.,  nearly  the 
whole  of  which  consists  of  cho- 
lesterin and  bilin.  Cholesterin 
is  almost  altogether  composed 
of  carbon  and  hydrogen.  Bi- 
lin contains  nitrogen.  Its  formula  is  C^'^H^'^O^'^N^  and  a  certain  amount 
of  sulphur. 

One  cause  of  the  discrepancies  in  the  analyses  of  bile  is  considered 
to  be  the  facility  with  which  it  undergoes  decomposition.  Such  has 
long  been  the  opinion  of  distinguished  chemists,  as  Berzelius  and  Mul- 
der, and  it  is  held  by  a  more  recent  analyst,  Strecker,  who  affirms  that 
bile  consists  essentially  of  two  soda  salts,  formed  of  soda  and  two  resin- 
ous acids — one  of  them  containing  nitrogen  and  no  sulphur;  the  other 
a  large  quantity  of  sulphur  and  no  nitrogen.  Bilin,  in  other  words,  is, 
according  to  him,  a  compound  substance  formed  of  cholate  or  glycocho- 
late,  and  of  sulpho-cholate,  choleate  or  taurocholate  of  soda, — all  the 
other  products  obtained  from  it  being  the  results  of  its  decomposition.'* 

'  Biilletino  Mediche  di  Bologna,  p.  IGO,  Agosto  et  Settembre,  1836. 

2  Op.  cit.,  S.  41. 

^  Hannov.  Annal.  1  and  2,  1845,  cited  in  Simon's  Animal  Cl'emistry,  Sydenham 
edition,  ii.  519,  London,  1846. 

^  For  the  analyses  of  Grunderlach  and  Strecker,  Mulder,  and  Bensch,  see  British  and 
Foreign  Medico-Chirurgical  Review,  Jan.,  1849,  p.  259  ;  also,  Carpenter's  Princii^Ies  of 
Human  Fhysiology,  4th  Amer.  edit.,  p.  620;  and  for  those  of  J.  Redtenbacher,  Bensch 
and  Strecker,  the  Report  of  Scherer  in  Canstatt  and  Eisenmann's  Jahresbericht  iiber 
die  Fovtschritte  in  der  Biologic  im  Jahre,  1848,  S.  78,  Erlang.,  1849. 
VOL.  1. — 30 


Crystals  of  Cholesterin,  with  Mucous  Corpuscles  and 
Blood-disGS. 


546  SECRETION" 

Messrs.  Kirkes  and  Paget^  think,  that  the  analysis  of  Berzelius  is  the 
most  nearly  correct  of  the  many  that  have  been  published;  but  that, 
after  all,  its  physiology  is  perhaps  more  illustrated  by  its  ultimate  ele- 
mentary composition,  which  shows,  that,  compared  with  the  organic 
parts  of  the  blood,  it  contains  a  large  preponderance  of  carbon  and 
hydrogen,  and  a  deficiency  of  nitrogen. 

The  specific  gravity  of  bile,  at  6°  centigrade,  according  to  M. 
Thdnard,  is  1-026,  and  John,  Schiibler  and  Kapff  accord  with  him. 
Frerichs  found  it  to  be,  in  one  case,  1-04:0 ;  in  another,  1-032.  Schultz 
found  that  of  an  ox,  after  feeding,  at  15°  to  be  1-026;  of  a  fasting 
animal,  1-030. 

Hepatic  and  cystic  bile  do  not  appear  to  differ  materially  from  each 
other,  except  in  the  greater  concentration  of  the  difierent  elements  in 
the  latter.  MM.  Leuret  and  Lassaigne^  found  them  to  be  alike  in  the 
dog.  M.  Orfila,^  however,  affirms,  that  human  hepatic  bile  does  not 
contain  picromel. 

When  bile  is  placed  in  contact  with  concentrated  nitric  acid,  it  first 
of  all  assumes  a  deep  green  tint,  which  passes  to  blue  on  the  addition 
of  a  fresh  portion  of  the  acid,  and  to  red  if  we  continue  to  add  the 
acid, — qualities  which  enable  it  to  be  detected  in  the  urine,  and  in  the 
serum  of  the  blood  of  the  jaundiced.'*  Examined  with  the  microscope, 
it  is  seen  to  contain  a  few,  and  but  a  few,  globules  of  mucus,  proceed- 
ing, according  to  M.  Mandl,*  from  the  muciparous  glands  of  the  gall- 
bladder ;  lamellge  of  cylinder-epithelium  swimming  in  an  amorphous 
liquid,  and  small  yellowish  globules.  At  times,  crystals  of  cholesterin 
are  also  observed  in  it. 

It  is  impracticable  to  fix  upon  any  average  amount  of  bile  secreted 
in  the  24  hours.  This  must  vary  according  to  the  amount  of  food,  and 
the  number  of  times  it  is  taken,  independently  of  other  circumstances. 
According  to  Burdach,^  from  the  experiments  of  De  Graaf  and  Keill 
on  dogs,  Haller  inferred,  that  24  ounces  are  secreted  by  man  in  that 
time.  It  was  not,  however,  from  the  experiments  of  De  Graaf  and 
Keill,  that  Haller  drew  such  inference,  but  from  those  of  Maurice  Van 
Reverhorst.^  Liebig  estimates  the  daily  discharge  at  from  17  to  24 
ounces.*  In  the  experiments  of  M.  Blondlot,^  twelve  and  a  half 
drachms  on  an  average  were  found  to  be  discharged  from  a  fistulous 
opening  in  the  gall-bladder  of  a  dog ;  and  if  the  liver  of  man  be  sup- 
posed— with  Haller — to  secrete  four  or  five  times  as  much  as  that  of 
the  dog,  we  should  have  from  six  to  eight  ounces  as  the  average  quan- 
tity of  h\\e  discharged  into  the  intestinal  canal  of  man  in  the  twenty- 
four  hours.  The  observations  of  Bidder  and  Schmidt'"  carry  it,  how- 
ever, much  beyond  this — to  from  three  to  four  pounds  in  the  twenty- 
four  hours. 

'  Manual  of  Physiology,  2d  Amer.  edit.,  p.  194,  Philad.,  1853. 

*  Recherches,  &c.,  sur  la  Digestiou,  Paris,  1825. 
s  Elt'in.  de  Chimie,  Paris,  1«17. 

*  The  Author's  Practice  of  Medicine,  3d  edit.,  i.  669,  Philad.,  1848. 

*  Manuel  d'Anatoraie  Generale,  p.  501,  Paris,  1843. 

*  Die  Physiologic,  u.  s.  w.  v.  2ti0,  Leipzig,  1835. 

'  Haller,  Elementa  Physiologic,  lib.  xxiii.,  sect.  3,  §  30,  Bern.,  1764. 

«  Animal  Chemistry,  edited  by  Gregory,  Amer.  edit.,  p.  62,  Cambridge,  1842. 

'  Essai  sur  les  Fonctions  du  Foie,  p.  61,  Paris,  1846. 

"'  Die  Verdauungssafte,  u.  s.  w.,  S.  287,  Mitau  und  Leipzig,  1852. 


OF  THE   LIVER.  547 

The  amount  of  bile  contained  in  the  gall-bladder  varies.  In  more 
than  one  hundred  cases  the  largest  quantity  was  111*65  grammes  (oz. 
3"6):  the  smallest  4*60  grammes  (dr.  1"18).  The  average  quantity,  ac- 
cording to  the  observations  of  Von  Gorup-Besanez'  is  from  20  to  30 
grammes  (dr.  5*14  to  dr.  7'72). 

The  great  uses  of  the  bile  have  been  detailed  under  the  head  of  di- 
gestion. It  has  been  conceived  to  be  a  necessary  depuratory  excretion, 
separating  from  the  blood  matters,  that  would  be  injurious  if  retained. 
This  last  idea  is  probable,  and  it  has  been  ingeniously  urged  by  MM. 
Tiedemann  and  Gmelin,^  who  regard  the  function  of  the  liver  to  be 
supplementary  to  that  of  the  lungs — in  other  words,  to  remove  hydro- 
carbon from  the  system.  The  arguments,  adduced  in  favour  of  their 
position,  are  highly  specious  and  ingenious.  The  resin  of  the  bile,  they 
say,  abounds  most  in  herbivorous  animals,  whose  food  contains  a  great 
disproportion  of  carbon  and  hydrogen.  The  pulmonary  and  biliary 
apparatuses  are  in  different  tribes  of  animals,  and  even  in  differnt  ani- 
mals of  the  same  species,  in  a  state  of  antagonism  to  each  other.  The 
size  of  the  liver  and  the  quantity  of  bile  are  not  in  proportion  to  the 
amount  of  food  and  frequency  of  eating,  but  inversely  proportionate  to 
the  size  and  perfection  of  the  lungs.  Thus,  in  warm-blooded  animals, 
that  have  large  lungs,  and  live  always  in  the  air,  the  liver,  compared 
with  the  body,  is  proportionally  less  than  in  those  that  live  partly  in 
water.  The  liver  is  still  larger  in  proportion  in  reptiles,  which  have 
lungs  with  large  cells  incapable  of  rapidly  decarbonizing  the  blood, — 
in  fishes,  which  decarbonize  the  blood  tardily  by  the  gills;  and,  above 
all,  in  molluscous  animals,  which  effect  the  same  change  very  slowly, 
either  by  gills,  or  by  small  imperfectly  developed  lungs.  Again; — 
the  quantity  of  venous  blood,  sent  through  the  liver,  increases  as  the 
pulmonary  system  becomes  less  perfect.  In  the  mammalia,  and  birds, 
the  vena  porta  is  formed  by  the  veins  of  the  stomach,  intestines,  spleen, 
and  pancreas;  in  the  tortoise,  it  receives  also  the  veins  of  the  hind  legs, 
pelvis,  tail,  and  the  vena  azygos;  in  serpents,  the  right  renal,  and  all 
the  intercostal  veins;  in  fishes,  the  renal  veins,  and  those  of  the  tail  and 
genital  organs.  Moreover,  during  the  hibernation  of  certain  of  the 
mammalia,  when  respiration  is  suspended,  and  no  food  taken,  the  secre- 
tion of  bile  goes  on.  Another  argument  is  deduced  from  the  physiology 
3f  the  foetus,  in  which  the  liver  is  proportionally  larger  than  in  the 
adult,  and  the  bile  secreted  copiously,  as  appears  from  the  great  in- 
crease of  the  meconium  during  the  latter  months  of  utero-gestation. 

Their  last  argument  is  drawn  from  pathological  facts.  In  pneumonia 
and  phthisis,  the  secretion  of  bile,  according  to  their  observations,  is 
increased;  in  diseases  of  the  heart,  the  liver  is  enlarged;  and  in  morbus 
3aeruleus  the  organ  retains  its  foetal  proportion.  In  hot  climates,  too, 
where,  in  consequence  of  the  greater  rarefaction  of  the  air,  respiration 
is  less  perfectly  effected  than  in  colder,  a  vicarious  decarbonization  of 
the  blood  is  established  by  an  increased  flow  of  bile.  That  the  sepa- 
ration of  bile  from  the  blood  is  not,  however,  an  indispensable  function, 
notwithstanding  the  experiments  of  Schwann,  to  be  mentioned  pre- 

'  Op.  cit.,  S.  28. 

*  Die  Verdauung  nach  Versuchen,  &c.,  traduit  par  Jourdan,  Paris,  1827. 


548  SECRETION" 

sentlj^,  is  shown  by  Dr.  Blundell/  who  gives  the  cases  of  two  children 
that  lived  for  four  months,  apparently  well  fed  and  healthy,  and,  on 
opening  their  bodies,  it  was  found,  that  the  biliary  ducts  terminated  in 
a  cul-de-sac,  and,  consequently,  not  a  drop  of  bile  had  been  discharged 
into  the  intestines. 

Admitting,  then,  that  the  bile  is  in  part  a  depuratory  secretion,  it  is 
probable,  that  the  depuration  is  effected  from  the  blood  of  the  hepatic 
artery  as  well  as  from  that  of  the  portal  system.  The  veins  of  the 
stomach  and  small  intestines  necessarily  absorb  much  heterogeneous 
matter,  which  may  be  separated  by  the  liver,  along  with  other  pro- 
ducts which  might  be  injurious  if  they  passed  into  the  mass  of  the 
blood.  Still,  although  ultimately  perhaps  largely  excrementitious,  but 
a  small  portion  of  it  is  thrown  out  of  the  economy  by  the  intestinal 
canal,  the  remainder  being  absorbed  from  the  mucous  membrane.  This 
is  shown  by  the  fact,  that  whilst  the  weight  of  the  faeces  discharged  in 
the  twenty-four  hours  has  been  estimated  at  five  or  six  ounces,  that  of 
the  bile  has  been  reckoned  at  between  three  or  four  pounds;  and  Bidder 
and  Schmidt  infer,  that  the  proportion  of  the  effete  rejected  matters  in 
the  intestinal  canal  is  not  more  than  one-eighth,  and  probably  under 
one-fifteenth,  of  its  solid  portion.^ 

The  views  of  Liebig^  on  this  function,  as  well  as  on  that  of  the  urin- 
ary secretion,  are  ingenious;  and,  if  not  true,  are  at  least  plausible. 
Venous  blood,  before  reaching  the  heart,  passes  through  the  liver; 
arterial  blood  through  the  kidney ;  and  both  these  organs  separate 
from  the  blood  substances  that  are  incapable  of  serving  for  the  nutri- 
tion of  the  tissues.  The  compounds  which  contain  the  nitrogen  of  the 
transformed  tissues  are  collected  in  the  urinary  bladder;  and,  not  being 
inservient  to  any  further  use,  are  expelled  from  the  body.  Those,  again, 
which  contain  the  carbon,  are  collected  in  the  gall-bladder,  in  the  form 
of  a  compound  of  soda — bile — which  is  miscible  with  water  in  every 
proportion,  and  passing  into  the  duodenum  mixes  with  the  chyme.  All 
those  parts  of  the  bile,  which,  during  the  digestive  process,  do  not  lose 
their  solubility,  return,  during  that  process,  into  the  circulation  in  a 
state  of  extreme  division.  The  soda  of  the  bile,  and  the  highly  car- 
bonized portions  which  are  not  precipitated  by  a  weak  acid,  retain  the 
capability  of  being  taken  up  by  the  absorbents  of  the  small  and  large 
intestines — a  capability  which  has  been  directly  proved  by  the  admin- 
istration of  enemata  containing  bile, — the  whole  of  the  bile  having 
disappeared  along  with  the  injected  fluid.  Liebig  affirms,  that  the 
constituents  of  bile  cannot  be  recognized  in  the  faeces  of  carnivorous 
animals;  whence  he  infers  that  the  whole  of  the  bile  has  been  reab- 
sorbed; and — he  believes — in  order  that  its  hydro-carbon  may  pass  off 
by  the  lungs.  This  can  scarcel}^,  however,  apply  to  man;  and  Liebig 
admits,  that  in  the  herbivora  a  certain  portion  of  the  elements  of  the 
bile  can  be  discovered  in  the  faeces.  Certainly,  a  marked  difference  is 
observable  in  them  when  the  biliary  ducts  are  obstructed.  As  to  the 
precise  change  effected  on  the  bile  in  order  to  fit  it  for  being  reabsorbed, 

'  Stokes,  Theory  and  Practice  of  Medicine,  American  Medical  Library  edition,  p.  104. 
Philad.,  1837. 

'^  T.  K.  Chambers,  Digestion  and  its  Derangements,  p.  178,  Lond.,  1856. 
3  Aninial  Chemistry,  Gregory's  edit.,  p.  57^  Cambridge,  Mass.,  1843. 


OF   THE    LIVER.  549 

Liebig  leaves  us  wholly  in  the  dark.  His  observations  on  this  matter 
afford  room  for  interesting  reflection;  but  they  can  only  at  present  be 
regarded  in  the  light  of  suggestions.  It  would  appear,  however,  from 
the  analyses  of  different  observers,  that  the  feces  of  both  children  and 
adults  contain  scarcely  any  evidences  of  bile,  except  in  cases  in  which 
they  are  hurried  through  the  canal  so  that  time  is  not  allowed  for  its 
absorption.^  Moreover,  the  experiments  of  Schwann^  seem  to  show, 
that  it  is  not  a  mere  excretory  fluid,  but  must  be  inservient  to  import- 
ant purposes  in  the  economy.  He  removed  a  portion  of  the  common 
choledoch  duct,  and  established  an  external  fistulous  opening  into  the 
gall-bladder,  so  that  the  bile,  when  secreted,  might  be  discharged  ex- 
ternally, and  not  be  permitted  to  enter  the  intestine.  The  general 
result  was,  that  of  eighteen  dogs  operated  upon,  ten  died  of  the  imme- 
diate effects  of  the  operation;  and  of  the  remaining  eight,  two  recovered, 
and  six  died.  In  the  latter,  death  appeared  to  result  altogether  from 
the  removal  of  the  bile.  After  the  third  day,  they  lost  weight  daily, 
and  had  every  sign  of  inanition — as  emaciation,  muscular  debility, 
uncertain  gait,  falling  off  of  the  hair,  &c.  They  lived  from  seven  to 
sixty-four  days  after  the  operation,  and  the  longer  they  survived,  the 
more  marked  were  the  signs  of  inanition.  Licking  the  bile,  as  it  flowed 
from  the  opening,  and  swallowing  it,  had  no  influence  on  the  results. 
In  the  two  dogs  that  recovered,  the  importance  of  the  bile  was  equally 
shown ;  for  it  was  found,  when  they  were  killed,  that  the  passage  of  the 
bile  into  the  intestine  had  been  restored,  and  the  period  of  its  restora- 
tion was  distinctly  shown  by  their  weight — which  had  previously  been 
regularly  and  progressively  decreasing — becoming  augmented,  and 
continuing  to  augment  until  it  amounted  to  what  it  was  before  the  ope- 
ration; and  likewise  by  the  fistulous  opening  into  the  gall-bladder 
healing,  and  the  discharge  of  bile  ceasing.  These  experiments  do  not, 
however,  lead  to  any  exact  inference  as  to  the  mode  in  which  the  bile 
exerts  its  important  agency. 

It  is  proper,  however,  to  add,  that  Schwann's  experiments,  when 
repeated  with  some  modifications  by  M.  Blondlot,^  led  to  very  different 
results.  In  the  first  of  these,  an  external  fistulous  opening  was  made 
into  the  gall-bladder  of  a  dog,  and  the  ductus  communis  choledochus 
having  been  tied  in  two  places,  it  was  divided  between  the  ligatures. 
At  first  the  animal  appeared  distressed,  but  in  a  few  hours  it  recovered. 
The  bile  continued  to  flow  from  the  external  opening,  and  was  con- 
stantly licked  off".  On  the  fifteenth  day,  the  wound  had  healed  with 
the  exception  of  the  small  aperture  through  which  the  bile  flowed. 
The  dog  was  then  muzzled  to  prevent  his  licking  it ;  after  which  the 
faeces  became  discoloured  and  hard.  At  this  time  he  had  become  much 
emaciated  although  he  had  eaten  heartily ;  but  he  now  began  to  regain 
his  flesh,  and  at  the  end  of  three  months  was  perfetly  well  and  active, 
and  so  continued.  Another  animal,  which  was  experimented  on  in  the 
same  way,  and  presented  the  same  phenomena,  was  killed  at  the  end  of 
forty  days,  when  it  was  found  that  the  ductus  communis  choledochus 

'  Tettenkofer,  cited  by  Von  Gorup-Besanez,  Untersuchungen  iiber  Galle,  S.  51,  Er- 
langeii,  184(5. 

^  Mailer's  Arcliiv.,  Heft  ii.,  1844. 

2  Es^ai  sur  les  Fouctions  du  Foie  et  de  ses  Annexes,  Paris,  1846. 


550  SECRETION 

"had  become  completely  obliterated.  He  subsequently^  experimented 
on  a  dog,  which  lived  five  years  after  a  biliary  fistula  had  been  esta- 
blished, by  which  the  bile  was  all  discharged.  Until  near  the  end  of 
its  existence,  it  did  not  appear  to  fall  off  in  its  nutrition,  had  a  good 
appetite,  and  bore  young  yearly.  From  these  experiments,  M.  Blondlot 
inferred,  that  the  bile  plays  no  important  part  in  the  process  of  diges- 
tion, and  that  it  is  essentially  and  wholly  an  excrementitious  fluid. 

If  the  excretion  of  the  bile  be  prevented  from  any  cause,  we  know 
that  derangement  of  health  is  induced;  but  it  is  probable,  that  its 
agency  in  the  production  of  disease  is  much  overrated ;  and  that,  as 
M.  Broussais  has  suggested,  the  source  of  many  of  the  affections  termed 
hiUous  is  in  the  mucous  membrane  lining  the  stomach  and  intestines; 
which,  owing  to  the  heterogeneous  matters  constantly  brought  into 
contact  with  it,  must  be  peculiarly  liable  to  be  morbidly  affected. 
AVhen  irritation  exists  there,  we  can  understand  how  the  secretion 
from  the  liver  may  be  consecutively  modified, — the  excitement  spread- 
ing directly  along  the  biliary  ducts  to  the  secretory  organ. 

It  has  been  shown  by  M.  Bernard,^  on  the  strength  of  experiments 
instituted  by  him,  that  a  regular  function  of  the  liver  is  the  formation 
of  sugar — glycogeny.  The  fact  of  the  conversion  of  amylaceous  into 
saccharine  matter  by  the  contact  of  blood,  saliva,  &c.,  has  been  else- 
where referred  to;^  but  from  his  researches,  it  would  follow,  that  the 
liver  alone  has  the  power  of  producing  sugar  without  starch,  and  that 
such  production  is  connected  with  the  integrity  of  the  pneumogastric 
nerves.  M.  Bernard,  after  several  experiments,  discovered  that  if  the 
floor  of  the  fourth  ventricle  was  pierced  within  a  very  circumscribed 
space,  in  less  than  half  an  hour,  a  very  considerable  quantity  of 
sugar — diabetic  sugar — was  found  in  the  blood  and  urine,  without 
the  regimen  of  the  animal  having  undergone  any  change  whatever. 
This  fact  attracted  his  attention  to  the  condition  of  the  floor  of  the 
fourth  ventricle  in  diabetic  patients,  and  in  one  case,  on  dissection, 
two  dark  spots  were  observed  on  the  part  w^hich  must  be  penetrated 
to  produce  the  sugar.  Increased  saccharine  formation  was  likewise 
caused  by  pricking  or  gently  galvanizing  the  eighth  pair  in  the  neck, 
whilst  it  was  suspended  by  dividing  both  pneumogastrics.  As  the 
sugar  is  formed  in  the  liver,  it  is  conveyed  away  by  the  veins  proceed- 
ing from  the  organ,  and  has  been  detected  by  M.  Bernard  in  the  hepa- 
tic veins,  vena  cava  superior,  and  right  cavities  of  the  heart;  whilst  in 
other  parts  of  the  body  the  blood  contains  none  or  very  feeble  traces 
of  it,  except  after  the  digestion  of  amylaceous  substances,  wdien  a 
notable  quantity  may  be  found  in  all  the  veins.  As  the  saccharine 
matter,  produced  by  the  liver  under  the  circumstances  mentioned,  is 
not  met  with  in  the  pulmonary  veins,  MM.  Magendie*  and  Bernard 
inferred  that  it  must  have  undergone  destruction  in  the  lungs;  and 
they  think  it  not  impossible,  that  from  such  destruction  the  carbonic 

'  Gazette  Medicale,  1851,  No.  2G,  p.  407. 

^  Archives  Gem-rales,  Nov.,  1848  ;  see,  also,  Ranking's  Half- Yearly  Abstract  of  the 
Medical  Sciences,  ix.  215,  Jan.  to  June,  1849. 

3  Page  132. 

*  Report  of  M.  Magendie's  Lectures  at  the  College  of  France,  in  Union  M'dicale, 
Nos.  72,  75  and  79,  and  in  British  and  Foreign  Medico-Chirurgical  Review,  p.  545,  Oct., 
1849. 


OF   THE   LIVER.  551 

acid  of  respiration  may  result,  as  has  been  presumed  by  many  pby- 
siologists  to  be  the  case  with  every  form  of  sugar.  All  sugars,  how- 
ever, do  not  appear  to  be  affected  in  the  same  manner.  If,  according 
to  Magendie,  we  inject  into  the  blood  a  solution  of  cane  sugar,  man- 
nite,  or  the  sugar  of  milk,  the  whole  of  it  will  be  found  in  the  urine; 
but  if  we  inject  glucose  or  grape  sugar,  except  in  large  quantity,  none 
of  it  can  be  detected  in  that  fluid.  But  if  an  animal  be  fed  on  the 
first  mentioned  varieties  of  sugar,  they  are  not  found  in  the  urine ; 
because,  according  to  M.  Magendie,  digestion  has  transformed  them 
into  glucose,  and  this  has  become  decomposed  in  the  lungs.  The  fol- 
lowing table  is  given  by  him  to  exhibit  the  quantity  of  the  different 
kinds  of  sugar  that  must  be  injected  into  the  jugular  vein,  in  order 
that  they  may  be  detected  in  the  urine.  It  shows — as  he  has  re- 
marked— that  "the  natural  sugar  of  the  economy  is  destroyed  in  the 
act  of  respiration  with  far  greater  facility  than  that  proceeding  from 
alimentary  substances : — 

Cane  sugar,          .         .         .         .    • 0-05 

Mannite, 0-05 

Sugar  of  milk, 0*25 

Glucose, 2-50 

Sugar  of  the  liver 12-00 

M.  Bernard^  found  sugar  in  the  livers  of  both  the  carnivora  and 
herbivora;  and  when  fasting  as  well  as  when  digesting.  In  the  car- 
nivora, no  sugar  could  be  detected  in  the  blood  of  the  vena  porta, 
whilst  it  was  present  in  considerable  quantity  in  that  of  the  hepatic 
veins;  whence  he  properly  infers  that  the  sugar  is  formed  in  the  liver. 
The  blood,  moreover,  which  leaves  the  liver,  whilst  it  contained  more 
sugar  than  that  which  entered  it,  was  found  to  have  no  more  fibrin 
and  much  less  albumen ;  hence  his  corollary  that  "  the  sugar  appears 
to  be  formed  in  the  liver  at  the  expense  of  the  albuminoid  matters  of 
the  blood."  A  report  made  to  the  French  Academy  of  Sciences  on 
various  and  varied  experiments  by  a  committee  of  that  body  confirms 
most  of  the  statements  of  M.  Bernard.  They  did  not  find,  however, 
that  animals  fed  on  flesh  afforded  the  same  amount  of  sugar  as  those 
fed  on  starch  or  sugar.^ 

As  to  the  precise  mode  in  which  the  sugar  is  produced  in  the  liver 
we  have  no  knowledge.  It  is  probably  by  the  agency  of  hepatic  cells, 
from  which  it  passes  into  the  hepatic  veins.  The  liver,  consequently — 
to  use  the  language  of  M.  Bernard^ — has  an  external  secretion — that  of 
the  bile — which  is  discharged ;  and  an  internal  secretion — that  of  sugar, 
which  enters  immediately  into  the  blood  of  the  general  circulation. 
Sugar — to  employ  the  language  of  Dr.  C.  Handfield  Jones,"*  in  his  last 
communication  on  the  liver — "seems  to  be  the  normal  product  of  the 
cells, — bile  of  the  ultimate  biliary  ducts." 

The  liver,  consequently,  not  only  secretes  bile,  but  is  a  great  assi- 
milating organ;  and  that  it  is  the  seat  of  energetic  nutritive  action  is 
shown  by  the  experiments,  hereafter  referred  to,  by  MM.  Bernard  and 
Walferdin,  which  exhibited  a  higher  temperature  of  the  blood  where 

'  Le  ons  de  Physiologie  Expcrimentale,  &c.,  p.  477,  Paris,  1855. 

2  Lancet,  July  28,  IS'SS.  '  Ibid.,  p.  100. 

*  Philosophical  Transactions,  vol.  clxiii.  pt.  1,  p.  21,  London,  1853. 


552 


SECRETION 


the  supra-hepatic  veins  eater  the  vena  cava  ascendens  than  in  any  other 
part  of  the  body. 

6.  Secretion  of  the  Kidneys. 

This  is  the  most  extensive  secretion  accomplished  by  any  of  the 
glandular  structures  of  the  body,  and  is  essentially  depuratory ;  its 
suppression  giving  rise  to  formidable  evils.  The  apparatus  consists  of 
the  kidneys^  which  secrete  the  fluid ;  the  ureters^  which  convey  the 
urine  to  the  bladder;  the  hiadler  itself,  which  serves  as  a  reservoir  for 
the  urine ;  and  the  urethra^  which  conveys  the  urine  externally.  These 
require  a  distinct  consideration. 

The  kidneys  are  two  glands  situate  in  the  abdomen ;  one  on  each 
side  of  the  spine,  in  the  posterior  ^art  of  the  lumbar  region.  They 
are  Avithout  the  cavity  of  the  peritoneum,  which  covers  them  at  the 
anterior  part  only;  and  are  situate  in  the  midst  of  a  considerable  mass 
of  adipous  areolar  tissue.  The  right  kidney  is  nearly  an  inch  lower 
than  the  left,  owing  to  the  presence  of  the  thick  posterior  margin  of 
the  right  lobe  of  the  liver.  Occasionally,  there  is  but  one  kidney ;  at 
other  times,  three  have  been  met  with.  They  have  the  form  of  the 
haricot  or  kidney  bean,  which  has  indeed,  been  called  after  them ;  and 
are  situate  vertically, — the  fissure  being  turned  inwards.  If  we  com- 
pare them  with  the  liver,  their  size  is  by  no  means  in  proportion  to 

Fig.  175. 


Right  Kidney  with  its  Renal 
Capsule. 

1.  Anterior  face  of  kidney.  2.  Exter- 
nal or  convex  edge.  3.  Itsiuternal  edge. 
4.  Hilum  renale.  5.  Inferior  extremity 
of  kidney.  6.  Pelvi.s  of  ureter.  7.  Ure- 
ter. S,  9.  Superior  and  inferior  branches 
of  emulgent  artery.  10,  11,  12.  Three 
T)ranche.s  of  the  emulgent  vein.  13.  An- 
terior face  of  renal  capsule.  14.  Its  su- 
perior edge.  15.  Its  external  edge.  IG. 
Its  internal  extremity.  17.  Fissure  on 
the  anterior  face  of  the  capsule. 


Plan  of  a  Longitudinal  Sectiun  of  the  Kidney  and 
Upper  Part  of  the  Ureter,  through  the  Hilus,  copied 
from  an  enlarged  model. 

a,  a,  a.  The  cortical  substance.  6,  6.  Broad  part  of  two  of 
the  pyramids  of  JIalpighi.  e,  e.  Section  of  the  narrow  part 
or  apex  of  two  of  these  pyramids,  lying  within  the  divisions 
of  the  ureter  marked  c,  c.  d,  d.  Summits  of  the  pyramids, 
called  papilla,  projecting  into  and  surrounded  by  the  divi- 
sions of  the  ureter,  c,  c.  Divisions  of  the  ureter,  called  the 
caliees  or  infundibula,  laid  open.  c'.  A  calix  or  infundibu- 
lum  unopened,  p.  Enlarged  upper  end  of  ureter,  named 
the  pelvis  of  the  kidney,  s.  Central  cavity  or  sinus  of  the 
kidney. 


the  extensive  secretion   effected  by  them.     Their  united  weight  does 
not  amount  to  more  than  six  or  eight  ounces.     Of  65  male  kidneys, 


OF   THE    KIDNEYS.  553 

weighed  by  Dr.  John  Eeid/  the  average  was  found  to  be  5  oz.  7  dr. 
for  the  right  kidney;  5  oz.  11|  dr.  for  the  left.  Of  28  female  kidneys, 
the  right  weighed  4  oz.  13  dr.;  the  left,  5  oz.  2  dr.  The  left  kidney 
generally  weighs  more  than  the  right  at  all  ages.  The  kidneys  of  the 
new-born  child,  although  absolutely  much  lighter  than  those  of  the 
adult,  are  yet,  according  to  M.  Iluschke,^  in  proportion  to  the  whole 
body  much  heavier;  inasmuch  as  their  weight  is  to  that  of  the  whole 
body  of  the  infant,  as  1  to  82-100;  in  the  adult  as  1  to  225.  They, 
therefore,  do  not  grow  uniformly  with  the  body,  although  the  secre- 
tion of  urine  becomes  more  energetic  after  birth. 

The  kidneys  are  hard,  solid  bodies,  of  a  brown  colour.  The  san- 
guiferous vessels,  which  convey  and  return  the  blood  to  them,  as  well 
as  the  excretory  duct,  communicate  with  them  at  the  fissure. 

The  anatomical  constituents  of  these  ors-ans  are: — 1.  The  renal 
artery^  which  arises  from  the  abdominal  aorta  at  a  right  angle,  and, 
after  a  short  course,  enters  the  kidney,  ramifying  in  its  substance.  2. 
The  excretory  ducts,  which  arise  from  every  part  of  the  tissue,  in  which 
tlie  ramifications  of  the  renal  artery  terminate.  They  end  in  the  pelvis 
of  the  kidney.  (Fig.  175.)  3.  The  re?2aZ  wm,s,  which  receive  the  super- 
fluous blood,  after  the  urine  has  been  separated  from  it,  and  terminate 
in  the  renal  or  emulgent  vein,  which  issues  at  the  fissure,  and  opens 
into  the  abdominal  vena  cava.  4.  Lymphatic  vessels,  arranged  in  two 
planes — a  superficial  and  a  deep-seated,  which  terminate  in  the  lumbar 
glands.  5.  Nerves,  which  proceed  from  the  semilunar  ganglion,  solar 
plexus,  &c.,  and  surround  the  renal  artery  as  with  a  network,  follow- 
ing it  in  all  its  ramifications.  6.  Areolar  membrane,  which,  as  in 
every  other  organ,  binds  the  parts  together.  These 
anatomical  elements,  by  their  union,  constitute  the  Fig.  176. 

organ  as  we  find  it.  . 

When  the  kidney  is  divided  longitudinally,  it  is 
seen  to  consist  of  two  substances,  which  differ  in  their      ' 
situation,  colour,  consistence,  and  texture.     One  of 
these,  and  the  more  external,  is  called  the  cortical,  ^"^^M 

glandular  OT  vascular  substance.    .It  forms  the  whole  ">     v 

circumference  of  the  kidney;  is  about  two  lines  in  ^■%i'wh~ 

thickness;  of  less  consistence  than  the  other;   of  a  t^^'--^-'^  ^ 

pale  red  colour;    and   receives  almost  entirely  the        ■>    ^;%'i;' 
ramifications  of  the  renal  artery.     The  other  and  in-  C^U  '        ^ 

nermost  is  the  tubular,  medullary,  iiriniferous,  conoidal  ^    ^  \  ;^, 

or  radiated  substance.   It  is  more  dense  than  the  other;  \kl>)j 

less  red;  and  seems  to  be  formed  of  numerous  minute  \M 

tubes,  which  unite  in  conical  bundles  of  unequal  size  \-A 

■ — pyramids  of  Malpiyhi — the  base  of  which  is  turned  v\ 

towards  the  cortical  portion, — the  apices  forming  the    Portion  of  Kidney  of 
pjapiUce  or  mammillary processes,  and  facing  the  pelvis  of      New-born  infant, 
the  kidney.   The  papillee  vary  in  number  from  five  to      a.  Natural  size.    b. 

•     1,  "^  D       n       •  1        1  ^  ^^      •  •     i        ^   small    portion   of   a 

eighteen;  are  of  a  norid  colour;  and  upon  their  points  magnified,  i,  i.  cor- 
or  apices  are  terminations  of  uriniferous  tubes  large    tuwu  urfufi^l-r*'    ^' 

'  Lond.  cand  Edinb.  Montlily  Journal  of  Med.  Science,  April,  1843,  p.  323. 
^  Eucyclop.  Anatom.,  traduit  jaar  Jourdan,  v.  321,  Paris,  1845. 


Ill 


554 


SECRETION 


enough  to  be  distinguislied  by  the  naked  eye.     Around  tbe  root  of 

each  papilla,  a   mem- 
Fig.  177.  branous     tube     arises 
3                  ,      a       .3                               called  ca?ia:  or  infundi- 

bulum ;  this  receives 
the  urine  from  the  pa- 
pilla, and  conveys  it 
into  the  pelvis  of  the 
kidney,  which  may  be 
regarded  as  the  com- 
mencement of  the 
ureter. 

The  cortical  part 
of  the  kidney  is  the 
most  vascular;  and  the 
plexus  formed  by  the 
tubuli  uriniferi appears 
to  come  there  in  closest 
relation  with  that  form- 
ed by  the  renal  capil- 
laries. The  corpora 
Malpigkiana  or  Mal- 
pighian  bodies  appear 
as  points  in  the  cortical 
substance.  They  are 
scattered  through  the 
plexus  formed  by  the 
bloodvessels  and  urini- 
ferous  tubes.  Each 
one,  when  examined 
by  a  high  magnifying 
power,  is  found  to  con- 
sist of  a  convoluted 
mass  of  minute  blood- 
vessels. In  them — it 
was  at  one  time  sup- 
posed— the  uriniferous 
tubes  originate ;  but 
the  examinations  of 
Miiller  and  Iluschke 
have  seemed  to  show, 
that  they  are  only  capa- 
ble of  injection  from 
the  arteries  or  veins. 
They  are  found  in  the 
kidneys  of  most,  if  not 
all,  of  the  vertebrata. 
In  the  cortical  sub- 
stance, according  to  "Wagner,^  the  tubuli  can  be  traced,  although  with 


Small  Portion  of  Kidney  magnified  60  diameters. 

1.  Csecal  extremity  of  a  tubulus.  2,  2.  Loops  of  tubuli.  3,  3.  Bifur 
eated  tubuli.  4,  .'5,  6.  Tubuli  converging  towards  the  papillse.  7,  7,  7 
Corpora  Malpigkiana.     8.  Arterial  trunk. 


'  Elements  of  Physiology,  by  R.  Willis,  §  193,  Lond.,  1842. 


OF   THE   KIDNEYS. 


555 


difficulty,  winding  among  the  vascular  plexuses  or  skeins,  mostly  looped 
towards  the  margin  of  the  organ,  and  running  into  one  another,  or 
having  blind  or  cascal  extremities;  more  rarely  enlarged  and  club- 
shaped,  and  occasionally  cleft.  The  entire  cortical  substance,  according 
to  Wagner,  consists  of  convolutions  of  the  uriniferous  tubes,  which 
present  a  nearly  uniform  diameter,  on  an  average,  from  about  the  60th 
to  the  50th  of  a  line.     Professor  Goodsir,^  however,  without  denying 


Section  of  the  Cortical  Substance  of  the  Human  Kidney. 

A,  A.  Tubnli  nriniferi  divided  transversely,  showing  the  spheroidal  epithelium  in  their  interior,  b. 
Malpighian  capsule,  a.  Its  afferent  branch  of  the  renal  artery,  b.  Its  glomerulus  of  capillaries,  c,  c. 
Secreting  plexus,  formed  by  its  efferent  vessels,    d,  d.  Fibrous  stroma. 

the  existence  of  occasional  blind  extremities  of  the  tubuli  uriniferi — 
the  result  probably,  he  thinks,  of  arrested  developement — states,  that 
he  has  never  seen  the  ducts  terminate 
in  this  way.  He  has  described  a 
fibro-areolar  framework,  which,  per- 
vading every  part  of  the  gland,  and 
particularly  its  cortical  portion,  per- 
forms the  same  office  in  the  kidney 
as  the  capsule  of  Glisson  does  in 
the  liver, — being  a  basis  of  support 
to  the  delicate  structure  of  the  gland, 
conducting  the  bloodvessels  through 
the  organ,  and  constituting  small 
chambers  in  the  cortical  portion,  in 
each  of  which  a  single  ultimate  coil 
or  loop  of  the  uriniferous  ducts  is 
lodged.  Mr.  Goodsir  believes,  that 
the  urine  is  formed  at  first  within  the 
epithelium  cells  of  the  ducts,  and  that 
these  burst,  dissolve,  and  throw  out 
their  contents,  and  are  succeeded  by 
others,  which  perform  the  same  func- 
tions. The  urine  of  man  has  not 
been  detected  by  Mr.  Goodsir  within 
the  cells,  that  line  the  ducts,  but  he  has  submitted  to  the  Royal  Society 


Tubuli  Uriniferi. 

A.  Portion  of  a  secreting  canal  from  the  cor- 
tical substance  of  the  kidney,  b.  The  epithe- 
lium or  gland-cells,  more  highly  magnified  (700 
times),  c.  Portion  of  a  canal  from  tho  medul- 
lary substance  of  the  kidney.  At  one  part  the 
basement  membrane  has  no  epithelium  lining  it. 


'  Lond.  and  Edinb.  Monthly  Journ.  of  Med.  Science,  May,  1842. 


556 


SECRETION 


Fis:.  ISO. 


of  Eclinburgli  a  memoir,  already  referred  to,  in  which  he  has  endea- 
voured to  show,  that  urine,  bile,  and  milk,  as  well  as  the  other  more 
important  secretions  in  the  lower  animals,  are  formed  within  the 
nucleated  cells  of  the  ducts  themselves;  and  he  is  of  opinion,  that  the 
urine  of  man  is  poured  at  first  into  the  cavities  of  the  nucleated  cells 
of  the  human  kidney. 

Mr.  Bowman^  describes  the  kidney  as  furnished  with  a  true  portal 
system,  and  is  of  opinion  that  the  urine,  like  the  bile,  is  secreted — in 
part  at  least — from  blood,  traversing  a  second  set  of  capillaries.  Accord- 
ing to  him,  each  of  the  exceedingly  tortuous  and  convoluted  urinary 
conduits  terminates,  at  its  final  extremity,  by  a  contracted  neck,  which 
leads  into  a  little  chamber  or  cyst, — capsule  of  Malpighi — in  which  is 

contained  the  true  glandule,  corpuscle  or 
ghmerule  of  Malpighi.  This  consists  of  a 
tuft  or  coil  of  capillary  bloodvessels,  totally 
naked,  which  originates  in  one  of  the  ulti- 
mate branches  of  the  renal  artery,  and  ter- 
minates in  an  efi'erent  vessel.  Several  of 
these  latter  form,  by  their  anastomosing 
ramifications,  the  plexus  that  surrounds 
each  urinary  conduit  and  tubule ,  the  uri- 
nary conduits  being  lined  by  thick  epithe- 
lium, and  their  necks  furnished  with  vi- 
bratile  cilia.  All  the  blood  of  the  renal 
artery,  according  to  Mr.  Bowman, — with 
the  exception  of  a  small  quantity  distri- 
o/severr.L^pthVarr4r7rrt?  l^^ted  to  the  capsule,  surrounding  fat,  and 
ferent  twig  to  the  capillary  tuft  contain-    the  coats  of  the  larger  vcsscls, — cutcrs  the 

ed  in  the  Malpighiaa  body,  ni;  from  the  .,,  „  pi  a  r    i     •     -   • 

Malpighian  body  the  uriniferous  tube  Is  Capillary  tUltS  Ot  tUC  COrpOra  Malpighiana; 

seen  taking  its  tortuous  course  to  (.   2,2.  .1  '     1.       ±.\  •^^  ^    „ 

Efferent  veins;  that  which  proceeds  from  theUCC    paSSeS     lUtO    thc     CapillarV    plCXUS 

'^^!^^:^i^:^7!^^  surrounding  the  uriniferous  tubes,  and 
capillary  venous  piexus,jamifying  upon    finally   Icavcs    the    Organ    through    the 

branches  of  the  renal  vein.  According 
to  this  view,  there  are  in  the  kidney  two 
perfectly  distinct  systems  of  capillary  ves- 
sels; \he  first,  i}i2ii  inserted  into  the  dilated  extremities  of  the  urinifer- 
ous tubes,  and  in  immediate  connexion  with  the  arteries — the  Mal])i- 
ghian  bodies; — the  second,  that  enveloping  the  convolutions  of  the  tubes, 
and  communicating  directly  with  the  veins.  The  efferent  vessels  of 
the  Malpighian  bodies,  that  carry  the  blood  between  these  two  systems, 
are  termed  by  Mr.  Bowman  the  fjorial  system  of  the  liidney.  The 
views  of  Mr.  Bowman  have  been  embraced  by  man}^  histologists,^  whilst 
every  one  of  them  has  been  strenuously  denied  by  others.  In  regard 
to  the  precise  arrangement  of  the  Malpighian  bodies,  histologists  are 
by  no  means  in  accordance,  Gerlach  for  example,  found,  that  instead 
of  the  flask-like  dilatation  being  placed,  as  maintained  by  ^[r.  Bow- 


Plan  of  the  Renal  Circulation. 


the  uriniferous  tube.  This  plexus  re- 
ceives its  blood  from  the  efferent  veins, 
2,  2,  and  transmits  it  to  the  branch  of  the 
renal  vein,  u. 


'  Proceedinss  of  the  Royal  Society,  No.  lii.,  Feb.  3,  1842;  and  Philos.  Transactions, 
Pt.  1,  p.  57,  Lond.,  1842. 

^  See  on  the  whole  subject  Dr.  Geo.  Johnson,  in  the  article  Ren,  Cyclopaedia  of  Ana- 
tomy and  Physiolosiy,  Pt.  xxxii.  p.  244,  Lond.,  August,  1848;  Gerlach,  Handbuch  der 
Gewebelehre,  S.  301,  Mainz,  1849  ;  and  A.  H.  Hassall,  The  Microscopic  Anatomy  of  the 
Human  Body,  Pt.  xiii.  p.  427,  Loud.,  1848. 


OF   THE   KIDNEYS.  557 

man,  at  the  extremity  of  a  nriniferous  tube,  it  may  be,  and  is  formed 
by  offsets  from  the  sides  of  the  tube;  so  that  the  capsules  maybe  either 
terminal  or  lateral.' 

In  the  quadruped,  each  kidney  is  made  up  of  numerous  lobes,  which 
are  more  or  less  intimately  united  according  to  the  species.  In  birds, 
the  kidney  consists  of  a  double  row  of  distinct,  but  connected,  glandu- 
lar bodies,  placed  on  both  sides  the  lumbar  vertebra. 

The  ureter  is  a  membranous  duct,  which  extends  from  the  kidney  to 
the  bladder.  It  is  about  the  size  of  a  goosequill ;  descends  through 
the  lumbar  region ;  dips  into  the  pelvis  by  crossing  in  front  of  the  primi- 
tive iliac  vessels  and  the  internal  iliac ;  crosses  the  vas  deferens  at  the 
back  of  the  bladder;  and,  penetrating  that  viscus  obliquely,  terminates 
by  an  orifice  ten  or  twelve  lines  behind  that  of  the  neck  of  the  bladder. 
At  first,  it  penetrates  two  of  the  coats  only  of  that  viscus;  running  for 
the  space  of  an  inch  between  the  mucous  and  muscular,  and  then  enter- 
ing the  cavity.  The  ureters  have  three  coats.  The  outermost  is  a  dense 
fibrous  membrane;  the  second  a  smooth  muscular  layer,  which  is  very 
distinct,  with  external  longitudinal,  and  internal  transverse  fibres,  to 
which,  towards  the  bladder,  internal  longitudinal  fibres  are  added.  In 
the  pelvis  of  the  kidney  the  two  muscular  layers  are  as  thick  as  in  the 
ureter;  but  in  the  calices  they  become  thinner  and  thinner,  and  cease 
where  the  latter  are  inserted  into  the  papillee.^  The  innermost  coat 
is  a  thin  mucous  layer,  which  is  continuous  at  its  lower  extremity  with 
the  inner  coat  of  the  bladder ;  and,  at  the  upper  end,  supposed  by  some 
to  be  reflected  over  the  papillo3,  and  even  to  pass  for  some  distance  into 
the  tubuli  uriniferi. 

Sie  bladder  is  a  musculo-membranous  sac,  situate  in  the  pelvis ; 
nor  to  the  rectum,  and  behind  the  pubes.  Its  superior  end  is  called 
upper  fundus;  and  the  lower  end,  inferior  fundus  or  has  fond ;  the  lody 
being  between  the  two.  The  part  where  it  joins  the  urethra  is  the 
nech.  The  shape  and  situation  of  the  organ  are  influenced  by  age  and 
sex.  In  very  young  infants,  it  is  cylindroid,  and  rises  almost  wholly 
into  the  abdomen.  In  the  adult  female,  who  has  borne  many  children, 
it  is  nearly  spherical ;  has  its  greatest  diameter  transverse,  and  is  more 
capacious  than  in  the  male.  Like  the  other  hollow  viscera,  the  bladder 
consists  of  several  coats.  1.  The  peritoneal^  which  covers  only  the 
fundus  and  back  part.  Towards  the  lower  portion  the  organ  is  invested 
by  areolar  membrane,  which  takes  the  place  of  the  peritoneal  coat  of 
the  fundus.  This  tissue  is  very  loose,  and  permits  the  distension  and 
contraction  of  the  bladder.  2.  The  muscular  coat  is  very  strong;  so 
much  so,  that  it  has  been  classed  amongst  the  distinct  muscles,  under 
the  name  detrusor  wince.  The  fibres  are  pale,  uustriped,  and  pass  in 
various  directions.  Towards  the  lower  part  of  the  bladder,  they  are 
particularly  strong;  arranged  in  fasciculi,  and  form  a  kind  of  network 
of  muscles  enclosing  the  bladder.  In  cases  of  stricture  of  the  urethra, 
where  much  efibrt  is  necessary  to  expel  the  urine,  these  fasciculi  acquire 

'  Gerlach,  op.  cit.,  and  in  Miiller's  Archiv.  fiir  Anatomic,  S.  378,  1845  ;  and  Ibid.,  S. 
102,  1848. 

^  Kolliker,  Mikroskopische  Anatomic,  2ter  Band.  S.  365,  Leipzig,  1854;  and  Amer. 
edit,  of  Svdenham  Society's  edit,  of  his  Manual  of  Human  Histology,  by  Dr.  Da  Costa, 
p.  607,  Piiilad.,  Ib54. 


558  SECRETION 

considerable  thickness  and  strength.  3.  The  mncous  or  villous  coat  is 
the  lining  membrane,  which  is  continuous  with  that  of  the  ureters  and 
urethra,  and  is  generally  rugous  in  consequence  of  its  being  more  exten- 
sive than  the  muscular  coat  without.  It  is  furnished  with  numerous 
follicles,  which  secrete  a  fluid  to  lubricate  it.  Towards  the  neck  of  the 
organ,  it  is  thin  and  white,  although  reddish  in  the  rest  of  its  extent, 
A  fourth  coat,  called  the  cellular  or  areolar  has  been  reckoned  by  most 
anatomists,  but  it  is  nothing  more  than  areolar  tissue  uniting  the  mucous 
and  muscular  coats.  The  part  of  the  internal  surface  of  the  bladder, 
situate  immediately  behind  and  below  its  neck,  and  occupying  the  space 
between  it  and  the  orifices  of  the  ureters,  is  called  vesical  triangle^  tri- 
gonus  Lieutaucli  or  trigone  vesical.  The  anterior  angle  of  the  triangle 
looks  into  the  orifice  of  the  urethra,  and  is  generally  so  prominent,  that 
it  has  obtained  the  name  uvula  vesicce.  It  is  merely  a  projection  of  the 
mucous  membrane,  dependent  upon  the  subjacent  third  lobe  of  the 
prostate  gland,  which,  in  old  people,  is  frequently  enlarged,  and  occa- 
sions difficulty  in  passing  the  catheter.  The  neck  of  the  bladder  pene- 
trates the  prostate;  but,  at  its  commencement,  it  is  surrounded  by  loose 
areolar  tissue,  containing  a  very  large  and  abundant  plexus  of  veins. 
The  internal  layer  of  muscular  fibres  is  here  transverse ;  and  they  cross 
and  intermix  with  each  other  in  different  directions,  forming  a  close, 
compact  tissue,  which  has  the  effect  of  a  particular  apparatus  for  retain- 
ing the  urine,  and  has  been  called  the  sphincter.  Anatomists  have  not 
usually  esteemed  this  structure  to  be  distinct  from  the  muscular  coat  at 
large;  but  Sir  Charles  Bell'  asserts,  that  if  we  begin  the  dissection  by 
taking  off  the  inner  membrane  of  the  bladder  from  around  the  orifice 
of  the  urethra,  a  set  of  fibres  will  be  discovered  on  the  lower  htfalf  of 
the  orifice,  which,  being  carefully  dissected,  will  be  found  to  run  m  a 
semicircular  form  around  the  urethra.  These  fibres  make  a  band  of 
about  half  an  inch  in  breadth,  particularly  strong  on  the  lower  part  of 
the  opening;  and  having  ascended  a  little  above  the  orifice  on  each 
side,  they  dispose  of  a  portion  of  their  fibres  in  the  substance  of  the 
bladder.  A  smaller  and  somewhat  weaker  set  of  fibres  will  be  seen  to 
complete  their  course,  surrounding  the  orifice  on  the  upper  part.  The 
arteries  of  the  bladder  proceed  from  various  sources,  but  chiefly  from 
the  umbilical  and  common  pudic.  The  veins  return  the  blood  into  the 
internal  iliacs.  They  form  a  plexus  of  considerable  size  upon  each  side 
of  the  bladder,  particularly  about  its  neck.  The  lymphatics  accompany 
the  principal  veins  of  the  bladder,  and,  at  the  under  part  and  sides, 
pass  into  the  iliac  glands.  The  nerves  are  from  the  great  sympathetic 
and  sacral. 

The  urethra  is  the  excretory  duct  of  the  bladder.  It  extends,  in  the 
male,  from  the  neck  of  the  bladder  to  the  extremity  of  the  glans;  and 
is  from  seven  to  ten  inches  in  length.  In  the  female  it  is  much  shorter. 
The  male  urethra,  in  the  state  of  flaccidity  of  the  penis,  has  several  cur- 
vatures; but  is  straight  or  nearly  so,  if  the  penis  be  drawn  forwards 
and  upwards,  and  the  rectum  be  empty.  The  first  portion  of  this  canal, 
which  traverses  the  prostate  gland,  is  called  the  prostatic  portion.  Into 
it  open, — on  each  side  of  a  caruncle,  called  verumontanum,  cajmt  galli- 

'  Anatomy  and  Physiol.,  5th  Amer.  edit,  by  Dr.  Godman,  ii.  375,  New  York,  1829. 


I 

i 


OF   THE   KIDNEYS.  559 

naginis  or  crista  urethralis, — the  two  ejaculatory  ducts,  those  of  the 
prostate,  and  a  little  lower,  the  orifice  of  Cowper's  glands.  Between 
the  prostate  and  the  bulb  is  the  memhranons  part  of  the  urethra,  which 
is  eight  or  ten  lines  long.  The  remainder  of  the  canal  is  called  corpus 
spongiosum  or  spongy  portion^  because  surrounded  by  an  erectile  spongy 
tissue.  It  is  situate  beneath  the  corpora  cavernosa,  and  passes  forward 
to  terminate  in  the  glans,  the  structure  of  which  will  be  considered 
under  Generation.  At  the  commencement  of  this  portion  of  the  urethra 
is  the  bulb,  the  structure  of  which  resembles  that  of  the  corpora  caver- 
nosa of  the  penis — to  be  described  hereafter.  The  dimensions  of  the 
canal  are  various.  At  the  neck  of  the  bladder  it  is  considerable ;  be- 
hind the  caput  gallinaginis  it  contracts,  and  immediately  enlarges  in  the 
forepart  of  the  prostate.  The  membranous  portion  is  narrower;  and 
in  the  bulb  the  channel  enlarges.  In  the  body  of  the  penis,  it  dimi- 
nishes successively,  till  near  the  glans,  when  it  is  so  much  increased  in 
size  as  to  have  acquired  the  name  fossa  navicularis.  At  the  apex  of 
the  glans  it  terminates  by  a  short  vertical  slit.  Mr.  Shaw^  has  described 
a  set  of  vessels,  immediately  on  the  outside  of  the  internal  membrane 
of  the  urethra,  which,  when  empty,  are  very  similar  in  appearance  to 
muscular  fibres.  These  vessels,  he  remarks,  form  an  internal  spongy 
body,  which  passes  down  to  the  membranous  part  of  the  urethra,  and 
forms  even  a  small  bulb  there.  Dr.  Horner,^  however,  says,  that  this 
appeared  to  him  to  be  rather  the  areolar  membrane  connecting  the  canal 
of  the  urethra  with  the  corpus  spongiosum.  The  whole  of  the  urethra 
is  lined  by  a  very  vascular  and  sensible  mucous  membrane,  which  is 
continuous  with  the  inner  coat  of  the  bladder.  It  has,  apparently,  a 
certain  degree  of  contractility ;  and  therefore,  by  some  anatomists,  is 
conceived  to  possess  muscular  fibres.  Sir  Everard  Home,  from  the 
results  of  his  microscopical  observations,  is  disposed  to  be  of  this 
opinion.  This  is,  however,  so  contrary  to  analogy,  that  it  is  probable 
the  fibres  may  be  seated  in  the  tissue  surrounding  it.  The  membrane 
contains  numerous  follicles,  and  several  lacunae,  one  or  two  of  which, 
near  the  extremity  of  the  penis,  are  so  large  as  occasionally  to  obstruct 
the  catheter,  and  convey  the  impression  that  a  stricture  exists. 

The  prostate  and  glands  of  Cowper,  being  more  concerned  in  gene- 
ration, will  be  described  hereafter. 

There  are  certain  muscles  of  the  perineum,  that  are  engaged  in  the 
expulsion  of  the  urine  from  the  urethra ;  and  some  of  them  in  defeca- 
tion, and  the  evacuation  of  sperm  likewise; — as  the  acceleratores  urince 
or  bulbo-urethrales,  which  propel  the  urine  or  semen  forward  ;^  the 
transversus  perinei  or  ischio-perinealis,  which  dilates  the  bulb  for  the 
reception  of  the  urine  or  sperm;  the  sp)hincter  ani,  which  draws  down 
the  bulb,  and  aids  in  their  ejection ;  and  the  levator  ain,  which  sur- 
rounds the  extremity  of  the  rectum,  the  neck  of  the  bladder,  the  mem- 
branous portion  of  the  urethra,  the  prostate  gland,  and  a  part  of  the 
vesiculae  seminales,  and  assists  in  the  evacuation  of  the  bladder,  vesi- 
culie  seminales,  and  prostate.     A  part  of  the  levator,  which  arises 

'  Manual  of  Anatomy,  ii.  118,  Lond.,  1822. 

^  Lessons  in  Practical  Anatomy,  3d  edit.,  p.  272,  Philad.,  1836. 

'  For  Dr.  Horner's  views  on  the  origin  of  the  acceleratores  urinse,  see  his  Special 
Anatomy  and  Histology,  8th  edit.,  Philad.,  1851. 


560 


SECRETIOlSr, 


from  the  pubis  and  assists  in  inclosing  the  prostate,  is  called  by  Scira- 
mering  compi-essor  prostatce.  Between  the  membranous  part  of  the 
urethra,  and  that  portion  of  the  levator  ani  which  arises  from  the  inner 

side  of  the  symphysis  pubis,  a 
Fig.  181.  reddish,  areolar,  and  very  vascu- 

lar substance  exists,  which  closely 
surrounds  the  canal,  has  been  de- 
scribed by  Mr.  Wilson^  under  the 
name  compressor  urethrce,  and  is 
termed,  by  some  of  the  French 
anatomists,  muscle  de  Wilson. 
By  many,  however,  it  is  con- 
sidered to  be  a  part  of  the  leva- 
tor ani.  M.  Amussat  asserts,  that 
the  membranous  part  of  the  ure- 
thra is  formed  externally  of  mus- 
cular fibres,  which  are  suscepti- 
ble of  energetic  contraction ;  and 
M,  Magendie^  confirms  his  asser- 
tion. 

With  regard  to  the  urinary  or- 
gans of  the  female: — the  kidnej'S 
and  ureters  have  the  same  situa- 
tion and  structure  as  those  of  the 
male.  The  bladder,  also,  holds 
the  same  place  behind  the  pubis; 
but  rises  higher  when  distended. 
It  is  proportionally  larger  than 
that  of  the  male,  and  is  broader 
from  side  to  side,  thus  permit- 
ting the  greater  retention  to  which 
females  are  often  necessitated. 
The  urethra  is  much  "  shorter, 
being  onlj^  about  an  inch  and  a 
half,  or  two  inches  long;  and  it  is  straighter  than  in  the  male,  having 
only  a  slight  curve  downwards  between  its  extremities,  and  passing 
almost  horizontally  under  the  symphysis  pubis.  It  has  no  prostate 
gland,  but  is  furnished,  as  in  the  male,  with  follicles  and  lacunae,  which 
provide  a  mucus  to  lubricate  it. 

In  birds  in  general,  and  in  many  reptiles  and  fishes,  the  urine,  prior 
to  expulsion,  is  mixed  with  the  excrement  in  the  cloaca.  Nothing 
analogous  to  the  urinary  organs  has  been  detected  in  the  lowest 
classes  of  animals,  although  in  the  dung  of  the  caterpillars  of  certain 
insects,  traces  of  urea  have  been  met  with. 

The  urine  is  formed  from  the  blood  in  the  kidneys ;  and  it  has,  until 
recently,  been  the  universal  belief,  that  it  is  secreted  from  arterial 
blood;    Mr.  Bowman,  however,   in   accordance   with   views   on   the 


the 


Part  of  the   Ossa   Pubis  and  Ischia,   with 
Root  of  the  Penis  attached.' 

a,  a.  Accelerator  urinae  muscle,  embracing  the 
bull}  of  the  urethra,  -which  is  slightly  notched  in 
the  middle  line,  e,  behind,  h,  h.  Anterior  slips  of 
the  accelerator  muscle,  which  pass  round  to  the 
dorsum  of  the  penis,  e,  c.  Crura  of  the  penis,  rf,  d. 
Erectores  penis  muscles  lying  on  the  crura.  /.  The 
corpus  spongiosum  urethrae.  g,  to  g.  Enlargement 
of  the  crus,  named  the  bulb  of  the  corpus  caverno- 
sum. 


1 


'  Kobelt,  De  I'Appareil  du  Sens  Genital  des  deux  Sexes,  traduit  de  I'Allemand,  par 
H.  Kaula,  D.  M.,  Strasbourg,  1851. 

^  Lectures  on  the  Structure  and  Physiology  of  the  Urinary  and  Genital  Organs, 
Loud.,  1821.  i»  Precis,  kc,  ii.  472. 


OF   THE   KIDNEYS.  561 

minute  anatomy  of  the  kidney  already  given,  has  attempted  to  show, 
that  it  is  separated  from  venous  blood.  His  main  conclusions  are  as 
follows : — First.  The  epithelium  lining  the  tubes  is  the  proper  organ 
that  secretes  the  characteristic  products  of  urine  from  the  blood ;  and 
it  does  this  by  first  assimilating  them  into  its  own  substance,  and 
afterwards  pouring  them  upon  its  free  surface.  Secondly.  These  pro- 
per urinous  products  require  for  their  solution  a  large  quantity  of 
water.  Tldrdly.  This  water  is  furnished  by  the  Malpighian  tufts  of 
capillaries,  placed  at  the  extremity  of  the  uriniferous  tubes ;  and 
Fourthly.  A  farther  use  of  the  Malpighian  bodies  seems  to  be  that  of 
sharing  in  regulating  the  amount  of  water  in  the  body.  He  thus 
makes  a  striking  analogy  between  the  liver  and  the  kidney  both  in 
structure  and  function ;  and  expresses  his  belief, — Jirst^  that  diuretic 
medicines  act  specially  on  the  Malpighian  bodies,  and  that  many  sub- 
stances, particularly  salts,  which,  when  taken  into  the  S3'stem,  have  a 
tendency  to  pass  off  by  the  kidneys  with  rapidity,  in  reality  escape 
through  the  Malpighian  bodies :  secondly^  that  certain  morbid  products 
occasionally  found  in  the  urine,  such  as  sugar,  albumen,  and  the  red 
particles  of  the  blood,  in  all  probability,  pass  oft'  through  this  bare 
system  of  capillaries.  The  discovery,  however,  by  Gerlach,^  and 
others,  that  the  proper  Malpighian  capsule  is  invariably  lined  by  in- 
numerable granular  cells,  naturally  suggested,  that  the  Malpighian 
body  is  destined  for  some  action  of  elaboration,  and  that  it  is  as  much 
concerned  in  the  proper  urinary  secretion  as  the  uriniferous  tubes; 
and  on  these  grounds  Mr.  Hassall  expresses  the  belief,  that  urine  is 
formed  in  every  part  of  the  tubular  and  Malpighian  surface  of  the 
kidney ;  and  he  thus  dissents  from  the  opinion  of  Mr.  Bowman,  that 
the  Malpighian  body  is  an  apparatus  destined  for  the  simple  separa- 
tion of  the  watery  parts  of  the  urine;  whilst  he  agrees  with  him,  that 
the  greater  portion  of  the  more  watery  parts  proceed  from  the  Malpig- 
hian bodies; — which  is  probable.  It  is  not  so  easy  to  accord  with 
him,  that  the  last  action  is  not  "effected  by  an  act  of  simple  separation 
but  by  one  of  secretion."  A  simple  physical  act  of  endosmose — -it 
need  scarcely  be  said — is  alone  needed  in  the  case  of  a  tenuous  fluid ; 
and  cell  agency  is  only  required  where  an  action  of  elaboration  has  to 
be  exerted. 

According  to  M.  Raspail,^  the  urine  is  a  kind  of  caput  mortuum^ 
ejected  into  the  urinary  bladder  by  the  kidneys.  They  separate  car- 
bon and  nitrogen  in  the  form  of  cyanogen,  which  unites  with  oxygen 
to  produce  cyanic  acid;  and  this  combines  with  ammonia — itself  a 
compound  of  nitrogen  and  hydrogen — to  form  urea,  which  is  the  cha- 
racteristic element  of  the  urinary  secretion.  They  separate  also,  and 
excrete  superfluous  fluid  from  the  bod}^  The  proofs  of  such  separa- 
tion are  easy  and  satisfactory ;  but  with  regard  to  the  mode  in  which 
the  operation  is  effected,  we  are  in  the  same  darkness  that  hangs  over 
glandular  secretions  in  general.  The  transformation  doubtless  occurs 
mainly  in  the  cortical  part  of  the  organ,  and  essentially  in  the  same 
manner  as  other  secretions  are  formed  from  the  blood; — the  action  of 

'  Op.  cit.  2  Chimie  Organique,  p.  505,  Paris,  1833. 

VOL.  I. — 36 


562  SECEETION  I 

elaboration  taking  place  through  the  agency  of  cells,  which  burst  and 
discharge  the  proper  urinary  matter  into  the  uriniferous  tubes. 

The  urinary  secretion  takes  place  continuously.  If  a  catheter  be 
left  in  the  bladder,  the  urine  drops  constantly ;  and  in  cases  of  exstro- 
pkia  of  that  organ — a  faulty  conformation,  in  which  a  red  mucous 
surface,  formed  by  the  inner  coat  of  the  bladder,  is  seen  in  the  hypo- 
gastric region  on  which  two  prominences  are  visible,  corresponding 
to  the  openings  of  the  ureters,  the  urine  is  observed  to  be  constantly 
oozing  from  the  openings.-^  A  case  of  the  kind  the  author  has  had 
repeated  opportunities  of  exhibiting  to  his  class  in  the  Jefferson  Me- 
dical College. 

After  the  secretion  has  been  effected  in  the  cortical  substance,  it 
flows  through  the  tubular,  and  issues  guttatim  through  the  apices  of 
the  papillas  into  the  pelvis  of  the  kidney,  whence  it  proceeds  along  the 
ureter  to  the  bladder.  If  the  uriniferous  cones  be  slightly  compressed, 
urine  issues  in  greater  quantity;  but,  instead  of  being  limpid,  as  when 
it  flows  naturally,  it  is  thick  and  troubled.  Hence  a  conclusion  has 
been  drawn,  that  it  is  really  filtered  through  the  hollow  fibres  of  the 
medullary  or  tubular  portion.  If  this  were  the  case,  what  must  become 
of  the  separated  thick  portion?  Ought  not  the  tubes  to  become  clogged 
up  with  it?  And  is  it  not  more  probable,  that  compression,  in  this 
case,  forces  out  with  the  urine  some  of  the  blood  that  is  concerned  in  the 
nutrition  of  the  organ?  The  fresh  secretion  constantly  taking  place  in 
the  kidney  causes  the  urine  to  flow  along  the  tubuli  uriniferi  to  the 
pelvis  of  the  organ,  whence,  in  the  erect  attitude,  it  proceeds  along  the 
ureter,  by  virtue  of  its  gravity:  the  fluid,  too,  continually  secreted  from 
the  kidney,  pushes  on  that  before  it:  moreover,  it  is  now  proved,  that 
a  contractile  action  is  exerted  by  the  ureters  themselves;  although,  as 
in  the  case  of  the  excretory  ducts  in  general,  such  a  power  had  been 
denied  them.  These,  with  the  cilia  of  the  lining  membrane,^  are  the 
chief  causes  of  the  progression  of  the  urine  into  the  bladder,  which  is 
aided  by  the  pressure  of  the  abdominal  contents  and  muscles;  and,  it 
is  supposed,  by  the  pulsation  of  the  renal  and  iliac  arteries ;  but  the 
agency  of  these  must  be  trivial. 

The  orifices  of  the  ureters  form  the  posterior  angles  of  the  trigone 
vesical^  and  are  contracted  somewhat  below  the  size  of  the  ducts  them- 
selves. They  are  said  by  Sir  Charles  BelP  to  be  furnished  with  a 
small  fasciculus  of  muscular  fibres,  which  runs  backwards  from  the 
orifice  of  the  urethra,  immediately  behind  the  lateral  margins  of  the 
triangle ;  and,  when  it  contracts,  stretches  the  orifice  of  the  ureter  so 
as  to  permit  the  urine  to  enter  the  bladder  with  facility.  As  the  urine 
passes  in,  it  gradually  distends  the  organ  until  the  quantity  has 
attained  a  certain  amount.  It  cannot  reflow  by  the  ureters,  on  account 
of  the  smallness  of  their  orifices  and  their  obliquity ;  and  as  the  blad- 
der becomes  filled, — owing  to  the  duct  passing  for  some  distance  be- 

'  A  case  of  this  kind  is  detailed  by  the  author,  in  Amer.  Med.  Intelligencer,  i.  137 ; 
and  another  by  Dr.  Pancoast,  ibid.,  p.  147,  Philad.,  1838. 

^  On  the  Ciliarv  Motion  of  the  Tubes,  see  Dr.  George  Johnson,  art.  Ren,  snpra  cit., 
p.  253. 

^  Anatomy  and  Physiology,  5th  American  edition,  by  Godman,  ii.  381,  Ne\y  York, 
1827. 


OF   THE   KIDNEYS.  563 

tween  the  muscular  and  mucous  coats, — the  sides  are  pressed  against 
each  other,  so  that  the  cavity  is  obliterated.  As,  however,  the  ureters 
have  a  tendency  to  lose  this  obliquity  of  insertion,  in  proportion  as 
the  bladder  is  emptied,  the  two  bands  of  muscular  fibres,  which  run 
from  the  back  of  the  prostate  gland  to  the  orifices  of  the  ureters,  not 
only  assist  in  emptying  the  bladder,  but,  at  the  same  time,  pull  down 
the  orifices  of  the  ureters,  and  thus  tend  to  preserve  the  obliquity. 
Moreover,  when  we  are  in  the  erect  attitude,  the  urine  would  have  to 
enter  the  ureters  against  gravity.  These  obstacles  are  so  effective, 
that  if  an  injection  be  thrown  forcibly  and  copiously  through  the  ure- 
thra into  the  bladder,  it  does  not  enter  the  ureters.  On  the  other 
hand,  equally  powerful  impediments  exist  to  its  being  discharged 
through  the  urethra.  The  inferior  fundus  of  the  bladder  is  situate 
lower  than  the  neck ;  and  the  sphincter  presents  a  degree  of  resist- 
ance, which  requires  the  bladder  to  contract  forcibly  on  its  contents, 
aided  by  the  abdominal  muscles  to  overcome  it.  Magendie^  considers 
the  contraction  of  the  levatores  ani  to  be  the  most  efficient  cause  of 
the  retention  of  the  urine;  the  fibres  which  pass  around  the  urethra 
pressing  its  sides  against  each  other,  and  thus  closing  it.  In  a  case  of 
exstrophy  of  the  bladder,  Mr.  Erichsen^  had  an  opportunity  of  mark- 
ing several  interesting  phenomena  connected  with  the  excretion  of 
urine.  The  orifice  of  each  ureter  in  the  bladder  appeared,  when 
closed,  as  a  small  irregularly  oval  depression,  about  a  line  in  diameter, 
situate  on  a  conical  papilla  of  the  mucous  membrane.  A  probe  might 
be  passed  up  the  ureters  for  several  inches  without  any  sensible  incon- 
venience being  sustained.  In  regard  to  the  phenomena  attending  the 
passage  of  the  urine  from  the  ureters  into  the  bladder,  it  appeared, 
that  in  the  first  place  a  drop  collected  within  the  papillary  termination 
of  the  ureter,  which  became  somewhat  distended ;  the  orifice  of  the 
canal  then  opened  to  an  extent  of  from  two  to  three  lines  in  diameter, 
and,  as  soon  as  it  had  allowed  the  drop  of  urine  to  pass,  it  contracted 
with  a  sphincter-like  action.  The  distension  of  the  lower  end  of  the 
ureter,  before  the  drop  of  urine  escaped,  was  very  distinct;  and  the 
relaxation  of  the  orifice  of  the  canal  had  the  appearance  of  being  occa- 
sioned by  the  accumulation  of  the  drop  of  fluid  that  collected  above  it. 
The  closure  of  the  vesical  termination  of  the  ureter,  after  the  escape  of 
the  drop  of  urine,  was  accompanied  by  a  slight  retraction  of  the  pa- 
pillary bulging  of  the  mucous  membrane  on  which  it  terminated,  and 
the  whole  process  resembled  an  ordinary  sphincter  action.  The  two 
ureters  did  not  open  at  the  same  time,  but  with  an  irregularly  alter- 
nating action.  During  the  periods  of  fasting,  they  opened  on  an  ave- 
rage about  three  times  in  a  minute;  consequently,  the  quantity  of 
urine  discharged  from  both  might  be  estimated  at  about  three 
large  drops  in  the  same  S])ace  of  time;  but  although  this  might  be 
taken  as  the  average  rate  of  discharge,  the  action  of  the  ureters  was 
by  no  means  regular,  inasmuch  as  two  or  three  drops  would  some- 
times flow  in  rapid  succession,  whilst,  at  other  times,  a  comparatively 
long  interval  would  elapse  between  the  escape  of  any  two.  When  the 
patient  lay  upon  his  back,  the  discharge  was  slow  and  gentle,  being 

'  Precis,  &c.,  edit,  cit.,  ii.  473.  ^  London  Medical  Gazette,  1S45. 


564  SECRETION 

unattended  with  the  distinct  opening  and  shutting  of  the  end  of  the 
tube  noticed  when  in  the  upright  position.  During  a  deep  inspira- 
tion, as  in  yawning  or  coughing,  or  whilst  straining  at  stool,  the  flow 
of  urine  was  suddenly  increased,  and  the  fluid  escaped  in  a  small 
stream,  or  in  several  large  drops  in  rapid  succession.  The  urine  itself 
was  invariably  acid,  and  often  highly  so,  whilst  the  mucous  membrane 
of  the  bladder  possessed  a  highly  alkaline  reaction.  It  was  covered 
by  a  viscid  glairy  mucus,  and  was  extremely  sensitive  to  the  touch. 

Urine  accumulates  in  the  bladder  until  the  desire  arises  to  expel  it: 
the  number  of  times  that  a  person  in  health  and  in  the  middle  period 
of  life  discharges  it  in  the  twenty-four  hours,  varies :  some  evacuate 
the  bladder  but  twice,  others  may  be  compelled  to  do  so  as  many  as 
twelve  or  fourteen  times.  Nine  times,  according  to  Dr.  Thomas  Thom- 
son,' is  a  common  number.  The  quantity  discharged  at  a  time  varies. 
The  greatest  observed  by  Dr.  Thomson  was  25  J  cubic  inches  or  some- 
what less  than  a  pint;  the  most  common  from  seven  to  nine  cubic 
inches.  During  its  stay  in  the  bladder,  it  is  believed  to  be  deprived 
of  some  of  its  more  aqueous  portions  by  absorption,  and  to  become  of 
greater  specific  gravity,  and  more  coloured:  it  is  here  that  depositions 
are  apt  to  take  place,  which  constitute  calculi;  although  they  are  met 
with  in  the  kidneys  and  ureters  also. 

As  in  every  excretion,  a  sensation  first  arises,  in  consequence  of  which 
the  muscles  required  for  the  ejection  of  the  secreted  matter  are  called 
into  action.  This  sensation  occurs  whenever  the  urine  has  accumulated 
to  the  necessary  extent,  or  when  it  possesses  irritating  qualities,  owing 
to  extraneous  substances  being  contained  in,  or  deposited  from,  it; 
or  if  the  bladder  be  unus'ially  irritable  from  any  morbid  cause,  the 
sensation  may  be  repeatedly — nay,  almost  incessantly^ — experienced. 
The  remarks  that  have  been  made  on  the  sensations  accompanying  the 
other  excretions  are  equally  applicable  here.  The  impression  takes 
place  in  the  bladder;  whence  it  is  conveyed  to  the  brain,  which  accom- 
plishes the  sensation;  and,  consecutively,  the  muscles,  concerned  in  the 
excretion,  are  called  into  action  by  volition.  Physiologists  have  difibred 
regarding  the  power  of  volition  over  the  bladder.  Some  have  affirmed, 
that  it  is  as  much  under  cerebral  control  as  the  muscles  of  locomotion ; 
and  they  have  urged,  in  support  of  this  view,  that  the  bladder  receives 
spinal  nerves,  which  are  voluntary;  that  it  is  paralysed  in  affections  of 
the  spinal  marrow,  like  the  muscles  of  the  limbs;  and  that  a  sensation, 
which  seems  destined  to  arouse  the  will,  is  always  the  precursor  of  its 
action.  Others  again  have  denied,  that  the  muscular  fibres  are  con- 
tractile under  the  will;  and  they  adduce  the  case  of  other  reservoirs, — 
the  stomach  and  rectum,  for  example, — whose  influence  in  excretion 
we  have  seen  to  be  involuntary;  as  well  as  the  fact  that  we  feel  the 
contraction  of  the  bladder  no  more  than  we  do  that  of  the  stomach  or 
intestines;  and  they  affirm,  that  the  action  of  the  bladder  itself  has 
been  confounded  with  that  of  the  accessory  muscles,  which  are  mani- 
festly under  the  influence  of  the  will,  and  are  important  agents  in  the 
expulsion  of  fluid  from  the  bladder.  The  views  last  expressed  appear 
to  be  most  accurate,  and  the  catenation  of  phenomena  seems  to  be  as 

'  BritisL.  Annals  of  Medicine,  p.  6,  Jan.,  1837. 


OF   THE   KIDNEYS.  565 

follows: — the  sensation  to  expel  the  urine  arises;  the  abdominal  mnscles 
are  thrown  into  contraction  by  volition ;  the  viscera  are  thus  pressed 
down  upon  the  pelvis;  the  muscular  coat  of  the  bladder  is,  at  the  same 
time,  stimulated  by  reflex  action  to  contraction;  the  levatores  ani  and 
the  sphincter  fibres  are  relaxed,  so  that  the  resistance  of  the  neck  of 
the  organ  is  diminished,  and  the  urine  is  forced  out  through  the  whole 
extent  of  the  urethra,  being  aided  in  its  course,  especially  towards  the 
termination,  by  the  contractile  action  of  the  urethra  itself,  as  well  as 
by  the  levatores  ani  and  acceleratores  urinse  muscles.  These  expel  the 
last  drops  by  giving  a  slight  succussion  to  the  organ,  and  directing  it 
upwards  and  forwards ;  an  effect  which  is  aided  by  shaking  it  to  remove 
the  drops  that  may  exist  in  the  part  of  the  canal  near  its  extremity. 
The  gradually  diminishing  jet,  which  we  notice  as  the  bladder  is  be- 
coming empty,  indicates  the  contraction  of  the  muscular  coat  of  the 
organ;  whilst  the  kind  of  intermittent  jet,  coincident  with  voluntary 
muscular  exertion,  indicates  the  contraction  of  the  urethral  muscles. 
When  we  feel  the  inclination  to  evacuate  the  bladder,  and  do  not  wish 
to  obey  it,  the  same  muscles, — levatores  ani,  acceleratores  urinas,  and 
the  fibres  around  the  membranous  portion  of  the  urethra  and  neck  of 
the  bladder, — are  thrown  into  contraction,  and  resist  that  of  the  bladder. 

Such  is  the  ordinary  mechanism  of  the  excretion  of  urine.  The  con- 
traction of  the  bladder  is,  however,  of  itself  sufficient  to  expel  its  con- 
tents. M.  Magendie^  affirms,  that  he  has  frequently  seen  dogs  pass 
urine  when  the  abdomen  was  opened,  and  the  bladder  removed  from 
the  influence  of  the  abdominal  muscles ;  and  he  further  states,  that  if, 
in  a  male  dog,  the  bladder,  with  the  prostate  and  a  small  portion  of  the 
membranous  part  of  the  urethra,  be  removed  from  the  body,  the  blad- 
der will  contract  after  a  few  moments,  and  project  the  urine,  with  an 
evident  jet,  until  it  is  entirely  expelled. 

Urine,  voided  in  the  morning — urina  sanguinis — by  a  person  who 
has  eaten  heartily,  and  taken  no  more  liquid  than  sufficient  to  allay 
thirst,  is  a  transparent,  limpid  fluid,  of  an  amber  colour,  saline  taste, 
and  peculiar  odour.  Its  specific  gravity  is  estimated  by  M.  Chossat  at 
from  1-001  to  1-038  ;  by  Cruikshank,  Wagner,^  and  Gregory,  from 
1-005  to  1-033 ;  by  Prout,  from  1-015  to  1-025 ;  by  Christison,^  on  the 
average,  1-024  or  1-025  ;  by  F.  d'Arcet,  from  1*001  to  1-060  [?]  ■*  by 
Eayer,*  and  Donne,®  on  the  average,  TOIS :  by  Dr.  Bostock,  M.  Martin 
Solon,^  and  J.  Vogel,  1-020;  by  Dr.  Routh,«  1-021 ;  by  Becquerel  and 
Eodier,^  in  man,  1-018*900;  in  woman,  1-015-120;  general  average, 
1-017-010;  by  Dr.  Elliotson,^°  from  1-015  to  1-025;  by  Simon,  1012;  and 

'  Precis,  ii.  474.  ^  Elements  of  Physiology,  by  R.  Willis,  §  200,  Lond.,  1842. 

'  On  GianuLar  Degeneration  of  the  Kidneys,  p.  34,  Edinb.,  1S39  ;  or  Amer.  Med. 
Library  edit.,  Philad!',  183i>. 

■*  L'Experience,  No.  Iv.,  Aug.,  1838. 

^  Traite  des  Maladies  des  Reins,  &c.,  torn,  i.,  Paris,  1839. 

^  Cours  de  Microscopie,  p.  226,  Paris,  1844. 

^  De  PAlbuminurie  on  Hydropisie  Causee  par  Maladie  des  Reins,  Paris,  1838! 

8  Lond.  Med.  Graz.,  Sept.,  1850.  See,  also,  Geo.  Johnson,  on  the  Diseases  of  the 
Kidney,  p.  43,  Lond.,  1852. 

^  Traite  de  Chimie  Pathologique  Applique  a  la  Medecine  Pratique,  p.  270,  Paris, 
1854. 

■0  Human  Physiology,  p.  293,  Lend.,  1835. 


566  SECRETION 

Dr.  Thomson^  found  it  in  an  individual,  from  50  to  60  years  of  age  and 
in  perfect  health,  on  the  average,  1-013 ;  the  lowest  specific  gravity, 
during  ten  days,  being  1*001;  and  the  highest,  1-026.  Dr.  Thomson 
has  published  tables^  showing  the  quantity  of  urine  passed  at  dift'erent 
times  during  ten  days  by  the  individual  in  question,  and  the  specific 
gravity  of  each  portion.  They  do  not  accord  with  the  opinion  gene- 
rally but  erroneously  entertained,  that  the  heaviest  urine  is  voided  on 
rising  in  the  morning, — urina  sanguinis.  No  generalization  can,  indeed, 
be  made  on  the  subject.  The  temperature  of  the  urine,  w^hen  recently 
passed,  varied  in  one  case  from  92°  to  95°.  Dr.  Brown-Sequard,  how- 
ever, found  its  ordinary  degree  to  be  102°-5.' 

Urine,  when  first  passed,  is  slightly  acid,  for  it  reddens  vegetable 
blues.  Although  at  first  transparent,  it  deposits  an  insoluble  matter  on 
standing;  so  that  that  which  is  passed  at  bed-time,  is  found  to  have  a 
light  cloud — encp.orema — floating  in  it  by  the  following  morning.  This 
substance  consists,  in  part,  of  mucus  from  the  urinary  passages ;  and, 
in  part,  of  the  super-lithate  of  ammonia,  which  is  much  more  soluble 
in  warm  than  in  cold  water.  Urine  is  extremely  prone  to  decompo- 
sition. When  kept  for  a  few  days  it  acquires  a  strong  smell,  which, 
being  sv.i  generis^  has  been  called  urinovs ;  and  as  the  decomposition 
proceeds,  it  becomes  extremely  disagreeable.  As  soon  as  these  changes 
commence,  it  ceases  to  have  an  acid  reaction.  In  a  short  time,  a  free 
alkali  makes  its  appearance;  and  a  large  quantity  of  carbonate  of 
ammonia  is  generated,  and  earthy  phosphates  are  deposited.  These 
phenomena  are  owing  to  the  decomposition  of  urea,  which  is  almost 
wholly  resolved  into  carbonate  of  ammonia. 

Dr.  Golding  Bird,"  states,  that  three  distinct  varieties  of  iirinarv  se- 
cretion may  be  recognised.  First.  That  passed  some  little  time  after 
drinking  freely  of  fluids,  which  is  generally  pale,  and  of  low  specific 
gravity — 1"003  to  1-009 — urina  potiis.  Secondly.  That  secreted  after 
the  digestion  of  a  full  meal,  varying  much  in  physical  characters,  and 
of  considerable  density — 1-020  to  1*028,  or  even  1-030 — urina  chyli 
sen  cihi.  Thirdhj.  That  secreted  from  the  blood  independently  of  the 
immediate  stimulus  of  food  and  drink,  as  that  passed  after  a  night's 
rest — urina  sanguinis^  which  is  usually  of  average  density — 1-015  to 
1-025 — and  presents  in  perfection  the  essential  characters  of  the  fluid. 

According  to  VogeV  a  healthy  man  may,  by  very  copious  water 
drinking,  reduce  the  specific  gravity  of  his  urine  to  1-000-5;  and  by  ab- 
staining from  fluids,  and  by  taking  such  violent  exercise  as  to  induce 
free  perspiration  may  raise  it  to  1*033,  and  even  more. 

The  following  table,  drawn  up,  as  far  as  1032,  by  M.  Becquerel,  and 
completed  from  the  observations  of  the  last  mentioned  inquirer,^  ex- 
hibits at  a  single  inspection  the  amount  of  solids  and  water  present  in 
1000  grains  of  urine  of  any  particular  density  ;  so  that  from  the  quan- 

'  British  Annals  of  Medicine,  p.  5,  Jan.,  1837. 

^  Op.  citat.,  p.  6. 

3  Med.  Examiner  for  Sept.,  1852,  p.  556. 

*  Urinary  Deposits,  2d  Amer.  edit..  \>.  31,  Philad.,  1851. 

*  Archiv.  d.  Vereins  fiir  Gemeinschaftlicli.  Arbt'iten,  Bd.  1,  Heft  1,  Giittingen,  1853  ; 
cited  by  Dr.  Geo.  E.  Day,  in  Brit,  and  For.  Med.-Chir.  Rev.,  July,  1855,  p.  73. 

6  Lond,  Med.  Gazette,  Feb.  10,  1843,  p.  (J78. 


OF   THE   KIDNEYS. 


567 


tity  of  urine  passed  in  twenty-four  hours  it  is  easy  to  calculate  how 
much  solid  matter  the  patient  is  parting  with  in  that  period. 


Water  in  1000 

Solids  in  1000 

Water  in  1000 

Solids  in  1000 

Density. 

grains. 

grains. 

Density. 

grains. 

grains.           1 

1001 

998-35 

1-65 

1029 

960-4 

39-6          I 

1002 

996-7 

3-3          1 

1026 

957-1 

42-9 

1004 

993-4 

6-6 

1028 

953-8 

46-2 

1006 

990-1 

9-9 

1030 

950-5 

49-5 

1008 

986-8 

13-2 

1032 

947-2 

52-8 

1010 

983-5 

16-5 

1034 

943-9 

56-1 

1012 

980-2 

19-8 

1036 

940-6 

59-4 

1014 

976-9 

23-1 

1038 

937-3 

62-7 

1016 

973-6 

26-4 

1040 

934- 

66- 

1018 

970-3 

29-7 

;         1042 

930-7 

69-3 

1020 

967- 

33- 

1044 

927-4 

72-6 

1022 

963-7 

36-3 

1046 

924-1 

75-9 

The  appearances  presented  by  the  urine  under  the  microscope  have, 
of  late  years,  given  rise  to  numerous  investigations:  these  of  course 
vary,  according  to  the  modifications  it  exhibits  in  health  and  disease. 
In  the  latter  condition,  much  information  has  been  collected,  so  that, 
according  to  M.  Donne,  the  study  of  the  urine  may  be  said  to  be  "the 
triumph  of  the  microscope."^  The  morbid  appearances,  however,  which 
it  presents,  do  not  belong  to  a  work  on  physiology. 

Dr.  Ilenry^  affirms,  that  the  following  substances  have  been  satis- 
factorily proved  to  exist  in  healthy  urine, — water,  free  phosphoric  acid, 
phosphate  of  lime,  phosphate  of  magnesia,  fluoric  acid,  uric  acid,  benzoic 
acid,  lactic  acid,  urea,  gelatin,  albumen,  lactate  of  ammonia,  sulphate 
of  potassa,  sulphate  of  soda,  fluoride  of  calcium,  chloride  of  sodium, 
phosphate  of  soda,  phosphate  of  ammonia,  sulphur  and  silex.  One  of 
the  most  elaborate  analyses  has  been  given  by  Berzelius.^  He  states  it 
to  consist — in  1000  parts — of  water,  933-00;  urea,  30-10;  sulphate  of 
potassa,  3-71 ;  sulphate  of  soda,  3-16  ;  phosphate  of  soda,  2-94;  chloride 
of  sodium,  4'45 ;  phosphate  of  ammonia,  1'65 ;  muriate  of  ammonia, 
1*50 ;  free  lactic  acid ;  lactate  of  ammonia ;  animal  matter  soluble  in 
alcohol,  and  urea  not  separable  from  the  preceding,  17'1'±;  earthy  phos- 
phates, with  a  trace  of  fluoride  of  calcium,  1*00 ;  lithic  acid,  1*00  ; 
mucus  of  the  bladder,  0-32 ;  silex,  0-03.  Dr.  Prout"  found  100  parts 
to  consist  of  lithic  acid,  90-16;  potassa,  3'45;  ammonia,  1'70;  sulphate 
of  potassa,  with  a  trace  of  chloride  of  sodium,  '95;  phosphate  of  lime, 
carbonate  of  lime,  and  magnesia,  "80;  and  animal  matter,  consisting  of 
mucus  and  a  little  colouring  matter,  2-94.  M.  RaspaiP  thinlcs  it  "pos- 
sible" that  uric  acid  is  merely  a  mixture  of  organic  matter  (albumen) 
with  an  acid  cyanide  of  ammonia ;  so  that  the  results  of  analysis  may 
differ  according  as  the  analyzed  substances  may  have  been  more  or  less 

'  Cours  de  Microscopie,  p.  213,  Paris,  1844. 

2  Elements  of  Experimental  Chemistry,  9th  edit.,  vol.  ii.  p.  435,  Lond.,  1823. 

^  Med.-Chirurg.  Transact.,  vol.  iii.  ;  Annals  of  Philos.,  ii.423  ;  and  The  Kidneys  and 
Urine,  by  J.  J.  Berzelius,  translated  from  the  German,  by  M.  H.  Boye,  and  F.  Learning, 
M.D.,'p.  97,  Philad.,  1843. 

•»  Annals  of  Philos.,  v.  415.  ^  Op.  citat.,  p.  507. 


568  SECRETION  ij 

separated  from  the  organic  matter.  The  physical  and  chemical  charac- 
ters of  true  uric  acid,  he  thinks,  accord  very  well  with  this  hypothesis. 

Elaborate  researches  have  been  undertaken  by  Liebig,^  as  regards 
the  constitution  of  the  urine, — whence  he  derives  the  following  infer- 
ences. First.  Neither  lactic  acid  nor  any  lactate  exists  in  healthy  urine. 
Secondly.  Hippuric  acid  is  a  constant  constituent.  Thirdly.  The  acid 
reaction  of  healthy  urine  is  due  to  the  presence  of  acid  phosphate  of 
soda.  Fourthly.  The  acidity  of  urine  is  maintained  and  increased  by 
the  following  changes.  The  urine  of  man  and  the  carnivora  has  a 
large  quantity  of  sulphates;  but  their  food  does  not  contain  either 
those  salts  ready  formed,  or  any  oxygen  compound  of  sulphur.  The 
sulphur  which  it  does  contain,  or  which  amounts  to  the  same  thing, 
the  sulphur  of  the  transformed  tissues  must,  therefore,  combine  with 
oxygen  in  the  body;  and  the  sulphuric  acid  thus  formed,  uniting  with 
part  of  the  alkali  of  the  alkaline  phosphates,  forms  acid  phosphates. 
Lastly.  It  follows,  that  whether  the  urine  be  acid  or  not  depends  upon 
the  nature  and  quantity  of  the  bases  taken  with  the  food.  If  the 
amount  be  sufiicient  to  neutralize  the  uric,  hippuric,  and  sulphuric 
acids  formed  by  the  organism,  and  the  acids  supplied  by  the  food,  the 
urine  must  be  neutral;  if  the  amount  be  more  than  enough,  the  urine 
must  be  alkaline;  if  less,  acid.  Hence  no  physiological  or  pathological 
inference  can  be  drawn  from  an  examination  of  the  urine,  unless  an 
account  be  taken  of  the  inorganic  acids,  salts,  and  bases  taken  with  the 
food.  Some  experiments  have  been  made  on  the  variations  of  the 
acidity  of  the  urine  in  health  by  Dr.  H.  Bence  Jones.^  When  a  mixed 
diet  was  employed,  the  acidity  of  the  urine  was  found  to  decrease  soon 
after  taking  food,  and  to  attain  its  lowest  limit  from  three  to  five  hours 
after  meals.  It  then  gradually  increased,  and  attained  its  highest  limit 
just  before  taking  food.  AVhen  animal  food  only  was  taken,  the  dimi- 
nution of  acidity  was  more  marked  and  more  lasting;  but  the  acidity 
before  food  did  not  rise  quite  so  high  as  it  did  with  the  animal  diet. 
When  vegetable  food  was  alone  taken,  the  decrease  in  acidity  was  not 
to  the  same  degree. 

Notwithstanding  the  view  of  Liebig,  that  the  uric  acid  of  the  urine 
is  held  in  solution  by  the  phosphate  of  soda,  combining  with  a  part  of 
the  base,  and  setting  free  a  portion  of  the  phosphoric  acid.  Dr.  Golding 
Bird''  adheres  to  the  opinion  of  Dr.  Prout,  that  uric  acid  is  combined 
with  ammonia.  "Uric  acid,"  he  says,  "at  the  moment  of  separation 
from  the  blood,  meets  the  double  phosphate  of  soda  and  ammonia  de- 
rived from  the  food,  and  forms  urate  of  ammonia,  evolving  phosphoric 
acid,  which  thus  produces  the  natural  acid  reaction  of  the  urine." 

Healthy  urine  has  been  analyzed  by  Becquerel,  Lehmann,  Simon, 
Marchard,  Day,  and  others.  The  analyses  of  Lehmann  and  Marchard 
approximate  that  of  Berzelius;  whilst  those  of  Becquerel,  Simon,  and 
Day,  agree  pretty  closely  with  each  other.''  The  following  are  two  of 
Simon's  analyses: — 

'  Annalon  der  Cliemie  land  Pharmacie,  Mai,  cited  in  London  Lancet,  June  1-8, 1844. 
2  IMiilosopliical  Transactions  for  1849,  Ft.  2.  '  Urinary  Deposits,  p.  48. 

''  Dr.  Day's  Report  on  Physiological  and  Pathological  Chemistry,  in  Ranking's  Ab- 
stract, Part  i.  p.  283,  Amer.  edit.,  New  York,  1845. 


OF   THE 

KIDNEYS. 

I. 
Water, 963-00 

11. 

956-000 

Solid  constituents, 

36-20 

44-00 

Urea,               .... 

12-46 

14-578 

Uric  acid,      .... 

0-52 

0-710 

Alcohol  extract  and  lactic  acid, 

5-10 

4-800 

Spi)-it  extract. 

2-60 

5-593 

Water  extract  and  mucus,      . 

1-00 

2-550 

Lactate  of  ammonia. 

1-03 

Chloride  of  ammonium. 

0-41 

Chloride  of  sodium. 

5-20 

7-280 

Sulphate  of  potassa, 

3-00 

3-508 

Phosphate  of  soda, 

2-41 

2-330 

Earthy  phosphates, 

0-58 

0-654 

Silica,             .... 

a  trace 

a  trace 

569 


M.  Becquerel's  analysis,^  whicli  has  been  adopted  by  Dr.  Prout, 
by  Dr.  Golding  Bird,^  is  as  follows : — 


and 


Water, 
Urea, 

Uric  acid,    . 
Colouring  matter. 
Mucus  and  animal 
extractive  matter, 

r 


Salts. 


Sulphates, 


Biphosphates, 


inseparable 

from 
each  other, 
1 


(  Soda, 
(  Potash, 

(Lime, 
Soda, 
Magnesia, 
Ammonia, 
f  Sodium, 
(  Potassium, 


Chlorides, 

Hippurate  of  soda, 
,  Fluoride  of  potassium, 
Silica,      . 


967 
14-230 

•468 

10-167 


8-135 


traces 


1000-000' 


The  yellowisli-red  incrustation,  deposited  on  the  sides  of  chamber 
utensils,  is  chiefly  urate  of  ammonia.  This  is  the  basis  of  one  of  the 
varieties  of  calculi. 

The  following  is  the  proportion,  which  each  principal  constituent 
bears  to  100  of  solid  residuum,  accordino-  to  dilYerent  observers.* 


Berzelius. 

Lelinianu. 

Simon. 

Marcliard 

Urea, 

45-10 

49-68 

33-80 

48-91 

Uric  acid, 

1-50 

1-61 

1-40 

1-59 

Extractive  matter,  ammonia  salts 
and  chloride  of  sodium. 

36-30 

28-95 

42-60 

32-49 

Alkaline  sulphates,     . 

10-30 

11-58 

11-14 

10-18 

Alkaline  phosphates. 

6-88 

5-96 

6-50 

4-57 

Phosphates  of  lime  and  magnesia, 

1-50 

1-97 

1-59 

1-81 

'  Semeiotique  des  Urines,  p.  7,  Paris,  1841.  An  analysis  of  tlie  urine  of  the  two 
sexes  is  given  by  him  in  his  Traite  de  Cliimie  Pathologique  Ajiplitjuee  a  la  Medecine,  p. 
270,  Paris,  1854;  and  an  elaborate  analysis  after  M.  Robin  is  given  in  Beraud,  Manuel 
de  Physiologic  de  I'Homme,  p.  232,  Paris,  1853. 

^  On  the  Nature  and  Treatment  of  Stomach  and  Renal  Diseases,  4th  edit.,  Amer. 
edit.,  p.  404,  Philad.,  1843. 

^  Urinary  Deposits,  Amer.  edit.,  p.  44,  Philad.,  1845. 

*  See  art.  Urine,  by  Dr.  Geo.  Rees,  in  Cycl.  of  Anat.  and  Phys.,  iv.  1272,  Lond., 
1852. 

^  Carpenter,  Principles  of  Human  Physiology,  Amer.  edit.,  p.  391,  Philad.,  1854. 


570  SECRETION 

The  quantity  of  urine  passed  in  the  twenty-four  hours  is  variable. 
Boissier  states  it  at  22  ounces;  Hartmann  at  28;  Dr.  Robert  Willis' 
at  from  30  to  40 ;  Prout  at  about  30  in  summer,  and  40  in  winter ; 
Robinson  at  35;  Von  Gorter  at  36;  Keill  at  38;  Rye  at  39;  Bostock 
at  40;  Sanctorius  at  44;  Stark  at  46;  Dalton  at  48 J;  Haller  at  49 ; 
Christison  .at  from  35  to  50;  Becquerel  at  about  46;  Dr.  Thomas 
Thomson  at  53;  Vogel  at  about  54,  and  Lining  at  from  56  to  59 
ounces.  On  the  average,  it  may  be  estimated  perhaps  at  two  pounds 
and  a-half ;  hence  the  cause  of  the  great  size  of  the  renal  artery,  which, 
according  to  the  estimate  of  Haller,  conveys  to  the  kidney  a  sixth  or 
eighth  part  of  the  whole  blood.  Its  quantity  and  character  differ 
according  to  age,  and,  to  a  certain  extent,  according  to  sex.  We  have 
already  seen,  under  the  head  of  cutaneoiLs  exhalation^  how  it  varies, 
according  to  climate  and  season;  and  it  is  inflaenced  by  the  serous, 
pulmonary,  and  areolar  exhalations  likewise :  one  of  the  almost  inva- 
riable concomitants  of  dropsy  is  diminution  of  the  renal  secretion. 
Its  character,  too,  is  modified  by  the  nature  of  the  substances  received 
into  the  blood.  Rhubarb,  turpentine,  and  asparagus,  for  example,  alter 
its  physical  properties ;  whilst  certain  articles  stimulate  the  kidney  to 
augmented  secretion,  or  are  "  diuretics." 

The  renal  secretion  may  be  considered  as  arising  from  different 
sources.  When  much  fluid  is  taken,  the  amount  of  the  urine  is  largely 
augmented,  so  that  it  is  manifestly  intended  to  remove  superfluous 
fluid  from  the  blood.  It  is  also,  as  just  shown,  materially  modified  by 
certain  ingesta;  and  not  unfrequently  the  character  of  the  food  taken 
may  be  detected  in  it;  hence,  it  has  been  conceived,  the  kidneys  may 
have  the  duty  of  removing  from  the  system  any  crude  or  undigested 
elements  of  the  food,  which  had  been  absorbed  whilst  traversing  the 
small  intestine,  and  entered  the  circidating  mass;  and  of  excreting  the 
often  noxious  results  of  imperfect  or  unhealthy  assimilation.  Leh- 
mann^  instituted  a  series  of  experiments  on  himself,  which  afforded 
interesting  information  in  regard  to  the  varying  composition  of  the 
urine,  according  as  an  animal,  a  vegetable,  a  mixed,  or  a  non-nitro- 
genized  diet  was  employed.  On  the  mixed  diet  he  lived  fifteen  days; 
ate  and  drank  moderately ;  and  abstained  from  all  fermented  liquors. 
He  took  an  exclusively  animal  diet  for  twelve  days,  consuming  thirt}'- 
two  eggs  each  day.  A  purely  vegetable  diet  was  also  continued  for 
twelve  days;  but  the  non-nitrogenized  was  only  taken  for  two  days. 
In  the  following  table  the  quantities  of  solid  matter  passed  daily  are 
represented  by  grammes  (about  15|-  grains  troy  each);  and  also  the 
proportional  amount  of  salts  and  animal  matter  in  that  quantity  of 
solid  matter. 

Extractive 
Solid  matter.  Urea.  TJric  acid.        Uric  salts.  matters. 

Mixed  diet         .         .  67-82  32-41)8  1-183  2-257  10-489 

Animal  diet       .         .  87-44  53-198  1-478  2-167  5-145 

Vegetable  diet  .         .  59-24  22-481  1-021  2-669  16-499 

Nou-nitrogenized  diet  41-68  15-408  0-735  5-276  11-854 


'  Urinary  Diseases  and  tlieir  Treatment,  Bell's  Library  edit.,  p.  14,  Philad.,  1839. 

^  L'Experience,  7  Dec,  1843;  cited  in  Edinb.  Med.  and  Surg.  Journal,  April,  1844, 
and  Art.  Harn,  Handworterbuch  der  Physiologie,  7te  Liel'erung,  S.  16,  Braunscliweig, 
1844;  and  Lelirbuch  der  Physiolog.  Cliemie,  ii.  447,  Leipzig,  1850;  or  Amer.  edit,  of 
Dr.  Day's  translation  by  Dr.  Robt.  E.  Rogers,  ii.  163,  Philad.,  1855. 


OF   THE   KIDNEYS.  571 

Lelimann's  results  certainly  show; — first^  that  animal  food  increases 
the  solid  matters  in  the  urine,  whilst  vegetable  substances,  and  espe- 
cially non-nitrogen ized  aliments,  diminish  them: — secondly^  that  the 
proportion  of  nitrogen  in  the  urine  depends  in  part  upon  the  kind  of 
food  taken, — food  rich  in  nitrogen  greatly  increasing  its  amount.  In 
his  experiments,  the  proportion  of  urea  to  the  other  solid  matters 
was  as  100  to  116  under  a  mixed  diet;  as  100  to  63  under  an  ammal 
diet;  as  100  to  156  under  a  vegetable  diet;  and  as  100  to  170  under 
a  non-nitrogenized  diet:  thirdly^  that  the  proportion  of  uric  acid  in  the 
urine  did  not  appear  to  have  reference  to  the  kind  of  food : — -fourthly^ 
that  the  urine  contained  quantities  of  sulphates  and  phosphates  pro- 
portioned to  the  quantity  of  nitrogenized  matters  that  had  been  ab- 
sorbed :  and,  fifthly^  that  under  an  animal  diet  the  quantity  of  extractive 
matters  diminishes  ;  whilst  it  is  increased  by  the  use  of  vegetable  diet. 
These  extractive  matters  contained,  according  to  the  researches  of 
Liebig,'  krealine  and  kreatinine^  two  substances  presumed  to  be  derived 
from  the  metamorphosis  of  muscular  tissues,  and  also  a  peculiar 
colouring  matter  derived  probably  from  the  hematin  of  the  blood. 
Experiments  by  Dr.  H.  Bence  Jones^  confirm  those  of  Lehmann  in 
certain  respects.  They  show,  that  all  food  causes  an  increase  in  the 
amount  of  uric  acid  excreted ;  but  that  there  is  no  great  difference 
between  animal  and  vegetable  food  in  the  production  of  such  increase. 

The  urine  does  not  appear  to  be  intended  for  any  local  function. 
Its  use  seems  to  be  restricted  to  the  removal  from  the  blood  of  the 
elements  of  the  substances  of  which  it  is  composed ;  hence,  it  is  solely 
depuratory  and  decomposing.  IIow  this  decomposition  is  accom- 
plished we  know  not.  We  have  already  referred  to  the  experiments, 
performed  by  MM.  Prevost  and  Dumas,  Segalas,  Gmelin,  Tiedemann 
and  Mitscherlich,  in  which  urea  was  found  in  the  blood  of  animals 
whose  kidneys  had  been  extirpated:  an  inquiry  has  consequently 
arisen — how  it  exists  there?  Prior  to  these  experiments,  it  was  uni- 
versally believed,  that  its  formation  is  one  of  the  mysterious  functions 
executed  in  the  intimate  tissue  of  the  kidney.  It  is  proper  to  add, 
however,  that  neither  MM.  Prevost  and  Dumas,  Tiedemann  and  Gmelin, 
nor  M.  Lecanu^  could  detect  the  smallest  trace  of  this  substance  in  the 
blood  of  animals  placed  under  ordinary  circumstances.  It  is  now, 
however,  admitted,  that  it  exists  there  normally,  but  in  very  small 
quantity.  It  is,  according  to  Wohler  and  Easpail,  a  cyanate  of 
ammonia,  and  contains  a  very  large  proportion  of  nitrogen. 

The  kidney  is  the  outlet  for  an  excess  of  nitrogen  in  the  system  in 
the  same  manner  as  the  lungs  and  liver  are  outlets  for  superfluous 
carbon.  The  quantity  of  nitrogen,  discharged  in  the  form  of  urea,  is 
so  great,  even  in  those  animals  whose  food  does  not  essentially  con- 
tain this  element,  that  it  has  been  conceived  a  necessary  ingredient  in 
the  nutrition  of  parts,  and  especially  in  the  formation  of  fibrin,  which 
is  a  chief  constituent  of  the  blood,  and  of  every  muscular  organ.  The 
remarks  made  on  the  absorption  of  nitrogen  during  respiration  indi- 
cate one  mode  in  which  it  is  received  into  the  system ;  and  it  has  been 

'  Chemistry  of  Food,  Lond.,  1847. 

2  Philosophical  Transactions,  Pt.  2,  for  1849. 

^  Etudes  Cliiuiiciues  sur  le  Sang  Humam,  Paris,  1837. 


572  SECRETION, 

presumed,  tliat  the  superfluous  portion  is  thrown  off  in  the  form  of 
urea. 

There  are  three  great  modes  in  which  the  nitrogen  thrown  off  by 
the  urine  may  be  obtained:  first^  from  the  air  of  respiration;  se- 
condly^ from  the  food;  for  compounds  of  protein  are  absorbed  from 
the  intestinal  canal ;  and  the  nitrogen  which  is  not  required  for  the 
wants  of  the  system  is  thrown  off  from  the  kidneys  in  the  form  of 
urea  and  uric  acid;  and  thirdly^  in  the  disintegration  of  the  tissues 
constantly  occurring  in  the  system  of  nutrition.  Whilst  certain  of  the 
elements  that  are  superfluous  are  thrown  off'  by  the  lungs  and  liver, 
the  kidneys  separate  and  throw  off  the  superfluous  nitrogen.  From 
the  results  of  Dr.  Lehmann's  experiments,  it  has  been  inferred,  that  so 
long  as  the  iugesta  contain  no  nitrogen,  the  whole  of  that  element  in 
the  urine  must  be  attributed  to  the  disintegration  or  waste  of  the  tis- 
sues, and  may  fairly  be  taken  as  a  measure  of  its  amount.  This,  how- 
ever, is  by  no  means  established.  We  have  no  positive  proof  that  the 
nitrogen  received  into  the  circulation  in  respiration  is  foreign  to  the 
formation  of  the  nitrogenized  compounds  contained  in  the  urine.  It 
has  been  found  in  the  urine  of  man  after  long  fasting ;  and  in  that  of 
reptiles,  which  had  not  taken  food  for  months.  Besides  serving  as  an 
outlet  for  the  superfluous  nitrogen,  there  is  no  question,  that  the  ex- 
cess of  the  sulphur  and  phosphorus,  which  have  become  oxidized  in 
the  organism,  and  converted  into  sulphates  and  phosphates  by  a  union 
with  bases,  is  removed  from  the  system  through  the  urinary  secretion. 

The  whole  subject  of  the  urine  in  its  chemical  and  chemico-ph}sio- 
logical,  and  chemico-pathological  history  is  full  of  interest ;  and  hence 
the  attention  paid  to  it  at  this  time  everywhere  by  the  chemists  espe- 
cially, who  have  sufficiently  shown  that  the  determination  of  its  exact 
constitution  is  one  of  the  most  abstruse  subjects  of  organic  chemistry.'^ 

The  removal  of  the  constituents  of  the  urinary  secretion  from  the 
blood  is  all-important.  Experiments  on  animals  have  shown,  that  if 
it  be  suppressed  by  any  cause  for  about  three  da^^s,  death  usually 
supervenes,  and  the  dangers  to  man  are  equally  imminent.  Yet  there 
are  some  strange  cases  of  protracted  suppression  on  record.  Haller 
mentions  a  case  in  which  no  urine  had  been  secreted  for  twenty-two 
weeks  ;  and  Dr.  liichardson,^  one  of  a  lad  of  seventeen,  who  had  never 
made  any,  and  yet  felt  no  inconvenience. 

a.   Connexion  heticeen  the  Stomach  and  Kidneys. 

In  consequence  of  the  rapidity  with  which  fluids  received  into  the 
stomach  are  sometimes  voided  by  the  urinary  organs,  it  has  been  ima- 
gined, either  that  vessels  exist,  which  communicate  directly  between 

'  For  the  recent  investigations  of  R.  Bunsen,  Millon,  Marcliard,  Allan  and  Hensch, 
"nard  and  Barreswil,  Strahl  and  N.  Lioberkuhn,  WiJliler  and  Frerichs,  &c.,  see 
ver,  in  Canstatt  and  Eisenniann's  Jaliresbericht  iiber  die  Forts cliritte  in  der  Bio- 
i^^ie  im  Jalire,  1848,  S.  88  ;  W.  Mareet,  in  a  Notice  of  tlie  Traite  de  Chiniie  Anato- 
mique,  &c.,  of  Robin  and  Verdeil,  in  Brit,  and  For.  Medico-Cliir.  Rev.,  April,  1853,  p. 
358;  and  for  the  investigations  of  Prof.  J.  Vogel,  Dr.  Fr.  Beneke  and  others';  see 
Gerber,  Ibid.,  for  July,  1855,  p.  71  ;  Becquerel  and  Rodier,  Traite  de  Cliiinie  Fatholo- 
gique,  &c.,  p.  267,  Paris,  1854,  and  Lehniann,  Lehrbuch  der  Physiolopisclien  C'hemie,  S. 
387,  Leipz.,  1850;  or  Amer.  edit,  of  Dr.  Day's  translation  by  Dr.  Robt.  E.  Rogers,  ii. 
106,  Philad.,  1855. 

'  Philos.  Transact,  for  1713. 


CONNEXION   BETWEEN   THE   STOMACH   AND   KIDNEYS.      573 

the  stomacli  and  bladder,  or  tliat  the  fluid  passes  through  the  interme- 
diate areolar  tissue,  or  through  the  anastomoses  of  lymphatics.  Ex- 
periments of  Mr.  Erichsen,^  which  consisted  in  introducing  certain 
substances,  that  are  readily  detected  by  appropriate  tests,  into  the 
stomach,  and  noting  their  appearance  in  the  urine,  signally  exhibit 
the  rapidity  of  this  transmission.  The  earliest  period  at  which  prus- 
siate  of  potassa  was  detected  was  about  one  minute  after  being  swal- 
lowed; and  the  longest,  thirty-nine  minutes, — the  difference  aippearing 
to  depend  upon  the  presence  or  absence  of  food  in  the  stomach  at  the 
time.  When  it  was  empty,  the  salt  was  discovered  in  from  one  to 
two  and  a  half  minutes;  whilst  soon  after  a  meal  it  required  from 
six  and  a  half  to  thirty-nine  minutes. 

In  support  of  the  opinion,  that  a  more  direct  passage  exists,  the 
assertion  of  M.  Chirac, — that  he  saw  the  urinary  bladder  become  filled 
with  urine  when  the  ureters  were  tied,  and  that  he  excited  urinous 
vomiting  by  tying  the  renal  arteries, — is  brought  forward.  It  has 
been  farther  affirmed,  that  the  oil,  composing  a  glyster,  has  been  found 
in  the  bladder.  Dr.  Darwin,^  having  administered  to  a  friend  a  few 
grains  of  nitrate  of  potassa,  collected  his  urine  at  the  expiration  of 
half  an  hour,  and  had  him  bled.  The  salt  was  found  in  the  urine,  but 
not  in  the  blood.  Mr.  Brande  made  similar  experiments  with  prus- 
siate  of  potassa,  from  which  he  inferred,  that  the  circulation  is  not  the 
only  medium  of  communication  between  the  stomach  and  urinary 
organs,  without,  however,  indicating  the  nature  of  the  supposed  me- 
dium; and  this  view  is  embraced  by  Sir  Everard  Home,^  and  Drs. 
Wollaston,  Marcet,  and  others.  Lippi,"*  of  Florence,  thinks  he_  has 
found  an  anatomical  explanation  of  the  fact.  According  to  him,  the 
chyliferous  vessels  have  not  only  numerous  inosculations  with  the 
mesenteric  veins,  either  before  their  entrance  into  the  mesenteric 
glands,  or  whilst  they  traverse  those  organs ;  but,  when  they  attain 
the  last  of  them,  some  proceed  to  open  directly  into  the  renal  veins, 
and  into  the  pelves  of  the  kidneys.  At  this  place,  according  to  him, 
the  chyliferous  vessels  divide  into  two  sets ;  the  one,  ascending,  and 
conveying  the  chyle  into  the  thoracic  duct ;  the  other,  descending,  and 
carrying  drinks  into  the  renal  veins  and  pelves  of  the  kidneys.  He 
affirms,  that  the  distinction  between  the  two  sets  is  so  marked,  that  an 
injection  sent  into  the  former  goes  exclusively  into  the  thoracic  duct, 
whilst  if  it  be  thrown  into  the  latter  it  passes  exclusively  to  the  kid- 
neys.    These  direct  vessels  Lippi  calls  vasa  chylopoietica  urinifera. 

A  kindred  and  equally  inconceivable  view  has  been  recently  main- 
tained by  M.  C.  Bernard,^  who  affirms,  that  when  he  introduced  prus- 
siate  of  potassa  into  the  intestine  of  an  animal,  he  recognized  it  sooner 
in  the  renal  vein  than  in  the  renal  arter}'.  To  account  for  this  he  insti- 
tuted a  series  of  researches,  from  which  he  concludes,  that  liquids 

'  Dublin  Medical  Press,  July  0,  1845,  aud  Raiiking's  Abstract,  Part  ii.  p.  241,  Amer. 
edit.,  New  York,  184(j.  ^  Zoonomia,  xxix.  3. 

*  Philosophical  Transactions,  xcviii.  51,  and  ci.  163,  for  1808  and  1811  ;  and  Lec- 
tures on  Comparative  Anatomy,  i.  221,  Lond.,  1814  ;  and  iii.  138,  Lond.,  1823. 

*  lUustrazioni  Fisiologiche  e  Patologiche  del  Sistema  Linfatico-Chilifero,  &c.,Firenz, 
1825. 

*  Union  Medicale,  No.  116,  cited  in  British  and  Foreign  Medico-Chirurgical  Review, 
for  Jan.,  1850,  p.  246. 


674  SECRETION. 

absorbed  from  the  intestines,  after  passing  through  the  portal  system 
and  arriving  in  the  vena  cava,  instead  of  ascending  towards  the  heart, 
descend  into  the  renal  veins,  which  conve}'-  them  to  the  renal  capilla- 
ries; so  that  a  considerable  portion  of  them  is  eliminated  without  pass- 
ing into  the  general  current  of  the  circulation. 

In  regard  to  the  assertions  of  Lippi,  were  they  anatomical  facts,  it 
would  obviously  be  difficult  to  doubt  some  of  the  deductions;  other 
anatomists  have  not,  however,  been  so  fortunate  as  he ;  and,  con- 
sequently, it  may  be  well  to  make  a  few  comments.  Yet — as  has 
been  elsewhere  seen — the  communication  between  the  abdominal 
lymphatics  and  veins  has  been  maintained  by  Dr.  Nuhn.'  Some 
of  these  chylopoietica  urinifera,  Lippi  affirms,  open  into  the  renal 
veins.  This  arrangement,  it  is  obvious,  cannot  be  invoked  to  account 
for  the  shorter  route — the  royal  road  to  the  kidney.  The  renal  vessel 
conveys  the  blood  back/ro77i  the  kidney,  and  every  thing  that  reaches 
it  from  the  intestines  must  necessarily  pass  intp  the  vena  cava,  and 
ultimately  attain  the  kidney  through  the  renal  artery.  The  vessels, 
therefore,  that  end  in  the  renal  veins,  must  be  put  entirely  out  of  the 
question,  so  far  as  regards  the  topic  in  dispute;  and  attention  be  con- 
centrated upon  those  that  terminate  in  the  pelvis  of  the  kidney.  Were 
this  termination  proved,  we  should  be  compelled,  as  we  have  remarked, 
to  bow  to  facts ;  but  not  having  been  so,  it  may  be  stated  as  seem- 
ino-ly  improbable,  that  the  ducts  in  question  should  take  the  circuitous 
course  to  the  pelvis  of  the  kidney,  instead  of  the  direct  one  to  the 
bladder. 

We  know,  then,  nothing  anatomically  of  any  canal  between  the  sto- 
mach and  bladder ;  and  have  not  the  slightest  evidence — positive  or 
relative — in  favour  of  the  opinion,  that  there  is  any  transmission  of 
fluid  through  the  intermediate  areolar  tissue.  There  is,  indeed,  absolute 
testimony  against  it.  ]SOI.  Tiedemann  and  Gmelin  having  examined  the 
lymphatics  and  areolar  tissue  of  the  abdomen,  in  cases  where  they  had 
administered  indigo  and  essence  of  turpentine  to  animals,  discovered  no 
traces  whatever  of  them,  whilst  they  could  be  detected  in  the  kidney. 
The  fcvcts^  again,  referred  to  by  Chirac,  are  doubtful.  If  the  renal 
arteries  be  tied,  the  secretion  cannot  be  effected;  yet,  as  we  have  seen, 
in  the  case  of  extirpated  kidneys,  urea  may  exist  in  the  blood,  and, 
consequently,  urinous  vomiting  be  possible.  If  the  ureters  be  tied,  the 
secretion  being  practicable,  death  will  occur  if  the  suppression  be  pro- 
tracted; and,  in  such  case,  the  secreted  fluid  may  pass  into  the  vessels, 
and  readily  give  a  urinous  character  to  the  perspiration,  vomited  mat- 
ters, &c,,  &c.  The  experiments  of  Darwin,  Brande,  Wollaston,  and 
others  only  demonstrate,  that  these  gentlemen  were  unable  to  detect  in 
the  blood  that  which  they  found  in  the  urine.  Against  the  negative 
results  attained  by  these  gentlemen,  we  may  adduce  the  positive  testi- 
mony of  M.  Fodera,^  an  experimentalist  of  weight,  especially  on  those 
matters.  lie  introduced  into  the  bladder  of  a  rabbit  a  plugged  cathe- 
ter, and  tied  the  penis  upon  the  instrument  to  prevent  the  urine  from 
flowing  along  its  sides.     He  then  injected  into  the  stomach  a  solution 

'  Page  241. 

2  Reclierclies  Experimentales  sur  TAbsorption  et  I'Exlialation,  Paris,  1824. 


VASCULAK   OR   DUCTLESS   GLANDS.  575 

of  ferrocyanuret  of  potassium.  This  being  done,  he  frequently  re- 
moved the  plug  of  the  catheter,  and  received  the  drops  of  urine  on  filter- 
ing paper.  As  soon  as  indications  of  the  presence  of  the  salt  appeared 
in  the  urine  by  the  appropriate  tests, — which  usually  required  from  five 
to  ten  minutes  after  its  reception  into  the  stomach, — the  animal  was 
killed;  and  on  examining  the  blood,  the  salt  was  found  in  the  serum 
taken  from  the  thoracic  portion  of  the  vena  cava  inferior,  right  and  left 
cavities  of  the  heart,  aorta,  thoracic  duct,  mesenteric  glands,  kidneys, 
joints,  and  mucous  membrane  of  the  bronchia.  M.  Magendie,^  too, 
states,  as  the  result  of  his  experiments, — First.  That  whenever  prus- 
siate  of  potassa  is  injected  into  the  veins,  or  is  exposed  to  absorption 
in  the  intestinal  canal,  or  in  a  serous  cavity,  it  speedily  passes  into 
the  bladder,  where  it  can  be  readily  recognised  in  the  urine.  Secondly. 
That  if  the  quantity  of  prussiate  injected  be  considerable  it  can  be 
detected  in  the  blood  by  reagents;  but  if  it  be  small,  it  is  impossible  to 
discover  it  by  the  ordinary  means.  Thirdly.  That  the  same  thing 
happens  if  the  prussiate  of  potassa  be  mixed  with  the  blood  out  of  the 
body.  Fourthly.  That  the  salt  can  be  detected  in  the  urine  in  every 
proportion. 

We  may  conclude,  therefore,  with  Dr.  Hale,^  who  has  written  an 
interesting  paper  on  this  subject,  that  the  existence  of  any  more  direct 
route  from  the  stomach  to  the  bladder  than  the  circulatory  S3'stem  and 
the  kidneys  is  disproved;  and  we  must  consider  the  absorption  of  fluids 
to  be  effected  through  the  vessels  described  under  Absorption  of  Drinks, 
The  facts,  referred  to  elsewhere,  (p.  487,)  which  show  the  extreme 
rapidity  of  the  circulation,  materially  facilitate  our  comprehension  of 
these  cases. 

Such  are  the  glandular  secretions  to  be  considered  in  this  place. 
There  are  still  two  important  secretions — 

7.  Secretion  of  the  Testes^ 

and 

8.  Secretion  of  the  Mammce^ 

which  will  be  investigated  under  the  Functions  of  Eeproduction, 

IV.   VASCULAR  OR  DUCTLESS  GLANDS. 

There  are  several  organs, — as  the  spleen,  thyroid,  thymus,  and  supra- 
renal capsules, — which  are  termed  glands — vascular  glands^  bloody  or 
ductless  glands^  by  many  anatomists;  but  by  M.  Chaussier  glandiform 
ganglions.  Of  the  uses  of  these  we  know  little.  Yet  it  is  necessary 
that  the  nature  of  the  organs  and  their  presumed  functions  should  meet 
with  notice.  The  offices  of  the  thyroid,  thymus,  and  supra-renal  cap- 
sules,— being  chiefly  confined  to  foetal  existence, — will  not  require 
consideration  here.  Although  they  have  no  ducts,  their  minute  ar- 
rangement greatly  resembles  that  of  the  true  glands;  and  they  are  all 
perhaps  concerned,  in  some  manner,  in  hoematosis  or  the  due  elabo- 
ration of  the  circulating  fluid.^     It  has  been  elsewhere  seen,  that  the 

'  Precis,  &c.,  ii,  477. 

2  Boylston  Prize  Dissertation  for  the  years  1819  and  1821,     Boston,  1821, 
'  See,  on  the  vvliole  subject  of  the  vascular  glands,  Ecker's  elaborate  article  Blutgefiiss- 
driisen,  in  Wagner's  Handworterbuch  der  Physiologie,  iv,  1U7,  Braunschweig.  1853. 


576  VASCULAR   OR   DUCTLESS   GLANDS. 

glands  of  Peycr  may  be  classed  under  this  head ;  and  Ecker  adds  the 
pituitary  gland  of  the  brain,' 

a.  The  Spleen. 

The  spleen  is  a  viscus  of  considerable  size,  situate  in  the  left  hypo- 
chondriac region  (Fig.  155),  beneath  the  diaphragm,  above  the  left 
kidney,  and  to  the  left  of  the  stomach.  Its  medium  length  is  about 
four  and  a  half  inches;  its  thickness  two  and  a  half,  and  its  weight 
about  eight  ounces.^  Its  absolute  weight,  and  its  weight  in  proportion 
to  that  of  the  whole  body,  increases  rapidly,  according  to  Huschke, 
after  birth;  and  its  proportionate  weight  soon  attains  its  highest  stand- 
ard, so  that,  in  the  adult,  it  has  not  a  decidedly  greater  proportion  to 
the  body  than  at  birth;  and  in  some  cases  even  decreases.  It  varies 
between  1  to  235  and  1  to  240.^  Its  relation  to  the  weight  of  the  liver 
is  proportionally  greater  in  the  adult  than  in  the  infant.  It  is  of  a  soft 
texture,  somewhat  spongy  to  the  feel,  and  easily  torn ;  and  in  a  very 
recent  subject  is  of  a  grayish-blue  colour;  which,  in  a  few  hours,  changes 
to  purple,  so  that  it  resembles  a  mass  of  clotted  blood.  At  its  inner 
surface,  or  that  which  faces  the  stomach  and  kidney,  a  fissure  exists,  by 
which  the  vessels,  nerves,  &c.,  enter  or  issue  from  the  organ. 

The  histology  of  the  spleen  has  been  much  investigated  of  late.  Its 
main  anatomical  elements  have  been  considered  to  be: — 1,  The  spdeydc 
artery^  which  arises  from  the  coeliac,  and  after  having  given  off  branches 
to  the  pancreas  and  the  left  gastro-epiploic  artery  divides  into  several 
branches,  which  enter  the  spleen  at  the  fissure,  and  ramify  in  the  tissue 
of  the  organ;  so  that  it  seems  to  be  exclusively  formed  by  them.  Whilst 
the  branches  of  the  artery  are  still  in  the  duplicature  of  the  gastro- 
splenic  omentum,  and  before  they  ramify  in  the  spleen,  they  furnish 
the  vasa  brevia  to  the  stomach.  The  precise  mode  of  termination  of 
the  arteries  in  the  spleen  is  unknown :  their  communication  with  the 
veins  does  not,  however,  appear  to  be  as  free  as  in  other  parts  of  the 
body,  nor  the  anastomoses  between  the  minute  arteries  as  numerous. 
If,  according  to  Assolant,''  one  of  the  branches  of  the  splenic  artery  be 
tied,  the  portion  of  the  spleen  to  which  it  is  distributed  dies;  and  if  air 
be  injected  into  one  of  these  branches,  it  does  not  pass  into  the  other; 
so  that  the  spleen  would  appear  to  be  a  congeries  of  several  distinct 
lobes;  and  in  certain  animals  the  lobes  are  so  separated  as  to  constitute 
several  spleens.  A  similar  appearance  is  occasional!}^  seen  in  the  human 
subject.  2.  The  splenic  vein  arises  by  numerous  radicles  in  the  tissue 
of  the  spleen :  these  become  gradually  larger,  and  less  numerous,  and 
leave  the  fissure  of  the  spleen  by  three  or  four  trunks,  which  ultimately 
unite  with  veins  from  the  stomach  and  pancreas  to  form  one,  that  opens 
into  the  vena  porta.  It  is  without  valves,  and  its  parietes  are  thin. 
These  are  the  chief  constituents.  8.  Lympihaiic  vessels,  which  are  large 
and  numerous.  4.  Nerves,  proceeding  from  the  coeliac  plexus:  they 
creep  along  the  coats  of  the  splenic  artery — upon  which  they  form  an 

'  Op.  cit.,  S.  160. 

2  Gross,  Elements  of  Pathological  Anatomy,  2d  edit.,  p.  674,  Philad.,  1845. 

3  The  French  translation  of  Jourdan  says  between  1  to  235  and  1  to  400, — Encyclop. 
Anatom.,  v.  172,  Paris,  1845. 

•*  llecherches  sur  la  Rate,  Pai'is,  1801. 


SPLEEN. 


577 


Fig.  182. 


intricate  plexus — into  the  substance  of  the  spleen.  5.  Areolar  tissue, 
which  serves  as  a  bond  of  union  between  these  various  parts ;  but  is 
in  extremely  small  quantity,  6.  A  j^roper  memhrcme,  which  envelopes 
the  organ  externall}^;  adheres  closely  to  it,  and  furnishes  fibrous  sheaths 
to  the  ramifications  of  the  artery  and  vein;  keeping  the  ramifications 
separated  from  the  tissue  of  the  organ,  and  sending  prolongations  into 
the  parenchyma,  which  gives  it  more  of  a  reticulated  than  a  spongy 
aspect.  7.  Of  hhod^  according  to  many  anatomists;  but  blood  differing 
from  that  of  both  the  splenic  artery  and  vein, — houe  splenique,  contain- 
ing, according  to  M.  Vauquelin,  less  colouring  matter  and  fibrin,  and 
more  albumen  and  gelatin,  than  any  other  kind  of  blood.  This,  by 
stagnating  in  the  organ,  is  conceived  to  form  an  integrant  part  of  it, 
Malpighi^  believed  it  to  be  contained  in  cells;  but  others  have  supposed 
it  to  be  situate  in  a  capillary  system  intermediate  between  the  splenic 
artery  and  vein, 

Assolant  and  Meckel'  believe,  that  the  blood  is  in  a  peculiar  state  of 
combination  and  of  intimate  union  with  the  other  organic  elements  of 
the  viscus,  and  with  a  large  quantity  of  albumen ;  and  that  this  com- 
bination of  the  blood  forms  the  dark  brown  pulpy  substance,  contained 
in  the  cells  formed  by  the  proper  coat,  and  which  can  be  easily  demon- 
strated by  tearing  or  cutting  the  spleen,  and  scraping  it  with  the  handle 
of  a  knife.  These  cells  and  the  character 
of  the  tissue  of  the  spleen  are  exhibited 
in  the  marginal  figure  (Fig,  182).  In 
addition  to  the  pulp,  there  is  an  abund- 
ance of  rounded  corpuscles,  varying  in 
size  from  an  almost  imperceptible  mag- 
nitude to  a  line  or  more  in  diameter. 
By  Malpighi,  these  were  conceived  to  be 
granular  corpuscles,  and,  by  Ruysch,^ 
simply  convoluted  vessels,  M,  AndraP 
affirms,  that  by  repeated  washings  the 
spleen  is  shown  to  consist  of  an  infinite 
number  of  cells,  which  communicate  with 
each  other,  and  with  the  splenic  veins. 
The  latter,  when  the  inner  surface  of  the 
large  subdivisions  of  the  splenic  veins 
are  examined,  appear  to  have  a  great 
number  of  perforations,  through  which 
a  probe  passes  directly  into  the  cells  of 
the  organ.  The  farther  the  subdivisions 
of  the  vein  examined  are  from  the  trunk, 
the  larger  are  these  perforations ;  and 
still  farther  on,  the  coats  of  the  vein  are 
not  a  continuous  surface,  bat  are  split  into  filaments,  which  do  not  differ 
from  those  forming  the  cells,  and  are  continuous  with  them.    M.  Bour- 


Section  of  the  Spleen. 


'  Op.  Omnia,  jmrs  ii.,  Loud.,  1(587  ;  and  Op.  Postlium.,  p.  42,  Lond.,  1097. 
2  llandbuch,  &c.,  traduit  par  Jourdan,  iii.  47li,  Paris,  1825. 
^  Meckel,  op.  citat. 

*  Precis  d'Anatouiie  Pathologique,  torn.  ii.  part  i.  p.  416,  Paris,  1832. 
VOL.  L — '61 


578  VASCULAR   OR   DUCTLESS   GLAXDS. 

gery  has  maintained,  that  the  fibrous  envelope  of  the  spleen  sends  off 
a  multitude  of  lamellte,  which  penetrate  its  interior,  forming  irregular 
spaces  of  unequal  dimensions.  These  short  spaces  he  calls  splew'c  vesi- 
cles. In  the  septa,  a  number  of  lymphatic  glands  exists.  The  capillaries 
of  the  arteries  communicate  directly  with  those  of  the  veins;  but,  accord- 
ing to  M.  Bourgery,  there  are,  in  addition,  veins  with  patulous  orifices. 
The  interior  of  the  vesicles  is  filled  with  a  soft  substance  of  a  deep  red 
colour,  in  which  the  small  white  corpuscles,  discovered  by  Malpighi, 
are  suspended.  M.  MandP  suggests,  that  the  white  corpuscles  may  be 
analogous  to  the  intestinal  villi,  in  which  the  lymphatics  originate  by 
a  ca^cal  extremity. 

The  minute  structure  of  the  spleen  has  been  intimately  investigated 
by  Dr.  Evans,^  and  by  Professor  Kolliker,''  and  still  more  recently  by 
Dr.  Sanders,-*  Mr.  Wharton  Jones,*  Mr.  Huxley,^  Mr.  Gray,^  Giins- 
burg,  Fiihrer,*  and  others.  The  organ,  according  to  Ktilliker,  is  essen- 
tially composed  of  a  fibrous  membrane,  formed  of  white  fibrous  tissue, 
and  in  many  of  the  lower  animals  having  unstriped  muscular  fibres 
intermixed,^  which  constitutes  its  exterior  envelope,  and  sends  trabe- 
cular prolongations  in  all  directions  across  its  interior,  so  as  to  divide 
it  into  a  number  of  irregularly  shaped  splenic  cells,  communicating 
freely  with  each  other  and  with  the  splenic  vein,  and  lined  by  a  mem- 
brane continuous  with  that  of  the  vein,  which  is  so  reflected  upon 
itself  as  to  leave  oval  or  circular  foramina,  by  which  each  cell  com- 
municates with  the  others  and  the  vein.  The  diameter  of  these  cells 
is  estimated  at  from  one-third  to  half  a  line,  and  they  are  generally 
traversed  by  filaments  of  elastic  tissue,  imbedded  in  which  a  minute 
artery  and  vein  may  frequently  be  observed.  Over  these  filaments 
the  lining  membrane  is  reflected  in  folds;  so  that  each  cell  is  thus  in- 
completely divided  into  two  or  more  small  compartments.  No  direct 
communication  exists  between  the  splenic  artery  and  the  interior  of 
the  cells;  but  its  branches  are  distributed  through  the  intercellular 
parenchyma,  and  the  small  veins,  which  collect  the  blood  from  the 
arterial  capillaries  of  the  organ,  carry  it  into  the  cells  whence  it  is  con- 
veyed away  by  the  splenic  vein.  The  cells  may  be  readily  injected 
from  the  vein  with  either  air  or  liquid,  provided  they  are  not  filled 

'  Manuel  d'Anatomie  Generale,  p.  518,  Paris,  1843. 

2  Lancet,  April  6,  1844. 

'  Mittlieilungen  der  Ziiricher  Naturforsclienden  Gesellschaft  vora  Jahre  1847  ;  Art. 
Spleen,  Cyclopredia  of  Anatomy  and  Physiology,  pts.  xxxvi.  and  xxxvii.,  June  and 
October,  1849;  and  Kolliker,  Mikroskopisclie  Anatomife,  ii.  253.  Leipzig,  1852;  or  Anier. 
edit,  of  the  translation  of  his  Manual  of  Histology,  by  Dr.  Da  Costa,  p.  551,  Philad., 
1854. 

■*  Goodsir's  Annals  of  Anatomy  and  Physiology,  No.  1,  p.  49,  Feb.,  1850. 

5  Brit,  and  For.  Med.-Chir.  Rev.,  Jan.,  1853,  p.  275. 

®  Quarterly  Journal  of  Microscopical  Science,  ii.  74,  London,  1854;  and  Kijlliker's 
Manual  of  Histology,  Amer.  edit,  by  Dr.  Da  Costa,  p.  786,  Philad.,  1854. 

'  Th(;  Structure  and  Use  of  the  Spleen,  Loud.,  1854. 

8  Cited  in  Canstatt's  Jahresbericht,  im  Jahre  1854,  ler  Bd.  S.  72. 

9  Sharpey,  in  Quain  and  Shai-pey's  edition  of  Quain's  Human  Anatomy,  by  Leidy, 
ii.  498,  Pliilad.,  1849,  Kolliker,  op.  citat. ;  and  Ecker,  art.  Blutgefassdriisen,  Wagner's 
Handwilrterbuch  der  Physiologie,  23ste  Lieferung,  S.  132,  Braunschweig,  1849.  Ma- 
zoun  states  tlaat  the  covering  and  trabecular  tissue  of  the  organ  in  man  contain  mus- 
cular fibre. — Miiller's  Archiv.,  i.  25,  Berlin,  1854;  and  J.  W.  Ogle,  Report  on  Micro- 
logy  in  Brit,  and  For.  Med.-Chir.  Rev.,  Oct.,  1855,  p.  530. 


SPLEEN.  579 

Avith  coagulated  blood;  and  they  are  so  distensible — as  has  been  long- 
known — that  the  organ  may  be  made,  with  very  little  force,  to  dilate 
to  many  times  its  original  size.  The  cells  of  the  spleen,  according  to 
Dr.  Evans,  never  contain  any  thing  but  blood;  and  a  frequent  appear- 
ance after  death  is  that  of  firmly  coagulated  blood  filling  them,  and 
giving  a  granular  aspect  to  the  organ,  which  is  sometimes  described 
as  morbid.  The  partitions  between  the  cells  are  formed  by  the  mem- 
branes already  mentioned,  and  by  the  proper  parenchyma  of  the  spleen. 
To  the  eye  it  has  a  semi-fluid  appearance,  but  when  an  attempt  is  made 
to  tear  it,  considerable  resistance  is  experienced,  in  consequence  of  its 
being  intersected  by  what  seem  to  be  minute  fibres.  When  a  small 
portion  is  pressed,  a  liquid  exudes — liquor  Uenis  or  splenic  blood — 
which  is  usually  described  as  filling  the  cells  of  the  spleen;  but  ac- 
cording to  Dr.  Evans  this  is  erroneous.  This  liquid,  when  diluted 
with  serum,  and  examined  under  the  microscope,  is  found  to  contain 
two  kinds  of  corpuscles, — one  apparently  identical  with  ordinary 
blood  corpuscles — the  other  with  the  corpuscles  characteristic  of  lymph, 
and  abundant  in  the  lymphatic  ganglions.  The  remaining  fibrous 
sabstance  consists  wholly  of  capillary  bloodvessels  and  lymphatics 
with  minute  corpuscles,  much  smaller  than  blood  corpuscles,  varying 
in  size  from  about  gy'^Qth  to  ^^^'g^th  of  an  inch,  of  spherical  form,  and 
usually  corrugated  on  the  surface.  These  lie  in  great  numbers  in  the 
meshes  of  the  sanguiferous  capillaries;  and  the  minute  lymphatics  are 
described  by  Dr.  Evans  as  connected  with  the  splenic  corpuscles,  and 
apparently  arising  from  them.  Lying  in  the  midst  of  the  parenchyma 
is  a  large  number  of  bodies,  of  about  a  third  of  a  line  in  diameter, 
which  are  evidently  in  close  connexion  with  the  vascular  system. 
These  are  the  Malpighian  bodies  of  the  spleen  or  splenic  corpuscles. 
According  to  Dr.  Evans,  they,  in  all  respects,  resemble  mesenteric  or 
lymphatic  ganglions  in  miniature — consisting,  as  they  do,  of  convo- 
luted masses  of  bloodvessels  and  lymphatics,  united  together  by  elastic 
tissue,  so  as  to  possess  considerable  firmness ;  and  they  farther  corre- 
spond with  them  in  this, — that  the  lymph  they  contain,  which  is  quite 
transparent  in  the  ailerent  vessels,  becomes  somewhat  milky,  from 
containing  a  large  number  of  lymph  corpuscles. 

Professor  Kolliker  describes  the  spaces  left  by  the  trabecular  })ro- 
longations  as  of  irregular  form  and  size,  and  occupied  by  the  peculiar 
splenic  or  Mal'pighian  corpuscles^  and  the  splenic  parenchyma.  These 
corpuscles,  according  to  him,  are  whitish  spherical  bodies,  imbedded 
in  the  parenchyma  of  the  spleen,  but  connected  with  the  smaller  arte- 
ries by  short  peduncles  in  a  racemose  manner.  They  are  seldom  seen 
in  the  human  subject,  owing  to  the  rapid  changes  they  undergo  after 
death  ;  but  Professor  Kolliker  has  no  doubt  of  their  being  invarial)ly 
present  in  health.  lie  affirms,  that  they  have  no  relation  to  the 
lymphatics;  but  are  closed  capsules,  resembling  the  elementary  cells 
of  glands  before  the  rupture  of  their  walls.  The  red  spleen  substance, 
spleen  pulp  ot  parenchyma  of  the  spleen,  consists  in  great  part  of  cells, 
which  correspond  in  appearance  with  those  of  the  Malpighian  corpuscles. 
Two  other  kinds,  however,  occur  in  it  seldom  met  with  in  the  latter ; 
and  numerous  free  nuclei  are  also  present.  Of  these,  one  set  bears  a 
strong  resemblance  to  red  blood  corpuscles;  the  others  are  pale  with 


580 


VASCULAR   OPw    DUCTLESS    GLANDS. 


one  or  two  nuclei,  or  colourless  granule  cells.  A  considerable  part  of 
the  pulp  appears  to  consist  of  blood  corpuscles  in  various  stages  of 
metamorphosis,  as  was  first  taught  bj  Professor  Kolliker.  "The 
blood   globules'" — he   remarks — "first   become   at   once  smaller  and 

darker,  whilst  the  elliptical  cor- 
Fig.  183.  puscles  of  the  lower  vertebrata 

also  become  rounder;  then,  in 
connection  with  some  blood  plas- 
ma, they  become  aggregated  into 
small  round  heaps ;  which  heaps, 
by  the  appearance  of  an  interior 
nucleus  and  of  an  outer  mem- 
brane, experience  a  transition 
into  spherical  cells  containing 
blood  corpuscles.  These  are 
from  5-lOOOths  to  15-lOOOths  of 
a  line  in  size,  and  contain  from 
one  to  twenty  blood  corpuscles. 
During  this  time,  the  blood  cor- 
puscles arecontinuall}^  diminish- 
ing in  size;  and,  assuming  a 
golden  }^llow,  brownish  red  or 
dark  colour,  they  undergo,  either 
immediately,  or  after  a  previous 
dissolution,  a  complete  transi- 
tion into  pigment  granules.  So 
that  these  cells  themselves  are 
changed  into  pigmentary  granule 
cells;  and  finally,  by  a  gradual  loss  of  colour  of  their  granules,  they 
form  themselves  into  completely  colourless  cells."^  These  are  found 
in  the  blood,  especially  of  the  splenic  vein,  vena  porta  and  inferior 
cava.  It  is  not,  however,  easy  to  see  how  the  corpuscles  can  leave  the 
splenic  arteries,  unless  they  have  a  direct  open  communication  with 
the  splenic  pulp,  which  is  not  admitted.  Professor  Kolliker  describes 
the  arterial  branches  as  ramifying  in  the  red  spleen  substance,  where 
each  twig  subdivides  into  smaller  and  smaller  arteries,  and,  when  they 
become  capillary,  constitute  a  close  and  beautiful  network  in  the 
splenic  pulp.  Gieskei',^  however,  considers  that  the  pulp  consists  of 
nothing  but  the  minutest  arteries  and  veins  united  by  fibrous  tissue. 
The  whole  subject,  however,  of  splenic  histology  appears  to  the  author 
to  be  far  from  determined,  and  to  demand  fresh  investigations. 

Besides  the  proper  membrane,  the  spleen  receives  also  a  peritoneal 
coat;  and,  between  the  stomach  and  it,  the  peritoneum  forms  the  gas- 
tro-s2')Ien'c  ep/plooji  or  <jastro-splemc  ligament,  m  the  duplicature  of  which 
are  situate  the  vasa  brevia.  Lastly ;  the  spleen,  as  remarked  above,  is 
capable  of  distension  and  contraction ;  and  is  possessed  of  little  sensi- 
bility in  the  healthy  state.     It  has  no  excretory  duct.^ 

'  Art.  Spleen,  Cj'clop.  of  Anat.  and  PhysioL,  kc,  p.  782. 
2  Cited  by  Kolliker,  p.  790. 

'  A  good  epitome  of  the  views  of  different  observers  in  recard  to  the  structure  of  the 
spleen,  with  observations  of  his  own,  is  given  by  Di-.  \\'m.  K.  Sanders,  op.  cit. 


Branch  of   Splenic    Artery,  the  ramifications  of 
■which  are  studded  with  Malpighian  Corpuscles. 


SPLEEN.  581 

The  hypotheses,  which  has  been  indulged  on  the  functions  of  the 
spleen,  are  beyond  measure  numerous  and  visionary ;  and,  after  all, 
we  are  in  much  obscurity  as  to  its  real  uses.  Many  of  these  hypo- 
theses are  too  idle  to  merit  notice;  such  are  those,  that  consider  it  to 
be  the  seat  of  the  soul; — the  organ  of  dreaming;  of  melancholy  and  of 
laughter,  of  sleep  and  the  venereal  appetite, — the  organ  that  secretes 
the  mucilaginous  fluids  of  the  joints;  that  serves  as  a  warm  fomentation 
to  the  stomach,  and  so  on.  It  was  long  regarded  as  a  secretory  appa- 
ratus for  the  formation  of  atrabilis, — of  a  fluid  intended  to  nourish  the 
nerves, — of  gastric  juice, — of  a  humour  intended  to  temper  the  alka- 
line character  of  the  chyle  or  bile,  &c.  The  absence  of  an  excretory 
duct  would  be  a  sufficient  answer  to  all  these  speculations,  if  the  non- 
existence of  the  supposititious  humours  were  insufficient  to  exhibit  their 
absurdity.  MM.  Tiedemann  and  Gmeliu'  consider  its  functions  to  be 
identical  with  those  of  the  mesenteric  glands.  They  regard  it  as  a 
ganglion  of  the  absorbent  system,  which  prepares  a  fluid  to  be  mixed 
with  the  chyle  and  effect  its  animalization.  In  favour  of  the  view,  that 
it  is  a  part  of  the  lymphatic  system,  they  remark,  that  it  exists  only  in 
those  animals  which  have  a  distinct  absorbent  system; — that  its  bulk  is 
in  a  ratio  with  the  developement  of  the  absorbent  system ; — that  the 
lymphatics  predominate  in  the  structure  of  the  organ;  that  its  texture 
is  like  that  of  the  lymphatic  ganglions;  and  lastly,  that  on  dissecting 
a  turtle  they  distinctly  saw  all  the  lymphatics  of  the  abdomen  passing 
first  to  the  spleen,  then  leaving  that  organ  of  larger  size,  and  proceed- 
ing to  the  thoracic  duct. 

In  support  of  their  second  position,  that  it  furnishes  some  material 
towards  ihe  animalization  of  the  chyle,  they  adduce, — the  large  size  of 
the  splenic  artery,  which  manifestly,  they  conceive,  carries  more  blood 
to  the  organ  than  is  needed  for  its  nutrition ;  and  affirm,  that,  in  their 
experiments,  they  have  frequently  found,  whilst  digestion  and  chylosis 
were  going  on,  the  lymphatic  vessels  of  the  spleen  gorged  with  a  red- 
dish fluid,  which  was  carried  by  them  into  the  thoracic  duct,  where 
the  chyle  always  has  the  most  rosy  hue;  and  that  a  substance  injected 
into  the  splenic  artery  passes  readily  into  the  lymphatics  of  the  spleen. 
Lastly,  after  extirpating  the  spleen  in  animals,  the  chyle  appeared  to 
them  to  be  more  transparent, — no  longer  depositing  coagula ;  and  the 
lymphatic  ganglions  of  the  abdomen  seemed  to  have  augmented  in 
size.  Views  similar  to  these  had  been  maintained  by  Sir  Everard 
Home.^ 

M.  Chaussier,  as  has  been  seen,  classes  the  spleen  amongst  the  glandi- 
form ganglions ;  and  affirms,  that  a  fluid,  of  a  serous  or  sanguineous 
character,  is  exhaled  into  its  interior,  which,  when  absorbed,  assists  in 
lyraphosis.  Many,  again,  have  believed,  that  it  is  a  sanguineous,  not 
a  lympliatic  ganglion,  but  they  have  differed  regarding  the  blood  on 
which  it  exerts  its  action;  some  maintaining,  that  it  prepares  the  blood 
for  the  secretion  of  gastric  juice;  others,  for  that  of  the  bile.  The 
former  of  these  views  is  at  once  repelled  by  the  fact,  that  the  vessels 

'  Versuclie  iiber  die  Wege  auf  welche  Substanzcn  aus  dem  Magen  und  Darmkanal 
im  Blut  gelangen,  p.  86,  Heidelb.,  1820. 

'  Philosoph.  Transactions  foi- 1808  and  1811  ;  and  Lect.  on  Comp.  Anatomy,  loc.  cit. 


582  VASCULAR   OR   DUCTLESS   GLANDS. 

whicli  pass  from  the  splenic  artery  to  tlie  stomach,  leave  that  vessel  be- 
fore it  enters  the  spleen.  The  latter  has  been  urged  by  M.  Yoisin.^ 
He  thinks,  the  principal  use  of  the  spleen  is  to  furnish  to  the  liver  blood 
containing  those  materials  that  enter  into  the  composition  of  the  bile ; 
but  as  to  the  changes  produced  on  the  blood,  the  greatest  difference  of 
sentiment  has  existed.  Mr.  Hewson^  believed,  that  the  spleen  is  the 
organ  ordained  by  nature  for  "the  more  perfectly  forming  the  red  par- 
ticles of  the  blood ;"  a  view  in  which  Prof.  J.  Hughes  Bennett  and 
Funke,^  accord;  whilst  Professor  Kcilliker  infers  from  his  observations 
— and  Professor  Ecker,"*  of  Basle,  Moleschott,  Mr.  Gray,  and  M.  Bdclard,* 
agree  with  him, — that  they  suffer  destruction  or  decomposition  in  the 
spleen,  becoming  changed  in  the  manner  before  described ;  but  in  one 
that  does  not  seem  very  intelligible.  He  supposes,  that  the  altered 
corpuscles  may  be  inservient  to  the  formation  of  bile,  the  colouring 
matter  of  which  is  nearly  allied  to  that  of  the  blood,  whilst  the  small 
nucleated  cells  of  the  Malpighian  bodies  may  be  concerned — it  has  been 
suggested — in  the  formation  of  fibrin. 

That  some  change  is  effected  by  the  organ  upon  the  blood  sent  to 
it  by  the  splenic  artery  has  long  seemed  to  be  confirmed  by  examina- 
tion of  that  fluid.  Since  the  period  of  Haller,  the  blood  of  the  splenic 
vein  has  been  presumed  to  differ  essentially  from  that  of  other  veins, 
which  naturally  led  to  the  belief,  that  some  elaboration  is  effected  in 
the  spleen  to  fit  the  blood  for  the  secretion  of  bile.  It  has  been  de- 
scribed as  more  aqueous,  albuminous,  and  unctuous,  and  blacker  than 
other  venous  blood ;  to  be  less  coagulable,  less  rich  in  fibrin,  and  the 
fibrin  it  does  contain  to  be  less  animalized.[?]  Yet  these  affirmations 
are  denied;  and  even  were  they  admitted,  we  have  no  positive  know- 
ledge, that  such  changes  adapt  it  better  for  the  formation  of  bile. 
Examinations  of  the  blood  of  the  splenic  and  other  veins  by  M.  Be- 
clard^  favour  the  views  of  Professor  Kolliker.  The  following  were  the 
results  of  an  examination  of  the  blood  of  four  successive  bleedings  of 
the  same  animal: — 

External  Jugular.  Mammary. 

Water,     ....         778-9  750-6 

Albumen,          .         .         .           79-4  89-5 

Red  corpuscles  and  fibrin,         141-72  159*9 

Farther  analyses  by  the  same  gentleman  showed  a  manifest  diminu- 
tion of  the  red  corpuscles,  and  an  increase  of  albumen  and  fibrin.^ 

The  ideas  that  have  existed,  in  regard  to  the  spleen  being  a  diver- 
ticulum for  the  blood,  have  been  mentioned  under  Circulation.  By 
some,  it  has  been  supposed  to  act  as  such  in  the  intervals  of  digestion; 
or  in  other  words,  to  be  a  diverticulum  to  the  stomach :  by  others,  its 

'  Nouvel  Aperu  sur  la  Physiologie  du  Foie  et  les  Usages  de  la  Bile,  Paris,  1833. 

^  Works  by  Gulliver,  Sydenliam  Society's  edit.,  p.  273,  Lond.,  I84b'. 

^  Henle  und  Pfeuffer's  Zeitschr.,  Bd.  i.  S.  172;  cited  in  Can.statt's  Jabresbericlit  im 
Jalire  1851,  B.  i.  S.  13b';  and  Rudolph  Wagner's  Lelirbucli  der  sijeciellen  Physiologie, 
von  Otto  Funke,  Iste  Liefemng,  S.  120,  Leipz.,  18;")4. 

*  Schmidt's  Jahrbiicher,  u.  s.  w..  No.  5,  S.  146,  Jahrgang,  1848,  and  art.  Blutgefiiss- 
driisen,  in  Wagner's  Handworterbuch  der  Phvsiologie,  23te  Lieferung,  S.  152,  Braun- 
schweig, 1849  ;  see,  also,  Dr.  W.  R.  Sanders,  Medical  Times,  April  21,  1849. 

^  Traite  Elementaire  de  Physiologie,  p.  411,  Paris,  1855. 

''  Annales  de  Chimie  et  de  Physique,  xxi.  506,  Paris,  1847. 

"  Coroptes  Rendus,  xxvi.  122. 


I 


Splenic. 

Vena  Porta 

746-3 

702-3 

124-4 

70-6 

128-9 

227-1 

SPLEEN.  583 

agency  in  tliis  way  is  believed  to  apply  to  the  whole  circulatory  sys- 
tem, so  that  when  the  flow  of  blood  is  impeded  or  arrested  in  otlier 
parts,  it  is  received  into  the  spleen.  Such  a  view  was  entertained  by 
Dr.  Rush,^  and  it  has  been  embraced  by  many  others. 

It  is  hard  to  say  which  of  these  speculations  is  the  most  ingenious. 
None  can  satisfy  the  judicious  physiologist,  especially  when  he  con- 
siders the  comparative  impunity  consequent  on  extirpation  of  the 
organ.  This  was  an  operation  performed  at  an  early  period.  Pliny 
affirms,  that  it  was  practiced  on  runners  to  render  them  more  swift. 
From  animals  the  spleen  has  been  repeatedly  removed ;  and  although 
many  of  these  died  in  consequence  of  the  operation,  several  recovered. 
M.  Adelon^  refers  to  the  case  of  a  man  who  was  wounded  by  a  knife 
under  the  last  false  rib  of  the  left  side.  Surgical  attendance  was  not 
had  until  twelve  hours  afterwards;  and  as  the  spleen  had  issued  at  the 
wound,  and  was  much  altered,  it  was  considered  necessary  to  extirpate 
it.  The  vessels  were  tied;  the  man  got  well  in  less  than  two  months, 
and  has  ever  since  enjoyed  good  health.  Sir  Charles  BelP  asserts, 
that  an  old  pupil  had  given  him  an  account  of  his  having  cut  off"  the 
spleen  in  a  native  of  South  America.  The  spleen  had  escaped  through 
a  wound,  and  had  become  gangrenous.  He  could  observe  no  effect 
from  the  extirpation.  T.  Chapman,'*  Esq.,  of  Purneah,  in  India,  has 
related  a  case  of  excision  of  a  portion  of  the  spleen  by  Dr.  Macdonald 
of  that  station.  A  native,  about  thirty  years  of  age,  was  gored  in  the 
abdomen  by  a  buffalo ;  and  through  the  wound,  which  was  about  three 
inches  in  length,  a  portion  of  the  spleen  protruded.  Six  days  after- 
wards, the  man  sought  advice  from  Dr.  ]Macdonald,  who  removed  the 
spleen  with  a  knife,  and  the  patient  rapidly  recovered. 

Dr.  O'Brien,  in  an  inaugural  dissertation,  published  at  Edinburgh 
in  1818,  refers  to  a  case  which  fell  under  his  own  management.  The 
man  was  a  native  of  Mexico:  owing  to  a  wound  of  the  abdomen,  the 
spleen  lay  out  for  two  days  before  the  surgeon  was  applied  to.  The 
bleeding  was  profuse;  the  vessels  and  other  connexions  were  secured 
by  ligature,  and  the  spleen  separated  completely  on  the  twentieth  day 
of  the  wound.  On  the  forty-fifth  day,  the  man  was  discharged  from 
the  hospital  cured;  and  he  remarked  to  some  one  about  this  time,  that 
"he  felt  as  well  as  ever  he  did  in  his  life."  The  case  of  a  man  has 
been  reported,  who  lived  in  good  health  for  thirteen  years  after  the 
spleen  had  been  removed  ;*  and  another  by  M.  Berthet  de  Gray  of  a 
middle-aged  man,  who  received  a  wound  in  the  side,  through  which 
the  spleen  eventually  protruded,  and  becoming  gangrenous  was  re- 
moved. The"  man  recovered,  and  lived  thirteen  years,  enjoying  sound 
health,  his  digestion  being  generally  good.  After  death  from  pneu- 
monia, all  that  remained  of  the  spleen  was  found  to  be  a  small  pojtion 
of  the  size  of  a  filbert,  adhering  to  the  stomach. 

'  Coxe's  Medical  Museum,  Pliilad.,  1807. 

^  Physiol,  de  THomme,  2de  edit.,  torn,  iii.,  Paris,  1829. 

^  Anat.  and  Physiol.,  5th  Amer.  edit.,  by  Dr.  Godman,  ii.  363,  New  York,  1827. 

*  India  Journal  of  Medicine,  vol.  viii.  p.  1  ;  and  London  Medical  Gazette  for  May 
20,  1837,  p.  285. 

5  Gazette  Medicale  de  Paris,  No.  28,  1S44,  cited  from  Oesterreich.  Med.  Wochen- 
schrift,  21  Sept.,  1844. 


58-i  VASCULAR    OR   DUCTLESS    GLANDS. 

Dulaurens,  Kerckring,  Baillie,'  aud  others,'^  refer  to  cases,  in  which 
the  spleen  was  wanting  in  man,  without  any  apparent  impediment  to 
the  functions;  and  the  author  has  seen  it  in  the  dead  body  not  larger 
than  an  almond,  when  there  had  been  no  reason  to  suspect  splenic 
disease. 

The  experiments,  which  have  been  made  on  animals,  by  removing 
the  spleen,  have  led  to  discordant  results.  Malpighi  says,  that  the 
operation  was  followed  by  increased  secretion  of  urine;  Dumas,  that 
the  animals  had  afterwards  a  voracious  appetite;  Mead  and  Mayer, 
that  digestion  was  impaired ;  that  the  evacuations  were  more  liquid, 
and  the  bile  more  watery ;  Tiedemann  and  Gmelin,  that  the  chyle 
appeared  more  transparent  and  devoid  of  clot;  Professor  Coleman,  that 
the  dogs, — subjects  of  the  experiment, — were  fat  and  indolent.  A 
dog,  whose  spleen  was  removed  by  Mr.  Mayo,^  became,  on  recovering 
from  the  wound,  fatter  than  before ;  in  a  year's  time  it  had  returned  to 
its  former  condition,  and  no  difference  was  observed  in  its  appearance 
or  habits  from  those  of  other  dogs.  Similar  results  followed  the  expe- 
riments of  Dr.  Blundell,  Mr.  Dobson,  and  Mr,  Eagle  •*  and  the  last 
gentleman  states,  that  an  offer  had  been  made  him  of  a  "smart  sum  of 
money"  by  a  dealer  in  Leadeuhall  Market,  if  he  would  tell  him  his 
method  of  fattening  animals. 

M.  Dupuytren  extirpated  the  spleen  of  forty  dogs  on  the  same  day, 
without  tying  any  vessel,  but  merely  stitching  up  the  wound  of  the 
abdomen, — yet  no  hemorrhage  supervened!  In  the  first  eight  days, 
half  the  dogs  operated  on  died  of  inflammation  of  the  abdominal  vis- 
cera induced  by  the  operation,  as  was  proved  by  dissection.  The  other 
twenty  got  well  without  any  accident,  at  the  end  of  three  weeks  at  the 
farthest.  At  first,  they  manifested  a  voracious  appetite,  but  it  soon 
resumed  its  natural  standard.  They  fed  on  the  same  aliment,  and 
drinks,  took  the  same  quantity  of  food,  and  digestion  seemed  to  be 
accomplished  in  the  same  time.  The  fieces  had  the  same  consistence 
and  appearance,  and  the  chyle  appeared  to  have  the  same  character. 
Nor  did  the  other  functions  offer  any  modification.  M.  Dupuytren 
opened  several  of  the  dogs  some  time  afterwards,  and  found  no  appa- 
rent change  in  the  abdominal  circulation, — in  that  of  the  stomach, 
epiploon,  or  liver.  The  last  organ,  which  a|)peared  to  some  of  the 
experimenters  to  be  enlarged,  did  not  seem  to  him  to  be  at  all  so.  The 
bile  alone  appeared  a  little  thicker,  and  deposited  a  slight  sediment. 
Similar  experiments  by  Bardeleben*  have  led  to  results  of  an  analo- 
gous kind.  Animals,  which  survived  the  extirpation  of  the  spleen, 
appeared  to  recover  their  health  speedily,  and  to  present  no  difference 
from  those  which  had  not  undergone  the  operation.  He  never  remarked, 
however,  that  they  were  more  voracious  than  other  animals.  In  no 
case  was  the  organ  regenerated.  An  animal  deprived  of  both  spleen 
aud  thyroid  presented  no  change  in  any  function, — a  circumstance, 

'  Morbid  Anatomy,  5tli  edit.,  p.  277,  Lond.,  1818. 

^  R.  Lebby,  Southern  Journ.  of  Med.  and  Pharmacy,  Sept.,  1846. 

*  Outlines'  of  Human  Physiology,  4th  edit.,  p.  107,  Lend.,  1838;  and  Outlines   of 
Human  Patholorrv,  p.  12S,  Lond.,  1836. 

*  Lond.  Lancet,  Oct.  8,  1842,  p.  58,  and  Dec.  10,  1842,  p.  406. 
"  Gazette  M  dicale  de  Paris,  23  Mars,  1844. 


CALORIFICATION".  585 

wliicli  is  in  opposition  to  the  view  of  Tiedemann,  that  the  lymphatic 
ganghons  and  thyroid  perform  tlie  functions  of  the  spleen,  when  that 
organ  has  been  extirpated.  The  incorrectness  of  the  opinion  of  cer- 
tain physiologists,  that  extirpation  of  the  spleen  causes  augmentation 
of  the  venereal  appetite,  but  abolition  of  the  procreative  power,  was 
shown  by  M.  Bardeleben,  by  breeding  with  dogs  from  which  both 
spleen  and  thyroid  had  been  removed. 

Professor  Mayer,  of  Bonn,'  has  affirmed  that  after  the  extirpation  of 
the  spleen,  the  small  lymphatic  ganglions  in  connexion  with  the  splenic 
artery  become  enlarged,  coalesce,  and  in  no  long  time  form  masses  of 
considerable  size,  which  probably  execute  to  a  certain  extent  the  func- 
tions of  the  extirpated  organ.  In  ten  months,  in  ducks  and  hens,  a 
glandular  mass  existed,  equal  in  size  to  the  original  spleen.  This,  he 
thinks,  will  account  in  part  for  the  trifling  disturbance  of  function 
resulting  from  extirpation  of  the  organ. 

It  is  impracticable,  then,  to  arrive  at  any  exclusive  theory  regarding 
the  functions  of  this  anomalous  organ.  Whilst  it  is  probably  inservient 
to  lymphosis  and  to  the  purposes  assigned  it  by  Tiedemann  and  Gmelin; 
its  office  must  be  of  a  supplementary  or  vicarious  nature;  for  it  is  mani- 
festly not  essential  to  life.  It  doubtless  serves  also  as  a  diverticulum ; — 
the  blood  speedily  passing,  after  it  has  been  extirpated,  into  other  chan- 
nels;— a  view,  which,  as  elsewhere  remarked,^  is  somewhat  confirmed 
by  the  splenic  enlargements  consequent  on  repeated  attacks  of  inter- 
mittent,— the  blood,  which  has  receded  from  the  surface,  accumulating 
perhaps  in  this  organ.  It  must  be  admitted,  however,  that  our  know- 
ledge of  the  function  is  of  a  singularly  negative  and  unsatisfactory 
character ;  and  this  is  strikingly  exemplified  by  the  suggestion  of  Dr. 
Paley'' — who  was  certainly  not  predisposed  to  arrive  at  such  a  conclu- 
sion— that  the  spleen  "  may  be  merely  a  stuffing,  a  soft  cushion  to  fill 
up  a  vacuum  or  hollow,  which,  unless  occupied,  would  leave  the  pack- 
age loose  and  unsteady." 


CHAPTEE  yil. 

CALORIFICATION. 

The  function  we  have  now  to  consider  is  one  of  the  most  important 
to  organized  existence,  and  one  of  the  most  curious  in  its  causes  and 
results.  It  has,  consequently,  been  an  object  of  interesting  examina- 
tion with  the  physiologist,  both  in  animals  and  plants;  and  as  it  has 
been  presumed  to  be  greatly  owing  to  respiration,  it  has  been  a  fa- 
vourite topic  with  the  chemist  also.  Most  of  the  hypotheses,  devised  for 
its  explanation,  have,  indeed,  been  of  a  chemical  character ;  and  hence 
it  will  be  advisable  to  premise  a  few  observations  regarding  the  physi- 
cal relations  of  caloric  or  the  matter  of  heat^ — an  imponderable  body, 
according  to  common  belief,  which  is  generally  distributed  throughout 

'  London  Med.  Times,  Mar.  25,  1845,  p.  550. 

^  Practice  of  Medicine,  ii.  103,  3d  edit.,  Philad.,  1848. 

*  Natural  Theology,  c.  11. 


586  CALORIFICATION". 

nature.  It  is  this  that  constitutes  the  temperature  of  bodies, — by  which 
is  meant,  the  sensation  of  heat  or  cold  we  experience  when  they  are 
touched  by  us ;  or  the  height  at  which  the  mercury  is  raised  or  de- 
pressed by  them,  in  the  instrument  called  the  thermometer ; — the  eleva- 
tion of  the  mercury  being  caused  by  the  caloric  entering  between  its 
particles,  and  thus  adding  to  its  bulk;  and  the  depression  produced  by 
the  abstraction  of  caloric. 

Caloric  exists  in  bodies  in  two  states ; — in  the  free^  uncomhined  or 
sensible;  and  in  the  latent  or  combined.  In  the  latter  case,  it  is  inti- 
mately united  with  the  other  elementary  constituents  of  bodies,  and  is' 
neither  indicated  by  the  feelings  nor  thermometer.  It  has,  conse- 
quently, no  agency  in  the  temperature  of  bodies ;  but,  by  its  proportion 
to  the  force  of  cohesion,  it  determines  their  condition  ; — whether  solid, 
liquid  or  gaseous.  In  the  former  case,  caloric  is  simply  interposed  be- 
tween the  molecules ;  and  is  incessantly  disengaged,  or  abstracted  from 
surrounding  bodies;  and,  by  impressing  the  surface  of  the  body  or  by 
acting  upon  the  thermometer,  indicates  to  us  their  temperature.  Equal 
■weights  of  the  same  body,  at  the  same  temperature,  contain  the  same 
quantities  of  caloric ;  but  equal  weights  of  different  bodies  at  the  same 
temperature  have  by  no  means  the  same.  The  quantity,  which  one 
body  contains,  compared  with  another,  is  called  its  specific  caloric  or 
specific  heat;  and  the  power  or  property,  which  enables  bodies  to  retain 
different  quantities  of  caloric,  is  called  capacity  for  caloric.  If  a  pound 
of  water  heated  to  156°  be  mixed  with  a  pound  of  quicksilver  at  40°, 
the  resulting  temperature  is  152°, — instead  of  98°,  the  exact  mean. 
The  water,  consequently,  must  have  lost  four  degrees  of  temperature, 
and  the  quicksilver  gained  one  hundred  and  twelve;  from  which  we 
deduce,  that  the  quantity  of  caloric,  capable  of  raising  one  pound  of 
mercury  from  -10°  to  152°  is  the  same  as  that  required  to  raise  one 
pound  of  water  from  152°  to  156°;  in  other  words,  that  the  same  quan- 
tity of  heat,  which  raises  the  temperature  of  a  pound  of  water  four 
degrees,  raises  the  same  weight  of  mercury  one  hundred  and  twelve 
degrees.  Accordingly,  it  is  said,  that  the  capacity  of  water  for  heat  is 
to  that  of  mercur}^,  as  28  to  1;  and  that  the  spjecific  heat  is  twenty- 
'^ eight  times  greater. 

All  bodies  are  capable  of  giving  and  taking  free  caloric;  and  conse- 
quently, all  have  a  temperature.  If  the  quantity  given  off  be  great, 
the  temperature  of  the  body  is  elevated.  If  it  takes  heat  from  the 
thermometer,  it  is  cooler  than  the  instrument.  In  inorganic  bodies, 
the  disengagement  of  caloric  is  induced  by  various  causes, — such  as 
electricity,  friction,  percussion,  compression,  the  change  of  condition 
from  a  fluid  to  a  solid  state  ;  and  by  chemical  changes,  giving  rise  to 
new  compounds,  so  that  the  caloric,  which  was  previously  latent,  be- 
comes free.  If,  for  example,  two  substances,  each  containing  a  certain 
amount  of  specific  heat,  unite,  so  as  to  form  a  compound  whose  spe- 
cific heat  is  less,  a  portion  of  caloric  must  be  set  free,  and  this  will  be 
indicated  by  a  rise  in  the  temperature.  It  is  this  principle,  which  is 
chiefly  concerned  in  some  of  the  theories  of  calorification. 

The  subject  of  the  equilibrium  and  conduction  of  caloric  is  else- 
where treated  of,  under  the  sense  of  Touch;  where  other  topics  are 
discussed,  that  bear  more  or  less  upon  the  present  inquiry.     It  is 


TEMPERATURE   OF   ANIMALS. 


587 


there  stated,  tliat  inorganic  bodies  speedily  attain  the  same  tempera- 
ture, either  by  radiation  or  condaction;  so  that  the  different  objects 
in  an  apartment  exhibit  the  same  degree  of  heat  by  the  thermo- 
meter; but  the  temperature  of  animals  being  the  result  of  a  vital 
operation,  they  retain  the  degree  of  heat  peculiar  to  them  with  but 
little  modification  from  external  temperature.  There  is  a  difference, 
however,  in  this  respect,  sufficient  to  cause  the  partition  of  animals 
into  two  great  divisions — the  warm-hhoded  and  cold-blooded ;  the  former 
comprising  those  whose  temperature  is  high,  and  but  little  influenced 
by  that  of  external  objects; — the  latter  those  whose  temperature  is 
greatly  modified  by  external  influences.  The  range  of  the  tempera- 
ture of  the  warm-blooded — amongst  which  are  all  the  higher  animals — 
is  limited;  but  of  the  cold-blooded  extensive.  The  following  table 
exhibits  the  temperature  of  various  animals  in  round  numbers ; — that 
of  man  being  estimated  at  98°  or  100°,  when  taken  under  the  tongue. 
Dr.  John  Davy^  makes  the  mean  of  numerous  observations,  thus 
taken,  100°.  The  temperature  in  the  axilla  is  something  less.  M. 
Gavarret,^  however,  estimates  it  from  about  98°  to  100°.  MM.  Prevost 
and  Dumas,^and  Dr.  Brown-Sequard^  would  place  the  normal  tempera- 
ture of  man  higher  than  this, — at  not  less  than  102°.  In  the  axilla, 
M.  Edwards*  found  it  vary,  in  twenty  adults,  from  96°  to  99°  Fahren- 
heit, the  mean  being  97*5°.  It  would  appear,  however,  to  difier  at 
different  periods  of  the  day.  Hallmann,  from  his  own  observations 
and  those  of  Gierse,^  found  that  the  temperature  of  healthy  individuals 
under  the  tongue  was  on  the  average  37°  Cent.,  or  98'66°  Fahr.;  late 
in  the  morning  and  evening  from  36*7°  to  36'8°  Cent., — from  98*06° 
to  98-24°  Fahr.;  in  the  forenoon,  at  87-3°  Cent.— 99-14°  Fahr.;  and 
in  the  afternoon,  at  37*5°  Cent. — 99-5°  Fahr. 

ANIMALS. 

Active  young  liorse,  four  years  old, 
Arctic  fox,         .... 
Arctic  wolf,       .... 
Squirrel,   ..... 
Hare,         ..... 

Whale, 

Arctomys  ciiillus,  zizil, — in  summer, 

Do.  when  torpid, 

Goat,         ..... 
She  goat,  three  months  old, 
Mother  of  the  same,  old,  and  in  poor  condition 
Bat,  in  summer. 
Musk,       ...... 


OBSERVERS. 

TEMPERATURE 

Metcalfe.'^ 

104° 

Capt.  Lyon.^ 

107 

Do. 
Pallas.9 

} 

105 

Do. 

Scoresby.'" 

} 

104 

Pallas. 

103 

Pallas. 

80  to  84 

Prevost  and  Dumas . ' ' 

103 

Metcalfe. 

107 

Do. 

104 

Prevost  and  Dumas. 
Do. 

} 

102 

'  Researches,  Physiological  and  Anatomical,  Amer.  edit.,  p.  290,  Philad.,  1840. 

2  De  la  Chaleur  Produite  par  les  Etres  Vivants,  p.  100,  Paris,  1855. 

3  Annales  de  Cliimie  et  de  Physique,  2e  Sgrie,  xxiii.  64. 

*  Med.  Examiner,  t=ept.,  1852,  p.  554. 

5  De  rinfiuence  des  Agens  Physiques,  &c.,  Paris,  1824;  or  Hodgkin's  and  Fisher's 
translation,  Lond.,  1832. 

^  Henle,  Handbuch  der  rationellen  Pathologie,  1  Band.  S.  301,  Braunschweig,  1846. 

7  Caloric,  its  Mechanical,  Chemical,  and  Vital  Agencies  in  the  Phenomena  of  Nature, 
ii.  567,  Lond.,  1843. 

*  Parry's  Second  Voyage  to  the  Arctic  Regions. 

9  Nov.  Species  Quadruped,  de  Glirium  Ordine,  Erlang.,  1774. 

'"  An  Account  of  the  Arctic  Regions,  Edinb.,  1820. 

"  Bibliotheque  Univers.,  xvii.  294. 


588 


CALORIFICATION. 


ANIMALS. 

OBSERVERS. 

TEMPERATl-KE. 

Marmota  bobac, — Bobac,    .         .         .         .         . 

Prevost  and  Dumas. 

101  or  102^ 

House  mouse,   ....... 

Do. 

101 

Arctomys  marmota,  marmot — in  summer,  . 

Do. 

101  or  102 

Do.                when  torpid, 

Do. 

43 

Rabbit, 

Delaroche. 

100  to  104 

Tame  young  rabbit,  two  months  old, 

Metcalfe. 

108 

Polar  bear, 

Capt.  Lyon. 

100 

Dog, 

Martine.' 

Do. 

Swine, 

Do. 

h    100  to  103 

Sheep, 

Do. 

Ox, 

Do. 

A  line  active  kitten,  two  months  old, 

Metcalfe. 

105-5 

A  vigorous  cat,  nearly  full  grown,     . 

Do. 

104 

Do. 

103-5 

A  very  old  cat,  said  to  be  in  its  19th  year, 

Do. 

102 

An  active  cur  dog,  three  months  old, 

Do. 

106 

Guinea-pig, 

Delaroche. 

100  to  102 

Arctomys  ylis,    ...... 

Pallas. 

99 

Shrew,      ....... 

Do. 

98 

Do. 

96 

Fringilla  arctica,  Arctic  finch,  . 

Braun.2 

\      "^ 

Pallas. 

Fringilla  liriaria,  lesser  red  poll. 

Do. 

110  or  111 

Do.                      1            TTf^ 

Caprimulgus  Europeeiis,  European  goat-sucker, 

Do.                    J 

^ 

Do. 

109  to  110 

Falco  lanarius,  lanner,       .... 

Do.                    I 

Do. 

Cor  V  us  cor  ax,  raven,           .... 

Despretz.' 

109 

Tardus,  thrush,  (of  Ceylon,)     . 

J.  Davy.* 

Tetrao  perdrix,  partridge, 

Pallas. 

Anas  clypeata,  shoveler,    .... 

Do.                   ] 

Tringa  pugnax,  rufl'e,          .... 

Do. 

Scolopax  limosa,  lesser  godwit. 

Do. 

Tetrao  tetrix,  grouse,           .... 

Do. 

108 

Fringilla  brumalis,  winterfinch, 

Do. 

Loxia  pyrrhula,           ..... 

Do. 

Falco  nisus,  sparrowhawk. 

Do. 

Vultur  barbatus,          ..... 

Do. 

Anser  pulchricollis,     ..... 

Do.                    1 

Colymbus  auritus,  dusky  grebe. 

Do. 

107 

Tringa  vanellus,  lapwing,  (wounded,) 

Do. 

Tetrao  lagopus,  ptarmigan, 

Do. 

Do. 

107  to  111 

Strix  passerina,  little  owl, 

Do.                   1 

Ilamatopiis  estralagus,  sea-pie,  . 

Do. 

Anas  penelope,  widgeon,    .... 

Do. 

106 

Anas  strepera,  g&dw all,      .... 

Do. 

Pelecanus  carbo,         ..... 

Do. 

Falco  ossifragns,  sea-eagle. 

Do.                   ^ 

Fulica  atra,  coot,       ..... 

Do. 

105 

Anas  acuta,  pintail-duck, 

Do. 

Falco  milvus,  kite,  (wounded,) 

Do. 

104 

Merops  apiaster,  bee-eater. 

Do. 

Groose, 

Martine. 

Hen, 

Do. 

■    103  to  107 

Dove, 

Do. 

Duck, 

Do. 

'  Med.  and  Philos.  Essays,  Loud.,  1740;  and  De  Similibus  Animalibus  et  AnimaL 
Galore,  &c.,  Lond.,  1740. 

^  Nov.  Comment.  Acad.  Petropol.,  xiii.  419. 
3  Annales  de  Chimie,  xxvi.  337,  Amst.,  1824. 
*  Edinb.  Philos.  Journal,  Jan.,  1826. 


TEMPERATURE   OF   PLANTS.  589 

ANIMALS.  OBSERVERS.  TEMPERATURE. 

Ardea  steUaris,  ......  Pallas.  ") 

Falco  albicollis, Do.  V  103° 

Picus  major,      .......  Do.  J 

Cossus  Ugniperda,      ......  Sliultze.  89  to  91 

Shark, J.  Davy.  83 

Torpedo  Marmorata,  .....  RudolpM.'  74 

It  will  be  observed,  that  according  to  this  table  the  inhabitants  of 
the  Arctic  regions — whether  belonging  to  the  class  of  mammalia  or 
birds — are  among  those  whose  temperature  is  highest.  That  of  the 
Arctic  fox  is  probably  higher  than  given  in  the  table,  as  it  was  taken 
after  death,  when  the  temperature  of  the  air  was  as  low  as  — 14°  of 
Fahrenheit,  and  when  loss  of  heat  may  be  supposed  to  have  occurred 
rapidly. 

It  is,  of  course,  impracticable  to  mark  the  temperature  of  the  smaller 
insects,  but  we  can  arrive  at  an  approximation  in  those  that  congre- 
gate in  masses,  as  the  bee  and  the  ant ;  for  it  is  difficult  to  suppose 
with  Miraldi,  that  the  augmented  temperature  is  dependent  upon  the 
motion  and  friction  of  the  wings  and  bodies  of  the  busy  multitudes. 
Juch^  found,  when  the  temperature  of  the  atmosphere  was  — 18°  of 
Tahrenheit,  |that  of  a  hive  of  bees  44°:  in  an  ant-hill,  the  thermometer 
stood  at  68°  or  70°,  when  the  temperature  of  the  air  was  55°;  and  at 
75°,  when  that  of  the  air  was  66°;  and  Ilausmann^  and  Rengger*  saw 
the  thermometer  rise  when  put  into  narrow  glasses  in  which  they  had 
placed  scarabiei  and  other  insects.*  Berthold  detected  the  elevation  of 
heat  only  when  several  insects  were  collected  together,  never  in  one 
isolated  from  the  rest.  This,  according  to  Mr.  Newport,^  must  have 
arisen  from  his  having  ascertained  the  temperature  only  whilst  the 
insect  was  in  a  state  of  repose;  for  Mr.  Newport  found,  that  although 
during  such  a  state,  the  temperature  of  the  insect  was  very  nearly  or 
exactly  that  of  the  surrounding  medium;  yet  when  it  was  excited  or 
disturbed,  or  in  a  state  of  great  activity  from  any  cause,  the  thermome- 
ter rose,  in  some  instances,  even  to  20°  Fahr.  above  the  temperature  of 
the  atmosphere, — for  instance,  to  91°,  when  the  heat  of  the  air  was  71°.^ 

The  power  of  preserving  their  temperature  within  certain  limits  is 
not,  however,  possessed  exclusively  by  animals.  The  heat  of  a  tree, 
examined  by  Mr.  Hunter,**  was  found  to  be  always  several  degrees 
higher  than  that  of  the  atmosphere,  when  the  latter  was  below  56°  of 
Fahr. ;  but  it  was  always  several  degrees  below  it  when  the  weather 
was  warmer.  Some  plants  develope  a  great  degree  of  heat  during  the 
period  of  blooming.  This  was  first  noticed  by  De  Lamarck^  in  Arurin 
Italicum.     In  Arum  cordifoUum^  of  the  Isle  of  Bourbon,  M.  Hubert 

'  Grundriss  der  Physiol.,  &c..  Band.  i.  166. 

^  Ideen  zu  einer  Zoocheinie,  i.  90. 

3  De  Animal.  Exsangnium  Respiratione,  p.  65. 

■*  Physiologische  Untersiicluxng.  \\\mv  die  Insecten,  p.  40,  Tiibing.,  1817. 

*  Tiedemann,  op.  citat.,  p.  511. 

fi  Philos.  Transact.,  for  1837,  part  ii.  p.  259. 

''  See  a  table  of  the  recorded  observations  of  J.  Davy,  Berthold,  Becquerel,  Newport, 
Dutrochet,  Hunter  and  Valentin,  on  the  excess  of  temperature  of  the  articulata  and 
annelida  over  that  of  the  circumambient  air,  in  Gavarret,  De  la  Chaleur  produite  par 
les  Etres  Vivants,  p.  130,  Paris,  1855. 

«  Philos.  Transact.,  1775  and  1778.  9  Eucyclop.  Method.,  iii.  9. 


590  CALORIFICATION. 

found,  when  the  temperature  of  the  air  was  80°,  that  of  the  spathe  or 
sheath  was  as  high  as  18-i°;  and  M.  Bory  de  St,  Vincent^  observed  a 
similar  elevation,  although  to  a  less  degree,  in  Arum  esculenium,  esculent 
arum  or  Indian  kale.  The  most  exact  and  elaborate  investigations 
appear  to  have  been  made  by  MM.  Vrolik  and  De  Vriese.^  According 
to  thern,  the  temperature  has  a  regular  periodicity  within  the  twenty - 
four  hours,  and  attains  its  maximum  in  the  afternoon  between  the  hours 
of  two  and  five.  The  difference  between  the  temperature  of  the  atmo- 
sphere and  that  of  the  root  is  sometimes  as  much  as  from  20°  to  30°  of 
Eeaurnur.  According  to  M.  de  Saussure,  the  root  of  an  arum  macu- 
latum  converted  thirty  times  its  volume  of  oxygen  into  carbonic  acid 
in  twenty-four  hours.  In  all  cases,  the  absolute  temperature  appeared 
to  depend  on  the  intensity  of  the  vital  processes,  and  was  higher  in 
proportion  to  the  vigour  of  the  vegetation  in  plants,  or  to  the  absorp- 
tion of  the  sap  and  the  activity  of  its  chemical  processes;'  and  accurate 
and  repeated  observation  seems  to  justify  the  conclusion  of  M.Gavarret,^ 
that  at  all  periods  of  the  developement  of  a  plant,  whether  we  study  it 
during  germination  or  vegetation,  in  its  green  parts  or  its  reproductive 
organs,  it  will  be  found — as  in  the  animal — that  the  physico-chemical 
phenomena  of  nutrition  are  the  true  sources  of  the  heat  which  it  pro- 
duces. 

The  temperature  of  the  animal  body  is  so  far  influenced  by  external 
heat  as  to  rise  or  fall  with  it;  but  the  range,  as  already  remarked,  is 
limited  in  the  warm  blooded  animal, — more  extensive  in  the  cold- 
blooded. Dr.  Currie  found  the  temperature  of  a  man  plunged  into  sea- 
water  at  44°  sink,  in  the  course  of  a  minute  and  a  half  after  immersion, 
from  98°  to  87°:  in  other  experiments,  it  descended  as  low  as  85°,  and 
even  to  83°.^  It  was  always  found,  however,  that,  in  a  few  minutes, 
the  heat  approached  its  previous  elevation ;  and  in  no  instance  could 
it  be  depressed  lower  than  83°,  or  15°  below  the  temperature  at  the 
commencement  of  the  operation.  Similar  experiments  have  been  per- 
formed on  other  warm-blooded  animals.  Mr.  Hunter  found  the  tem- 
perature of  a  common  mouse  to  be  99°,  that  of  the  atmosphere  being 
60°:  when  the  same  animal  was  exposed  for  an  hour,  to  an  atmosphere 
of  15°,  its  heat  had  sunk  to  83°;^  but  the  depression  could  be  carried 
no  farther.  He  found,  also,  that  a  dormouse, — whose  heat  in  an  atmo- 
sphere at  64°,  was  81 1° — when  put  into  air,  at  20°,  had  its  temperature 
raised  in  the  course  of  half  an  hour  to  93°;  an  hour  after,  the  air  being 
at  30°,  it  was  still  93°;  another  hour  after,  the  air  being  at  19°,  the 
heat  of  the  pelvis  was  as  low  as  83°, — an  experiment  which  strongly 
proves  the  great  counteracting  influence  exerted,  when  animals  are 
exposed  to  an  unusually  low  temperature.  In  this  experiment  the 
dormouse  had  maintained  its  temperature  about  70°  higher  than  that 
of  the  surrounding  medium,  and  for  the  space  of  two  hours  and  a  half. 
In  the  hibernating  torpid  quadruped  the  reduction  of  temperature, 
during  their  torpidity,  is  considerable.    Jenner^  found  the  temperatare 

'  Voyage  dans  les  Quatre  Principales  lies  des  Mers  d'Afrique,  ii.  66. 

2  Annales  de  Chimie  et  de  Physique,  xxi,  27!). 

"  Scdileiden,  Principles  of  Scientific  Botany,  by  Dr.  Lankester,  p.  541,  London,  1849. 

*  Op.  cit..  p.  544.  *  Philos.  Transact,  for  1792,  p.  199. 

6  Il.id.,  177S,  p.  21. 

'  Hunter,  On  the  Animal  Economy,  with  Professor  Owen's  notes,  p.  165,  Philad.,  1840. 


TEMPEKATUEE   IN   ARCTIC   REGIONS.  591 

of  a  hedgehog,  in  the  cavity  of  the  abdomen,  towards  the  pelvis,  to  be 
95°,  and  that  of  the  diaphragm  97°  of  Fahrenheit,  in  summer,  when 
the  thermometer  in  the  shade  stood  at  78°;  whilst  in  winter,  the  tem- 
perature of  the  air  being  44:°,  and  the  animal  torpid,  the  heat  in  the 
pelvis  was  45°,  and  that  of  the  diaphragm  48|°.  When  the  tempera- 
ture of  the  atmosphere  was  26°,  the  heat  of  the  animal  in  the  cavity  of 
the  abdomen,  where  an  incision  was  made,  was  reduced  as  low  as  80°; 
but — what  singularly  exhibits  the  power  possessed  by  the  system  of 
regulating  its  temperature — when  the  same  animal  was  exposed  to  a 
cold  atmosphere  of  26°  for  two  days,  the  heat,  in  the  rectum,  marked 
98°,  or  67°  above  that  of  the  atmosphere.  At  this  time,  however,  it 
was  lively  and  active,  and  the  bed  on  which  it  lay  felt  warm.  In  the 
cold-blooded  animal,  we  have  equal  evidence  of  the  generation  of  heat. 
Hunter  found  the  heat  of  a  viper,  placed  in  a  vessel  at  10°,  reduced,  in 
ten  minutes,  to  37°;  in  the  next  ten  minutes,  the  temperature  of  the 
vessel  being  18°,  it  fell  to  35°;  and  in  the  next  ten,  that  of  the  vessel 
being  20°,  to  31°.^  In  frogs,  he  was  able  to  lower  the  temperature  to 
31°;  but  beyond  this  point  it  was  not  possible  to  depress  it,  without 
destroying  the  animal. 

In  the  Arctic  regions,  animal  temperature  appears  to  be  steadily 
maintained  notwithstanding  the  intense  cold  that  prevails;  and  we 
have  already  seen,  that  the  animals  of  those  hyperborean  latitudes 
possess- a  more  elevated  temperature  than  those  of  more  genial  climes. 
In  the  earlier  enterprising  voyages,  undertaken  by  the  British  govern- 
ment for  the  discovery  of  a  northwest  passage,  the  crews  of  the  ships 
were  frequently  exposed  to  the  temperature  of  — 40°  or  — 50°  of  Fah- 
renheit's scale ;  and  the  same  thing  happened  during  the  disastrous 
campaign  of  Russia  in  1812,  in  which  so  many  of  the  French  army 
perished  from  cold.  The  lowest  temperature  noticed  by  Captain 
Farry^  was  — 55°  of  Fahrenheit.  Captain  Franklin,^  on  the  northern 
part  of  this  continent,  observed  the  thermometer  on  one  occasion — 
Feb.  7,  1827, — as  low  as  —58°  of  Fahrenheit.  Von  Wrangel^  states 
that,  in  January,  on  the  north  coast  of  Siberia,  it  reaches  — 59°  of 
Fahrenheit.  Mr.  Eae,^  at  Repulse  Bay,  early  in  January,  marked  the 
thermometer  at  — 47°.  In  the  Arctic  expedition  of  1851,  the  lowest 
temperature  was  noted  on  the  22d  of  February,  when  the  ship's  ther- 
mometer gave  — 46°  ;  Dr.  Kane's  "off-ship  spirit"  — 52° ;  and  his  self- 
registering  thermometers,  placed  on  a  hummock  away  from  the  ves- 
sels, gave  — 53°  as  the  mean  of  two  instruments.^  Mr.  Saunders, 
commander  of  the  North  Star,  records  — 63|-°  as  the  lowest  tempera- 

'  Op.  citat. 

2  Journal  of  a  Voyage  for  the  Discovery  of  a  Northwest  Passage,  American  edition, 
p.  130,  Philadelphia,  1821. 

3  Narrative  of  a  Second  Expedition  to  the  Sliores  of  the  Polar  Sea,  &o.,  American 
edition,  p.  245,  Philadelphia,  1835. 

*  Reise  des  kaiserlich  Kussischen  Flotten  Lieutenants  Ferdinand  Von  Wrangel, 
langs  der  Nordkiiste  von  Siberien,  u.  s.  w.,  Berlin,  1839,  translated  in  Harper's  Family 
Library. 

*  Narrative  of  an  Expedition  to  the  Shores  of  the  Arctic  Sea  in  1846  and  1847, 
Lond.,  1850. 

s  The  U.  S.  Grinnel  Expedition  in  search  of  Sir  John  Franklin,  By  Elisha  Keut 
Kane,  M.  D.,  U.  S.  N.,  p.  310,  New  York,  1853. 


592 


CALORIFICATION. 


ture  observed  in  "Wolstenliolme  Sound,  in  the  winter  of  1850 ;'  and 
Sir  John  Richardson^  noted  it  at  Fort  Confidence  in  66°  5i'  X.  L., 
and  118°  49'  W.  L.,  at  —65°  in  the  winter  of  1818-9.  The  extremes 
of  cold  experienced  by  Captain  McClure  and  his  party  at  Mercy  Bay 
in  Jan.  and  Feb.,  1855,  were  — 62°  and  — ^5°.  In  the  Arctic  expe- 
dition of  1858-4,  under  the  command  of  Dr.  Kane,  the  range  of  eleven 
spirit  thermometers,  selected  as  standards,  varied  from  — 60°  to  — 75°. 
The  mean  annual  temperature  was  5°. 2 : — the  lowest  ever  registered. 
Captain  Back,^  in  his  expedition  to  the  Arctic  regions  of  this  conti- 
nent, on  the  17th  of  January,  1834,  noticed  the  thermometer  at  — 70° 
of  Fahrenheit.  Mr.  Erman"  states,  that  at  Yakutsk  it  was  at  — 72-5 
of  Fahrenheit;  and  Sir  George  Simpson*  affirms,  that  it  has  fallen  in 
Siberia  to  — 83°  or  115°  below  the  freezing  point,  which — if  the 
thermometers  could  be  depended  upon — may  be  regarded  as  tlie 
greatest  depression  observed  in  any  climate.  The  great  variation, 
however,  even  in  spirit  instruments  selected  as  standards,  at  these  very 
depressed  temperatures  as  observed  by  Dr.  Kane,  throws  doubts  as  to 
the  actual  temperature  unless  taken  by  different  thermometers. 

During  the  second  voyage  of  Captain  Parry,®  the  following  temjie- 
ratures  of  animals,  immediately  after  death,  were  taken  principally  by 
Captain  Lyon. 

Temperature  of  the 


Nov.  15. 

An  Arctic  fox 

Dec.  3. 

Do. 

Do. 

11. 

Do. 

15. 

Do. 

17. 

Do. 

19. 

Do. 

1822. 

Jan.     3. 

Do. 

9. 

A  white  hare 

10. 

An  Arctic  fox 

17. 

Do. 

24. 

Do. 

Do. 

Do. 

27. 

Do. 

Feb.     2. 

A  -vrolf 

Animal. 

Atmosphere. 

106f 

—  14^ 

lOli 

—    5 

100 

—    3 

lOlA 

—  21 

993 

—  15 

98 

—  10 

99| 

—  14 

104^ 

—  23 

101 

—  21 

100 

—  15 

106 

—  32 

103 

—  27 

103 

—  27 

102 

—  25 

101 

—  32 

105 

—  27 

These  animals  must,  therefore,  have  to  maintain  a  temperature  at 
least  100°  higher  than  that  of  the  atmosphere  throughout  the  whole 
of  winter ;  and  it  would  seem  as  if  the  counteracting  energy  becomes 
proportionately  greater  as  the  temperature  is  more  depressed.     It  is, 

'  Journal  of  a  Voyage  in  Baifin's  Bay  and  Barrow's  Straits  in  the  j-ears  1850 — 1  S51, 
performed  by  H.  M.  Ships  Lady  Franklin  and  Sophia,  under  the  command  of  Mr.  Wil- 
liam Penny,"  &c.  &c.,  By  Peter  C.  Sutherland,  M.  D.,  &c.,  i.  285,  London,  1852. 

^  Arctic  Searching  Expedition  :  a  Journal  of  a  Boat's  Voyage  through  Rupert's  Land 
and  the  Arctic  Sea,  in  search  of  the  discovery  ships  under  command  of  Sir  Jolm 
Franklin,  ii.  102,  London,  1851. 

2  Narrative  of  the  Arctic  Land  Expedition  to  the  mouth  of  the  Great  Fish  River, 
&c.,  in  the  years  1833,  1834,  and  1835,  London.  1836. 

*  Travels  in  Siberia,  translated  from  the  German,  by  W.  D.  Coolev,  ii.  369,  London, 
1848. 

*  An  Overland  Journey  round  the  World,  Amer.  edit.,  part  ii.  p.  134,  Philad.,  1847. 
^  Op.  citat.,  p.  157. 


EFFECTS  OF  DEPRESSED  TEMPERATURE.        593 

however,  a  part  of  their  nature  to  be  constaDtlj  eliciting  this  unusual 
quantity  of  caloric,  and  therefore  they  do  not  suffer.  Where  animals, 
not  so  accustomed,  are  placed  in  an  unusually  cold  medium,  the  efforts 
of  the  system  rapidly  exhaust  the  nervous  energy ;  and  when  this  is 
so  far  depressed  as  to  interfere  materially  with  the  function  of  calorifi- 
cation, the  temperature  sinks,  and  the  sufferer  dies  lethargic — or  as  if 
struck  with  apoplexy.  The  ship  Endeavour,  being  on  the  coast  of 
Terra  del  Fuego,  on  the  21st  of  December,  1769,  Messrs.  Banks,  So- 
lander,  and  others  were  desirous  of  making  a  botanical  excursion  on 
the  hills  on  the  coast,  which  did  not  appear  to  be  far  distant.  The 
party,  consisting  of  eleven  persons,  were  overtaken  by  night,  during 
extreme  cold.  Dr.  Solander,  who  had  crossed  the  mountains  which 
divide  Sweden  from  Norway,  knowing  the  almost  irresistible  desire 
for  sleep  produced  by  exposure  to  great  cold,  more  especially  when 
united  with  fetigue,  enjoined  his  companions  to  keep  moving,  what- 
ever pains  it  might  cost  them,  and  whatever  might  be  the  relief  pro- 
mised by  an  indulgence  in  rest.  "  Whoever  sits  down,"  said  he, 
"will  sleep,  and  whoever  sleeps  will  wake  no  more."  Thus  admo- 
nished, they  set  forward,  but  whilst  still  upon  the  bare  rock,  and  be- 
fore the}'"  had  got  among  the  bushes,  the  cold  suddenly  became  so 
severe  as  to  produce  the  effects  that  had  been  dreaded.  Dr.  Solander 
himself  was  the  first  who  found  the  desire  irresistible,  and  insisted  on 
being  suffered  to  lie  down.  Mr.  Banks  (afterwards  Sir  Joseph)  en- 
treated and  remonstrated  in  vain.  The  doctor  lay  down  upon  the 
ground,  although  it  was  covered  with  snow;  and  it  was  with  the 
greatest  difficulty  that  his  friend  could  keep  him  from  sleeping, 
iiichmond,  one  of  the  black  servants,  began  to  linger  and  to  suffer 
from  the  cold,  in  the  same  manner  as  Dr.  Solander.  Mr.  Banks,  there- 
fore, sent  five  of  the  company  forward  to  get  a  fire  ready  at  the  first 
convenient  place  they  came  to  ;  and  himself,  with  four  others,  remained 
with  the  Doctor  and  Eichmoud,  whom,  partly  by  persuasion  and 
partly  by  force,  they  carried  forward;  but  when  they  had  got  through 
the  birch  and  swamp,  they  both  declared  they  could  go  no  farther. 
Mr.  Banks  had  again  recourse  to  entreaty  and  expostulation,  but 
without  effect.  When  Eichmond  was  told,  that  if  he  did  not  go  on, 
he  would,  in  a  short  time,  be  frozen  to  death,  he  answered,  that  he 
desired  nothing  but  to  lie  down  and  die.  Dr.  Solander  was  not  so 
obstinate,  but  was  willing  to  go  on,  if  the}'"  would  first  allow  him  to 
take  some  sleep,  although  he  had  before  observed,  that  to  sleep  was 
to  perish.  Mr.  Banks  and  the  rest  of  the  party  found  it  impossible  to 
carry  them,  and  they  were  consequently  suffered  to  sit  down,  being 
partly  supported  by  the  bushes,  and,  in  a  few  minutes,  they  fell  into 
a  profound  sleep.  Soon  after,  some  of  the  people,  who  had  been  sent 
forward,  returned  with  the  welcome  intelligence,  that  a  fire  had  been 
kindled  about  a  quarter  of  a  mile  farther  on  the  way.  Mr.  Banks 
then  endeavoured  to  rouse  Dr.  Solander,  and  happily  succeeded  ;  but, 
although  he  had  not  slept  five  minutes,  he  had  almost  lost  the  use  of 
his  limbs,  and  the  soft  parts  were  so  shrunk,  that  his  shoes  fell  from 
his  feet.  He  consented  to  go  forward  with  such  assistance  as  could 
be  given  him;  but  no  attempts  to  relieve  Eichmond  were  successful. 
He,  with  another  black  left  with  him,  died.  Several  others  began  to 
VOL,  I. — 88 


594  CALORIFICATION, 

lose  their  sensibility,  having  been  exposed  to  tlie  cold  near  an  liour 
and  a  half,  but  the  fire  recovered  them. 

The  preceding  history  is  interesting  in  another  point  of  view  be- 
sides the  one  for  which  it  was  more  especially  narrated.  Both  the 
individuals,  who  perished,  were  blacks;  and  it  has  been  a  common 
observation,  that  they  bear  exposure  to  great  heat  with  more  impu- 
nity, and  suffer  more  from  intense  cold,  than  the  white  variety  of  the 
species.  As  regards  inorganic  bodies,  it  has  been  satisfactorily  shown, 
that  the  phenomena  of  the  radiation  of  caloric  are  connected  with  the 
nature  of  the  radiating  surface ;  and  that  those  surfaces,  which  radiate 
most,  possess,  in  the  highest  degree,  the  absorbing  power;  in  other 
words,  bodies  that  have  their  temperatures  most  readily  raised  by 
radiant  heat  are  those  that  are  most  easily  cooled  by  their  own  radia- 
tion. In  the  experiments  of  Professor  Leslie^  it  was  found,  that  a 
clean  metallic  surface  produced  an  effect  upon  the  thermometer  equal 
to  12;  but  when  covered  with  a  thin  coat  of  glue  its  radiating  power 
was  so  far  increased  as  to  produce  one  equal  to  80 ;  and,  on  covering 
it  with  lampblack,  it  became  equal  to  100.  We  can  thus  understand 
why,  in  the  negro,  there  should  be  a  greater  expense  of  caloric  than 
in  the  white,  owing  to  the  greater  radiation;  not  because  as  much 
caloric  may  not  have  been  elicited  as  in  the  white.  In  the  same  man- 
ner we  can  comprehend,  that,  owing  to  the  greater  absorbing  power 
of  his  skin,  he  may  suffer  less  from  excessive  heat.  To  ascertain, 
whether  such  be  the  fact,  the  following  experiments  were  instituted 
by  Sir  Everard  Home.^  He  exposed  the  back  of  his  hand  to  the  sun 
at  twelve  o'clock,  with  a  thermometer  attached  to  it,  another  being 
placed  upon  a  table  with  the  same  exposure.  The  temperature,  indi- 
cated by  that  on  his  hand,  was  90°  ;  by  the  other,  102".  In  forty -five 
minutes,  blisters  arose,  and  coagulable  lymph  was  thrown  out.  The 
pain  was  very  severe.  In  a  second  experiment,  he  exposed  his  face, 
eyelids,  and  the  back  of  his  hand  to  water  heated  to  120° ;  in  a  few 
minutes  they  became  painful;  and,  when  the  heat  was  farther  in- 
creased, he  was  unable  to  bear  it;  but  no  blisters  were  produced.  In 
a  third  experiment,  he  exposed  the  backs  of  both  hands,  with  a  ther- 
mometer upon  each,  to  the  sun's  rays.  The  one  hand  was  uncovered ; 
the  other  had  a  covering  of  black  cloth,  under  which  the  ball  of  the 
thermometer  was  placed.  After  ten  minutes,  the  degree  of  heat  of 
each  thermometer  was  marked,  and  the  appearance  of  the  skin  ex- 
amined. This  was  repeated  at  three  different  times.  The  first  time, 
the  thermometer  under  the  cloth  stood  at  91°  ;  the  other  at  85°;  the 
second  time,  they  indicated  respectively  9-1°  and  91°;  and  the  third 
time,  106°  and  98°.  In  every  one  of  these  trials,  the  skin  that  was 
uncovered  was  scorched;  whilst  the  other  had  not  suffered  in  the 
slightest  degree.  From  all  his  experiments.  Sir  Everard  concludes, 
that  the  power  of  the  sun's  ra3''s  to  scorch  the  skin  of  animals  is 
destroyed,  when  applied  to  a  black  surface;  although  the  absolute 
heat,  in  consequence  of  the  absorption  of  the  rays,  is  greater. 

When  cold  is  applied  to  particular  parts  of  the  body,  their  heat 

'  Ou  Heat.  Loud.,  1788  ;  and  Dr.  Stark,  in  Philosoph.  Transact.,  part  ii.  for  1833. 
^  Lect.  on  Comp.  Anat..  iii.  217,  London,  1823. 


EFFECTS    OF   DEPRESSED   TEMPERATURE.  595 

sinks  lower  than  the  minimum  of  depressed  temperature.  Although 
Mr,  Hunter  was  unable  to  heat  the  urethra  one  degree  above  the 
maximum  of  elevated  temperature  of  the  body,  he  succeeded  in  cool- 
ing it  29°  lower  than  the  minimum  of  depressed  temperature,  or  to 
58°.  He  cooled  down  the  ears  of  rabbits  until  thej  froze ;  and  when 
thawed  thej  recovered  their  natural  heat  and  circulation.  The  same 
experiment  was  performed  on  the  comb  and  wattles  of  a  cock.  Ee- 
suscitation  was,  however,  in  no  instance  practicable  where  the  whole 
body  had  been  frozen.'  The  same  distinguished  observer  found,  that 
the  power  of  generating  heat,  when  exposed  to  a  cooling  influence, 
was  possessed  even  by  the  egg.  One,  that  had  been  frozen  and 
thawed,  was  put  into  a  cold  mixture  along  with  one  newly  laid.  The 
latter  was  seven  minutes  and  a  half  longer  in  freezing  than  the  former. 
In  another  experiment,  a  fresh-laid  egg,  and  one  that  had  been  frozen 
and  thawed,  were  put  into  a  cold  mixture  at  15° ;  the  thawed  one 
soon  rose  to  32°,  and  began  to  swell  and  congeal;  the  fresh  one  sank 
to  29|-°,  and  in  twenty-five  minutes  after  the  dead  one,  rose  to  32°, 
and  began  to  swell  and  freeze.  All  these  facts  prove,  that  wdien  the 
living  body  is  exposed  to  a  lower  temperature  than  usual,  a  counter- 
acting power  of  calorification  exists;  but  that,  in  the  human  species, 
such  exposure  to  cold  is  incapable  of  depressing  the  temperature  of 
the  system  lower  than  about  15°  beneath  the  natural  standard.  In 
fish,  the  vital  principle  can  survive  the  action  even  of  frost.  Captain 
Franklin  found,  that  those  which  they  caught  in  Winter  Lake,  froze 
as  they  were  taken  out  of  the  net ;  but  if,  in  this  completely  frozen 
condition,  they  were  thawed  before  the  fire,  they  recovered  their  ani- 
mation. This  was  especially  the  case  with  a  carp,  which  recovered 
so  far  as  to  leap  about  with  some  vigour  after  it  had  been  frozen  for 
thirty-six  hours. 

On  the  other  hand,  when  the  living  body  is  exposed  to  a  temperature 
greatly  above  the  natural  standard,  an  action  of  refrigeration  is  exerted; 
so  that  the  animal  heat  cannot  rise  beyond  a  certain  number  of  degrees; 
— to  a  much  smaller  extent  in  fact  than  it  is  capable  of  being  depressed 
by  the  opposite  influence.  Boerhaave^  maintained  the  strange  opinion, 
that  no  warm-blooded  animal  could  exist  in  a  tempei'ature  higher  than 
that  of  its  own  hodj.  In  some  parts  of  Virginia,  there  are  days  in 
every  summer,  in  which  the  thermometer  reaches  98°  of  Fahrenheit; 
and  in  other  parts  of  this  country  it  is  occasionally  much  higher.  The 
meteorological  registers  show  it  to  be,  at  times,  at  108°  at  Council  Blufis, 
in  Missouri;  at  104:°  in  New  York;  and  at  100°  in  Michigan;^  whilst 
in  most  of  the  states,  in  some  days  of  summer,  it  reaches  96°  or  98°. 
At  Sierra  Leone,  Messrs.  Watt  and  Winterbottom"  saw  it  frequently 
at  100°,  and  even  as  high  as  102°  and  103°,  at  some  distance  from  the 
coast.     Adanson  observed  it  at  Senegal  as  high  as  108J°.     Sir  John 

'  Sir  E.  Home's  Lect.,  &c.,  iii.  438. 

^  "  Observatio  docet  nullum  animal  quod  pulniones  liabet  posse  in  aere  vivere,  cujus 
eadem  est  temperies  cum  suo  sanguine."     Eleanent.  Chemiae,  i.  275,  Lug.  Bat.,  1732. 

^  Meteorological  Register,  for  the  years  1822, 1823, 1824,  and  1825,  from  observations 
made  by  the  surgeons  at  the  military  posts  of  the  United  States.  See,  also,  a  similar 
register  for  the  years  1826,  1827,  1828,  1829,  and  1830,  Philad.,  1840;  and  another 
from  1843  to  1854,  inclusive,  Washington,  1S55. 

*  Account  of  the  Native  Africans,  vol.  i.  pp.  32  and  33, 


596  CALORIFICATION". 

Barrow/  at  the  village  of  Graaf  Eeynet,  in  South  Africa,  noted  it  on 
the  2-ith  of  November,  at  108°  in  the  shade  and  open  air.  Brydore 
affirms,  that  when  the  sirocco  blows  in  Sicily  the  heat  rises  to  112°.^ 
Dr.  Chalmers  observed  a  heat  of  115°^  in  South  Carolina;  Humboldt* 
of  110°  to  115°  in  the  Llanos  or  Plains  near  the  Orinoco;  and  Captain 
Tuckey  asserts,  that  on  the  Red  Sea  he  never  saw  tlie  thermometer  at 
midnight  under  94°  ;  at  sunrise  under  104°;  or  at  midday  under  112°. 
In  British  India  it  has  been  seen  as  high  as  130°.* 

As  long  ago  as  1758,- Governor  Ellis^  of  Georgia  had  noticed  how 
little  the  heat  of  the  body  is  influenced  by  that  of  the  external  atmo- 
sphere. "I  have  frequently,"  he  remarks,  "walked  an  hundred  yards 
under  an  umbrella  with  a  thermometer  suspended  from  it  by  a  thread, 
to  the  height  of  my  nostrils,  when  the  mercury  has  rose  to  105°,  which 
is  prodigious.  At  the  same  time  I  have  confined  this  instrument  close 
to  the  hottest  part  of  my  body,  and  have  been  astonished  to  observe, 
that  it  has  subsided  several  degrees.  Indeed  I  could  never  raise  the 
mercury  above  97°  with  the  heat  of  my  body."  Two  years  after  the 
date  of  this  communication,  the  power  of  resisting  a  much  higher 
atmospheric  temperature  was  discovered  by  accident.  MM.  Duhamel 
and  Tillet,^  in  some  experiments  for  destroying  an  insect,  that  infested 
the  grain  of  the  neighbourhood  in  Angoumois, — having  occasion  to  use 
a  large  public  oven,  on  the  same  day  in  which  bread  had  been  baked 
in  it, — were  desirous  of  ascertaining  its  temperature.  This  they  en- 
deavoured to  accomplish  by  introducing  a  thermometer  into  the  oven 
at  the  end  of  a  shovel.  On  being  withdrawn,  the  thermometer  indi- 
cated a  degree  of  heat  considerably  above  that  of  boiling  water ;  but  M. 
Tillet,  feeling  satisfied,  that  the  thermometer  had  fallen  several  degrees 
in  approaching  the  mouth  of  the  oven,  and  seeming  to  be  at  a  loss  how 
to  rectify  the  error,  a  girl, — one  of  the  servants  of  the  baker,  and  an 
attendant  on  the  oven, — offered  to  enter  and  mark  with  a  pencil  the 
height  at  which  the  thermometer  stood  within.  She  smiled  at  M.  Tillet's 
hesitation  in  accepting  her  proposition;  entered  the  oven,  and  noted 
the  temperature  to  be  260°  of  Fahrenheit.  M.  Tillet,  anxious  for  her 
safety,  called  upon  her  to  come  out;  but  she  assured  him  she  felt  no 
inconvenience,  and  remained  ten  minutes  longer,  when  the  thermometer 
had  risen  to  280°  and  upwards.  She  then  came  out  of  the  oven,  with 
her  face  considerably  flushed,  but  her  respiration  by  no  means  quick 
or  laborious. 

These  facts  excited  considerable  interest;  but  no  farther  experiments 
appear  to  have  been  instituted,  until,  in  the  year  177-1,  Dr.  Geo. 
Fordyce,  and  Sir  Charles  Blagden^  made  their  celebrated  trials  with 
heated  air.  The  rooms,  in  which  these  were  made,  were  heated  by  flues 
in  the  floor.     Ilaving  taken  off  his  coat,  waistcoat,  and  shirt,  and  being 

'  Auto-biographical  Memoir,  p.  193,  London,  1847. 

*  Lawrence's  Lectures  on  Comparative  Anatomy,  Physiology,  &c.,  p.  306,  London, 
1819. 

*  Account  of  the  Weather  and  Diseases  of  South  Carolina,  London,  1776. 

*  Tableau  Physique  des  Regions  Equatoriales. 

5  Prof.  Jameson,  British  India,  Amer.  edit.,  iii.  170,  New  York,  1832. 

^  Philosophical  Transactions,  i758,  p.  755. 

''  Memoir,  de  TAcademie  des  Sciences,  p.  186,  Paris,  1762. 

*  Philosophical  Transactions  for  1775,  p.  111. 


EFFECTS  OF  ELEVATED  TEMPERATURE.         597 

provided  witli  wooden  shoes  tied  on  with  list,  Dr.  Fordyce  went  into 
one  of  the  rooms,  as  soon  as  the  thermometer  indicated  a  degree  of 
heat  above  that  of  boiling  water.  The  first  impression  of  the  heated 
air  upon  his  body  was  exceedingly  disagreeable ;  but  in  a  few  minutes 
all  uneasiness  was  removed  by  copious  perspiration.  At  the  end  of 
twelve  minutes  he  left  the  room  very  much  fatigued;  but  not  otherwise 
disordered.  The  thermometer  had  risen  to  220°.  In  other  experi- 
ments, it  was  found,  that  a  heat  even  of  260°  could  be  borne  with 
tolerable  ease.  At  this  temperature,  every  piece  of  metal  was  intolera- 
bly hot;  small  quantities  of  water,  in  metallic  vessels,  quickly  boiled; 
and  streams  of  moisture  poured  down  over  the  whole  surface  of  his 
body.  That  this  was  merely  the  vapour  of  the  room,  condensed  by  the 
cooler  skin,  was  proved  by  the  fact,  that  when  a  Florence  flask,  tilled 
with  water  of  the  same  temperature  as  the  body,  was  placed  in  the 
room,  the  vapour  condensed  iu  like  manner  upon  its  surface,  and  ran 
down  in  streams.  Whenever  the  thermometer  was  breathed  upon,  the 
mercury  sank  several  degrees.  Every  expiration — especially  if  made 
with  any  degree  of  violence — communicated  a  pleasant  impression  of 
coolness  to  the  nostrils,  scorched  immediately  before  by  the  hot  air 
rushing  against  them  when  they  inspired.  In  the  same  manner,  their 
comparatively  cool  breath  cooled  the  fingers,  whenever  it  reached  them. 
"  To  prove,"  says  Sir  Charles  Blagden,  "  that  there  was  no  fallacy  in 
the  degree  of  heat  shown  by  the  thermometer,  but  that  the  air  which 
we  breathed  was  capable  of  producing  all  the  well-known  effects  of  such 
an  heat  on  inanimate  matter,  we  put  some  eggs  and  beef-steak  upon  a 
tin  frame,  placed  near  the  standard  thermometer,  and  farther  distant 
from  the  cockle  than  from  the  wall  of  the  room.  In  about  twenty 
minutes  the  eggs  were  taken  out  roasted  quite  hard ;  and  in  forty-seven 
minutes,  the  steak  was  not  only  dressed,  but  almost  dry.  Another  beef- 
steak was  rather  overdone  in  thirty-three  minutes.  In  the  evening, 
when  the  heat  was  still  greater,  we  laid  a  third  beef-steak  in  the  same 
place;  and  as  it  had  now  been  observed,  that  the  effect  of  the  heated 
air  was  much  increased  by  putting  it  in  motion,  we  blew  upon  the  steak 
with  a  pair  of  bellows,  which  produced  a  visible  change  on  its  surface, 
and  seemed  to  hasten  the  dressing;  the  greatest  part  of  it  was  found 
pretty  well  done  in  thirteen  minutes."  In  all  these  experiments,  and 
others  of  a  like  kind  were  made  in  the  following  year,  by  Dr.  Dobson,^ 
of  Liverpool,  the  heat  of  the  body,  in  air  of  a  high  temperature, 
speedily  reached  100°;  but  exposure  to  212°  and  more  did  not  carry 
it  higher. 

These  results  are  not  exactly  in  accordance  with  those  of  MM.  Ber- 
ger  and  Delaroche,^  from  experiments  performed  in  1806.  Flaving 
exposed  themselves,  for  some  time,  to  a  stove,^the  temperature  of 
which  was  39°  of  lieaumur  or  120°  of  Fahrenheit — their  temperature 
was  raised  3°  of  Eeaumur  or  6|°  of  Fahrenheit;  and  M,  Delaroche 
found,  that  his  rose  to  4°  of  Eeaumur  or  9°  of  Fahrenheit,  when  he 
had  remained  sixteen  minutes  in  a  stove  heated  to  176°  of  Fahrenheit. 

'  Philosophical  Transactions  for  1775,  p.  463.  , 

^  Exp^r.  sur  les  Effets  qu'une  forte  Chaleur  produit  sur  I'Economie,  Paris,  1805  ;  and 
Journal  de  Physique,  Ixiii.  207,  Ixxi,  289,  and  Ixxvii.  1. 


598  CALORIFICATION. 

According  to  Sir  David  Brewster,' — the  distinguished  sculptor,  Chantry, 
exposed  himself  to  a  temperature  yet  higher.  The  furnace  which  he 
employed  for  drying  his  moulds  was  about  14  feet  long,  12  high,  and 
12  broad.  When  raised  to  its  highest  temperature,  with  the  doors 
closed,  the  thermometer  stood  at  350°,  and  the  iron  floor  was  red-Jiot. 
The  workmen  often  entered  it  at  a  temperature  of  840°,  walking  over 
the  floor  with  wooden  clogs,  which  were,  of  course,  charred  on  the 
surface.  On  one  occasion.  Sir  Francis,  accompanied  by  five  or  six  of 
his  friends,  entered  the  furnace,  and  after  remaining  two  minutes, 
brought  out  a  thermometer,  which  stood  at  320°.  Some  of  the  party 
experienced  sharp  pains  in  the  tips  of  their  ears,  and  in  the  septum  of 
the  nose,  whilst  others  felt  a  pain  in  the  eyes.  In  certain  experi- 
ments of  Chabert,  who  exhibited  his  powers  as  a  "  Fire  King,"  in  this 
country  as  well  as  in  Europe,  he  is  said  to  have  entered  an  oven  with 
impunity,  the  heat  of  which  was  from  400°  to  600°  of  Fahrenheit. 

Experiments  have  shown,  that  the  same  power  of  resisting  excessive 
heat  is  possessed  by  animals.  Drs.  Fordyce  and  Blagden  shut  up  a 
dog,  for  half  an  hour,  in  a  room,  the  temperature  of  which  was  be- 
tween 220°  and  236° ;  at  the  end  of  this  time  a  thermometer  was 
applied  between  the  thigh  and  flank  of  the  animal;  and  in  about  a 
minute  the  mercury  sank  to  110° ;  but  the  real  heat  of  the  body  was 
certainly  less  than  this,  as  the  ball  of  the  thermometer  could  not  be 
kept  a  sufficient  time  in  proper  contact;  and  the  hair,  which  felt  sen- 
sibly hotter  than  the  bare  skin,  could  not  be  prevented  from  touching 
the  instrument.  The  temperature  of  this  animal,  in  the  natural  state, 
is  101°. 

We  find  in  organized  bodies  astonishing  cases  of  adaptation  to  the 
medium  in  which  they  live.  Sonnerat  saw,  in  India,  Yitex  aguus  castus 
flourishing  near  a  spring,  whose  temperature  was  144°;  and  Foster 
found  it  at  the  foot  of  a  volcano  in  the  Island  of  Tanna,  the  tempera- 
ture of  the  ground  being  176°.  Adanson  affirms,  that  difierent  plants 
vegetate  and  preserve  their  verdure  in  Senegal,  although  their  roots 
are  plunged  in  sand  at  a  temperature  at  times  as  high  as  142°;  and 
M.  Desfontaines  found  several  plants  surrounding  the  springs  at  Bonne 
in  Barbary,  the  heat  of  which  was  as  high  as  171°.- 

Although  man  is  capable  of  breathing  with  impunity  air  heated  to 
above  the  boiling  point  of  water,  we  have  seen,  that  he  cannot  bear  the 
contact  of  water  much  below  that  temperature.  Yet  we  find  certain 
of  the  lower  animals — as  fish — living  in  water  at  a  temperature  which 
would  be  sufficient  to  boil  them  if  dead.  In  the  thermal  springs  of 
Bahia,  in  Brazil,  many  small  fishes  are  seen  swimming  in  a  rivulet, 
which  raises  the  thermometer  to  88°,  when  the  temperature  of  the  air 
is  only  77|°.  Sonnerat  found  fishes  existing  in  a  hot  spring  at  the 
Manillas,  at  158°  Fahr.;  and  MM.  Humboldt  and  Bonpland,  in  travel- 
ling through  the  province  of  Quito,  in  South  America,  perceived  them 
thrown  up  alive,  and  apparently  in  health,  from  the  bottom  of  a  vol- 
cano, in  the  course  of  its  explosions,  along  with  water  and  heated 
vapour,  which  raised  the  thermometer  to  210°,  or  only  two  degrees 

'  Letters  on  Katural  Magic,  p.  281,  Amer.  edit.,  Now  York,  1832. 
'^  (iirou  de  Buzareingues,  Precis  Llementaire  de  Fhysiologie  Agricole,  p.  126,  Paris, 
1849. 


DIFFERS   ACCORDING  TO   SEX,   ETC.  699 

short  of  the  boiling  point,^  Dr.  Reeve  found  living  larvee  in  a  spring, 
whose  temperature  was  208°;  Lord  Bute  saw  conferv£e  and  beetles  in 
the  boiling  springs  of  Albano,  which  died  when  plunged  into  cold  water; 
and  Dr.  Elliotson  knew  a  gentleman,  who  boiled  some  honey-comb,  two 
years  old,  and,  after  extracting  all  the  sweet  matter,  threw  the  refuse 
into  a  stable,  which  was  soon  filled  with  bees.^ 

When  the  heating  influence  is  applied  to  a  part  of  the  body  only,  as 
to  the  urethra,  the  temperature  of  the  part,  it  has  been  affirmed,  is  not 
increased  beyond  the  degree  to  which  the  whole  body  can  be  raised. 

From  all  these  facts,  then,  it  may  be  concluded,  that  when  the  body 
is  exposed  to  a  temperature  greatly  above  the  ordinary  standard  of  the 
animal,  a  frigorific  influence  is  exerted ;  but  this  is  effected  at  a  great 
expense  of  vital  energy;  and  hence  is  followed  by  considerable  ex- 
haustion, if  the  effort  be  prolonged.  In  the  cold-blooded  animal,  the 
power  of  resisting  heat  is  not  great ;  so  that  it  expires  in  water  not 
hotter  than  the  human  blood  occasionally  is.  M.  Edwards  found  that 
a  frog,  which  can  live  eight  hours  in  water  at  32°,  is  destroyed  in  a  few 
seconds  in  water  at  105°;  this  appears  to  be  the  highest  temperature 
that  cold-blooded  animals  can  bear.  "Warm-blooded  animals,  when 
exposed  to  a  high  temjierature,  have  their  temperature  increased  to  a 
certain  extent ;  but  Avhenever  it  passes  this  they  perish,  M.  James-' 
took  two  rabbits,  whose  normal  temperature  was  about  102'2°,  and 
placed  them  in  two  stoves,  one  at  212°,  the  other  at  140°,  The  first 
died  sooner  than  the  second;  but  the  temperature  of  each  at  the  mo- 
ment of  death  was  the  same,  111'2°,  The  same  experiment,  over  and 
over  again  repeated,  showed,  that  whatever  might  be  the  degree  at 
which  the  heat  was  applied,  the  animal  died  when  an  increase  of  nine 
degrees  was  attained.  In  birds,  whose  normal  temperature  was  111 "2°, 
the  same  at  which  the  rabbits  died,  death  ensued  on  the  same  increase 
of  nine  degrees,  or  when  their  blood  reached  120*2°, 

Observation  has  shown,  that  although  the  average  temperature  of 
an  animal  is  such  as  we  have  stated  in  the  table,  particular  circum- 
stances may  give  occasion  to  some  fluctuation,  A  slight  difference 
exists,  according  to  sex,  temperament,  idiosyncrasy,  &c,  MM.  Ed- 
wards and  Gentil  found  the  temperature  of  a  young  female  half  a 
degree  less  than  that  of  two  boys  of  the  same  age.  Edwards'*  tried 
the  temperature  of  twenty  sexagenarians,  thirty-seven  septuagenarians, 
fifteen  octogenarians,  and  five  centenarians,  at  the  large  establishment 
of  Bicetre,  and  observed  a  slight  difference  in  each  class.  Dr.  John 
Davy^  found,  that  the  temperature  of  a  lamb  was  a  degree  higher  than 
that  of  its  mother ;  and  in  five  new-born  children,  the  heat  was  about 
half  a  degree  higher  than  that  of  the  mother,  and  it  rose  half  a  degree 
more  in  the  first  twelve  hours  after  birth.  He  subsequently  examined 
the  temperature  of  the  aged.^  In  eight  old  men  and  women,  all,  with 
one  exception,  between  eighty-seven  and  ninety-five  years  of  age,  the 

'  Animal  Physiology,  Library  of  Useful  Knowledge,  p.  3. 

2  Physiology"  p.  247,  Lond.,  1840. 

3  Gazette  Medicale  de  Paris,  27  Avril,  1844. 

*  De  rinfluence  des  Agens,  &c.,  p.  436,  Paris,  1826. 
5  Philosopli.  Transact.^  p.  602.  for  1814. 

*  Philosophical  Transactions  for  1844,  p.  57. 


600  CALORIFICATION. 

temperature  under  the  tongue  was  98°,  or  9S'5° ;  therefore  little,  if  at 
all,  below  tlie  average  of  adult  persons  in  like  circumstances.  Two 
observations,  however,  showed,  that  on  exposure  to  external  cold,  the 
temperature  was  more  reduced  than  in  young  persons.  In  one  case  it 
fell  to  95°  ;  in  the  other  to  96*5°.  A  few  observations  were  also  made 
on  persons  working  in  rooms  at  a  temperature  of  92°  :  in  one  case,  the 
temperature  was  100°,  in  another  100*5°;  and  in  a  third,  the  external 
temperature  being  73°,  it  was  99°.  The  same  slight  variations  of  the 
temperature  of  superficial  parts  in  accordance  with  changes  of  external 
temperature  were  shown  bv  repeated  observations  on  a  healthy  man  in 
the  different  seasons,  at  Constantinople.  By  moderate  exercise,  the 
temperature  on  the  surface  of  the  extremities  was  raised — but  not 
above  the  general  average — and  was  not  affected  in  the  internal  parts. 
Dr.  G.  C.  Holland^  found  that  the  mean  temperature  of  forty  infants 
exceeded  that  of  the  same  number  of  adults  by  lf°:  twelve  of  the 
children  had  a  temperature  of  from  100  to  10oJ°.  M.  Edwards,  on 
the  other  hand,  found,  that,  in  the  warm-blooded  animal,  the  faculty 
of  producing  heat  is  less,  the  nearer  to  birth ;  and  that,  in  many  cases, 
as  soon  as  the  young  dropped  from  the  mother,  the  temperature  fell 
to  within  a  degree  or  two  of  that  of  the  circumambient  air;  and  he 
moreover  affirms,  that  the  faculty  of  producing  heat  is  at  its  minimum 
at  birth,  and  increases  successively  to  the  adult  age.  His  trials  on 
children  at  the  large  Hopital  des  Enfa-ns  of  Paris,  and  on  the  aged  at 
Bicetre,  showed  that  the  temperature  of  infants,  one  or  two  days  old, 
was  from  93°  to  95°  of  Fahrenheit;  of  the  sexagenarian  from  95°  to 
97°;  of  the  octogenarian,  9-1°  or  95°;  and  that,  as  a  general  rule,  it 
varied  according  to  age.  In  his  experiments  connected  with  this  sub- 
ject, he  discovered  a  striking  analogy  between  warm-blooded  animals 
in  general.  Some  of  these  are  born  with  the  eyes  closed;  others  with 
them  open :  the  former,  until  the  e3^es  are  opened,  he  found  to  resem- 
ble the  cold-blooded  animal;  the  latter — or  those  born  with  the  eyes 
open — the  warm-blooded.  Thus,  he  remarks,  the  state  of  the  eyes, 
although  having  no  immediate  connexion  with  the  production  of  heat, 
may  coincide  with  an  internal  structure  which  influences  that  func- 
tion, and  it  certainly  furnishes  signs,  which  indicate  a  remarkable 
change  in  this  respect;  for,  at  the  period  of  the  opening  of  their  eyes, 
all  young  mammalia  have  nearly  the  same  temperature  as  adults. 
Now,  in  accordance  with  analogy,  a  new-born  infant  at  the  full  period, 
having  its  eyes  open,  should  have  the  power  of  maintaining  a  pretty 
uniform  temperature  during  the  warm  seasons;  but  if  birth  should 
take  place  at  the  fifth  or  sixth  month,  the  case  is  altered ;  the  pupil  is 
generally  covered  with  the  memhrana  jnqnllaris,  which  places  it  in  a 
condition  similar  to  that  of  closure  of  the  eyelids  in  animals.  Analogy, 
then,  would  induce  us  to  conclude,  that,  in  such  an  infant,  the  power 
of  producing  heat  should  be  inconsiderable,  and  observation  confirms 
the  conclusion :  although  we  obviouslv  have  not  the  same  facilities,  as 
in  the  case  of  animals,  of  exposing  the  infant  to  a  depressed  tempera- 
ture. The  temperature  of  a  seven  months'  child,  though  well  swathed, 
and  near  a  good  fire,  v/as,  within  two  or  three  hours  after  birth,  no 

'  An  Inquiry  into  the  La-\vs  of  Life,  &e.,  Edinb.,  1829. 


CIRCUMSTANCES   INFLUENCING.  601 

more  than  89*6°  Fahrenheit.  Before  the  period  at  which  this  infant 
was  born,  the  membrana  pupillaris  disappears ;  and  it  is  probable,  as 
M.  Edwards  has  suggested,  that  if  it  had  been  born  prior  to  the  dis- 
appearance of  the  membrane,  its  power  of  producing  heat  might  have 
been  so  feeble,  that  it  would  scarcely  have  differed  from  that  of  mam- 
malia born  with  the  eyes  closed.' 

An  extensive  series  of  experiments  has  been  instituted  by  M.  Roger,^ 
in  regard  to  the  temperature  of  children  in  health  and  various  diseases. 
In  nine  examinations  from  one  to  twenty  minutes  after  birth,  the  tem- 
perature observed  in  the  axilla  was  from  99'95°  to  95'45.°  Immedi- 
ately after  birth  it  was  at  the  highest,  but  quickly  fell  to  near  the 
lowest  point  stated  above.  By  the  next  day,  however,  it  was  entirely, 
or  nearly,  what  it  was  before.  The  rapidity  of  the  pulse  and  respira- 
tion appeared  to  have  no  certain  relation  to  the  temperature.  In 
thirty-three  infants,  from  one  to  seven  days  old,  the  most  freq^ient 
temperature  was  98*6°;  the  average  98*75°;  the  maximum — one  case 
only — was  102*2°;  the  minimum — also  one  case — 96*8°.  All  the  in- 
fants were  healthy.  The  frequency  of  respii'ation  had  no  evident  or 
constant  relation  to  the  temperature.  A  few  of  the  infants  Avere  of  a 
weakly  habit;  their  average  temperature  was  97*7°:  the  others  were 
strong,  and  their  average  temperature  99*531°.  The  age,  at  this  period, 
had  no  influence  on  its  temperature ;  nor  had  its  sex,  state  of  sleeping 
or  waking,  nor  the  period  after  sucking. 

In  twenty-four  children,  chiefly  boys,  from  four  months  to  fourteen 
years  old,  the  most  frequent  temperature  was  above  98*6°;  the  average 
98*978°;  the  minimum  98*15°;  the  maximum  99*95°.  The  average  of 
those  six  years  old,  or  under,  was  98*798°;  of  those  above  six  years, 
99*158°.  The  average  number  of  pulsations  in  the  minute  was,  in 
those  under  six  years,  102;  above  that  age,  77;  yet  the  temperature  of 
the  latter  was  higher  than  that  of  the  former  and  of  younger  infants. 
There  was  no  evident  relation  between  the  temperature  and  frequency 
of  respiration  ;  nor,  in  a  few  examinations,  was  the  temperature  affected 
in  a  regular  way,  by  active  exercise  for  a  short  time,  or  by  the  stage 
of  digestion. 

The  state  of  the  system,  as  to  health  or  disease,  also  influences  the 
evolution  of  heat.  Dr.  Francis  Home,^  of  Edinburgh,  took  the  heat  of 
various  patients  at  different  periods  of  their  indispositions.  He  found 
that  of  two  persons  labouring  under  the  cold  stage  of  an  intermittent 
to  be  101°;  whilst,  during  the  sweat  and  afterwards,  it  fell  to  101°,  and 
to  99°.  In  every  case  of  severe  rigor,  Jochraann  found*  the  tempera- 
ture to  rise.  In  one  case,  it  speedily  mounted  from  about  100°  before 
the  rigor  to  upwards  of  103°  during  its  continuance.  The  highest, 
which  Dr.  Home  noticed  in  fever,  was  107°.  The  author  has  witnessed 
it  at  106°  in  scarlatina  and  in  tj^phus,  but  it  probably  rarely  exceeds 
this,  although  it  is  stated  to  have  been  as  high  as  112°;*  and  this  is  the 
point  designated  as  "fever  heat"  on  Fahrenheit's  scale.  In  a  case  of 
double  pleurisy,  with  tuberculosis  of  the  lung,  it  was  observed  by  Joch- 

'  Op.  infra  cit.  '^  Archiv.  General,  de  Medeoine,  Jiiillet,  Aout,  1844. 

'  Medical  Facts  and  Experim.,  Lond.,  1759. 

'  Op.  cit.,  p.  73. 

^  G.  T.  Morgan's  First  Principles  of  Surgery,  p.  80,  Lond.,  1837. 


602  CALOEIFICATIOlir. 

mann^  as  liigli  as  105°  nearly.  M.  Edwards  alludes  to  a  case  of  tetanus, 
in  a  child,  the  particulars  of  which  were  communicated  to  him  by  M. 
Prevost,  of  Greneva,  in  which  the  temperature  rose  to  110'75°  Fahr^^n- 
iieit.^  Mr.  Hunter^  found  the  interior  of  a  hydrocele,  on  the  day  of 
operation,  to  be  92°;  on  the  following  day,  when  inflammation  had 
commenced,  it  rose  to  99°.  The  fluid  obtained  from  the  abdomen  of 
an  indiyidual  tapped  for  the  seyenth  time  for  ascites  indicated  a  tem- 
perature of  101°.  Twelve  days  thereafter,  when  the  operation  was 
repeated  for  the  eighth  time,  it  was  10-1°.  Dr.  Granville"  has  asserted 
that  the  temperature  of  the  uterus  sometimes  rises  as  high  as  120° — 
the  elevation  seeming  to  bear  some  ratio  to  the  amonnt  of  action  in 
the  organ.  Tlie  author  has  frequently  been  struck  with  the  seemingly 
elevated  temperature  of  the  vagina  under  those  circumstances;  but 
cannot  help  suspecting  inaccuracy  in  the  observations  of  Dr.  Granville, 
the  temperature  which  he  indicates  being  so  much  higher  than  has  ever 
been  noticed  in  any  condition  of  the  system.  Under  this  feeling,  seve- 
ral experiments  were  made,  at  the  authors  request,  by  Dr.  Barnes,*  at 
the  time  one  of  the  resident  physicians  of  the  Philadelphia  Hospital, 
which  exhibit  only  a  slight  difference  between  the  temperature  of  the 
vagina  and  that  of  the  uterus  during  parturition.  In  two  cases,  that 
of  the  labia  was  100°,  and  in  a  third  105°;  whilst  that  of  the  uterus 
was  100°,  102°,  and  106°,  respectively.  Dr.  James  Currie  had  himself 
bled;  and  during  the  operation,  the  mercury  of  a  thermometer,  held 
in  his  hand,  sank,  at  first  slowly,  and  afterwards  rapidly,  nearly  10°; 
and  when  he  fainted,  the  assistant  found  that  it  had  sunk  8°  farther. 
In  diseased  states,  M.  Poger®  found  that  the  temperature  of  the  skin 
may  descend  in  children  to  74'3°,  and  rise  as  high  as  108'5°.  Its  range 
is,  consequently,  greater  than  in  adults,  in  whom  M.  Andral  found  it 
not  to  vary,  in  different  diseases,  more  than  from  95°  to  107*6°.  His 
estimates  are,  however,  much  too  limited;  as  in  Asiatic  cholera  the 
temperature  has  been  marked  as  low  as  67°,  whilst  in  disease  it  has 
certainly  risen  as  high  as  nearly  111°  Fahrenheit. 

MM.  Edwards  and  Gentil  assert,  that  they  have  likewise  observed 
diurnal  variations  in  the  temperature,  produced,  apparently,  by  the 
particular  succession  in  the  exercise  of  the  different  organs;  as  where 
intellectual  meditation  was.  followed  by  digestion.  The  variations,  they 
affirm,  frequently  amounted  to  two  or  three  degrees  between  morning 
and  evening. 

Such  are  the  prominent  facts  connected  with  the  subject  of  animal 
heat.  It  is  obvious,  that  it  is  disengaged  by  an  action  of  the  system, 
which  enables  it  to  counteract,  within  certain  limits,  the  extremes  of 
atmospheric  heat  and  cold.  The  animal  body,  like  all  other  substances, 
is  subjected  to  the  laws  affecting  the  equilibrium,  conduction,  and  radi- 
ation of  caloric;  but,  by  virtue  of  the  important  function  we  are  now 
considering,  its  own  temperature  is  neither  elevated  nor  depressed  by 
those  influences  to  any  great  extent.     Into  the  seat  and  nature  of  this 

'  Beobachtuntren  iiber  die  Koi-perwarme  in  chronisclien  fieberliafteu  Krankheiten, 
B.  15.  Berlin,  1853. 

2  Edwards,  op.  citat.,  p.  490.  »  On  the  Blood,  kc,  p.  296,  Lond.,  1794. 

*  Philos.  Transact,  for  1825,  p.  262 ;  and  Sir  E.  Home,  in  Lect.  on  Comp.  Anat.,  v. 
201,  Lond.,  1828. 

*  American  Medical  Intelligencer,  Feb.  15,  1839,  p.  346.  *  Op.  cit. 


THEORIES    OF   CALORIFICATION.  603 

mysterious  process,  find  various  ingenious  theories  that  have  been 
indulged  in  regard  to  it,  we  shall  now  inquire. 

Physiologists  have  been  by  no  means  agreed  as  to  the  organs  or 
apparatus  of  calorification.  Some,  indeed,  have  affirmed  that  there  is 
not,  strictly  speaking,  any  such;  and  that  it  is  a  result  of  all  the  other 
vital  operations.  Amongst  those,  too,  who  admit  the  existence  of  such 
an  apparatus,  a  difference  of  sentiment  prevails;  some  thinking  that  it 
is  heal  or  effected  in  a  special  part  of  the  organism;  others,  that  it  is 
general  or  disseminated  through  the  whole  economy.  Under  the  name 
caloricite,  M.  Chaussier  admitted  a  primary  vital  property,  by  virtue  of 
which  living  beings  disengage  the  caloric  on  which  their  proper  tem- 
perature is  dependent,  in  the  same  manner  as  .they  accomplish  their 
other  vital  operations  by  distinct  vital  properties;  and  in  support  of  the 
views,  he  adduced  the  circumstance,  that  each  living  body  has  its  own 
proper  temperature; — which  is  coexistent  only  with  the  living  state;  is 
common  to  every  living  part;  ceases  at  death;  and  augments  by  every 
cause  that  excites  the  vital  activity.  It  has  been  properly  objected, 
however,  tothis  view,  that  the  same  arguments  would  equally  apply  to 
many  other  vital  operations, — and  that  it  would  be  obviously  improper 
to  admit,  for  each  of  these  functions,  a  special  vital  property.  The 
notion  has  not  experienced  favour  from  the  physiologist,  and  is,  we 
believe,  confined  to  the  individual  from  whom  it  emanated. 

So  striking  a  phenomenon  as  animal  temperature  could  not  fail  to 
attract  early  attention;  and  according!}',  we  find  amongst  the  ancients 
various  speculations  on  the  subject.  The  most  prevalent  was, — that  its 
seat  is  in  the  heart;  that  the  heart  is  communicated  to  the  blood  in  that 
viscus,  and  is  afterwards  sent  to  every  part  of  the  system ;  and  that 
the  great  use  of  respiration  is  to  cool  the  heart.  This  hypothesis  is 
liable  to  all  the  objections  that  apply  to  the  notion  of  any  organ  of  the 
hody  acting  as  a  furnace, — that  such  organ  ought  to  be  calcined;  and 
it  has  the  additional  objection,  applicable  to  all  speculations  regarding 
the  ebullition  and  effervescence  of  the  blood  as  a  cause  of  heat,  that  it 
is  purely  conjectural,  without  the  slightest  fact  or  plausible  argument 
in  its  favour.  It  was  not,  indeed,  until  the  chemical  doctrines  pre- 
vailed, that  any  thing  like  argument  was  adduced  in  support  of  the 
local  disengagement  of  heat;  the  opinions  of  physiologists  then  settled 
almost  universally  upon  the  lungs ;  and  this,  chiefly,  in  consequence  of 
its  being  observed,  that  animals,  which  do  not  breathe,  have  a  tempera- 
ture but  little  superior  to  the  medium  in  which  they  live;  whilst  man 
and  animals  that  breathe  have  a  temperature  considerably  higher  than 
the  medium  heat  of  the  climate  in  which  they  exist,  and  one  which  is 
but  little  affected  by  changes  in  the  thermal  condition  of  that  medium ; 
and,  moreover,  that  birds,  which  breathe,  in  proportion,  a  greater  quan- 
tity of  air  than  man,  have  a  still  higher  temperature  than  he.  Mayow,^ 
whose  theor}'-  of  animal  heat  was,  in  other  respects,  sufficiently  unmean- 
ing, affirmed,  that  the  effect  of  respiration  is  not  to  cool  the  blood,  as 
had  been  previously  maintained,  but  to  generate  heat,  which  it  does  by 
an  operation  analogous  to  combustion.  It  was  not,  however,  until  the 
promulgation  of  Dr.  Black's  doctrine  of  latent  heat,  that  any  plausible 

'  Tract.  4uiuciue,  Oxon.,  1(!74. 


604  CALORIFICATIOISr. 

explanation  of  the  phenomenon  appeared.  According  to  that  distin- 
guished philosopher,  a  part  of  the  latent  heat  of  the  inspired  air  be- 
comes sensible;  consequently,  the  temperature  of  the  lungs,  and  of  the 
blood  passing  through  them,  must  be  elevated ;  and,  as  the  blood  is  dis- 
tributed to  the  whole  system,  it  must  communicate  its  heat  to  the  parts 
as  it  proceeds  on  its  course.  But  this  view  was  liable  to  an  obvious 
objection,  which  was,  indeed,  fatal  to  it,  and  so  Dr.  Black  himself 
appears  to  have  thought,  from  his  silence  on  the  subject.  If  the  whole 
of  the  caloric  were  disengaged  in  the  lungs,  as  in  a  furnace,  and  were 
distributed  through  the  bloodvessels,  as  heated  air  is  transmitted  along 
conducting  pipes,  the  temperature  of  the  lungs  ought  to  be  much 
greater  than  that  of  the  parts  more  distant  from  the  heart;  and  so  con- 
siderable as  to  consume  that  important  organ  in  a  short  space  of  time. 
The  doctrine,  maintained  by  MM.  Lavoisier^  and  Seguin,  was : — that 
the  oxygen  of  the  inspired  air  combines  with  the  carbon  and  Iwdrogen 
of  the  venous  blood,  and  produces  combustion.  The  caloric  given  off 
is  then  taken  up  by  the  bloodvessels,  and  is  distributed  over  the  body. 
The  arguments,  which  they  urged  in  favour  of  this  view,  were: — the 
great  resemblance  between  respiration  and  combustion,  so  that  if  the 
latter  gives  ofl"  heat,  the  former  ought  to  do  so  likewise ; — the  generally 
admitted  fact,  that  arterial  blood  is  somewhat  warmer  than  venous; — 
and  certain  experiments  of  Lavoisier  and  La  Place,^  which  consisted  in 
placing  animals  in  the  calorimeter,  and  comparing  the  quantity  of  ice 
which  they  melted,  and,  consequently,  the  quantity  of  heat,  which  they 
gave  off",  with  the  quantity  of  carbonic  acid  produced;  and  finding,  that 
the  quantity  of  caloric,  which  would  result  from  the  carbonic  acid  formed, 
was  exactly  that  disengaged  by  those  animals.  Independently,  how- 
ever, of  other  objections,  this  hypothesis  is  liable  to  those  already  urged 
against  that  of  Black,  which  it  closely  resembles.  The  objection,  that 
the  lungs  ought  to  be  much  hotter  than  they  really  are — both  absolutely 
and  relativel}^ — was  attempted  to  be  obviated  by  Dr.  Crawford^  in  a 
most  ingenious  and  apparently  logical  manner.  The  oxygen  of  the 
inspired  air,  according  to  him,  combines  with  the  carbon  given  out  by 
the  blood,  so  as  to  form  carbonic  acid.  But  the  specific  heat  of  this  is 
less  than  that  of  oxygen;  and  accordingly  a  quantity  of  latent  caloric 
is  set  free;  and  this  caloric  is  not  only  sufficient  to  support  the  tem- 
perature of  the  body,  but  also  to  carry  oft"  the  water — which  was  sup- 
posed to  be  formed  by  the  union  of  the  hydrogen  of  the  blood  and  the 
oxygen  of  the  air — in  the  state  of  vapour,  and  to  raise  the  temperature 
of  the  inspired  air.  So  far  the  theory  of  Crawford  was  liable  to  the 
same  objections  as  those  of  Black,  and  Lavoisier  and  Seguin.  lie 
affirmed,  however,  that  the  same  process  by  which  the  oxygen  of  tlie 
inspired  air  is  converted  into  carbonic  acid,  converts  the  venous  into 
arterial  blood  ;  and  as  he  assumed  from  his  experiments,  that  the  capa- 
city of  arterial  blood  for  caloric  is  greater  than  that  of  venous,  in  the 
proportion  of  1"0300  to  0'8928 ;  he  conceived,  that  the  caloric,  s^t  free 
in  the  formation  of  the  carbonic  acid,  in  place  of  raising  the  tempera- 

'  Mem.  de  I'Acad.  des  Sciences  pour  1777,  17S0,  and  1790. 
*  Memoir,  de  I'Acad.  des  Sciences  pour  1780. 

^  Experiments  and  Observations  on  Animal  Heat,  &c.,  2d  edit.,  London,  1788  ;  and 
Fleming,  Philosophy  of  Zoology,  i.  387,  Edinb.,  1822. 


THEORIES   OF   CALORIFICATION'.  605 

ture  of  the  arterial  blood,  is  employed  in  saturating  its  increased  capa- 
city, and  maintaining  its  temperatare  at  the  same  degree  with  tlie 
venous.  According  to  this  view,  therefore,  the  heat  is  not  absolutely 
set  free  in  the  lungs,  although  arterial  blood  contains  a  greater  quan- 
tity of  caloric  than  venous;  but  when,  in  the  capillaries,  the  arterial 
becomes  converted  into  venous  blood,  or  into  blood  of  a  less  capacity 
for  caloric,  the  heat  is  disengaged,  and  this  occasions  the  temperature 
of  the  body. 

Were  the  facts,  which  served  as  a  foundation  for  this  beautiful  theory 
true,  the  deductions  would  be  irresistible;  and,  accordingly,  it  was  at 
one  time  almost  universally  received,  especially  by  those  who  consider, 
that  all  vital  operations  can  be  assimilated  to  chemical  processes;  and 
it  is  still  favoured  by  many.  "The  animal  heat,"  observes  a  recent 
writer,'  "has  been  accounted  for  in  different  ways  by  several  ingenious 
physiologists ;  from  the  aggregate  of  their  opinions  and  experiments,  I 
deduce,  that  heat  is  extricated  all  over  the  frame,  in  the  capillaries,  by 
the  action  of  the  nerves,  during  the  change  of  the  blood,  from  scarlet 
arterial  to  purple  venous ;  and  also  whilst  it  is  changing  in  the  lungs 
from  purple  to  scarlet.  There  is  a  perpetual  deposition  by  the  capillary 
system  of  new  matter,  and  decomposition  of  the  old  all  over  the  frame, 
influenced  by  the  nerves;  in  this  decomposition  there  is  a  continual  dis- 
engagement of  carbon,  which  mixes  with  the  blood  returning  to  the 
heart,  at  the  time  it  changes  from  scarlet  to  purple;  this  decomposition, 
being  effected  by  the  electric  agency  of  the  nerves,  produces  a  constant 
extrication  of  caloric;  again,  in  the  lungs  that  carbon  is  thrown  off"  and 
united  with  oxygen,  during  which  caloric  is  again  set  free,  so  that  we 
have  in  the  lungs  a  charcoal  fire  constantly  burning,  and  in  the  other 
parts  a  wood  fire,  the  one  producing  carbonic  acid  gas,  the  other  carbon, 
the  food  supplying  through  the  circulation  the  vegetable  (or  what  an- 
swers the  same  end,  animal)  fuel,  from  which  the  charcoal  is  prepared 
which  is  burned  in  the  lung." 

Numerous  objections  have,  however,  been  made  against  the  view 
of  Crawford.  In  the  first  place,  it  was  urged,  that  our  knowledge 
is  limited  to  the  fact,  that  oxygen  is  taken  into  the  pulmonary  vessels, 
and  carbonic  acid  given  off',  but  that  we  have  no  means  of  knowing 
whether  the  one  goes  immediately  to  the  formation  of  the  other.  Dr. 
Crawford  had  inferred  from  his  experiments,  that  the  specific  heat  of 
oxygen  is  4*74:90;  of  carbonic  acid,  l-O-iSi;  of  nitrogen,  0-7936;  and 
of  atmospheric  air,  1'7900 ;  but  the  more  recent  experiments  of  MM. 
Delaroche  and  Berard  make  that  of  oxygen,  0*2361  ;  carbonic  acid, 
0*2210  ;  of  nitrogen,  0-2754: ;  and  of  atmospheric  air,  0-2669  ;  a  differ- 
ence of  such  trifling  amount,  that  it  has  been  conceived  the  quantity 
of  caloric,  given  out  by  oxygen  during  its  conversion  into  carbonic 
acid,  would  be  insufficient  to  heat  the  residual  air  in  the  lungs  to  its 
ordinary  elevation.  Secondly.  The  elevation  of  temperature  of  one  or 
two  degrees,  which  appears  to  take  place  in  the  conversion  of  venous 
into  arterial  blood,  although  generally  believed,  is  not  demonstrated. 
The  experiments  instituted  on  this  point  have  been  few  and  imprecise; 
and  those  of  MM.  Becquerel  and  Breschet,^  made  by  introducing-  deli- 

'  Billing,  First  I'rinoiples  of  Medicine,  2d  edit.,  p.  19,  London,  1837. 
2  Comptes  Rendus,  Oct.,  1841. 


606  CALORIFICATION. 

cate  thermometers  into  the  auricles  of  the  heart  of  dogs,  invariably 
gave  the  temperature  of  arterial,  only  a  few  fractions  of  a  degree 
higher  than  that  of  venous,  blood.     A  coup-de-grace  has,  however, 
been  given  to  this  view  by  the  experiments  of  Prof.  Bernard,  who  con- 
stantly found  the  blood  of  the  right  ventricle  w^armer  than  that  of  the 
left.     Without  opening  the  chest,  he  introduced  in  succession  the 
same  thermometer  into  the  right  and  the  left  ventricle  by  passing  the 
instrument  into  the  jugular  vein  and  the  brachio-cephalic  trunk.    The 
operation  was  performed  on  fifteen  living  sheep ;  seven  times  the  ther- 
mometer was  introduced  at  first  into  the  right  ventricle  and  then  into 
the  left ;  and  eight  times  the  order  was  reversed.     The  result  was  the 
same  in  all.     From  his   experiments  on  dead  animals  M.  Bernard 
accounts  for  the  temperature  of  the  blood  in  the  left  side  of  the  heart 
having  been  rated  higher  than  that  in  the  right  side  by  the  fact  of  the 
comparative  thinness  of  the  parietes  of  the  right  side  allowing  of  the 
blood  being  sooner  cooled  by  refrigerating  influences — as  the  admis- 
sion of  cold  air.^     From  these  researches  it  is  diflBcult  to  avoid  the 
inference  by  M.  Gavarret,  that  the  researches  of  M.  Bernard  establish 
incontestably,  that  the  blood  is  cooled  in  passing  through  the  lungs; 
and  that,  normally,  the  temperature  of  the  left  cavities  of  the  heart  is 
inferior  to  that  of  the  right;  a  fact,  which  had  been  discovered  in  1832 
by  M,  Malgaigne,  by  passing  the  thermometer  into  the  cavities  of  the 
heart  in  the  same  manner  as  was  done  by  M.  Bernard.     Thirdly.  M. 
Dulong,^ — on  repeating  the  experiments  of  Lavoisier  and  La  Place, 
for  comparing  the  quantities  of  caloric  given  oft"  by  animals  in  the 
calorimeter  with  that  which  would  result  from   the   carbonic   acid 
formed  during  the  same  time  in  their  respiration — did  not  attain  a 
like  result.     The  quantity  of  caloric  disengaged  by  the  animal  was 
always  superior  to  that  which  would  result  from  the  carbonic  acid 
formed.     Fourtldy.  The  estimate  of  Crawford  regarding  the  specific 
heat  of  venous  and  arterial  blood  has  been  contested.     He  made  that 
of  the  former,  we  have  seen,  0-8928;  of  the  latter,  I'OSOO.     The  result 
of  the  experiments  of  Dr.  John  Davy^  give  0*903  to  the  former,  and 
0-913  to  the  latter ;  and  in  another  case,  the  result  of  which  has  been 
adopted  by  M.  Magendie,  the  specific  heat  of  venous  was  greater  than 
that  of  arterial  blood,  in  the  proportion  of  '852  to  -839.     Granting, 
however,  the  case  to  be  as  stated  by  Crawford,  it  is  insufficient  to  ex- 
plain the  phenomena.     It  has,  indeed,  been  attempted  to  show,  that  if 
the  whole  of  the  caloric,  set  free  in  the  manner  mentioned,  were  im- 
mediately absorbed,  it  would  be  insufficient  for  the  constitution  of  the 
arterial  blood;  and  that,  instead  of  the  lung  running  the  risk  of  being 
calcined,  it  would  be  threatened  with  congelation.     Lastly^  the  accu- 
rate experiments  of  Edwards,  Magnus  and  others  elsewhere  referred 
to,  by  demonstrating  the  larger  amount  of  oxygen  in  the  arterial 
blood,  and  of  carbonic  acid  in  the  venous  blood ;  have  shown  that  the 
oxygen  of  the  atmosphere  unites  with  the  carbon  in  every  part  of  the 
system  of  nutrition;  and  not  in  the  lungs  exclusively. 

'  Gavarret,  De  la  Clialeur  produite  par  les  Etres  Vivants,  p.  110,  Paris,  1855.  Notes 
of  M.  Bernard's  Lectures  on  the  Blood,  &c.,  by  Walter  F.  Atlee,  M.  D.,  pp.|23  and  140, 
riiilad.,  1854. 

2  Magendie's  Journal  de  Phjsiologie,  iii.  45.  '  Philos.  Transactions  for  1814. 


THEORIES   OF   CALOEIFICATION.  607 

The  theory  of  combustion  in  the  lungs  is  still,  however,  maintained 
by  many  physiologists,^  and  an  able  writer  of  this  country,  Dr.  Met- 
calfe,^ from  a  consideration  of  the  various  facts  observed  by  himself 
and  others,  thinks  we  are  authorized  to  conclude ; — first.,  that  during 
the  passage  of  dark  venous  blood  through  the  lungs,  it  gives  off  vari- 
able proportions  of  carbon  and  hydrogen,  which  unite  chemically  with 
atmospheric  oxygen  to  form  carbonic  acid  and  water  as  in  ordinary 
combustion,  by  which  it  acquires  an  addition  of  caloric,  and  a  bright 
florid  hue ;  and  secondly.,  that  during  its  circulation  through  the  sys- 
temic capillaries,  the  caloric  obtained  from  the  atmosphere  is  trans- 
ferred to  the  solids,  by  which  their  temperature  and  vitality  are  main- 
tained; and  the  blood  returns  to  the  heart  of  a  dark  modena  hue, 
having  lost  its  power  of  stimulating  the  organs,  until  it  acquires  an 
additional  quantity  of  caloric  from  the  lungs. 

Dr.  Spencer,-'  formerly  of  Geneva  College,  N.  Y.,  wdio  regards  the 
great  end  and  function  of  respiration  to  be,  to  aid,  both  directly  and 
indirectly,  in  the  office  of  the  generation  and  diftusion  of  animal  heat, 
maintains,  that  the  substance  thrown  off  from  the  venous  blood  in 
respiration  is  hydrate  of  carbon: — that  the  carbon,  on  coming  in  con- 
tact with  atmospheric  oxygen  combines  with  it,  forming  carbonic  acid, 
which  is  exhaled  from  the  lungs  and  skin  by  expiration  and  perspira- 
tion;— that  the  amount  of  latent  heat  of  the  oxygen  employed  is  much 
greater  than  that  of  the  carbonic  acid  formed  in  the  lungs,  and  hence 
caloric  is  set  free,  which  imparts  heat  to  the  blood  and  surface  ; 
that  this  free  heat  also  combines  with  the  water  of  the  hydrate 
of  carbon  and  converts  it  into  vapour ; — that  the  lungs  and  cutaneous 
surface  aid  in  regulating  animal  temperature  by  the  conversion  of  water 
into  vapour,  thus  conveying  off  any  excess  of  free  caloric  in  the  sys- 
tem, by  combining  with  it  in  the  form  of  latent  heat; — that  the  water 
of  the  hydrate  of  carbon  is  converted  into  vapour  in  the  lungs,  and 
upon  the  surface,  precisely  as  when  wood  is  burned,  and  hence 
assumes  the  form  of  insensible  respiratory  and  perspiratory  transpira- 
tion;— and  that  the  systemic  red  capillaries  are  the  antagonists  of  the 
pulmonary ;  and  are  constantly  decomposing  carbonic  acid,  and  form- 
ing, with  water,  hydrate  of  carbon, — or,  in  other  words,  carbonizing 
the  blood ;  from  which  union  water  and  carbonic  acid  are  transformed 
into  a  solid  substance,  and  hence  latent  becomes  free  heat,  at  every 
point  where  red  blood  circulates.  The  views  of  Dr.  Spencer  are  in- 
genious, but  far  from  convincing ;  and  are  presented  by  him,  although 
aphoristically,  in  some  detail.  He  objects  to  the  view,  which  holds 
that  hydro-carbon  is  thrown  off  from  the  blood  in  the  lungs  by  its 
union  with  ox3'gen,  because'  hj^dro-carbon  is  an  inj aginary  compound. 
The  same  objection,  however,  applies  to  his  hydrate  of  carbon,  which, 
he  thinks,  exists  in  the  blood  in  the  solid  state,  and  is  analogous  to,  if 
not  identical  with,  the  lignin  of  vegetables.  In  regard  to  his  opinion, 
that  the  systemic  red  capillaries  are  the  antagonists  of  the  pulmonary 
capillaries,  it  must  not  be  forgotten,  that  there  are  also  red  capillaries 

'  Nasse,  Art.  Thierisolie  Wiirme,  in  Wagner's  Handworterbucli  der  Physiologie ; 
23ste  Lieferiing,  S.  1,  Braunschweig,  1849. 

^  Caloric,  its  Mechanical,  Chemical,  and  Vital  Agencies,  &c.,  ii.  555,  London,  1843. 
*  Lectures  on  Animal  Heat,  Geneva,  N.  Y.,  1845. 


608  CALORIFICATIO^r. 

in  the  lungs ;  and  that  in  the  system  of  nutrition  ever}^  where  arterial 
is  converted  into  venous  blood;  and  doubtless  with  the  same  pheno- 
mena. 

The  pulmonary  combustion  theory  has  received  the  powerful  sup- 
port of  Liebig,  and  many  elucidations  and  expansions  from  that  dis- 
tinguished chemist.  According  to  him,  the  carbon  and  hydrogen  of 
the  food,  in  being  converted,  through  the  agency  of  oxygen,  into  car- 
bonic acid  and  water,  must  give  out  as  much  heat  as  if  these  gases 
were  burned  in  the  open  air.  The  temperature  of  the  human  body  is 
essentially  the  same  in  the  torrid  as  in  the  frigid  zone;  but  as  the 
body  may  be  regarded  in  the  light  of  a  heated  vessel,  which  cools  with 
the  greater  rapidity  the  colder  the  surrounding  medium,  the  fuel,  ne- 
cessary to  maintain  its  heat,  must  vary  in  different  climates.  How 
unequal  must  be  the  loss  of  heat  at  Palermo,  where  the  external  tem- 
perature is  nearly  equal  to  that  of  the  body,  and  in  the  polar  regions, 
where  the  external  temperature  is  from  70°  to  90°  lower.  In  the 
animal  body,  food  is  fuel,  and  with  a  proper  supply  of  oxygen  we 
obtain  the  heat  durino;  its  oxidation  or  combustion.  In  winter,  when 
we  take  exercise  in  a  cold  atmosphere,  and  the  amount  of  inspired 
oxygen  consequently  increases,  the  necessity  for  food  containing  carbon 
and  hydrogen  increases  in  the  like  ratio,  and,  by  gratifying  the  appe- 
tite thus  excited,  we  obtain  the  most  efficient  protection  against  pierc- 
ing cold.  A  starving  man  is  soon  frozen  to  death ;  and  every  one, 
says  Liebig,  knows,  that  the  animals  of  prey  in  the  Arctic  regions  far 
exceed  those  of  the  torrid  zone  in  voracity.  Our  clothing  is  merely 
an  equivalent  for  a  certain  amount  of  food.  Were  we  to  go  naked, 
like  certain  savage  tribes,  or  exposed  in  hunting  or  fishing  to  the  same 
degree  of  cold  as  the  Samoyedes,  we  should  be  able  to  consume  with 
ease  sixteen  pounds  of  flesh,  and  perhaps  a  dozen  tallow  candles,  as 
travellers  have  related  of  those  people.  We  should,  also,  be  able  to 
take  the  same  quantity  of  brandy  or  train-oil  without  bad  effects,  be- 
cause the  carbon  and  hydrogen  of  these  substances  would  only  suffice 
to  keep  up  the  equilibrium  between  the  external  temperature  and  that 
of  our  bodies.  The  whole  process  of  respiration,  he  thinks,  is  clearly 
exhibited  when  we  view  the  condition  of  man  or  animals  under  absti- 
nence from  food.  Oxygen  is  abstracted  from  the  air,  and  carbonic 
acid  and  water  expired,  because  the  number  of  respirations  remains 
unaltered.  With  the  continuance  of  the  abstinence  the  carbon  and 
hydrogen  of  the  body  diminish.  The  first  effect  of  abstinence  is  the 
disappearance  of  the  fat,  which  can  be  detected  neither  in  the  scanty 
fteces  nor  urine ;  its  carbon  and  hydrogen  are  thrown  off"  by  the  skin 
and  lungs,  in  the  form  of  a  compound  of  oxygen.  These  consti- 
tuents, then,  have  served  for  the  purposes  of  respiration.  Every  day, 
32|  ounces  of  oxygen  are  inspired;  and  these  must  remove  their 
equivalents  of  carbon  to  form  carbonic  acid.  When  this  combination 
ceases  to  go  on,  respiration  terminates:  death  has  ensued.  The  time 
required  for  starving  an  animal  to  death  depends  on  its  fatness,  state 
of  activit}^,  the  temperature  of  the  air,  and  the  presence  or  absence  of 
water.  That  the  quantity  of  heat  evolved  by  the  combustion  of  13*9 
ounces  of  carbon  is  amply  sufficient  to  account  for  the  temperature  of 
the  human  body,  may  be  estimated  by  figures.     An  ounce  of  carbon 


THEORIES   OF   C ALORIFICATIOX.  609 

burned,  according  to  the  experiments  of  Despretz,  would  evolve  14067 
degrees  of  lieat;  and  13*9  oz.  would,  therefore,  give  out  19553 1'3 
degrees  of  heat.  This  would  suffice  to  boil  67*9  pounds  of  water  at 
32°,  or  to  convert  11"4  pounds  of  water  at  98*3°  into  vapour.  If  we 
consider  the  quantity  of  water  vaporized  through  the  skin  to  be,  in 
twenty-four  hours,  48  ounces  or  3  pounds,  there  will  then  remain,  after 
deducting  the  necessarj''  amount  of  heat,  144137*7  degrees  of  heat, 
which  are  dissipated  by  radiation  in  heating  the  expired  air,  and  in 
excrementitious  matters.' 

The  views  of  Liebig  necessarily  attracted  the  devout  attention  of 
the  chemical  physiologist,  and  whilst  thej  have  met  with  unqualified 
support  from  some,  they  have  been  as  much  condemned  by  others,  who 
appear  to  have  a  horror  at  the  introduction  of  chemical  explanations 
to  account  for  vital  phenomena.  Yet  it  cannot  be  contested,  that  the 
function  of  calorification  is  an  act  of  vital  chemistry ;  and,  consequently, 
although  the  views  of  Liebig  may  fail  to  convince,  they  certainly  have 
taken  the  proper  direction,  and,  all  must  grant,  have  been  plausibly 
and  ably  supported.  The  division  of  aliments  by  him  into  the  nitro- 
genized  or  plastic  elements  of  nutrition,  and  the  non-nitrogenized  or 
elements  of  respiration  and  calorification,  has  been  referred  to  else- 
where^ and  been  the  subject  of  comment  in  other  relations.  It  appears 
that  no  doubt  ought  to  exist  in  regard  to  nitrogenized  food  being  in- 
servient  to  the  production  of  heat.  Some  of  the  animjals,  which  are 
purely  carnivorous,  are  noted  for  their  elevated  temperature  in  the 
coldest  climates  and  seasons;  and  the  large  amount  of  nitrogenized 
material  necessary  to  relieve  the  feeling  of  debility — not  of  hunger — 
in  the  voyages  to  Arctic  regions  confirms  this  view.  Dr.  Kane  in- 
formed the  author,  that  in  his  last  voyage  to  those  regions,  to  pro- 
duce a  feeling  of  satiety,  six  or  eight  ducks  in  the  day  were  needed. 
Yet  it  was  not  hunger  that  was  experienced,  but  an  overwhelming 
sense  of  debility  that  could  be  relieved  in  no  other  manner. 

It  has  been  objected  to  the  theory  of  Liebig,  that  if  even  it  were 
admitted  to  be  applicable  to  mammalia,  birds,  and  reptiles,  it  by  no 
means  follows,  that  it  should  be  so  to  animals  that  respire  by  means  of 
branchite  or  gills,  all  of  which  consume  little  oxygen,  comparatively 
speaking ;  yet  many  of  them  devour  enormous  quantities  of  food.  Even 
the  largest  and  most  voracious  of  the  reptiles,  as  alligators,  crocodiles, 
\'c.,  under  a  burning  climate  too,  breathe  feebly  with  their  vesicular 
lungs,  and  consume  but  little  oxygen.  Fishes,  too,  whose  blood  is  but 
imperfectly  oxygenized  by  their  branchial  apparatus,  are  perliaps 
amongst  the  most  voracious  of  animals;  yet,  according  to  this  theory, 
they  ought  to  eat  little,  because  they  consume  little  oxygen.  These 
and  other  facts  were  eagerly  urged  by  M.  Virey,^  as  objections  to  the 
views  of  the  then  Professor  of  Giessen.  It  may  be  replied,  however, 
that  in  such  cases  a  large  portion  of  the  carbon  must  pass  off  in  the 
excrements.  There  is  no  country  in  the  world,  according  to  Madame 
Calderon  de  la  Barca,''  where  so  much  animal  food  is  consumed  as  in 

'  Animal  Chemistry,  Amer.  edit,  by  "Webster,  p.  33,  Cambridge,  1842. 

2  Page  115. 

^  Journal  de  Pharmacie,  Mai,  1842. 

*  Life  in  Mexico,  vol.  i.  p.  152,  Boston,  1842. 

VOL.  I. — 39 


610  CALORIFICATION. 

Mexico,  "  and  there  is  no  country  in  which  so  little  is  required."  To 
this  and  to  want  of  exercise  she  ascribes  the  early  fading  of  beauty  in 
the  higher  classes,  the  decay  of  teeth,  and  the  over-corpulency  so  com- 
mon amongst  them;  and  in  regard  to  the  last  she  is,  doubtless,  correct. 

To  the  statement  of  Liebig  respecting  the  greater  voraciousness  of 
the  animals  of  prey  of  the  Arctic  regions,  it  has  been  replied,^  that  a 
Bengal  tiger  or  Cape  hyena  requires,  in  proportion  to  its  size,  quite 
as  much  aliment  as  any  of  the  Arctic  carnivora ;  and  that  the  vultures 
of  Hindostan  and  Persia  exceed,  perhaps,  all  other  animals  in  gluttony. 
The  voraciousness  of  the  shark,  too,  even  within  the  tropics,  is  pro- 
verbial. "  Those  who  ride  over  the  Pampas  in  South  America,"  says 
Dr.  Graves,  "  at  the  rate  of  one  hundred  miles  a  day,  exposed  to  a 
burning  sun,  subsist  entirely  on  boiled  beef  and  water,  without  a  par- 
ticle of  vegetable  food  of  any  kind,  and  yet  they  attain  to  an  extraor- 
dinary condition^  and  capability  of  enduring  violent  and  long-continued 
exertion.  Liebig's  theory  must  be  very  ductile,  if  it  can  explain  how 
it  happens,  that  an  exclusively  animal  diet  agrees  with  man  quite  as 
well  at  the  equator  as  within  the  Arctic  circle."^  Numerous  facts, 
indeed,  can  be  brought  forward  of  an  opposite  tendency  to  those  of 
Liebig,  which  render  it  impracticable  for  us,  in  the  present  state  of  our 
knowledge,  to  embrace  all  his  positions.  Under  Eespiration,  the  theory, 
supported  by  him,  that  the  blood  corpuscles  are  the  carriers  of  oxygen 
from  the  lungs  to  the  tissues,  and  the  conveyers  of  carbonic  acid  back 
from  the  tissues  to  the  lungs,  was  mentioned.  Were  this  view  tenable 
it  would  seem,  that  if  the  amount  of  blood  corpuscles  should  become 
diminished  from  any  cause,  the  function  of  calorification  ought  to  be 
impaired  to  a  like  extent.  To  discover  what  effect  would  be  produced 
on  the  temperature  of  the  living  body  by  a  diminution  in  the  quantity 
of  blood  corpuscles,  M.  Andral  instituted  some  experiments,  which 
showed,  that  the  temperature  remained  normal,  even  in  cases  in  which 
the  corpuscles  had  experienced  the  greatest  diminution  in  number.  In 
the  axilla,  the  temperature  was  98°  or  99°  of  Fahrenheit  in  persons, 
the  proportion  of  whose  blood  corpuscles  was  not  higher  than  50,  40, 
80,  and  even  21  parts  in  the  1000;  the  healthy  ratio  being  127.  In- 
deed, notwithstanding  the  great  depression  in  ancemic  patients,  the 
heat  rose,  as  usual,  when  they  were  attacked  with  fever,  to  which  they 
are  as  subject  as  other  individuals.' 

But  the  combustion  theories  of  calorification  w^ere  most  seriously 
assailed  by  experiments,  tending  to  show,  that  the  function  of  calorifi- 
cation is  derived  from  the  great  nervous  centres.  When  an  animal  is 
decapitated,  or  the  spinal  marrow,  or  the  brain,  or  both,  are  destroyed, 
the  action  of  the  heart  may  still  be  kept  up,  provided  the  lungs  be  arti- 
ficially inflated.  In  such  case,  it  is  found,  that  the  usual  change  in  the 
blood,  from  venous  to  arterial,  is  produced ;  and  that  oxygen  is  ab- 
sorbed and  carbonic  acid  exhaled  as  usual.  Sir  Bei^ijamin  Brodie,"*  in 
performing  this  experiment,  directed  his  attention  to  the  point — whe- 

'  R.  J.  Graves,  A  System  of  Clinical  Medicine,  p.  57,  Dublin,  1843. 
^  See,  on  all  this  subject,  Metcalfe  on  Caloric,  vol.  ii.  chap.  2,  London,  1843. 
'  Andral,  Heniatologie  Pathologique,  p.  GO,  Paris,  1S43. 

■•  Philos.  Trans,  for  1811  and  1812;  and  Physiological  Researches,  p.  1-37,  Lond., 
1851. 


THEORIES   OF   CALORIFICATION.  611 

ther  animal  heat  is  evolved  under  sucli  circumstances,  and  the  tem- 
perature maintained,  as  where  the  brain  and  spinal  marrow  are  entire — 
and  he  found,  that  although  the  blood  appeared  to  undergo  its  ordinary- 
changes,  the  generation  of  animal  heat  seemed  to  be  suspended ;  and 
consequently,  if  the  inspired  air  happened  to  be  colder  than  the  body, 
the  effect  of  respiration  was  to  cool  the  body ;  so  that  an  animal,  in 
which  artificial  respiration  had  been  kept  up,  became  sooner  cold  than 
one  killed  and  left  undisturbed.  The  inference  from  these  experiments, 
was,  that  instead  of  circulation  and  respiration  maintaining  heat,  they 
dissipate  it ;  and  that  as  the  heat  is  diminished  by  the  destruction  of 
the  nervous  centres,  its  disengagement  must  be  ascribed  to  the  action 
of  those  centres,  and  especially  to  that  of  the  encephalon. 

Thirty  years  ago,  M.  Chossat^  endeavoured  to  discover  the  precise 
part  of  the  nervous  system  that  is  engaged  in  calorification ;  but  the 
results  of  his  experiments  were  not  such  as  to  induce  him  to  refer  it 
exclusively,  with  Sir  B.  Brodie,  to  the  encephalon.  He  divided  the 
brain,  anterior  to  the  pons  Varolii,  in  a  living  animal,  so  that  the 
eighth  nerve  was  uninjured.  Respiration,  consequently,  continued,  and 
inflation  of  the  lungs  was  unnecessary.  Notwithstanding  this  serious 
mutilation,  the  circulation  went  on;  and  M,  Cliossat  observed  distinctly, 
that  arterial  blood  circulated  in  the  arteries.  Yet  the  temperature  of 
the  animal  gradually  sank,  from  104°  Fahr., — its  elevation  at  the  com- 
mencement of  the  experiment, — to  76°,  in  twelve  hours,  when  the  ani- 
mal died.  It  seemed  manifest  to  M.  Chossat,  that,  from  the  time  the 
brain  was  divided,  heat  was  no  longer  given  off',  and  the  body  gradually 
cooled,  as  it  would  have  done  after  death.  He,  moreover,  noticed,  that 
the  time,  at  which  the  refrigeration  occurred  most  rapidl}'  was  that  in 
which  the  circulation  was  most  active, — at  the  commencement  of  the 
experiment.  In  other  experiments,  M.  Chossat  paralysed  the  action  of 
the  brain  by  violent  concussion,  and  injected  a  strong  decoction  of 
opium  into  the  jugular  vein, — keeping  up  artificial  respiration.  The 
results  were  the  same.  From  these  experiments,  he  drew  the  conclu- 
sion, that  the  brain  has  a  direct  influence  over  the  production  of  heat. 

His  next  experiments  were  directed  to  the  discovery  of  the  medium 
through  which  the  brain  acts, — the  eighth  pair  of  nerves,  or  spinal  mar- 
row. He  divided  the  eighth  pair  in  a  dog,  and  kept  up  artificial  respi- 
ration. The  temperature  sank  gradually;  and,  at  the  expiration  of 
sixty  hours,  when  the  animal  died,  it  was  reduced  to  68°  of  Fahrenheit. 
Yet  death  did  not  occur  from  asphyxia  or  suspension  of  the  phenomena 
of  respiration ;  for  the  lungs  crepitated,  exhibited  no  signs  of  infiltra- 
tion, and  were  partly  filled  with  arterial  blood.  The  animal  appeared 
to  M.  Chossat  to  expire  from  cold.  As,  however,  the  mean  depression 
of  heat  Avas  less  than  in  the  preceding  experiments,  he  inferred  that  a 
slight  degree  of  heat  is  still  disengaged  after  the  section  of  the  eighth 
pair;  whilst,  after  injury  done  to  the  brain  directly,  heat  is  no  longer 
given  oft'.  Again,  he  divided  the  spinal  marrow  beneath  the  occiput, 
and  although  artificial  respiration  was  maintained,  as  in  the  experi- 
ments of  Sir  B.  Brodie,  the  temperature  gradually  fell,  and  the  animal 
died  ten  hours  afterwards,  its  heat  being  79°;  and  as  death  occurred 

'  Sur  la  Chaleur  Aniraale,  Paris,  1820,  and  Adclon,  op.  cit.,  iii.  416. 


612  CALORIFICATION. 

in  tliis  case  so  mucli  more  speedily  than  in  the  last,  he  inferred,  that 
the  influence  of  the  brain  over  the  production  of  heat  is  transmitted 
rather  by  the  spinal  marrow  than  by  the  eighth  pair.  In  his  farther 
experiments,  M.  Chossat  discovered,  when  the  spinal  marrow  was  divided 
between  each  of  the  twelve  dorsal  vertebras,  that  the  depression  of  tem- 
perature occurred  less  and  less  rapidly,  the  lower  the  intervertebral 
section,  and  at  the  'lowest  was  imperceptible ;  he,  therefore,  con- 
cluded, that  the  spinal  marrow  does  not  act  directly  in  the  function, 
but  indirectly  throngh  the  trisplanchnic  nerve.  To  satisfy  himself  on 
this  point,  he  opened  the  left  side  of  a  living  animal,  beneath  the  twelfth 
rib,  and  removed  the  left  supra-renal  capsule,  dividing  the  trisplanch- 
nic where  it  joins  the  semilunar  plexus.  The  animal  lost  its  heat  gra- 
dually, and  died  ten  hours  afterwards  in  the  same  condition,  as  regarded 
temperature,  as  when  the  spinal  marrow  Avas  divided  beneath  the  occi- 
put. Desiring  to  obtain  more  satisfactory  results, — the  last  experi- 
ment appljdng  to  only  one  of  the  trisplanchnic  nerves, — he  tied  the 
aorta,  which  supplies  both,  beneath  the  place  where  it  passes  through 
the  arch  of  the  diaphragm,  at  the  same  time  preventing  asphyxia  by 
inflating  the  lungs.  The  animal  lost  its  heat  much  more  rapidly;  and 
died  in  live  hours.  In  all  these  cases,  according  to  M.  Chossat,  death 
occurred  from  cold ;  the  function,  by  which  the  caloric,  constantly 
abstracted  from  the  organism  by  the  surrounding  medium,  is  generated 
having  been  rendered  impracticable.  To  obtain  a  medium  of  compari- 
son, he  killed  several  animals  by  protracted  immersion  in  cold  water, 
and  found,  that  the  lowest  temperature  to  which  the  warm-blooded 
could  be  reduced,  and  life  persist,  was  79°  of  Fahrenheit.  He  also 
alludes  to  cases  of  natural  death  by  congelation,  which,  he  conceives, 
destroy  in  the  manner  before  suggested, — that  is,  by  impairing  the 
nervous  energy,  as  indicated  by  progressive  stupor,  and  debility  of  the 
chief  functions  of  the  economy.  Lastly : — on  killing  animals  suddenly, 
and  attending  to  the  progress  of  refrigeration  after  death,  he  found  it 
to  be  identical  with  that  which  follows  direct  injury  of  the  brain,  or  the 
division  of  the  spinal  marrow  beneath  the  occiput.  A  view  somewhat 
analogous  to  this  of  M.  Chossat,  was  embraced  by  Sir  Everard  Home.' 
He  considered,  that  the  phenomenon  is  restricted  to  the  ganglionic  part 
of  the  nervous  system;  resting  his  opinion  chiefly  on  the  circumstance, 
that  there  are  animals,  which  have  a  brain,  or  some  part  equivalent  to 
one,  and  whose  temperature  is  not  higher  than  that  of  the  surrounding 
medium;  whilst  all  the  animals  that  evolve  heat  are  provided  with 
nervous  ganglia.^ 

The  doctrines  of  Brodie,  Chossat,  and  Home  have  been  considered  by 
the  generality  of  the  chemists — by  Brande,^  Thomson,''  and  Paris,* — 
to  be  completely  subversive  of  the  chemical  view,  which  refers  the  pro- 
duction of  animal  heat  to  respiration;  and  their  position, — that  it  is  a 
nervous  function, — has  seemed  to  be  confirmed  by  the  facts  attendant 

'  Philos.  Trans.,  p.  257,  for  1825  ;  Journal  of  Science  and  Arts.  xx.  307  ;  and  Lect. 
on  Comparative  Auat.,  v.  121  and  194,  Lond.,  1828. 

^  See,  on  the  effect  of  diminution  of  its  temperature  on  the  life  of  an  animal,  Dr. 
Brown-Seqiiard,  in  Med.  Examiner,  Sept.,  1852,  p.  550. 

3  Manual  of  Chemistry,  vol.  iii.  ■*  System  of  Chemistry,  vol.  iv. 

6  Medical  Chemistry,  p.  327,  Lond.,  1825. 


THEORIES    OF    CALORIFICATION.  613 

upon  injury  done  to  the  nerves  of  parts,  and  by  what  is  witnessed  in 
paralytic  limbs,  the  heat  of  which  is  generally  and  markedly  inferior 
to  that  of  the  sound.  But  there  are  many  difficulties  in  the  way  of  ad- 
mitting, that  the  nervous  system  is  the  special  organ  for  the  production 
of  animal  temperature.  I)r,  Wilson  Philip,^  from  a  repetition  of  the 
experiments  of  Sir  Benjamin  Brodie,  was  led  to  conclude,  that  the 
cause  of  the  temperature  of  the  body  diminishing  more  rapidly,  when 
artificial  inflation  was  practised,  than  when  the  animal  was  left  undis- 
turbed, was — too  large  a  quantity  of  air  having  been  sent  into  the 
lungs;  for  he  found,  when  a  less  quantity  was  used,  that  the  cooling 
process  was  sensibly  retarded  by  the  inflation.  The  experiments  of 
Legallois,^  Hastings,^  and  Williams,''  although  differing  from  each  other 
in  certain  particulars,  corroborate  the  conclusion  of  Dr.  Philip;  and, 
what  is  singular,  appear  to  show,  that  the  temperature  occasionally 
rises  during  the  experiment;  a  circumstance  which  tends  rather  to  con- 
firm the  view,  that  respiration  is  concerned  materially  in  the  evolution 
of  heat. 

Many  of  the  facts  detailed  by  M.  Chossat  are  curious,  and  exhibit 
the  indirect  agency  of  the  nervous  system;  but  his  conclusion,  that 
the  trisplanchnic  is  the  great  organ  for  its  developement,  is  liable  to 
the  objections  already  brought  against  the  theory,  which  looks  upon 
the  lungs  as  a  furnace  for  the  disengagement  of  caloric, — that  they 
ought  to  be  consumed  in  a  short  space  of  time.  All  the  facts, 
however,  clearly  show,  that,  in  the  upper  classes  of  ^nimals,  the  three 
great  acts  of  innervation,  respiration,  and  circulation  are  indirectly 
concerned  in  the  function;  but  not  that  any  one  of  them  is  the  special 
seat.  M.  Edwards  has  maintained,  that  it  is  more  connected  with  the 
second  of  these  than  with  either  of  the  others.  Thus,  animals,  he 
argues,  whose  temperature  is  highest,  bear  privation  of  air  least:  cold- 
blooded animals  suffer  comparatively  little;  and  young  animals  are  less 
affected  than  the  adult.  Now,  the  greater  the  temperature  of  the  ani- 
mal, and  the  nearer  the  adult  age,  the  greater  is  the  consumption  of 
oxygen.  He  further  observed,  that  whilst  season  modifies  calorification, 
it  aftects  also  respiration;  and  if,  in  summer,  less  heat  be  elicited,  and 
in  winter  more,  it  is  found  that  respiration  consumes  less  oxygen  in  the 
former  than  in  the  latter  season. 

The  experiments  of  M.  Legallois,  as  well  as  those  instituted  by  M. 
Edwards,  led  the  latter  to  infer,  that  there  is  a  certain  ratio  between 
heat  and  respiration  in  both  cold-blooded  and  warm-blooded  animals, 
and  in  hibernating  animals  both  in  the  periods  of  torpidity  and  full 
activity.  When  the  eighth  pair  of  nerves  is  divided  in  the  young  of 
the  mammalia,  a  considerable  diminution  is  produced  in  the  opening 
of  the  glottis;  so  that,  in  puppies  recently  born,  or  one  or  two  days 
old,  so  little  air  enters  the  lungs,  that  when  the  experiment  is  made 
under  ordinary  circumstances  the  animal  perishes  as  quickly  as  if  it 
were  entirely  deprived  of  air.  It  lives  about  half  an  hour.  But,  if  the 
same  operation  be  performed  upon  puppies  of  the  same  age  benumbed 

'  An  Experimental  Inquiry  into  the  Laws  of  the  Vital  Functions,  3d  edit.,  p.  180. 

^  Aunnles  de  Cliimie,  iv.  .^,  Paris,  1817. 

'  Wilson  Philip,  op.  cit. ;  and  Journal  of  Science,  kc,  xiv.  'JO. 

*  Edinburgh  Medico-Chirurtjiual  Transactions,  ii.  192. 


61-i  CALORIFICATION. 

with  cold,  tliey  live  a  whole  day.  In  the  first  case  ^l.  Edwards  thinks, 
and  plausibly,  the  small  quantity  of  air  is  insufficient  to  counteract  the 
effect  of  the  heat,  whilst,  in  the  other,  it  is  sufficient  to  prolong  life  con- 
siderably; and  he  draws  the  following  practical  inferences  applicable 
to  the  adult  age,  and  particularly  to  man.  A  person  is  asphyxied  by 
an  excessive  quantity  of  carbonic  acid  in  the  air  he  breathes;  the  pulse 
is  no  longer  perceptible;  the  respiratory  movements  cannot  be  dis- 
cerned, but  his  temperature  is  still  elevated.  How  should  we  proceed 
to  recall  life?  Although  the  action  of  the  respiratory  organs  is  no 
longer  perceptible,  all  communication  with  the  air  is  not  cut  off.  It  is 
in  contact  with  the  skin,  on  which  it  exerts  a  vivifying  influence:  it  is 
also  in  contact  with  the  langs,  in  which  it  is  renewed  by  the  agitation 
constantly  taking  place  in  the  atmosphere,  and  by  the  heat  of  the  body, 
w^hich  rarefies  it.  The  heart  continues  to  beat,  and  a  certain  degree  of 
circulation  is  kept  up,  although  not  perceptible  by  the  pulse.  The 
temperature  of  the  body  is  too  high  to  allow  the  feeble  respiration  to 
produce  upon  the  system  all  the  effect  of  which  it  is  capable.  The 
temperature  must,  therefore,  be  reduced ;  the  patient  withdrawn  from 
the  deleterious  atmosphere ;  be  stripped  of  his  clothes,  in  order  that 
the  air  may  have  a  moi^e  extended  action  upon  his  skin;  be  exposed 
to  the  cold,  although  it  be  winter,  and  cold  water  be  thrown  upon  his 
face  until  the  respiratory  movements  reappear.  This  is  precisely  the 
treatment  adopted  to  revive  an  individual  from  a  state  of  asphyxia.  If, 
instead  of  cold,  continued  w^armth  were  to  be  applied,  it  would  be  one 
of  the  most  effectual  means  of  extinguishing  life, — a  consequence  which, 
like  the  former,  is  confirmed  by  experience.  In  sudden  faintings,  when 
the  pulse  is  weak  or  imperceptible,  the  action  of  the  respiratory  organs 
diminished,  and  sensation  and  voluntary  motion  suspended,  persons, 
the  most  ignorant  of  medicine,  are  aware,  that  means  of  refrigeration 
must  be  employed, — such  as  exposure  to  air,  ventilation,  and  sprinkling 
with  cold  water.  In  violent  attacks  of  asthma,  also,  when  the  extent 
of  respiration  is  so  limited  that  the  patient  experiences  a  sense  of  suffo- 
cation, he  courts  the  cold  air  even  in  the  severest  weather;  opens  the 
windows;  breathes  a  frosty  air,  and  finds  himself  relieved. 

As  a  general  rule,  an  elevated  temperature  accelerates  the  respira- 
tory movements,  but  the  degree  of  temperature  requisite  to  produce 
this  effect  is  not  the  same  in  all  pei'sons.  The  object  of  the  accele- 
rated respiration  is,  that  more  air  may  come  in  contact  with  the  lungs 
in  a  given  time,  so  as  to  reanimate  what  the  heat  depresses.  It  is 
proper  to  remark,  however,  that  we  meet  with  many  exceptions  to 
the  rule  endeavoured  to  be  laid  down  by  M.  Edwards  as  regards  the 
constant  ratio  between  heat  and  respiration.  Experiments  on  the 
lower  animals,  and  pathological  cases  in  man,  have  shown,  that  lesions 
of  the  upper  part  of  the  spinal  marrow  give  occasion,  at  times,  to  an 
extraordinary  developement  of  heat.  In  the  case  of  a  man  at  St. 
George's  Hospital,  London,  labouring  under  a  lesion  of  the  cervical 
vertebra.  Sir  B.  Brodie  observed  the  temperature  to  rise  to  111°,  at  a 
time  when  the  respirations  were  not  more  than  five  or  six  in  a 
minute.^     Drs.  Graves  and  Stokes^  give  the  case  of  a  patient  who 

'  London  Mpdical  Gazette  for  June,  183G. 

2  Dul)lin   Hospital  Reixn-ts,  voL    v.  ;  and  Dr.   Graves,  Clinical  Lectures,  American 
Med.  Lib.  edit.,  p.  12tJ,  Fhilad.,  1838. 


THEORIES   OF   CALORIFICATION.  615 

laboured  under  very  extensive  developement  of  tubercles,  had  tuber- 
cular abscesses  in  the  upper  portions  of  botti  lungs,  and  general  bron- 
chitis. In  this  case,  at  a  period  when  the  skin  was  hotter  than  usual, 
and  the  pulse  126,  the  respirations  were  only  14:  in  a  minute.  Be- 
sides, as  Dr.  Alison^  has  remarked,  the  temperature  of  the  body  is 
not  raised  by  voluntarily  increasing  or  quickening  the  acts  of  respi- 
ration, but  by  voluntary  exertions  of  other  muscles,  which  accelerate 
the  circulation,  and  thus  necessitate  an  increased  frequency  of  respira- 
tion;— a  fact,  which  would  seem  to  show,  that  calorification  is  depend- 
ent not  simply  on  the  application  of  oxygen  to  the  blood,  but  on  the 
changes  that  take  place  during  the  circulation,  and  to  the  mainte- 
nance of  which  its  oxygenation  is  one  essential  condition.  Moreover, 
in  the  foetus  in  utero,  there  is,  of  course,  no  respiration ;  yet  its  tem- 
perature equals,  and  indeed  is  said  to  even  exceed,  that  of  the  mother; 
and  we  know  that  its  circulation  is  more  rapid,  and  its  nutrition  more 
active.^ 

That  innervation  is  indirectly  concerned  in  the  phenomenon  is 
proved  by  the  various  facts,  which  have  been  referred  to ;  and  Legal- 
lois,  although  he  does  not  accord  with  Sir  B.  Brodie,  conceives  that 
the  temperature  of  the  body  is  greatly  under  the  influence  of  the 
nervous  system,  and  that  whatever  weakens  the  nervous  power,  pro- 
portionally diminishes  the  capability  of  producing  heat.  Dr.  Philip, 
too,  concluded  from  his  experiments,  that  the  nervous  influence  is  so 
intimately  connected  with  the  power  of  evolving  heat,  that  it  must  be 
looked  upon  as  a  necessary  medium  between  the  different  steps  of  the 
operation.  He  found,  that  if  the  galvanic  influence  be  applied  to 
fresh-drawn  arterial  blood,  an  evolution  of  heat,  amounting  to  three 
or  four  degrees,  takes  place;  at  the  same  time,  the  blood  assumes  the 
venous  hue,  and  becomes  partly  coagulated.  He  regards  the  process 
of  calorification  as  a  secretion;  and  explains  it  upon  his  general  prin- 
ciple of  the  identity  of  the  nervous  and  galvanic  influences,  and  the 
necessity  for  the  exercise  of  such  influence  in  the  function  of  secretion. 

Mr.  H.  Earle^  found  the  temperature  of  paralysed  limbs  slightl}^ 
lower  than  that  of  sound  limbs,  and  the  same  effect  is  observed  to 
supervene  on  traumatic  injuries  of  the  nerves.  In  a  case  of  hemi- 
plegia, of  five  months'  duration,  under  the  author's  care  at  the  Block- 
ley  Hospital,  the  thermometer  in  the  right — the  sound — axilla  of  the 
man  stood  at  96|^°  ;  in  the  axilla  of  the  paralysed  side,  at  96°.  The 
difference  in  temperature  of  the  hands  was  more  marked — that  of  the 
right  being  87°,  whilst  that  of  the  left  was  only  79|^°.  In  another 
case — that  of  a  female — of  two  weeks'  duration,  accompanied  with 
signs  of  cerebral  turgescence,  the  temperature  in  the  axilla  of  the 
sound  side  was  100°  ;  in  that  of  the  paralysed  98'25° :  of  the  hand  of 
the  sound  side,  94° ;  of  the  other,  90°.     It  is  a  general  fact,  that  the 

'  Outlines  of  Physiology,  Lond.,  1831. 

'  On  tlie  connexion  of  respiration  with  calorification,  see  P.  H.  Berard,  art.  Chaleur 
Animale,  in  Diet,  de  Med.,  2de  edit.,  vii.  175,  Paris,  1834;  and  Mr.  Newport  on  the 
Temperature  of  Insects,  and  its  Connexion  with  the  Functions  of  Respiration  and  Cir- 
cuhition  in  this  Class  of  Invertebrated  Animals,  Philos.  Transact.,  part  ii.  4to.  p.  77, 
Lond.,  1837. 

"  Medico-Cliirurgical  Transactions,  vii.  173,  Lond.,  1819. 


616  CALORIFICATION". 

temperature  of  the  paralysed  side  in  hemiplegia  is  less  than  that  of 
the  sound;  yet  the  irregularity  of  nervous  action  is  so  great,  and  the 
power  of  resistance  to  excitant  or  depressing  agents  so  much  dimin- 
ished, that  the  author  has  not  unfrequently  ibund  it  more  elevated.-' 
In  such  cases,  moreover,  the  nutrition  of  the  limb  will  fall  off,  in  con- 
sequence of  the  want  of  exercise;  and  this  circumstance  might  account 
for  any  diminution  of  temperature  manifested. 

Many  singular  phenomena,  as  regards  the  function  of  calorification, 
are  produced  by  injuries  of  the  nervous  centres,  or  by  a  division  of 
nerves  proceeding  to  a  part.  Thus,  one  of  the  first  effects  of  division 
of  the  spinal  cord  in  the  back  is  to  raise  the  temperature  of  the  poste- 
rior part  of  the  body  ;2  and  the  elevation  continues  for  some  hours. 
A  case  is  described  by  Sir  Benjamin  Brodie''  of  severe  injury  of  the 
cord  on  the  lower  part  of  the  cervical  region,  which  paralyzed  the 
whole  of  the  nerves  passing  oft"  below  the  injured  part,  yet  the  tem- 
perature of  the  inside  of  the  groin  was  not  less  than  111°;  although 
respiration  was  imperfectly  executed,  the  number  of  respirations  con- 
siderably diminished  and  the  countenance  livid.  Budge,"*  too,  found, 
that  if  the  spinal  cord  Avas  extirpated  on  one  side  between  the  last 
cervical  and  the  third  thoracic  vertebra,  the  temperature  of  the  corre- 
sponding side  of  tlie  face  rose  in  from  ten  to  fifteen  minutes.  Prof. 
Bernard'  and  Dr.  Brown-S^quard^  observed,  that  an  elevation  of  tem- 
perature took  place  on  one  side  of  the  face,  when  the  trunk  which  unites 
the  cervical  ganglia  of  the  sympathetic  of  that  side  was  divided.  The 
same  phenomena  resulted,  and  in  a  greater  degree,  when  the  superior 
cervical  ganglion  was  removed;  and  they  continued  for  months.  It 
has  been  suggested  by  the  latter  physiologist,  that  the  phenomena  are 
owing  to  the  induced  paralysis  and  the  consequent  dilatation  of  the 
bloodvessels;  the  blood  reaches  the  part  supplied  by  the  nerve  in 
greater  quantity,  and  nutrition  is  therefore  more  active.  The  increased 
sensibility  of  the  part  he  considers  to  be  the  result  of  the  augmented 
vital  properties  of  the  nerves  when  their  nutrition  is  increased. 
It  is  difficult  to  account  satisfactorilv  for  the  phenomena;  but  they 
are,  doubtless,  owing  to  modified  nutritive  action  in  the  parts. 

Lastly,  that  the  circulation  is  necessary  to  calorification,  we  have 
evidence  in  the  circumstance,  that  if  the  vessels  proceeding  to  a  part 
be  tied,  animal  heat  is  no  Icmger  disengaged  from  it.  It  has  been  seen, 
however,  that  there  is  no  certain  ratio  between  the  heat  and  frequency 
of  the  pulse. 

It  is  manifest,  then,  that  in  animals,  and  especially  in  the  warm- 
blooded, the  three  great  vital  operations  are  necessary  for  the  disen- 

'  American  Med.  Intelligencer,  Oct.  15,  1338,  p.  252. 

2  Brown-Seqnard,  Med.  Examiner,  March,  1853,  p.  138. 

3  Med.  Gazette,  June,  183(j ;  and  Physiological  Researches,  p.  121,  Lend.  1851. 

*  Memoranda  der  Speciellen  Physiologic  des  Menschen,  5te  Auflage,  S.  143,  Weimar, 
1853. 

"  Gazette  Medicale,  21  Fevr.,  1852 ;  and  Notes  of  M.  Bernard's  Lectures  on  the  Blood, 
by  Walter  F.  Atlee,  M.  D.,  p.  164,  Philad.,  1854. 

6  Med.  Examiner,  August,  1852,  p.  489;  and  ibid.,  Mar.,  1853,  p.  140;  and  Sur  les 
Resultats  de  la  Section  et  de  la  Galvanisation  du  Nerf  Grand  Sympathique  au  Con, 
(Gazette  Med.  de  Paris,  Annee,  1854.  See,  also.  Dr.  J.  Drummond,  Art.  Sympathetic 
Nerve,  in  Cyclop,  of  Anat.  and  Physiol.,  pt.  xlvii.,  p.  470,  Lond.,  Aug.,  1855. 


THEORIES    OF    CALORIFICATION".  617 

gagement  of  the  due  temperature,  but  we  have  no  sufficient  evidence 
of  the  direct  agency  of  any  one:  whilst  we  see  heat  ehcited  in  the 
vegetable,  in  which  these  functions  are  at  all  events  rudimental ;  and 
the  existence  of  one  of  them — innervation — more  than  doubtful. 

The  views  of  those  who  consider,  that  the  disengagement  of  caloric 
occurs  in  the  intermediate  system,  or  in  the  system  of  nutrition  of  the 
whole  body,  appear  to  be  most  consistent  with  observed  phenomena. 
These  have  varied  according  to  the  physical  circumstances,  that  have 
been  looked  upon  as  producing  heat.  By  some,  it  was  regarded  as  the 
product  of  an  effervescence  of  the  blood  and  humours;  by  others,  as 
owing  to  the  disengagement  of  an  igneous  matter  or  spirit  from  the 
blood;  by  others  ascribed  to  an  agitation  of  the  sulphureous  parts  of 
the  blood;  whilst  Boerhaave^  and  Douglas^  ascribed  it  to  the  friction  of 
the  blood  against  the  parietes  of  the  vessels,  and  of  the  corpuscles 
against  each  other. 

In  favour  of  the  last  hypothesis,  it  was  urged,  that  animal  heat  is 
in  a  direct  ratio  with  the  velocity  of  the  circulation,  the  circumference 
of  the  vessels,  and  the  extent  of  their  surface ;  and  that  we  are  thus 
able  to  explain,  why  the  heat  of  parts  decreases  in  a  direct  ratio  with 
their  distance  from  the  heart ;  whilst  the  greater  heat  of  the  arterial 
blood  in  the  lungs  was  accounted  for  by  the  supposition,  that  the 
pulmonary  circulation  is  far  more  rapid.  Most  of  these  notions — it 
need  scarcely  be  said — were  entirely  hypothetical.  The  data  were 
generally  incorrect,  and  the  deductions  characteristic  of  the  faulty 
physics  of  the  period  in  which  they  were  hazarded.  The  correct 
view,  it  appears  to  us,  is,  that  caloric  is  disengaged  in  every  part, 
by  a  special  chemico-vital  action,  modified  in  animals  by  the  nervous 
influence.  In  this  manner,  calorification  becomes  a  ilmction  exe- 
cuted in  the  whole  system  of  nutrition;  and,  therefore,  appropri- 
ately considered  in  this  place.  It  has  been  remarked  by  Tiedemann,^ 
that  the  intussusception  of  alimentary  matters,  and  their  assimilation 
by  digestion  and  respiration;  the  circulation  of  the  humours;  nutri- 
tion and  secretion ;  the  renewal  of  materials  accompanying  the  exer- 
cise of  life,  and  the  constant  changes  of  composition  in  the  solid  and 
liquid  parts  of  the  organism, — all  of  which  are  influenced  by  the 
nervous  system, — participate  in  the  evolution  of  heat,  and  we  deceive 
ourselves,  when  we  look  for  the  cause  in  one  of  those  acts  only.  In 
certain  experiments  by  Dr.  Eobert  E,  Eogers,^  then  of  the  University  of 
Virginia,  he  found  that  when  recently  drawn  venous  blood,  contained 
in  a  freshly  removed  pig's  bladder,  was  immersed  in  oxygen  gas,  there 
was  a  remarkable  elevation  of  temperature.  Dr.  Davy^  performed 
experiments  which  led  to  the  same  results.  In  one  of  these,  he  took 
a  very  thin  vial,  of  the  capacity  of  eight  fluidounces,  and  carefully 
enveloped  it  in  badly  conducting  substances, — for  example,  in  several 

'  Van  Swieten,  Comment,  in  Boerhaav.  Apliorism.,  ko.,  §§  382,  675,  Lngd.  Bat., 
1742-1772. 

2  On  Animal  Heat,  p.  47,  Lond.,  1747. 

*  Traite  de  Physiologie,  &o.,  trad.  jmr.  Jourdan,  p.  514,  Paris,  1831. 

*  Amer.  Journal  of  the  Med.  Sciences,  p.  297,  for  Aug.,  1836. 

*  Proceedings  of  the  Royal  Society  for  1837-8,  No.  34  ;  and  Researches  Physiological 
and  Anatomical,  .imerican  Med.  Lit),  edit.,  p.  89,  Philad.,  1840. 


618  CALORIFICATION". 

folds  of  flannel,  fine  oiled  paper,  and  oiled  cloth.  Thus  prepared,  and 
a  perforated  cork  being  provided  holding  a  delicate  thermometer,  two 
cubic  inches  of  mercury  were  introduced,  and  immediately  after  it 
was  filled  with  venous  blood  kept  liquid  by  agitation.  The  vial  was 
then  corked,  and  shaken.  The  thermometer  included  was  stationary 
at  4:0°.  After  five  minutes,  during  which  it  remained  so,  it  was  with- 
drawn ;  the  vial,  closed  by  another  cork,  was  transferred  inverted  to 
a  mercurial  bath,  and  IJ  cubic  inch  of  oxygen  introduced.  The  com- 
mon cork  was  returned,  and  the  vial  was  well  agitated  for  about  a 
minute;  the  thermometer  was  now  introduced;  it  rose  immediately  to 
46°,  and  by  continuing  the  agitation,  to  46*5°,  and  very  nearly  47°. 
This  experiment  was  made  on  the  blood  of  the  sheep.  These,  and 
other  experiments  of  a  similar  character,  Dr.  Davy  thinks,  appear  to 
favour  the  idea,  that  animal  heat  is  owing,  first,  to  the  fixation  or  con- 
densation of  oxygen  in  the  blood  of  the  lungs  in  its  conversion  from 
venous  to  arterial ;  and  secondly,  to  the  combinations  into  which  it 
enters  in  the  circulation  in  connexion  with  the  different  secretions  and 
changes  essential  to  animal  life. 

Subsequent  experiments  by  M.  Chossat'  confirm  the  view  of  the 
great  dependence  of  calorification  on  the  proper  supply  of  materials 
on  which  changes  have  to  be  eftected  in  the  system  of  nutrition.  lie 
found,  that  birds,  totally  deprived  of  food  and  drink,  experienced  a 
gradual,  although  slight  daily  diminution  of  temperature.  This  was 
not  shown  so  much  by  a  fall  of  their  maximum  heat,  as  by  an  increase 
in  the  diurnal  variation  which  existed  in  the  healthy  state.  The 
amount  of  this  variation  in  birds  properly  supplied  with  food  is  1|° 
of  Fahrenheit  daily — the  maximum  being  about  noon,  and  the  minimum 
at  midnight.  In  the  state  of  inanition,  however,  the  average  variation 
was  about  6°,  and  it  increased  as  the  animal  became  weaker.  The 
gradual  rise  of  temperature,  too,  which  should  have  taken  place  be- 
tween midnight  and  noon,  was  retarded;  whilst  the  fall  subsequent  to 
noon  commenced  much  earlier  than  in  the  healthy  state;  so  that  the 
average  of  the  whole  day  was  lowered  by  about  4i°  between  the  first 
and  last  day  but  one  of  this  condition.  On  the  last  da}^,  the  diminu- 
tion took  place  very  rapidly,  and  the  thermometer  fell  from  hour  to 
hour,  until  death  supervened — the  whole  loss  on  that  day  being  about 
25°  Fahrenheit,  making  the  total  depression  about  29|°.  On  exa- 
mining the  amount  of  loss  sustained  by  the  different  organs  of  the 
body,  it  was  found  that  93  per  cent,  of  the  fat  had  disappeared, — all, 
in  fact,  that  could  be  removed ;  whilst  the  nervous  centres  exhibited 
scarcely  any  diminution  in  weight.  The  loss  in  the  weight  of  the 
whole  body  averaged  about  40  per  cent.  This  preservation  of  weight 
on  the  part  of  the  nervous  centres  has  been  regarded,  but  with  little 
plausibility,  to  favour  the  idea,  that  they  may  be  formed  from  fatty 
matter,^ — a  portion  of  the  fat  absorbed  being  appropriated  for  their 
nutrition;  yet  it  would  be  strange,  if  proteinaceous  compounds  should 
be  required  for  other  organized  structures,  and  the  highest  of  all  in 

'  Recherclies  Experimentales  sur  rinanition,  Paris,  1843;  noticed  in  Brit,  and  For. 
Med.  Rev.,  April,  1844. 

^  Carpenter,  Principles  of  Human  Physiology,  2d  edit.,  p.  675,  London,  ]844. 


THEORIES   OF   CALORIFICATION".  619 

importance  sliould  originate  from  a  non-nitrogenized  material,  or  what 
Liebig  terms  an  "element  of  respiration."  Dr.  Carpenter, — in  com- 
menting on  the  experiments  of  Chossat, — remarks,  that  from  the  con- 
stant coincidence  between  the  entire  consumption  of  the  fat,  and  the 
depression  of  temperature,  joined  to  the  fact  that  the  duration  of  life 
under  the  inanitiating  process  evidently  varied  cceteris  paribus  with  the 
amount  of  fat  previously  accumulated  in  the  body,  the  inference  seems 
irresistible,  that  the  calorifying  power  depended  chiefly — if  not  wholly 
— on  the  materials  supplied  by  this  substance ;  and  he  adds — when- 
ever the  store  of  combustible  matter  in  the  system  was  exhausted, 
whether  by  the  respiratory  process  alone,  or  by  this  in  conjunction 
with  the  conversion  of  adipous  matter  into  the  materials  for  the  nerv- 
ous or  other  tissues,  the  inanitiated  animals  died  by  the  cooling  of 
their  bodies  consequent  upon  the  loss  of  calorifying  power.  This  is 
plausible;  yet  it  can  be  readily  imagined,  that  the  loss  of  the  accus- 
tomed supply  of  aliment  may  so  interfere  with  changes  perpetually 
taking  place  in  the  system  of  nutrition,  as  to  give  occasion  to  the  func- 
tional changes,  which  eventuate  in  the  loss  of  life,  and  that  the  system 
cannot  exist  for  any  length  of  time  on  the  materials  that  are  taken  up 
from  itself  The  use  of  the  fot  as  a  nutriment  deposited  for  special 
occasions  is  generally  admitted  by  physiologists.  Its  use  as  an  ele- 
ment of  respiration  has  only  been  suggested  of  late  years;  and  it  must 
be  admitted,  that  the  view  which  has  been  embraced  by  Dr.  Carpenter  is 
somewhat  supported  by  the  experiments  of  M.  Chossat,  who  found  that  if 
inanitiated  animals,  when  death  is  impending,  were  subjected  to  artificial 
heat,  they  were  almost  uniformly  restored  from  a  state  of  insensibility 
and  want  of  muscular  power  to  a  condition  of  comparative  activity ; 
their  temperature  rose;  muscular  power  returned;  they  flew  about  the 
room  and  took  food  when  it  was  presented  to  them ;  and  if  the  arti- 
ficial assistance  was  sufficiently  prolonged,  and  they  were  not  again 
subjected  to  the  starving  process,  most  of  them  recovered.  In  other 
words,  it  might  be  said,  that  the  application  of  artificial  warmth  pre- 
vented the  farther  consumption  of  the  fuel — fat — and  exerted  a  most 
salutary  agency  on  the  organic  as  well  as  the  animal  functions. 

The  experiments  of  M.  Chossat  are  the  more  worthy  of  attention  and 
of  careful  repetition,  from  their  seeming  to  lead  to  a  conclusion,  which, 
Dr.  Carpenter  thinks,  can  scarcely  be  questioned,  from  the  similarity  of 
the  phenomena, — that  inanitiation  with  its  consequent  depression  of 
temperature  is  the  immediate  cause  of  death  in  various  diseases  of  ex- 
haustion. Hence  it  has  been  suggested,  that  in  those  forms  of  febrile 
maladies  in  which  no  decided  lesion  is  discoverable  after  death,  a  judi- 
cious and  timely  application  of  artificial  heat  might  prolong  life  until 
the  malignant  influence — as  in  cases  of  narcotic  poisoning — had  passed 
away.  It  has  been  suggested,  too,  that  the  beneficial  result  of  alcohol 
in  protracted  cases  of  such  fevers,  and  the  large  amount  in  which  it 
may  be  given  with  impunity,  may  probably  be  accounted  for  on  this 
principle.  "  We  cannot  support  the  system  in  fever  by  aliment,  for  this 
would^not  be  digested,  even  if  it  were  taken  into  the  stomach.  But  we 
well  know  the  beneficial  effects  of  alcohol  in  its  advanced  stages ;  and 
the  large  quantity  of  this  stimulus  that  may  be  administered  in  many 
cases  of  fever  is  a  matter  of  familiar  experience.     Now,  admitting  that 


620  CALORIFICATION". 

its  beneficial  operation  is  partly  due  to  its  specific  effect  upon  the  ner- 
vous system,  we  cannot  help  thinking,  that  we  are  to  regard  it  as  also 
resulting  from  the  new  supply  of  combustible  material,  which  is  thus 
introduced  in  the  only  form  in  which  it  can  be  taken  up  by  the  vascular 
system.  If  we  turn  our  attention  for  a  moment  to  the  state  of  the  di- 
gestive apparatus  at  this  period,  we  shall  at  once  see  why  no  other  sub- 
stance should  answer  the  same  purpose.  In  the  advanced  stage  of 
fever,  the  secretion  of  gastric  fluid,  and  the  special  absorbent  process 
which  takes  place  through  the  villi  and  lacteals,  seem  to  be  in  complete 
abeyance.  Still,  however,  simj^le  imbibition  may  go  on  through  the 
walls  of  the  bloodvessels,  provided  the  circumstances  are  favourable 
to  the  production  of  endosmose;  that  is,  provided  the  fluid  in  the 
alimentary  canal  is  less  dense  than  the  blood.  Now,  the  substances  on 
which  we  ordinarily  depend  for  the  support  of  the  respiratory  j)rocess 
are  either  of  an  oily,  a  saccharine,  or  a  mucilaginous  character.  Oily 
substances  cannot  be  taken  in  by  imbibition,  since  they  completely 
check  the  endosmotic  current.  Saccharine  and  mucilaginous  substances 
can  only  be  taken  in,  when  their  solution  is  so  dilute  as  to  be  of  a 
density  much  inferior  to  that  of  the  blood;  hence  they  must  be  given 
in  a  large  bulk  of  fluid;  a  practice  of  which  experience  has  shown  the 
benefit.  But  alcohol,  being  already  of  a  density  far  inferior  to  that  of 
the  blood,  is  easily  absorbed ;  and,  from  deficiency  of  other  materials, 
it  is  rapidly  consumed,  so  that  a  very  large  quantity  may  be  thus  in- 
gested, without  its  stimulating  effects  being  perceptible;  just  as  we  see 
that,  in  ft  very  cold  atmosphere,  large  quantities  of  spirituous  licjuors 
may  be  taken  with  impunit}^,  on  account  of  the  rapid  combustion  they 
undergo."^ 

It  is  by  the  theory  of  the  general  evolution  of  caloric  in  the 
tissues  or  in  the  system  of  nutrition,  that  we  are  able  to  account  for 
the  increased  heat  that  occurs  in  certain  local  affections,  in  which  the 
temperature  greatly  exceeds  that  of  the  same  parts  in  health.  By 
some,  it  has  been  doubted,  whether,  in  local  inflammation,  any  such 
augmentation  of  temperature  exists;  but  the  error  seems  to  have  arisen 
from  the  temperature  of  the  part  in  health  having  been  generally  ranked 
at  blood  heat;  whereas  it  differs  essentially  in  different  parts.  Dr. 
Thomson  found,  that  a  small  inflamed  spot  in  his  right  groin  gave  out, 
in  the  course  of  four  days,  a  quantity  of  heat  sufficient  to  have  heated 
seven  wine-pints  of  water  from  40°  to  212° ;  yet  the  temperature  was 
not  sensibly  less  than  that  of  the  rest  of  the  body  at  the  end  of  the 
experiment,  when  the  inflammation  had  ceased,^  By  supposing,  too, 
that  calorification  is  effected  in  every  part  of  the  body,  we  can  under- 
stand why  different  portions  should  have  different  temperatures;  as  the 
activity  of  the  function  may  vary,  in  this  respect,  according  to  the 
organ.  MM.  Chopart  and  Dessault  found  the  heat  of  the  rectum  100°; 
of  the  axilla  and  groin,  when  covered  with  clothes,  96°;  and  of  the 
chest,  92°.  Dr.  Davy^  found  the  temperature  of  a  naked  man,  just 
risen  from  bed,  to  be  90°  in  the  middle  of  the  sole  of  the  foot ;  98'  be- 
tween the  inner  ankle  and  tendo  achillis ;  91'5°  in  the  middle  of  the 

'  Brit,  and  For.  Med.  Rev.,  April,  1844,  p.  356. 
^  Aiuials  of  Philoj^ophy,  ii.  27. 
^  rhilosopli.  Trausact.  fur  1S14. 


THEOKIES   OF   CALORIFICATION.  621 

shin;  93°  in  the  calf;  95°  in  the  ham  ;  91°. in  the  middle  of  the  thigh; 
96'0°  in  the  fold  of  the  groin ;  95°  at  three  lines  beneath  the  umbili- 
cus; 94°  on  the  sixth  rib  of  the  left  side;  93°  on  the  same  rib  of  the 
right  side  ;  and  98°  in  the  axilla.  MM.  Edwards  and  Gentil  found  the 
temperature  of  a  strong  adult  male  in  the  rectum  and  mouth,  102° ; 
in  the  hands,  100°;  in  the  axilla  and  groins,  98°;  on  the  cheeks,  97°; 
on  the  prepuce  and  feet,  96° ;  and  on  the  chest  and  abdomen,  95°.  It 
is  obvious,  however,  that  all  these  experiments  concern  only  the  tem- 
perature of  parts  which  can  be  readily  modified  by  the  circumambient 
medium.  To  judge  of  the  comparative  temperature  of  the  internal 
organs,  Dr.  Davy  killed  a  calf,  and  noted  that  of  difl'erent  parts,  both 
external  and  internal.  The  blood  of  the  jugular  vein  raised  the  ther- 
mometer to  105*5°;  that  of  the  carotid  artery  to  107°.  The  heat  of 
the  rectum  was  105*5°;  of  the  metatarsus,  97°;  of  the  tarsus,  90°;  of 
the  knee,  102°  ;  of  the  head  of  the  femur,  103°  ;  of  the  groin,  104° ;  of 
the  under  part  of  the  liver,  106° ;  of  the  substance  of  that  organ,  106° ; 
of  the  lung,  106*5°;  of  the  left  ventricle,  107°;  of  the  right,  106°  ; 
and  of  the  substance  of  the  brain,  104°.  M.  Chevallier^  investigated 
the  temperature  of  the  urine  on  issuing  from  the  bladder.  He  found 
it  to  be  affected  by  rest,  fatigue,  change  of  regimen,  remaining  in  bed, 
&c.  The  lowest  temperature,  which  was  observed  on  rising  in  the 
morning,  was  about  92°  ;  the  highest,  after  dinner  and  when  fatigued, 
99°,  In  the  case  of  another  person,  the  temperature  of  the  fluid  was 
never  lower  than  101°  ;  and  occasionall}^,  when  he  was  fatigued,  it  was 
upwards  of  102°.  By  M.  Brown-Scquard,^  its  mean  temperature  in 
man  was  observed  to  be  102*6°;  and  he  rates  that  of  the  thoracic  and 
abdominal  viscera,  in  the  human  species,  in  both  sexes,  between  102° 
and  103°.  Berger,  and  Maunoir,  and  himself,  found  the  temperature 
of  the  rectum  in  healthy  persons  between  100°  and  102°  of  Fahrenheit. 
In  the  case  of  fistulous  opening  into  the  stomach,  observed  by  Dr. 
Beaumont,^  the  thermometer  indicated  a  difference  of  three-fourths  of 
a  degree  between  the  heat  of  the  splenic  and  pyloric  orifices  of  the  sto- 
mach; the  temperature  of  the  latter  being  more  elevated. 

Some  interesting  observations  have  been  made  in  this  direction  by 
MM.  Bernard  and  Walferdin,  the  results  of  which  were  communicated 
to  M.  Gavarret."  It  has  been  already  remarked,  that  the  blood  of  the 
right  side  of  the  heart  is  hotter  than  that  of  the  left.  It  was  found, 
moreover,  that  the  blood  in  the  superior  vena  cava,  and  of  all  the  veins 
opening  into  it,  was  constantly  cooler  than  that  of  the  arch  of  the  aorta, 
and  of  the  arteries  sent  off  from  it  at  the  same  distance  from  the  heart. 
The  results  were  more  complex,  as  regarded  the  vena  cava  ascendens, 
and  the  descending  aorta,  and  their  branches.  Thus,  the  blood  of  the 
renal  vein  was  warmer  than  that  of  the  renal  arterj^;  that  of  the  vena 
porta,  before  its  entrance  into  the  liver,  was  of  less  temperature  than 
that  of  the  supra-hepatic  veijis ;  that  of  the  supra-hepatic  veins  warmer 
than  that  of  the  aorta  immediately  below  the  diaphragm,  and  that  of 

'  Essai  sur  la  Dissolution  de  la  Gravello,  &c.,  p.  120.  Paris,  1S37. 
2  Medical  Examiner,  Sept.,  1852,  p.  .556. 

^  Exp.  and  Observations  on  the  Oastric  Juice,  p.  274,  Plattsburg,  1833. 
■•  De  la  Chaleur  Produite  par  les  Etros  Vivauts,  p.  109,  Paris,  1855, 


622  CALORIFICATION". 

the  loAver  limbs  less  than  that  of  the  corresponding  arteries.  The  same 
was  the  case  with  the  blood  of  the  iliac  veins  and  arteries;  that  of  the 
vena  cava  ascendens  as  far  as  the  entrance  of  the  renal  vein  was  also 
of  less  temperature  than  that  of  the  descending  aorta  below  the  origin 
of  the  renal  arteries.  The  mixture  of  the  blood  of  the  renal  vein  with 
that  returning  from  the  lower  limbs  has  this  result,  that  in  the  vena 
cava  comprised  between  the  mouth  of  the  renal  vein  and  the  liver, 
the  blood  is  warmer  than  in  the  portion  of  the  descending  aorta,  which 
extends  from  the  diaphragm  to  the  origin  of  the  renal  arteries;  and 
lastly,  at  the  point  where  the  supra-hepatic  veins  disgorge  their  blood 
into'^the  vena  cava  ascendens,  the  temperature  of  the  blood  in  the  last 
vein  again  rises  and  passes  much  above  that  of  the  blood  of  the  corre- 
sponding part  of  the  aorta.  The  confluence  of  the  supra-hepatic  veins 
and  the  vena  cava  is  the  ivarmest  place  in  the  economy.  The  blood, 
at  least,  has  there  the  maximum  of  observed  temperature. 

It  is  not  easy  to  account  for  these  differences,  without  supposing,  that 
each  part  has  the  power  of  disengaging  its  own  heat,  and  that  the  com- 
munication of  caloric  from  one  part  to  another  is  not  sufficiently  ready 
to  prevent  the  difference  from  being  perceptible. 

Of  the  mode  in  which  heat  is  evolved  in  the  system  of  nutrition,  it 
is  impossible  for  us  to  arrive  at  any  satisfactory  information.  The 
result  alone  indicates,  that  the  process  has  been  accomplished.  In  the 
present  state  of  our  knowledge,  we  are  compelled  to  refer  it  to  some 
cheinico-vital  action,  of  the  nature  of  which  we  are  ignorant ;  but 
which  seems  to  be  possessed  by  all  organized  bodies, — vegetable  as 
well  as  animal.  We  know  that  wherever  carbon  unites  with  oxygen 
to  form  carbonic  acid ;  oxygen  with  hydrogen  to  form  water ;  or  with 
phosphorus  or  sulphur  to  form  phosphoric  acid,  and  sulphuric  acid,  as 
is  constantly  the  case  in  organized  bodies,  heat  must  be  disengaged.^ 
We  shall  have  to  refer  hereafter,  when  treating  of  the  phenomena  of 
DEATH,  to  interesting  observations  of  Dr,  Dowler  of  New  Orleans,  and 
others,  showing,  that  the  heat  of  the  body  may  rise  after  somatic 
death, — that  is,  after  the  cessation  of  circulation  and  respiration ;  and 
that  the  elevation  of  temperature  varies  materially  in  different  parts  of 
the  body.  The  disengagement  of  caloric,  which  takes  place  until  the 
supervention  of  the  putrefactive  process,  must  manifestly  be  of  a  phy- 
sical character,  and  of  course  in  no  respect  connected  with  respiration. 
Still,  it  may  admit  of  a  question,  whether  it  be  identical  with  that  which 
takes  place  in  the  living  body,  and  constitutes  the  function  now  under 
consideration.  This  much,  however,  the  observations  establish,  that 
physical  changes  in  the  recently  dead  may  give  occasion  to  the  evolu- 
tion of  heat  in  a  manner  strikingly  analogous  to  what  takes  place 
daring  life.^ 

It  was  stated  early  in  this  chapter,  that  man  possesses  the  power  of 
resisting  cold  as  well  as  heat  within  certain  limits,  and  of  preserving 
his  temperature  greatly  unmodified,  A  few  remarks  are  needed  in  re- 
gard to  the  direct  and  indirect  agents  of  these  counteracting  influences. 

'  Lelimann,  Handbucli  der  physiologisclien  Chemie,  S,  295,  Leipzig,  1854. 

2  See,  on  the  whole  subject  of  the  causes  of  the  production  of  heat  in  organized 
beings,  Gavarret,  De  la  Chaleur  produite  par  les  Etres  Vivants,  pp.  141  and  529,  Paris, 
1855T 


THEOKIES   OF   CALOKIFICATION.  623 

As  the  mean  temperature  of  the  warmest  regions  does  not  exceed  85° 
of  Fahrenheit,  it  is  obvious  that  he  must  be  constantly  giving  off  caloric 
to  the  surrounding  medium; — still,  his  temperature  remains  the  same. 
This  is  effected  by  the  mysterious  agency  which  we  have  been  con- 
sidering, materially  aided,  however,  by  several  circumstances,  both 
intrinsic  and  extrinsic.  The  external  envelope  of  the  body  is  a  bad 
conductor  of  caloric,  and  therefore  protects  the  internal  organs,  to  a 
certain  extent,  from  the  sudden  influence  of  excessive  heat  or  cold. 
But  the  cutaneous  system  of  man  is  a  much  less  efficient  protection 
than  that  of  animals.  In  the  warm-blooded,  in  general,  the  bodies  are 
covered  with  hair  or  feathers.  The  whale  is  destitute  of  hair;  but, 
besides  the  protection  which  is  afforded  by  the  extraordinary  thickness 
of  the  skin,  and  the  stratum  of  fat — a  bad  conductor  of  caloric — with 
which  the  skin  is  lined,  as  the  animal  constantly  resides  in  the  water, 
it  is  not  subjected  to  the  same  vicissitudes  of  temperature  as  land  ani- 
mals. Seals,  bears,  and  walruses,  which  seek  their  food  in  the  colder 
seas,  sleep  on  land.  They  have  a  coating  of  hair  to  protect  them.  In 
the  case  of  certain  of  the  birds  of  the  genus  Anas,  of  northern  regions, 
we  meet  with  a  singular  anomaly, — the  whole  of  the  circumference  of 
the  anus  being  devoid  of  feathers ;  but,  to  make  amends  for  this  de- 
ficiency, the  animal  has  the  power  of  secreting  an  oleaginous  substance, 
with  which  the  surface  is  kept  constantly  smeared.  It  may  be  remarked, 
that  we  do  not  find  the  quantity  of  feathers  on  the  bodies  of  birds  to 
be  proportionate  to  the  cold  of  the  climates  in  which  they  reside,  as  is 
pretty  universally  the  case  regarding  the  quantity  of  hair  on  the  mam- 
malia. 

Man  is  compelled  to  have  recourse  to  clothing  for  the  purpose  of 
preventing  the  sudden  abstraction  or  reception  of  heat.  This  he  does 
by  covering  himself  with  substances  that  are  bad  conductors  of  caloric, 
and  retain  an  atmosphere  next  to  the  surface,  which  is  warmed  by  the 
caloric  of  the  body.  He  is  compelled,  also,  in  the  colder  seasons,  to 
have  recourse  to  artificial  temperature ;  and  it  will  be  obvious,  from 
what  has  been  said,  that  the  greater  the  degree  of  activity  of  any 
organ  or  set  of  organs,  the  greater  will  be  the  heat  developed :  and  in 
this  way  muscular  exertion  and  digestion  must  influence  its  produc- 
tion. By  an  attention  to  all  these  points,  and  by  his  acquaintance 
with  the  physical  laws  relative  to  the  developement  and  propagation 
of  caloric,  man  is  enabled  to  live  amongst  the  Arctic  snows,  as  well  as 
in  climates  where  the  temperature  is  frequently,  for  a  length  of  time, 
upwards  of  150°  lower  than  that  of  his  own  body.  The  contrivances 
adopted  in  the  polar  voyages,  under  the  various  discoverers,  are 
monuments  of  ingenuity  directed  to  obviate  one  of  the  greatest 
obstacles  to  prolonged  existence  in  cold  inhospitable  regions,  for 
which  man  is  naturally  incapacitated,  and  for  which  he  attains  the 
capability  solely  by  the  exercise  of  that  superior  intellect  with  which 
he  has  been  vested  by  the  Author  of  his  being.  In  periods  of  intense 
cold,  the  extreme  parts  of  the  body,  unless  carefully  protected,  do  not 
possess  the  necessary  degree  of  vital  action  to  resist  congelation.  Jn 
the  disastrous  expedition  of  Napoleon  to  Russia,  the  loss  of  the  nose 
and  ears  was  a  common  casualty ;  and,  in  Arctic  voyages,  frost-bites 


624  CALORIFICATIOX. 

occur  iu  spite  of  every  care.^  When  the  temperature  of  the  whole 
bocl}^  sinks  to  about  78°  or  79°,  death  takes  place,  preceded  by  the 
symptoms  of  nervous  depression,  which  have  been  previously  detailed. 
The  counteracting  influence  exerted,  Avhen  the  body  is  exposed  to  a 
temperature  greatly  above  the  ordinary  standard  of  the  animal,  is  as 
difficult  of  appreciation  as  that  by  which  calorification  is  effected.  The 
probability  is,  that  in  such  case  the  disengagement  of  heat  is  sus- 
pended; and  that  the  body  receives  it  from  without  by  direct,  but 
not  by  rapid,  communication,  owing  to  its  being  an  imperfect  con- 
ductor of  caloric.  Through  the  agency  of  this  extraneous  heat,  the 
tempei'ature  rises  a  limited  number  of  degrees;  but  its  elevation  is 
generally  considered  to  be  checked  by  the  evaporation  constantly 
taking  place  through  the  cutaneous  and  pulmonary  transpirations. 
For  this  last  idea  we  are  indebted  to  Dr.  Franklin,^  and  its  correctness 
and  truth  have  been  maintained  by  most  observers.  MM.  Berger  and 
Delaroche  put  into  an  oven,  heated  to  from  120°  to  140°,  a  frog,  and 
one  of  those  porous  vessels  called  aharazas — which  permit  the  transu- 
dation of  the  fluid  within  them  through  their  sides — filled  with  water 
at  the  temperature  of  the  animal,  and  two  sponges,  imbibed  with  the 
same  water.  The  temperature  of  the  frog  at  the  expiration  of  two 
hours,  was  99°  ;  and  the  otlier  bodies  continued  at  the  same.  Having 
substituted  a  rabbit  for  the  frog,  the  result  was  identical.  On  the 
other  hand,  having  placed  animals  in  a  warm  atmosphere,  so  saturated 
with  humidity  that  no  evaporation  could  occur,  they  received  the 
caloric  by  communication,  and  their  temperature  rose;  whilst  inert, 
evaporable  bodies,  put  into  a  dry  stove,  became  but  slightly  warmed; 
— much  less  so,  indeed,  than  the  warm-blooded  animals  iu  the  moist 
stove.  Hence,  they  concluded,  that  evaporation  is  a  great  refrigera- 
tive  agent  when  the  bod}^  is  exposed  to  excessive  heat;  and  that  such 
evaporation  is  considerable  is  shown  by  the  loss  in  weight  which  ani- 
mals sustain  by  the  experiment.  It  has  been  contested,  however,  that 
the  cutaneous  evaporation  has  any  effect  in  tempering  the  heat  of  the 
bod3\  MM.  Becquerel  and  Breschet^  found,  when  the  hair  of  rabbits 
had  been  shaved  off,  and  the  skin  covered  with  an  impermeable  coat- 
ing of  strong  glue,  suet,  and  resin,  that  the  animals  died  soon  after- 
wards; and,  they  thought,  hj  a  process  of  asphyxia  in  consequeuce  of 
the  transpiration  from  the  skin  being  prevented.  In  these  experi- 
ments, to  their  surprise,  the  temperature  of  the  animals,  instead  of 
rising,  fell  considerably.  Thus,  the  temperature  of  the  first  rabbit, 
before  it  was  shaved  and  covered  with  the  impermeable  coating,  was 
38°  Centigrade;  but  immediately  after  the  coating  was  dry,  the  tem- 
perature of  the  muscles  of  the  thigh  and  breast  had  fallen  to  24"5° 
Centigrade.  In  another  rabbit,  on  which  the  coating  was  put  on  with 
more  care, — as  soon  as  it  was  dried,  the  temperature  was  found  to 
have  fallen  so  much  that  it  Avas  only  three  degrees  above  that  of  the 
surrounding  atmusphere,  which  was,  on  that  day,  17°  Centigrade.  An 
hour  after  the  animal  died.     These  experiments — and  the}'  have  been 

'  Larrey,  Memoires  de  Chirurgie  Militaire  et  Campasjnes,  torn.  iv.  p.  01,  106.  and 
123,  Paris,  1817. 

^  Works,  iii.  294,  Pliilad.,  1809  ;  or  Sparks's  edit.,  vi.  213,  Boston,  1838. 
3  Coniptes  Rendus,  Oct.,  1S41. 


THEORIES   OF   CALORIFICATION.  625 

repeated  with  like  results  bj  M.  Magendie^ — clearly  exhibit  the  im- 
portance of  the  functions  executed  by  the  skin.  Dr.  Carpenter^  thinks 
they  place  in  a  very  striking  point  of  view  the  importance  of  the  cuta- 
neous surface  as  a  respiratory  organ,  and  enable  us  to  understand  how, 
when  the  aerating  power  of  the  lungs  is  nearly  destroyed  by  disease, 
the  heat  of  the  body  is  kept  up  to  its  natural  standard  by  the  action  of 
the  skin.  "  A  valuable  therapeutical  indication,  also,"  he  adds,  "  is 
derivable  from  the  knowledge  which  we  thus  gain  of  the  importance 
of  the  cutaneous  respiration  ;  for  it  leads  us  to  perceive  the  desirable- 
ness of  keeping  the  skin  moist  in  those  febrile  diseases  in  which  there 
is  great  heat  and  dryness  of  the  surface,  since  aeration  cannot  properly 
take  place  through  a  dry  membrane."  It  has  been  already  shown,^ 
that  local  derangement  of  the  apparatus  engaged  in  the  important 
functions  of  nutrition,  calorification  and  secretion,  is  the  cause  of  many 
affections  which  have  been  ascribed  to  a  fancied  check  to  perspiration 
in  the  part. 

M.  Edwards,  in  his  experiments  on  the  influence  of  physical  agents 
on  life,  observed,  that  warm-blooded  animals  have  less  power  of  pro- 
ducing heat,  after  they  have  been  exposed  for  some  time  to  an  elevated 
temperature,  as  in  summer;  whilst  the  opposite  eft'ect  occurs  in  winter. 
He  instituted  a  series  of  experiments,  which  consisted  in  exposing 
birds  to  the  influence  of  a  freezing  mixture,  first  in  February,  and 
afterwards  in  July  and  August;  observing  in  what  degree  they  were 
cooled  by  remaining  in  this  situation  for  equal  lengths  of  time ;  the 
result  was,  that  the  same  kind  of  animal  was  cooled  six  or  eight 
times  as  much  in  the  summer  as  in  the  winter  months.  This  prin- 
ciple he  presumes  to  be  of  great  importance  in  maintaining  the  regu- 
larity of  the  temperature  at  different  seasons;  even  more  so  than  eva- 
poration, the  efiect  of  which,  in  this  respect,  he  thinks,  has  been  greatly 
exaggerated.  From  several  experiments  on  yellow  hammers,  made  at 
different  periods  in  the  course  of  the  year,  it  would  result,  that  the 
averages  of  their  temperature  ranged  progressively  upwards  from  the 
depth  of  winter  to  the  height  of  summer,  within  the  limits  of  five  or 
six  degrees  of  Fahrenheit;  and  the  contrary  was  observed  in  the  fall 
of  the  year.  Hence,  M.  Edwards  infers,  and  with  probability,  that  the 
temperature  of  man  experiences  a  similar  fluctuation." 

When  exposed  to  high  atmospheric  temperature,  the  ingenuity  of 
man  has  to  be  as  much  exerted  as  under  opposite  circumstances.  The 
clothing  must  be  duly  regulated  according  to  physical  principles,*  and 
perfect  quietude  be  observed,  so  that  undue  activity  of  any  of  the 
organs,  that  materially  influence  the  disengagement  of  animal  heat, 
may  be  prevented.  It  is  only  within  limits,  that  this  refrigerating 
action  is  sufficient.  At  a  certain  degree,  the  transpiration  is  inade- 
quate; the  temperature  of  the  animal  rises,  and  death  supervenes. 

'  Gazette  Medicale  de  Paris,  6  Dec,  1843. 

*  Principles  of  Human  Physiology,  Amer.  edit.,  p.  414,  Philad.,  1855. 
3  Page  520. 

*  De  rintluence  dos  Agens  Physiques,  p.  489  ;  and  Hodgkin's  and  Fisher's  transla- 
tion, Loud.,  1832. 

*  See  the  chapter  on  Clothing  in  the  author's  Human  Health,  p.  340,  Philadelphia. 
1844. 

VOL.  I. — 10 


.626  SENSIBILITY. 


BOOK   II. 
ANIMAL  FUNCTIONS. 

The  animal  functions  or  functions  of  relation  comprise  sensibility, 
and  muscular  motion,  including  expression  or  language.  Those  that 
are  executed  with  consciousness  are  subject  to  intermission,  constitut- 
ing sleep  ;  a  condition  which  has,  consequently,  by  many  physiologists, 
been  investigated  under  this  class  ;  but  as  the  functions  of  reproduction 
are  influenced  by  the  same  condition,  the  consideration  of  sleep  will  be 
deferred  until  the  third  class  of  functions  has  received  attention. 

The  animal  functions — as  tlie  name  imports — are  characteristic  of 
the  animal;  and  must,  consequently,  be  accomplished  by  parts  that 
appertain  to  it  alone.  They  are  all — in  other  words — attributes  of  a 
nervous  system, — nothing  identical  with  innervation  existing  in  the 
vegetable. 

CHAPTER  I. 

SENSIBILITY. 

Sensibility,  in  its  general  acceptation,  means  the  property  possessed 
by  living  parts  of  receiving  impressions,  whether  the  being  exercising 
it  has  consciousness  or  not.  To  the  first  of  the  cases — in  which  there 
is  consciousness — Bichat  gave  the  epithet  anirnal;  to  the  second,  organic; 
the  latter  being  common  to  animals  and  vegetables,  and  presiding  over 
i\\e  organic  functions  of  nutrition,  absorption,  exhalation,  secretion,  &c.; 
the  former  existing  only  in  animals,  and  presiding  over  the  sensations, 
internal  as  well  as  external,  and  the  intellectual  and  moral  manifes- 
tations. 

Pursuing  the  plan  already  laid  down,  the  study  of  this  interesting 
and  elevated  function  will  be  commenced,  by  pointing  out,  as  far  as 
may  be  necessary,  the  apparatus  that  effects  it,  the  nervous  system. 

1.   NERVOUS  SYSTEM. 

Under  the  name  nervous  system^  anatomists  include  all  those  organs 
that  are  composed  of  nervous  or  pulpy  tissue — neurine.  In  man,  it  is 
constituted  of  three  portions:  first^  of  what  has  been  called  the  cerebro- 
spinal ox  cranio ■sjmial  axis,  a  central  part  having  the  form  of  a  long  cord, 
expanded  at  its  superior  extremity,  and  contained  within  the  cavities 
of  the  cranium  and  spine;  secondly,  of  cords,  called  nerves,  in  number 
thirty-nine  pairs,  according  to  some, — forty-two,  according  to  others, — 
passing  laterally  between  the  cerebro-spinal  axis  and  every  part  of  the 
body;  and,  lastly,  of  a  nervous  cord,  situate  on  each  side  of  the  spine, 
from  the  head  to  the  pelvis,  forming  ganglia  opposite  each  vertebral 
foramen,  and  called  the  great  sympathetic. 


EXCEPHALON. 


627 


Fig.  184. 


itll'^' 


1.  Encephalon. — Under  this  term  are  included  the  contents  of  the 
cranium, — namely,  the  cerehrum  or  hrain  proper,  the  cerehellum  or  little 
hrain,  and  the  medulla  oblongata.  These  parts  col- 
lectively have  been  by  some  called  brain. 

When  we  look  at  a  section  of  the  encephalon, 
in  its  natural  position,  we  find  many  distinct  parts, 
and  the  appearances  of  numerous  and  separate 
organs.  So  various,  indeed,  are  the  prominences 
and  depressions  observable  on  the  dissection  of  the 
brain,  that  it  is  generally  esteemed  one  of  the 
most  difficult  subjects  of  anatomy;  yet,  owing  to 
the  attention  paid  to  it  in  all  ages,  it  is  now  one  of 
the  structures  best  understood  by  the  anatomist. 
This  complicated  organ  presents  a  striking  illus- 
tration of  the  truth,  that  the  most  accurate  ana- 
tomical knowledge  does  not  necessarily  teach  the 
function.  The  elevated  actions,  which  the  ence- 
phalon has  to  execute,  have,  indeed,  attracted  a 
large  share  of  the  attention  of  the  physiologist, — 
too  often,  however,  without  any  satisfactory  re- 
sult; yet  it  may,  we  think,  be  safely  asserted,  that 
we  have  become  better  instructed  regarding  the 
uses  of  particular  parts  of  the  brain,  within  the 
last  few  years,  than  during  the  whole  of  the  cen- 
tury preceding. 

The  encephalon  being  of  extremely  delicate 
organization,  and  its  functions  easily  deranged,  it 
was  necessary  that  it  should  be  securely  lodged 
and  protected  from  injuries.  Accordingly,  it  is 
placed  in  a  round,  bony  case ;  and  by  an  admira- 
ble mechanism  is  defended  against  damage  from 
surrounding  bodies.  Amongst  these  guardian 
agents  or  iutamina  cerebri  must  be  reckoned ; — 
the  hair  of  the  head ;  the  skin ;  muscles ;  pericra- 
nium; bones  of  the  skull;  the  diploe  separating 
the  two  tables  of  which  the  bones  are  composed, 
and  the  dura  mater. 

It  is  not  an  easy  matter  to  assign  probable  uses 
for  the  hair  on  various  parts  of  the  body.  On  the 
head,  its  function  seems  more  readily  appropria- 
ble. It  deadens  the  concussion,  which  the  brain 
would  experience  from  the  infliction  of  heavy 
blows,  and  prevents  the  skin  of  the  scalp  from 
being  injured  by  the  attrition  of  bodies.  In  mili- 
tary service,  the  former  of  these  uses  has  been 
taken  advantage  of;  and  an  arrangement,  some- 
what similar  to  that  which  exists  naturally  on  the 
head,  has  been  adopted  with  regard  to  the  helmet. 
The  metallic  substance,  of  which  the  ancient  and 
modern  helmets  are  formed,  is  readily  thrown  into  vibration;  and  this 
vibration  being  communicated  to  the  brain  might,  after  heavy  blows, 


Anterior  view  of  the  Cere- 
bro-Sioinal  Axis. 

1,  1.  Hemispheres  of  the 
cerebrum.  2.  Great  middle 
Assure.  3.  Cerebrum.  4.  Ol- 
factory nerves.  5.  Optic 
nerves.  6.  Corpora  albican- 
tia.  7.  Motor  oculi  nerves. 
S.  Pons  Varolii.  9.  Fourth 
pair  of  nerves.  10.  Lower 
portion  of  medulla  oblongata. 
11,11.  Medulla  spinali.s.  12, 
12.  Spinal  nerves.  13.  Cauda 
equina. 


628  SENSIBILITY. 

derange  its  functions  more  even  than  a  wound  inflicted  by  a  shafp 
instrument.  To  obviate  this,  in  some  measure,  the  helmet  has  been 
covered  with  horse-hair;  an  arrangement  which  existed  in  the  helmet 
worn  by  the  Roman  soldier.  There  can  be  no  doubt,  moreover,  that 
being  bad  conductors  of  caloric,  and  forming  a  kind  of  felt  which  inter- 
cepts the  air,  the  hairs  may  tend  to  preserve  the  head  of  a  more  uni- 
form temperature.  They  are  likewise  covered  with  an  oily  matter, 
which  prevents  them  from  imbibing  moisture,  and  causes  them  to  dry 
speedily.  Another  use  ascribed  to  them  by  M.  Magendie,'  is  more 
hypothetical; — that,  being  bad  conductors  of  electricity,  they  may  put 
the  head  in  a  state  of  insulation,  so  that  the  brain  may  be  less  affected 
by  the  electric  fluid. 

It  is  unnecessary  to  explain  in  detail  the  different  layers  of  which 
the  scalp  is  composed.  The  areolar  membrane  beneath ;  the  pan- 
niculus  carnosus  or  occipito-frontalis  muscle ;  and  the  pericranium 
covering  the  bone,  act  the  parts  of  tutamina.  The  most  important  of 
these  protectors  is  the  bony  case  itself.  In  an  essay  written  by  a  dis- 
tinguished physiologist,^  we  have  some  beautiful  illustrations  of  the 
wisdom  of  (iod  as  displayed  in  the  mechanism  of  man,  and  of  his  skull 
in  particular ;  and  although  some  of  his  remarks  may  be  liable  to  the 
censures  that  have  been  passed  upon  them  by  Dr.  Arnott,^  most  of  them 
are  admirably  adapted  to  the  contemplated  object.  It  is  impossible, 
indeed,  for  the  uninitiated  to  rise  from  the  perusal  of  his  interesting 
essay,  without  being  ready  to  exclaim  with  the  poet,  "  How  wonderful, 
how  complicate  is  man !  how  passing  wonder  He  that  made  him  such !" 
Sir  Charles  Bell  attempts  to  prove,  that  the  best  illustration  of  the  form 
of  the  head  is  the  dome ;  whilst  Dr.  Arnott  considers  it  to  be  "  the 
arch  of  a  cask  or  barrel,  egg-shell,  or  cocoa-nut,  &e.,  in  which  the  tena- 
city of  the  material  is  many  times  greater  than  necessary  to  resist  the 
influence  of  gravity,  and  comes  in  aid,  therefore,  of  the  curve  to  resist 
forces  of  other  kinds  approaching  in  all  directions,  as  in  falls,  blows, 
unequal  pressures,"  &c.  The  remarks  of  Dr.  Arnott  on  this  subject 
are  just :  and  it  is  owing  to  this  form  of  the  cranium,  that  any  blow 
received  upon  one  part  of  the  skull  is  rapidly  distributed  to  every 
other ;  and  that  a  heavy  blow,  inflicted  on  the  forehead  or  vertex,  may 
cause  a  fracture,  not  in  the  parts  struck  but  in  the  occipital  or  splie- 
noidal  bone. 

The  skull  does  not  consist  of  one  bone,  but  of  many.  These  are 
joined  together  by  sutures, — so  called  from  the  bones  seeming  as  if 
they  were  stitched  together.  Each  bone  consists  likewise  of  two  tables; 
an  external,  fibrous,  and  tough ;  and  an  internal,  of  a  harder  character 
and  more  brittle,  hence  called  tabula  vitrea.  The  two  are  separated 
from  each  other  by  a  cellular  or  cancellated  structure,  called  diphe. 
On  examining  the  mode  in  which  the  tables  form  a  function  with  each 
other  at  the  sutures,  we  find  additional  evidences  of  design  exhibited. 
The  edges  of  the  outer  table  are  serrated,  and  so  arranged  as  to  be 

'  Precis  Elementaire,  edit,  cit.,  i.  177. 

*  Sir  Charles  Bell,  in  Animal  Mechanics — Library  of  Useful  Knowledge,  London, 
1829. 

*  Elements  of  Physics  or  Natural  Philosophy.  General  and  Medical,  London,  1827 — 
reprinted  in  this  country,  Philad.,  1841. 


ENCEPHALON.  629 

accurately  dovetailed  into  eacli  other;  the  tough  fibrous  texture  of  the 
external  plate  being  well  adapted  for  such  a  junction.  On  the  other 
hand,  the  tabula  vitrea,  which,  on  account  of  its  greater  hardness, 
would  be  liable  to  fracture  and  chip  off,  is  merely  united  with  its  fellow 
at  the  suture  by  what  is  called  harmony ;  the  tables  are  merely  placed 
in  contact. 

The  precise  object  of  the  sutures  is  not  apparent.  In  the  mode  in 
which  ossification  takes  place  in  the  bones  of  the  skull,  the  radii  from 
different  ossific  points  must  necessarily  meet  by  the  "  law  of  conjuga- 
tion," in  the  progress  of  ossification.  This  has,  by  many,  been 
esteemed  the  cause  of  the  sutures;  but  the  explanation  is  insufiicient. 
Howsoever  it  may  be,  the  kind  of  junction  affords  a  beautiful  example 
of  adaptation.  During  the  foetal  state,  the  sutures  do  not  exist.  They 
are  fully  formed  in  youth;  are  distinct  in  the  adult  age;  but  in  after 
periods  of  life  become  entirely  obliterated,  the  bone  then  forming  a 
solid  spheroid.  It  does  not  seem  that  after  the  sutures  are  established, 
any  displacement  of  the  bones  can  take  place;  and  observation  has 
shown,  that  they  do  not  possess  much,  if  any,  effect  in  putting  a  limit 
to  fractures.  In  all  cases  of  severe  blows,  the  skull  appears  to  resist 
as  if  it  were  constituted  of  one  piece.  But  the  separation  of  the  skull 
into  distinct  bones,  which  have  a  membranous  union,  is  of  striking 
advantage  to  the  foetus  in  parturition.  It  enables  the  bones  to  overlap 
each  other;  and,  in  this  way,  to  occupy  a  much  smaller  space  than  if 
ossification  had  united  them  as  in  after  life.  It  has  been  imagined  by 
some,  that  there  is  an  advantage  in  the  pressure  made  on  the  brain 
by  the  investing  bones, — that  the  foetus  does  not  suffer  from  the  violent 
efforts  made  to  extrude  it;  but,  during  the  passage  through  the  pelvis, 
is  in  a  state  of  fortunate  insensibility.  Pressure  suddenly  exerted 
upon  the  brain  is  certainly  attended  with  these  effects, — a  fact,  which 
has  to  be  borne  in  mind  in  the  management  of  apoplexy,  fracture  of 
the  skull,  &c. 

The  uses  of  the  dii^he,  which  separates  the  two  tables  of  the  skull, 
are  not  equivocal.  Composed  of  a  cancellated  structure,  it  is  well 
adapted  to  deaden  the  force  of  blows;  and  as  it  forms,  at  the  same 
time,  a  bond  of  union  and  of  separation,  a  fracture  might  be  inflicted 
upon  the  outer  table  of  the  skull,  and  yet  be  prevented  from  extend- 
ing to  the  tabula  vitrea.  Such  cases  have  occurred,  but  they  are  rare. 
It  will  generally  happen,  that  a  blow,  intended  to  cause  serious  bodily 
injury,  will  be  sufficient  to  break  through  both  tables,  or  neither. 

Lastly,  the  dura  mater,  which  has  been  reckoned  as  one  of  the  tuta- 
mina  cerebri,  lines  the  skull,  and  constitutes  a  kind  of  internal  perios- 
teum to  it.  It  may  also  be  inservient  to  useful  purposes,  by  deadening 
the  vibrations,  into  which  the  head  may  be  thrown  by  sudden  concus- 
sions; as  the  vibrations  of  a  bell  are  arrested  by  lining  it  with  a  soft 
material.  It  is  chiefly,  however,  to  protect  the  brain  against  itself, 
that  we  have  the  arrangement  which  prevails.  The  cerebrum,  as  well 
as  the  cerebellum,  consists  of  two  hemispheres;  and  its  posterior  part 
is  situate  immediately  above  the  cerebellum.  It  is  obvious,  then,  that 
without  some  protection,  the  hemisphere  of  one  side  would  press  upon 
its  I'ellow,  when  the  head  is  inclined  to  the  opposite  side ;  and  that  the 


630 


SENSIBILITY. 


Fig.  185. 


posterior  lobes  of  the  brain  would  weigh  upon  the  cerebellum  in  the 
erect  attitude. 

The  hemis'plieres  are  separated  from  each  other  by  the  falx  cerelri^ 
in  the  upper  margin  of  which  is  the  superior  lonrjitudinal  ^inus.  The 
falx  passes  between  the  hemispheres.  The  tentorium  cerehello  superex- 
tensum — a  prolongation  of  the  dura  mater — passes  horizontally  for- 
wards so  as  to  support  the  posterior  lobes  of  the  brain,  and  prevent 

them  from  pressing  injuriously  on 
the  cerebellum.  A  process  of  the 
dura  mater  passes  also  between  the 
hemispheres  of  the  cerebellum.  In- 
dependently of  the  protection  af- 
forded to  the  encephalon,  the  dura 
mater  lodges  the  great  sinuses  into 
which  the  veins  discharge  their 
blood.  These  different  sinuses 
empty  themselves  into  the  torcular 
Heroph.iU  or  confluence  of  the  sinuses ; 
and  ultimately  proceed  to  consti- 
tute the  lateral  sinuses^  which  pass 
through  the  temporal  bone,  and 
form  the  internal  jugular  veins. 

The  tutamina  are  not  confined  to 
the  contents  of  the  cranium.  The 
spine  appears  to  be,  if  possible,  still 
better  protected.  In  the  skull,  we 
see  a  firm,  bony  case ;  in  the  spine, 
a  structure  admitting  considerable 
motion  of  the  parts,  without  risk  of 
pressure  to  the  marrow.     Accord- 


Falx  Cerebri  and  Sinuses  of  upper  and  back 
part  of  Skull. 

1,  2,  3.  Section  of  the  bones   of  the   cranium, 
showing  the  attachment  of  the  falx  major.     4. 

Anterior  portion  of  superior  longitudinal  sinus.      •        ■<  ■,  •  •  n 

5.  Middle  portion.     6.  Inferior  portion;  the  outer     lUglv,  the    SpiUC    COUsistS  of    numcr- 
table   of    the   cranium   removed.     7.  Commence-  T    x-       ^  i  ^    i  -xi 

ment  of  the  inferior  longitudinal  sinus.  8.  Its  OUS  CllStmCt  DOUeS  Or  VerteOraS,  Wltll 
termination  in  the  straight  sinus.  9.  Sinus 
qiiartus  or  rectus.  10.  Vena  Galeni.  11.  One 
of  the  lateral  sinuses.  12.  Torcular  Herophili. 
13.  Sinus  of  the  falx  cerehelli.  14.  Internal  ju- 
gular vein.  1.5.  Dura  mater  of  the  spinal  mar- 
row. 16.  Tentorium  cerebelU.  17,  17.  Falx  ce- 
rebri. 


fibro-cartilaginous — technically  call- 
ed intervertebral — substances  placed 
between  each,  so  that,  although  the 
extent  of  motion  between  any  two 
•  of  these  bones  may  be  small,  when 

all  are  concerned,  it  is  considerable.  The  great  use  of  this  interver- 
tebral substance  is  to  prevent  the  jar,  that  would  necessarily  be  com- 
municated to  the  delicate  parts  within  the  cavities  of  the  spine  and 
cranium,  were  the  spine  composed  entirely  of  one  bone.  In  fldls  from 
a  height  upon  the  feet  or  breech,  these  elastic  cushions  are  forcibly 
compressed;  but  they  immediately  return  to  their  former  condition, 
and  deaden  the  force  of  the  shock.  In  this  they  are  aided  by  the 
curvatures  of  the  spine,  which  give  it  the  shape  of  the  Italic  /,  and 
enable  it  to  resist — in  the  same  manner  as  a  steel  spring — any  force 
acting  upon  it  in  a  longitudinal  direction.  So  well  is  the  medulla 
spinalis  protected  by  the  strong  bony  processes  jutting  out  in  various 
directions  from  the  spine,  that  it  is  extremely  rare  to  meet  with  lesions 
of  the  marrow;  and  it  is  comparatively  in  recent  periods  that  any  ex 
profcsso  treatises  have  appeared  on  the  subject. 


ENCEPHALON". 


631 


Besides  the  protection  afforded  by  the  bony  strnctiire  to  the  delicate 
medulla,  M.  Magendie  has  pointed  out  another,  which  he  was  the  fii'st 
to  detect.  The  canal,  formed  by  the  dura  mater  around  the  spinal 
cord,  is  much  larger  than  is  necessary  to  contain  that  organ ;  but, 
during  life,  the  whole  of  the  intermediate  space  is  filled  with  a  serous 
fluid,  which  strongly  distends  the  membrane,  so  that  it  will  frequently 
spirt  out  to  a  distance  of  several  inches,  when  a  puncture  is  made  in 
the  membrane.  To  this  fluid  he  has  given  the  epithet  cephalo-sjjinal ; 
and   he   conceives,   that   it 

may  act  as  one  of  the  tuta-  Fig-  186. 

mina  of  the  marrow — which 
is,  as  it  were,  suspended  in 
the  fluid — and  exert  upon 
it  the  pressure  necessary  for 
the  healthy  performance  of 
its  functions. 

Beneath  the  dura  mater 
•is  a  very  delicate  mem- 
brane, the  aracJmoid,  be- 
longing to  the  class  of  se- 
rous membranes.  It  sur- 
rounds the  encephalon  in 
every  part ;  but  is  best  seen 
at  the  base  of  the  brain. 
Its  chief  use  is  to  secrete  a 


Longitudinal  Section  of  the  Brain  on  the  Mesial  Line. 
1.  Inuer  surface  of  the  left  hemisphere.     2.  Divided  sur- 
face of  the  cerebellum,  showing  the  arbor  vitie.     3.  Medulla 
oblongata.     4.  Corpus  callosum,  continuous  with  5,  the  for- 
nix.    6.  One  of  the  crura  of  the  fornix  descending  to  7,  one 
tliin     fliiirl      tn    Inl-iricotfi    tliA     of  the   corpora   albicautia.     8.  Septum   lucidum.     9.  Velum 
lUlU     iiuiu,     LU    lUUllOctLt;    LUC     iuterpusitum,  communicating  with  the  pia  mater  of  the  con- 
brain         This  membrane  en-      volutlons  through  the  fissure  of  Blchat.     10.  Section  of  the 
.  .    .  „    middle  commissure  in  the  third  ventricle.     11.  Section  of  the 

terS  into  all  the  cavities  Ot  anterior  commissure.  12.  Section  of  the  po.sterior  commis- 
sure; the  commissure  is  somewhat  above  and  to  the  left  of 
the  number.  The  interspace  between  10  and  11  is  the  fora- 
men commune  anterius,  in  which  the  crus  of  the  fornix  (6) 
is  situate.  The  interspace  between  10  and  12  is  the  foramen 
commune  posterius.  13.  Corpora  quadrigemina,  upon  which 
is  tlie  pineal  gland,  14.  l.i.  Iter  a  tertio  ad  quartum  veutri- 
culum.  16.  Fourth  ventricle.  17.  Pons  Varolii,  through 
which  are  passing  the  diverging  fibres  of  the  corpora  pyi'a- 
midalia.  IS.  Crus  cerebri  of  the  left  side,  with  the  third 
nerve  arising  from  it.  19.  Tuber  cinereum,  from  which  pi-o- 
jects  the  infundibulum  having  the  pituitary  gland  appended 


the  organ,  and  in  them  ful- 
fils a  like  function.  When 
the  fluid  accumulates  to  a 
great  extent,  the  resulting 
disease  is  hydrocephalus 
chronicus.  Henle  has  shown 
that  it  is  not  a  serous  sac, 
like  the  pleura  or  pericar- 
dium. Its  inner  surface, 
according  to  Kcilliker,^  with 
its  epithelium,  is  every- 
where in  close  contact  with 
the  dura  mater,  so  that  a 
cavunn  arachnoidece  does  not 
exist. 

Anatomists  usually  de- 
scribe a  third  tunic  of  the 
brain — the  pia  mater.  This 
is  generally  conceived  to 
consist  of  the  minute  termi- 


te Its  extremity, 
factory  nerve. 


20.  One  of  the  optic  nerves.     21.  Left  ol- 


Fig.  187. 


Convolutions  of  one  Side  of  the  Cerebrum  as  seen 

from  above. 

1.  Anterior  lobe  of  the  cerebrum.     2.  Posterior  lobe. 

3.  Middle  lobe. 


'  Mikroskopisclie  Anatomie,  Bd.  ii.  S.  491,  Leipz.,  1850;  and  Amer.  edit,  of  Syden- 
ham Society's  edition  of  his  Human  Histolotry,  by  Dr.  Da  Costa,  p.  395,  Philad.,  18.54. 
See,  also,  .Jones  and  Sieveking,  Manual  of  Patlioiogical  Anatomy,  x\mer.  edit.,  p.  231, 
Philad.,  1854. 


632 


SENSIBILITY. 


Fig.  188. 


nations  of  the  cerebral  arteries,  and  those  of  the  corresponding  veins; 
forming  at  the  surface  of  the  brain  a  vascular  network,  which  passes 
into  the  cavities ;  and,  in  the  ventricles,  forms  the  plextis  choroides  and 
tela  choroidea.  The  dura  and  pia  mater  were  so  called  by  the  older 
anatomists,  because  they  were  conceived  to  be  the  origin  of  all  the 
other  membranes  of  the  body. 

The  cerebrum  or  hrain  proper  has  the  form  of  an  oval,  larger  behind. 
On  its  outer  surface  are  varions  undulating  eminences,  called  convolu- 
tions^ because  they  have  been  thought  to  resemble  the  folds  of  the  in- 
testines. They  are  separated  from  each  other  by  depressions  called 
anfractuosities.  They  form  the  hemispherical  ganglion  of  Mr.  Solly. 
In  the  brain  of  man,  these  convolutions  are  larger  than  in  animals; 
and  the  anfractuosities  deeper.  In  different  brains,  the  number,  size, 
and  arrangement  of  these  vary.     They  are  not  the  same,  indeed,  in 

the  same  individual;  those  of  the  right 
hemisphere  being  disposed  differently 
from  those  of  the  left. 

The  hemispheres,  it  has  been  seen, 
are  separated  above  by  the  falx  cerebri : 
beloiv,  they  are  united  by  a  white  medul- 
lary commissure,  coipus  callosiim,  meso- 
lobe  or  great  commissure^ — great  trans- 
verse commissure  of  Mr.  Solly.  If  we 
examine  the  brain  at  its  base,  we  find 
that  each  hemisphere  is  divided  into 
three  lobes, — an  anterior^  which  rests 
on  the  vault  or  roof  of  the  orbit, — a 
middle  or  temporal,  filling  the  middle 
and  lateral  parts  of  the  base  of  the  cra- 
nium, and  separated  from  the  former 
by  a  considerable  depression,  called  yi5- 
sure  of  Sylvius, — and  a,  posterior,  which 
rests  on  the  tentorium  cerebelli.  This 
part  of  the  cerebrum  is  divided  into 

Furnix,  &c.,  as  given  by  a  Transverse    ^WO  VCrV  distiuct    portioUS    by  the   mC- 
Section  of  the  Cerebrum.  in        i 'i  .  a      i      •        ^      -^  ii 

dulla  oblongata.   Anterior  to  it  are  the 

1.  Section  of  the  os  frontis.  2.  Section  of 
the  OS  occipitis.  3.  Section  of  the  ussa  pa- 
rietalia.  4,  5.  Anterior  and  posterior  extre- 
mities of  the  middle  fissure  of  the  cerebrum. 

6.  Anterior  extremity  of  the  corpus  callosum. 

7.  Its  posterior  extremity  joining  the  fornix. 
S,  8.  Point  to  where  the  corpus  callosum  joins 
the  lateral  medullary  matter  of  the  cerebrum. 
!).  Its  place  of  junction  anteriorly.     10.  Pos- 


Superior  Part  of  the  Lateral  Ventricles, 
Corpora     Striata,    Septum     Lucidum, 


crura  cerebri  or  cerebral  peduncles — by 
most  anatomists  considered  to  be  a 
continuation  of  the  anterior  fasciculi 
which  form  the  spinal  marrow  and 
medulla  oblongata,  and  proceeding  to 
terior  "point  of  union    11.  Middle  portion  of  f^^J.^   ^^q   hemispheres   of  the   bralu. 

the  corpora  striata  (lateral  ventricle).   I'J^rse-  1        _  .    .  „ 

Between  the  anterior  extremities  of 
the  peduncles  are  two  hemispherical 
projections,  called  eminentice  mamrnil- 
lares,  which  are  possessed  by  man  ex- 
clusively ;  have  the  shape  of  a  pea ;  and  are  formed  of  white  nervous 
tissue  externally,  of  gray  within.  Anterior  to  these  again  is  the  m- 
fundibulum;  and  a  little  farther  forwards,  the  chiasma  of  the  optic 
nerves  or  the  part  at  which  these  nerves  come  in  contact. 

Laterally,  and  at  the  inferior  surface  of  the  anterior  lobes,  is  a  groove 


nia  striata.  1.3.  Septum  lucidum.  14.  Fifth 
veatricle.  1.5.  Fornix.  16.  Posterior  crura.  17. 
Plexus  choroides.  IS.  Ergot  or  hippocampus 
minor.  19.  Posterior  crura  of  the  lateral 
ventricle. 


[ 


ENCEPHALON". 


633 


or  furrow,  running  from  behind  to  before,  and  from  without  to  within, 
in  which  the  olfactory  nerve  is  lodged.  At  the  extremity  of  this  furrow 
is  a  tubercle,  which  is  trifling  in  man,  but  in  certain  animals  is  equal 
to  the  rest  of  the  brain  in  bulk.  From  this  the  olfactory  nerve  has 
been  conceived  to  arise.     It  is  called  the  olfactory  tiihercle  or  hie. 

When  we  examine  the  interior  of  the  brain,  we  find  a  number  of 
parts  to  which  the  anatomist  assigns  distinct  names.  Of  these  the  fol- 
lowing chiefly  concern  the  physiologist.  It  has  been  already  remarked, 
that  the  corpus  callosum  forms 

at  once  the  bond  of  union  and  Fig-  1S9. 

of  separation  between  the  two 
hemispheres.  It  is  distinctly 
perceived,  in  the  form  of  a  long 
and  broad  white  band,  on  sepa- 
rating these  parts  from  each 
other.  Beneath  the  corpus  cal- 
losum is  the  septum  Ivcidum  or 
median  septum,  which  passes 
perpendicularly  downwards, 
and  separates  from  each  other 
the  two  largest  cavities  of  the 
brain, — the  lateral  ventricles.  It 
is  formed  of  two  laminjB,  which 
leave  a  cavity  between  them, 
called  the  fifth  ventricle.  The 
fornix  or  inferior  longitudinal 
commissure  of  Mr.  Solly,  whose 
office  is  to  connect  the  anterior 
and  j)osterior  parts  of  the  same 
hemisphere,  as  the  transverse 
commissures  do  those  of  the 
opposite  hemisphere,  is  placed 
horizontally  below  the  last. 
The  band  of  fibres  which  runs 
in  each  hemisphere  above  the 
corpus  callosum,  on  the  edge  of 
the  longitudinal  fissure,  is  the 
swperior  longitudinal  commissure 
of  Mr.  Solly.  Its  use  is  sup- 
posed to  resemble  that  ascribed 
to  the  inferior  longitudinal  com- 
missure. The  fornix  is  of  a 
triangular  shape ;  and  consti- 
tutes the  upper  paries  of  another  cavity — the  third  ventricle.  Beneath 
the  fornix,  and  behind,  are  i\\Q  pineal  gland  and  its  peduncles,  forming 
the  pineal  commisstire  of  Mr.  Solly,  respecting  which  so  much  has  been 
said,  by  Descartes,'  and  others,  as  the  seat  of  the  soul.  Within  it  is  a 
small  cavity;  and,  after  six  or  seven  years  of  age,  it  always  contains 
some  concretions.   Again,  anterior  to  the  pineal  gland,  and  immediately 

'  Tractatus  de  Homine,  p.  5. 


Section  of  the  Cerebrum,  displaying  the  surfaces 
of  the  Corpora  Striata,  and  Optic  Thalami,  the 
cavity  of  the  Third  Ventricle,  and  the  upper  sur- 
face of  the  Cerebellum, 

a,  e.  Corpora  quadrigemina, — a,  testes;  e,  nates,  h. 
Soft  commissure,  c.  Corpus  callosum.  /.  Anterior  pil- 
lar.s  of  fornix,  g.  Anterior  cornu  of  lateral  ventricle, 
fc,  k.  Corpora  striata.  I,  I.  Optic  thalami.  *.  Anterior 
tubercle  of  the  left  thalamus.  2  to  *.  Third  ventricle. 
In  front  of  z,  anterior  commissure,  h.  Soft  commissure. 
s.  Posterior  commissure,  p.  Pineal  gland  with  its  pe- 
duncles, n,  n.  Processus  a  cerebello  ad  testes,  m,  in. 
Hemispheres  of  the  cerebellum,  h.  Superior  vermiform 
process,    i.  Notch  behind  the  cerebellum. 


634 


SENSIBILITY. 


Fig.  190. 


An  nnder  View  of  the  Cerebellum,  seen  from  behind, 
the  Medulla  Oblongata,  m,  having  been  cut  off  a 
short  way  below  the  Pons. 

c.  Pons  Varolii,  d.  Middle  crus  of  cerebellum,  e,  e. 
Crura  cerebri.  i.  Notch  on  posterior  border.  k.  Cora- 
nienceraent  of  horizontal  fissure.  I.  Flocculus,  or  sub- 
peduncular  lobe.  ni.  Medulla  oblongata  cut  through,  q  to 
8.  The  inferior  vermiform  process,  lying  in  the  vallecula. 
X>.  Pyramid,  r.  Uvula,  n,  n.  Amygdalie.  s.  Nodule,  or 
laminated  tubercle,  x.  Posterior  velum,  partly  seen.  ?«. 
Eight  and  left  hemispheres  of  cerebellum.  3  to  7.  Nerves. 
3,  .3.  Motores  oculorum.  ,5.  Trigeminal.  6.  Abducent  nerve. 
7.  Facial  and  auditory  nerves. 

Fig.  191. 


Posterior  Superior  View  of   the  Pons  Varolii,  Cere- 
bellum, and  Medulla  Oblongata  and  M.  Spinalis. 

1,  1.  Crura  cerebri.  2.  Pons  Varolii  or  tuber  annulare. 
3.  Its  middle  fossa.  4.  Oblique  band  of  medullary  matter 
seen  passing  from  its  side.  5.  External  surface  of  the  crus 
cerebelli.  6.  Same  portion  deprived  of  outer  layer.  7. 
Nervous  matter  which  unites  it  to  \.  S.  Trigeminus  or  fifth 
pair  of  nerves.  9.  Portion  of  the  auditory  nerve.  The 
white  neurine  seen  passing  from  the  oblique  band  which 
comes  from  the  corpus  restiforme  to  the  trigeminus  nerve 
in  front,  and  the  auditory  nerve  behind.  10,  11.  Superior 
portion  of  the  hemispheres  of  the  cereliellum.  12.  Lobulus 
amygdaloides.  13.  Corpus  olivare.  14.  Corpus  pyramidale. 
15.  Medulla  spinalis. 

pass  downwards  to  the  motor  tract  of  the 
the  commissural  fibres,  which  establish 
rious  parts  of  the  periphery,  and  of  the 


below  the  fornix,  is  another 
cavity — the  third  ventncle.  Its 
bottom  is  very  near  the  base 
of  the  brain,  and  is  fornisd 
by  the  nervous  layer  which 
unites  the  peduncles  of  the 
brain  with  the  eminentiae 
mammillares.  At  the  sides, 
it  has  the  thalami  nervorum 
opticorum. 

In  the  lateral  ventricles, 
situate  on  each  side  of  the 
corpus  callosum,  some  j^arts 
exist  which  demand  atten- 
tion. In  the  upper  or  ante- 
rior half,  commonly  called 
anterior  cornu,  and  in  the  an- 
terior part  of  this,  two  pyri- 
form  eminences  are  seen,  (^f  a 
brownish-gray  colour,  which, 
owing  to  their  being  formed 
of  an  assemblage  of  alternate 
layers  of  white  and  gray  sub- 
stance, are  called  coiyora  stri- 
ata, the  anterior  cerebral  gan- 
glio7is  of  Mr.  Solly.  Behind 
these,  are  two  whitish  medul- 
lary bodies  called  thalami 
nervorum  opticorum — posterior 
cerebral  ganglions — which  are 
situate  before  the  corpora 
quadrigemina,  and  envelope 
the  anterior  extremities  of 
the  crura  cerebri. 

Three  main  sets  of  fibres 
may  be  distinguished  in  the 
medullary  substance,  of  which 
the  great  mass  of  the  cere- 
brum is  composed.  First,  the 
ascending  fibres,  which  pro- 
ceed from  the  sensory  tract 
of  the  medulla  spinalis,  and 
diverge  from  the  thalami  op- 
tici  to  the  periphery  of  the 
brain;  secondly,  the  descend- 
ing fibres,  which  converge 
from  the  periphery  towards 
the  corpora  striata,  and  then 
medulla  spinalis;  and,  thirdly^ 
a  connexion  between  the  va- 
substance  of  the  brain.     The 


CEREBELLUM. 


635 


bulk  of  the  human  brain,  and  of  that  of  the  higher  animals,  is  greatly 
dependent  upon  the  large  proportion  borne  by  these  last  fibres  to  the 
rest.* 

The  cerebellum  occupies  the  lower  occipital  foss£e,  or  the  whole  of  the 
cavity  of  the  cranium  beneath  the  tentorium  cerebelli.  It  consists  of 
two  lateral  hemispheres  or  lobes,  composed  of  a  peculiar  arrangement 
of  vesicular  and  tubular  substance ;  and  of  a  central  lobe,  composed  also 
of  these  substances,  and  known  by  the  name  of  the  icorm  or  vermiform 
process.  Its  size  and  weight,  like  those  of  the  brain,  differ  according  to 
the  individual,  and  the  age  of  the  subject  under  examination.     We  do 

Fig.  192. 


Analytical  Diagram  of  the  Encephalon — it)  a  Vertical  Section. 

S.  Spinal  cord.  r.  Restiform  bodies  passing  to  c,  tlie  cerebellum,  d.  Corpus  dentatum  of  the  cerebel- 
lum, o.  Olivary  body.  /.  Columns  continuous  -with  the  olivary  bodies  and  central  part  of  the  medulla 
oblongata,  and  ascending  to  the  tubercula  quadrigemina  and  optic  thalami.  p.  Anterior  pyramids,  v. 
Pons  Varolii,  n,  h.  Tubercula  quadrigemina.  g.  Geniculate  body  of  the  optic  thalamus,  t.  Processus 
cerebelli  ad  testes,     a.  Anterior  lobe  of  the  brain,     q.  Posterior  lobe  of  the  brain. 

not  observe  convolutions  in  it.     It  appears  rather  to  consist  of  laminas 
in  superposition,  separated  from  each  other  by  furrows.     We  shall  see, 

'  Carpenter,  Human  Physiology,  p.  215,  Lond.,  1842. 


636 


SENSIBILITY. 


hereafter,  that  the  number  of  cerebral  convolutions  has  been  esteemed, 
in  some  respects,  to  accord  with  the  intellect  of  the  individual;  and 
Malacarne  asserts,  that  he  has  observed  a  similar  correspondence,  as 
regards  the  number  of  laminte  composing  the  cerebellum;  that  he  found 
only  three  hundred  and  twenty-four  in  the  cerebellum  of  an  insane  in- 
dividual; whilst  in  others  he  had  counted  upwards  of  eight  hundred. 

From  the  medullary  part  of  the  cerebellum,  two  large  white  cords 
pass  to  the  pons  Varolii,  having  the  same  disposition  as  the  crura 
cerebri.     They  are  the  crura  cerebelli. 

Owing  to  the  peculiar  arrangement  of  the  white  and  gray  cerebral 
substances,  when  one  of  the  hemispheres  of  the  cerebellum  is  divided 
vertically,  an  arborescent  appearance  is  presented, — the  trunks  of  the 
arborization  being  white,  the  surrounding  substance  gray.  This  ap- 
pearance is  called  nrhor  vitce.  The  part  where  all  these  arborizations 
meet,  near  the  centre  of  the  cerebellum,  is  called  corpus  denticulatum 
seu  rhomho'idaJe.  Gall  was  of  opinion,  that  this  body  has  great  agency 
in  the  production  of  the  cerebellum.  Lastly,  the  cerebellum  covers  the 
posterior  part  of  the  medulla  oblongata,  and  forms  with  it  a  cavity, 
Cdlledi  fourth  ventricle. 

The  medulla  oblongata  is  so  called,  because  it  is  the  continuation  of 
the  medulla  spinalis  in  the  cavity  of  the  cranium.  It  is  likewise  termed 
mesocephale^  from  its  being  continuous  with  the  spinal  marrow  in  one 
direction,  and  sending  towards  the  brain  strong  prolongations — crura 


Fig.  193. 


Fig.  194. 


Anterior  View  of  the  Medulla  Oblongata. 

p,  p  Pyramidal  bodies,  dfcussating  at  d. 
o,  0.  Olivary  bodies,  r,  r.  Restiform  bodies. 
a,  a.  Arciform  fibres,  v.  Lower  fibres  of  the 
pons  Varolii. 


Posterior  View  of  the  Medulla  Oblongata. 

p,  p.  Posterior  pyramids,  separated  by  the  posterior 
fissure,  r,  r.  Restiform  bodies,  composed  of  c,  c,  poste- 
rior columns,  and  d,d,  lateral  part  of  the  antero-lateral 
columns  of  the  cord,  a,  a.  Olivary  columns,  as  seen  on 
the  floor  of  the  fourth  ventricle,  separated  by  *,  the  me- 
dian fissure,  and  crossed  by  some  fibres  of  origin  of  n,  n, 
the  seventh  pair  of  nerves. 


cerebri;  and  to  the  cerebellum  similar  prolongations — crura  cerebelli; 
so  that  it  appears  to  be  the  bond  of  union  between  these  various  parts. 
In  its  lower  portion,  it  seems  to  be  merely  a  continuation  of  the  me- 


MEDULLA   OBLONGATA.  637 

dulla  spinalis,  except  tliat  it  is  more  expanded  superiorly  where  it  joins 
the  pons  Varolii.  This  portion  of  the  medulla  oblongata  is  called,  by 
some,  tail  of  the  medulla  oblongata;  by  others,  the  racliidian  bulb;  and, 
by  others  again  it  is  regarded  as  the  medulla  oblongata.  Its  lower  sur- 
face rests  on  the  basilary  gutter  of  the  occipital  bone,  and  exhibits  a 
groove  which  divides  the  spinal  cord  into  two  portions.  On  each  side 
of  this  furrow  are  two  oblong  eminences,  the  innermost  of  which  is 
called  coiyus  'pyramidale^  the  outermost,  corjms  olivare.  These  oval 
bodies  are  surrounded  by  a  superficial  groove,  which,  in  some  instances, 
is  partially  interrupted  by  arciform  fibres,  which  cross  it  at  its  lower 
part.  At  the  lower  third  of  the  medulla  oblongata,  fibres  of  the  ante- 
rior pyramids  decussate,  and  form  an  anatomical  demarcation  between 
the  medulla  oblongata  and  the  spinal  cord.  The  decussation  takes 
place  by  from  three  to  five  bundles  of  fibres  from  each  pyramidal 
body.  This  decussation,  as  will  be  seen  hereafter,  is  interesting  in 
regard  to  the  cross  effect  induced  by  certain  diseases  of  the  brain.  On 
the  posterior  surface  of  the  medulla  oblongata,  the  posterior  fasciculi 
separate  to  form  the  fourth  ventricle:  at  the  sides  of  this  ventricle  are 
the  corpora  restiformia^  or  inferior  peduncles  of  the  cerebellum^ — so  called 
because  they  seem  to  aid  in  the  formation  of  that  part  of  the  encepha- 
lon ;  and  on  the  inner  side  of  each  corpus  restiforme  is  the  small  body 
— i\iQ  posterior  pyramid.  Again,  in  addition  to  the  corpora  pyramidalia 
and  olivaria — which  derive  their  origin  from,  or  are  continuous  with, 
the  anterior  and  lateral  ftisciculi  of  the  spinal  cord,  and  are  destined, 
according  to  some,  to  form  the  brain, — and  the  corpora  restiformia, 
which  are  continuations  of  the  posterior  fasciculi,  and  are  destined  to 
form  the  cerebellum,  there  exist,  according  to  some  anatomists,  other 
fasciculi  in  the  rachidian  bulb.  All  these  are  interesting  points  of 
anatomy,  but  are  not  of  so  much  importance  physiologically;  notwith- 
standing even  the  views  promulgated  by  Sir  Charles  Bell.^  lie  con- 
siders that  a  column  exists  between  the  corpora  olivaria  and  corpora 
restiformia,  which  extends  below  through  the  whole  spine,  but  above 
does  not  proceed  farther  than  the  point  where  the  rachidian  bulb  joins 
the  tuber  annulare ;  and  that  this  column  gives  origin  to  a  particular 
oi'der  of  nerves — the  respiratory.  The  corpora  olivaria,  and  the  pos- 
terior corpora  pyramidalia,  are  regarded  by  Mr.  Solly'^  as  ganglia; — the 
former  of  the  function  of  respiration,  the  latter  of  the  sense  of  hearing. 
The  anterior  and  upper  half  of  the  medulla  oblongata  bears  the 
names  pons  Varolii^  tuber  annulare^  and  nodus  cerebri;  and  to  this  are 
attached,  superiorly,  the  corpora  or  tubercula  quadrigemina.  In  the  very 
centre  of  the  pons,  the  crura  cerebri  bury  themselves;  and  by  many 
they  are  considered  to  decussate;  by  others,  to  be  prolongations  of  the 
anterior  column  of  the  spinal  marrow.  Sir  C.  Bell  thinks,  that  the  pons 
Varolii  stands  in  the  same  relation  to  the  lateral  portions  of  the  cere- 
bellum, that  the  corpus  callosum  does  to  the  cerebrum; — that  it  is  the 
great  commissure  of  the  cerebellum,  uniting  its  lateral  parts,  and  asso- 
ciating the  two  organs. 

'  Thf  Nervous  System  of  the  Human  Borly,  fiom  Transactions  of  the  Royal  Society 
from  1821  to  1829,  London,  1830;  reprinted  in  this  country,  Washingtcm,  1833. 

*  The  Human  Brain,  its  Configuration,  Structure,  Devehiimient,  and  Physiology,  &c., 
p.  147,  London,  1836.  See,  on  this  suhject.  Dr.  John  Reid,  On  the  Anatomy  of  the  Me- 
dulla Oblongata,  in  Ediub.  Med.  and  Surg.  Journ.,  .Jan.,  1841,  p.  12. 


S38 


SENSIBILITY. 


The  medulla  oblongata  consists  chiefly  of  the  centres  of  the  nerves 
of  respiration  and  deglutition,  which,  as  elsewhere  shown,  are  strictly 
reflex  in  their  action. 

2.  The  spinal  marrow  extends,  in  the  vertebral  canal,  from  the  fora- 
men magnum  of  the  occipital  bone  above  to  the  first  or  second  lumbar 
vertebra,  where  it  terminates  in  the  cauda  equina. 
Fig.  195.  It  is  chiefly  composed  of  medullary  matter,  but  not 

P  _  entirely  so.  Within,  the  cineritious  substance  is 
ranged  irregularly,  but  has  a  crucial  form  when  a 
section  is  made.  The  marginal  illustrations  exhibit 
sections  of  the  spinal  cord  of  man  at  different  points; 
and  the  proportion  of  gray  and  white  matter  at  each. 
From  the  calamus  scriptorius  in  the  fourth  ventricle, 
and  the  rima  formed  by  the  corpora  pyramidalia 
before,  two  fissures  extend  downwards,  which  divide 
the  spinal  marrow  into  lateral  portions.  The  two 
lateral  portions  are  divided  by  some  into  an  anterior 
and  a  posterior,  so  that  the  cord  is  considered  to 
have  four  distinct  portions.  It  is  generally,  how- 
ever, described  as  consisting  of  three  columns — an 
anterior^  a  posterior,  and  a  uniddle  or  lateral.  The  an- 
tero-lateral  column,  as  seen  in  Fig.  192,  is  traceable 
through  the  medulla  oblongata  and  pons  Varolii  to 
the  corpora  striata;  and  the  postero-lateral  to  the 
thalami  nervorum  opticorum. 

The  vertebral  canal  is  lined  by  a  strong  liga- 
mentous sheath,  running  down  its  whole  length. 
The  dura  mater  likewise  envelopes  the  medulla  at 
the  occipital  foramen,  being  firmly  united  to  the 
ligaments;  but  farther  down  it  constitutes  a  separate 
tube.  The  tunica  arachnoidea  from  the  brain  ad- 
heres loosely  to  the  cord,  having  the  cephalo-spinal 
fluid  within  it ;  and  the  pia  mater  closely  em- 
braces it. 

3.  Nerves. — The  nerves  are  cords  of  the  same  nerv- 
ous substance  as  that  which  composes  the  encepha- 
lon  and  spinal  marrow;  extending  from  these  parts, 
and  distributed  to  the  various  organs  of  the  body, 
ramids.  'b^'ai  middle^ of  many  of  them  interlacing  in  their  course,  and  form- 
between  cervicaTandium^-  ing  plexuses:  others  having  knots  or  ganglions,  and 
buib.^"F,''Aii  Tnch'ii'owen  almost  all  vanishing  in  the  parts  to  which  they  are 
F.  Very  near  the  lower    distributed.     The  generality  of  English  anatomists 

end.    a.  Anterior  surface.  .       '-'  p        "^  .       '-'    p  , 

p.  Posterior  surface.  The  rcckou  thirty-nme  or  lorty  pairs  or  nerves;  the 
CruerLTudTosterior  Frcuch,  with  morc  propriety,  forty-two.  Of  these, 
Iiso\e°en""'  '^'^'^^''^  "^^^  uiuc,  accordiug  to  the  English — twelve,  according 
to  the  French — draw  their  origin  from,  or  are  con- 
nected with,  the  encephalon;  and  are  hence  called  encephalic  nerves;  and 
thirty  or  thirty-one  from  the  medulla  spinalis;  and  hence  termed  spinal. 
The  encephalic  nerves  emerge  from  the  cranium  by  means  of  foramina 
at  its  base.  They  are — proceeding  from  before  to  behind — the  first 
pair  or  olfactory,  distributed  to  the  organ  of  smell:  the  second  pair  or 


Transverse  Sections  of 
the  Spinal  Cord. 

A.    Immediately  below 
the  decussation  of  the  py- 


NERVES. 


639 


optic^  tlie  expansion  of  which  forms  the  retina;  the  third  pair,  motores 
oculi  or  common  oculo-m>(scidar,  which  send  fiLaments  to  most  of  the 
muscles  of  the  eye ;  the 

fourth  pair,   trochleares^  ^^S-  ^^^• 

pathetici  or  internal  ocv,- 
lo-muscular,  distributed 
to  the  greater  oblique 
muscle  of  the  eye ;  the 
ffth  p>air^  trifacial,  tri- 
gemini  or  symmetri- 
cal nerve  of  the  head, 
(Bell,)  which  send  their 
branches  to  the  eye, 
nose,  and  tongue ;  the 
sixth  pair,  ahducentes  or 
external  oculo-muscular, 
which  are  distributed 
to  the  abductor  or  rec- 
tus externus  oculi ;  the 
facial  nerve,  portio  dura 
of  the  seventh  pair, 
nervus  commimicans  fa- 
ciei or  respiratory  nerve 
of  the  face,  distributed 
to  the  muscles  of  the 
face;  the  acoustic  nerve, 
auditory  nerve  or  portio 
mollis  of  the  seventh 
pair,  which  passes  to 
the  organ  of  hearing; 
the  eiyJdh  pair,  p)neu- 
mogastric,  par  vagum 
or  middle  sympathetic, 
which  is  dispersed  par- 
ticularly on  the  larynx, 
lungs,  heart,  and  sto- 
mach ;  the  ghsso-pha- 
ryngeal,  often  consider- 
ed as  part  of  the  last, 
and  whose  name  indicates  its  distribution  to  the  tongue  and  pharynx ; 
the  great  hypoglossal,  rdnth  2^air  or  lingual  nerve  distributed  to  the 
tongue;  and  the  spinal  accessory  of  Willis,  which  arises  from  the  spinal 
cord  in  the  cervical  region ;  ascends  into  the  cranium,  and  issues  by 
one  of  the  foramina  to  be  distributed  to  the  muscles  of  the  neck.  All 
these  proceed,  perhaps,  from  the  medulla  oblongata ; — the  brain  and 
cerebellum  not  furnishing  one. 

The  thirty  or  thirty-one  spinal  nerves  on  each  side  make  their  exit 
by  the  intervertebral  foramina,  and  are  divided  into  eight  cervical^ 
twelve  dorsal,  five  lumhar,  and  five  or  six  sacral. 

The  encephalic  nerves  are  irregular  in  their  formation,  and,  with 
the  exception  of  the  fifth  pair,  originate  from  one  root.     Each  of  the 


Shows  the  under  Surface  or  Base  of  the  Encephalon  freed  from 
its  Membranes. 

A,  anterior,  b,  middle,  and  c,  posterior  lobe  of  cerebrum. — a.  The 
fore  part  of  the  great  longitudinal  fissure,  b.  Notch  between  hemi- 
spheres of  the  cerebellum,  c.  Optic  commissure,  d.  Left  peduncle 
of  cerebrum,  e.  Posterior  perforated  space,  e  to  i.  Intorpeduncular 
space.  /,  /'.  Convolution  of  Sylvian  fissure,  h.  Termination  of 
gyrus  fornicatus  behind  the  Sylvian  fissure,  i.  Infundibulum.  I. 
Kight  middle  crus  or  peduncle  of  cerebellum,  m,  to.  Hemispheres 
of  cerebellum,  n.  Corpora  albicantia.  o.  Pons  Varolii,  continuous 
at  each  side  with  middle  crura  of  cerebellum,  p.  Anterior  perfo- 
rated space,  q'.  Horizontal  fissure  of  cerebellum,  r.  Tuber  cine- 
reum.  s,  s'.  Sylvian  fissure,  t.  Left  peduncle  or  crus  of  cerebrum. 
u,  u.  Optic  tracts,  v.  Medulla  oblongata,  x.  Marginal  convolution 
of  the  longitudinal  fissure.— 1  to  9  indicate  the  several  pairs  of  cere- 
bral nerves,  numbered  according  to  the  usual  notation,  viz.,  1.  Ol- 
factory nerve.  2.  Optic.  3.  Motor  nerve  of  eye.  4.  Pathetic.  6. 
Trifacial.  6.  Abducent  nerve  of  eye.  7.  Auditory,  and  7'.  FaciaL 
8.  Glosso-pharyngeal,  S'.  Vagus,  and  8".  Spinal  accessory  nerve. 


640  SENSIBILITY. 

spinal  nerves  arises  from  two  fasciculi,  the  one  anterior,  and  the  other 
posterior :  these  roots  are  separated  from  each  other  by  the  ligamentum 
deniiciilare ;  but  they  unite  beyond  this  ligament,  and  near  the  inter- 
vertebral foramen  present  one  of  those  knots,  known  under  the  name 
of  ganglions  or  ganglia,  in  the  formation  of  which  the  posterior  root  is 
alone  concerned. 

When  the  nerves  have  made  their  exit  from  the  cranium  and  spine, 
they  proceed  to  the  organs  to  which  they  have  to  be  distributed; 
ramifying  more  and  more,  until  they  are  ultimately  lost  sight  of,  even 
when  vision  is  aided  by  a  powerful  microscope.  It  is  not  positively 
decided,  whether  the  nervous  fibres  have  any  distinct  terminations 
either  in  the  nervous  centres,  or  in  the  organs  to  which  they  are  dis- 
tributed. In  the  gray  matter  of  the  brain  of  the  vertebrata,  they  have 
been  considered  to  form  a  kind  of  plexus  of  loops ;  and  the  ultimate 
fibres  do  not  seem  to  anastomose.  The  following  has  been  described 
as  the  mode  in  which  the  nervous  fibres  are  generally  distributed  to 
the  peripheral  organs.  The  trunks  subdivide  into  small  fasciculi, 
each  of  which  consists  of  from  two  to  six  fibres,  and  these  form  plex- 
uses, whose  arrangement  bears  a  general  resemblance  to  that  of  the 
elements  of  the  tissue  in  which  they  are  placed.  The  primitive  fibres 
then  separate ;  and  each,  after  passing  over  several  elementary  parts 
of  the  containing  tissue,  or  after  forming  a  single  narrow  loop,  as  in 
the  sensory  papillie,  returns  to  the  same  or  to  an  adjoining  plexus, 
and  pursues  its  way  to  the  nervous  centre  from  which  it  set  out.  Ac- 
cording to  this  view,  there  is  no  more  a  termination  of  nerves,  than 
there  is  of  bloodvessels.  Both  form  circles.  More  recent  observa- 
tions seem,  however,  to  have  demonstrated,  that  in  different  situations 
the  loop-like  appearance  is  fallacious ;  and  that  the  ultimate  fibres 
divide  into  fibrils,  the  terminations  of  which  are  lost  in  the  tissues. 
It  is  probable,  indeed,  that  this  may  be  the  general  mode  of  termi- 
nation. 

Investigations  by  Henle  and  Kolliker'  show,  that  some  of  the  peri- 
pheral nervous  fibrils  terminate  in  small  bodies,  seated  especially  in 
the  nerves  of  the  fingers  and  toes,  which  have  been  called  Pacinian 
or  Vateriari  corpuscles ;  but  of  whose  uses  little  can  be  said.  They  have 
not  been  observed  on  any  motor  nerves,  so  that  they  would  not  seem 
to  have  anything  to  do  with  motion.  They  exist  in  many  nerves  of 
the  sympathetic  class,  and  are  not  present  on  many  sensitive  nerves; 
so  that,  it  has  been  properly  inferred,  they  are  probably  not  connected 
with  acuteness  of  sensation. 

Another  example  of  the  termination  of  a  nerve  is  in  the  so-called 
tactile  or  touch  corpuscles,  axile  bodies,  composed  of  a  horizontally  lami- 
nated mass  of  areolar  tissue,  which  are  found  in  the  papilla?  of  parts 
endowed  with  great  tactile  sensibility,  and  into  which  the  nerves  of 
touch  enter. 

'  Uiiber  (lie  Pacinischen  Korperclien  an  den  Nerven  des  Mensclien  und  der  Sauge- 
thiere,  Ziirifli,  18-t4;  reviewed  in  Brit,  and  For.  Med.  Rev.,  January,  1845,  p.  78; 
Todd  and  Bowman,  Physiological  Anat.  and  Physiology  of  Man,  i.  3y5,  London,  1845, 
or  Anier.  edit.,  Pliilad.,  1850;  and  W.  Bowman,  Cyclopaedia  of  Anat.  and  Physiol.,  by 
Dr.  Todd,  })t.  xxvii.  p.  87t),  Lond.,  Mar.,  1840.  See,  on  their  discovery  by  Vater, 
Strahl,  in  Miiller's  Areliiv.  fiir  Anatomie,  ii.  s.  w.,  Berlin,  1848  ;  and  the  Author's 
Medical  Dictionary,  art.  Corpuscles,  Pacinian,  13th  edit.,  Philad.,  185(j. 


NERVES. 


641 


Fig.  197. 


Fig.  198. 


Fig.  199. 


Pacinian  Corpuscles. 


A.  Nerve  from  the  finger,  natural  size; 
showing  the  Pacinian  corpuscles. 

B.  Unusual  form,  from  the  mesentery  of 
the  cat ;  showing  two  included  in  a  common 
envelope  : — a,  h  are  the  two  nerve-tubes  be- 
longing to  them. 


Tactile  Corpuscles  from  the  Skin  of  the  Palmar  Sur- 
face of  the  Forefinger. 
A,  in  the  natural  state  ;  b,  treated  with  acetic  acid. 


^fe% 


Of  the  encephalic  nerves,  the  olfactory,  auditory,  and  acoustic — 
nerves  of  special  sensibility — clearly  pass  on  to  their  destination,  with- 
out communicating  with  any  other  nerve.  The  spinal  nerves,  at  their 
exit  from  the  intervertebral  foramina,  divide  into  two  branches,  an 
anterior  and  a  posterior,  one  being  sent  to  each  aspect  of  the  body. 
The  anterior  branches  of  the  four  superior  cervical  pairs  form  the  cer- 
vical "plexus^  from  which  all  the  nerves  of  the  neck  arise;  the  last  four 
cervical   pairs   and   the    first 

dorsal  form  the  hrachial plexus,  Fig-  200. 

whence  proceed  the  nerves  of 
the  upper  extremities ;  whilst 
the  branches  of  the  five  lum- 
bar nerves,  and  the  five  sacral 
form  the  lumbar  and  sciatic 
plexuses;  the  former  of  which 
gives  rise  to  the  nerves  dis- 
tributed to  the  parts  within 
the  pelvis;  the  second  to  those 
of  the  lower  limbs.  The  an- 
terior branches,  moreover,  at  a  little  distance  from  the  exit  of  the 
nerve  from  the  vertebral  canal,  communicate  with  an  important  and 
unique  portion  of  the  nervous  system,  the  great  sympathetic. 

Each  nerve  consists  of  numerous  fasciculi  surrounded  by  areolar 
membrane;  and,  according  to  KeiV  of  an  external  envelope,  called 
neurilemma,  which,  in  the  opinion  of  most  anatomists,  is  nothing  more 
than  a  fibro-areolar  envelope,  similar  to  that  which  surrounds  the 
vessels  and  muscular  fibres. 


A  Nerve  consisting  of  many  smaller  Cords  or  Funi- 
culi wrapped  up  in  a  common  areolar  Sheath. 


A.  The  nerve, 
the  rest. 


B.    A  single  funiculus  drawn  out  from 


VOL.  I. — 41 


'  De  Structura  Nervorum,  Hal.,  1796. 


642 


SENSIBILITY. 


Fig.  201. 


1.  Anterior  or  motor  root  of  a  spinal 
nerve. 

2.  Posterior  or  sensory  root. 

3.  Ganglion  connected  with  the  latter. 


Fig.  202. 


Until  of  late  years,  tlie  nerves  were  universally  divided,  according 
to  their  origin,  into  encephalic  and  spinal;  but,  more  recently,  anato- 
mical divisions  have  been  proposed, 
based  upon  the  uses  they  appear  to  fulfil 
in  the  economy.  For  one  of  the  most 
beautiful  of  this  kind  we  are  mainly  in- 
debted to  Sir  Charles  Bell.  It  has  been 
already  seen,  that  the  encephalic  nerves 
are  connected  with  the  encephalon  by 
one  root,  whilst  the  spinal  nerves  arise 
from  two ;  the  one  connected  with  the 
anterior  tract  of  the  spinal  marrow;  the 
other  with  the  posterior.  If  these  dif- 
ferent roots  be  experimented  on,  we  meet 
A  portion  of  the  Spinal  Marrow,  siiow-  w^ith  rcsults  varying  Considerably.  If 
ing  the  Origin  of  some  of  the  Spinal    ^q  divide  the  anterior  Toot,  the  part  to 

which  the  nerve  is  distributed  is  de- 
prived of  motion;  if  the  posterior  root 
be  cut,  the  part  is  deprived  of  sensibility. 
We  conclude,  therefore,  that  each  of  the 
spinal  nerves  consists  of  filaments  destined  for  both  motion  and  sen- 
sation ;  that  the  encephalic  nerves,  which  have  but  one  root,  are  des- 
tined for  one  of  these  exclusively,  and 
that  they  are  either  nerves  of  motion,  or 
of  sensation,  according  as  their  roots 
arise  from  the  anterior  or  the  posterior 
tract  of  the  medulla. 

It  has  already  been  remarked,  that  the 
medulla  oblongata,  according  to  some 
anatomists,  is  composed  of  three  fasciculi 
or  columns  on  each  side ; — an  anterior, 
a  middle^  and  a.  posterior;  and  it  has  been 
affirmed  by  Sir  Charles  Bell,  that  whilst 
the  anterior  column  gives  origin  to 
nerves  of  motion;  and  the  posterior  to 
nerves  of  sensation ;  the  middle  gives 
rise  to  a  third  order,  having  the  function 
of  presiding  over  the  respiratory  move- 
ments; and  which  Sir  Charles,  accord- 
ingly, calls  respiratory  nerves.  To  this 
third  order  belong, — the  accessory  nerve 
of  Willis  or  superior  respiratory;  the 
vagus ;  the  ghsso-pliaryngeal ;  the  facial, 
called  by  him  the  respiratory  nerve  of  the 
face;  the  phrenic;  and  another  having 
the  same  origin — the  external  respiratory. 
Sir  Charles's  views,  if  admitted,  lead, 
consequently,  to  the  belief,  that  there 
are  at  least  three  sets  of  nerves, — one 
destined  for  sensation;  another  for  motion ;  and  a  third  for  a  particu- 
lar kind  of  motion — the  respiratory ;  and  that  every  nerve  of  motion 


Plans  in  outline,  showing  the  Front  A, 
and  the  Side  b,  of  the  Spinal  Cord, 
with  the  Fissures  upon  it ;  also  sec- 
tions of  the  Gray  and  White  Mat- 
ter, and  the  Roots  of  the  Spinal 
Nerves. 

a,  a.  Anterior,  p.p.  Posterior  fissure. 
h.  Posterior,  and  c.  Anterior  horn  of  gray 
matter,  t.  Gray  commissure,  a,  e,  c. 
Anterior  white  column,  c,  e.,  h.  Lateral 
columns,  a,  e,  b.  Antero-lateral  column. 
b,  e,  p.  Posterior  columns,  r.  Anterior, 
aud  s.  Posterior  roots  of  a  spinal  nerve. 


SIR   CHARLES   BELL's   DIVISION   OF  NERVES.  643 

communicates  to  the  muscles,  to  wliich  it  is  distributed,  the  power  of 
aiding,  or  taking  part  in,  motions  of  one  kind  or  another;  so  that  a 
muscle  may  be  paralyzed,  as  regards  certain  movements,  by  the  sec- 
tion of  one  nerve,  and  yet  be  capable  of  others  of  a  different  kind,  by 
means  of  the  nerves  that  are  uninjured. 

Yet  this  division  is  now  by  no  means  generally  admitted;  and  even 
by  some  who  are  of  opinion,  that  the  sensory  and  motor  filaments 
arise  from  distinct  tracts  of  the  spinal  cord,  it  is  denied  that  this  is  the 
case  with  those  that  originate  from  the  upper  part  of  the  cord ;  there 
being  in  ]the  medulla  oblongata  a  blending  of  the  sensory  and  motor 
tracts  which  cannot  easily  be  explained.  Pathological  cases,  too,  occa- 
sionally occur,  which  throw  great  difficulty  on  this  matter.  Two  of 
the  kind  have  been  related  by  Mr.  Stanley  and  Dr.  Budd,'  ih  which 
there  was  disease  confined  to  the  posterior  column ;  yet  sensation  re- 
mained unimpaired,  whilst  the  power  of  motion  in  the  lower  extremi- 
ties was  lost. 

Much  evidently  remains  to  be  accomplished,  before  the  precise 
arrangement  of  the  columns  of  the  spinal  cord,  and  of  the  relations  of 
the  nerves  connected  with  them,  can  be  esteemed  establislied.  Sir 
Charles  Bell,^  indeed,  subsequently  renounced  his  first  opinion,  that 
the  posterior  roots  of  the  spinal  nerves  proceed  from  the  posterior 
column,  and  described  them  as  arising  from  the  middle  or  lateral 
column;  affirming,  at  the  same  time,  that  it  is  not  impossible  that  the 
posterior  column  may  be  connected  with  the  sensory  roots  of  the  spinal 
nerves,  although  he  has  not  hitherto  succeeded  in  tracing  it.  Messrs. 
Grainger  and  Swan  maintain,  that  both  sets  are  connected  with  the 
lateral  columns  only;  the  anterior  and  posterior  lateral  fissures  defi- 
nitely limiting  the  two  roots.  Perhaps,  as  has  been  suggested,^  both 
these  statements  may  be  too  exclusive.  The  anterior  roots  would  seem 
to  have  a  connexion  with  both  the  anterior  and  lateral  columns;  and  the 
posterior  cannot  be  said  to  be  restricted  to  the  lateral  column,  some  of 
their  fibres  entering  the  posterior  division  of  the  cord. 

Most  physiologists  are  now  of  opinion,  both  from  experiment  and 
reflection,  that  there  is  no  special  column  destined  for  respiration,  and 
that  there  appears  to  be  nothing  so  peculiar  in  the  action  of  the  respi- 
ratory muscles,  that  they  should  require  a  distinct  set  of  nerves."* 

Sir  C.  Bell  proposed  a  further  arrangement  of  the  nerves,  more 
natural  and  philosophical  than  the  unmeaning  numeration  according 
to  the  system  of  Willis,  and  better  adapted  to  facilitate  the  com- 
prehension of  this  intricate  portion  of  anatomy.  According  to  this, 
all  the  nerves  of  the  body  may  be  referred  to  two  great  classes — the 
original^  "priraiiive  or  syrtimelrical^ — and  the  irregular  or  superadded. 
It  has  been  already  remarked,  that  a  division  of  the  spinal  cord' has 
been  presumed  to  correspond  to  the  cerebrum;  and  another  to  the  cere- 
bellum. Now,  every  regularnerve  has  two  roots,  one  from  the  anterior 
of  these  columns,  and  another  from  the  posterior.  Such  are  the  filth 
pair;  the  sub-occipital;  the  seven  cervical;  the  twelve  dorsal;  the  five 

'  Medico-Cliirurgical  Transactions,  vol.  xxiii.,  Lond.,  1840. 

*  Nervous  System,  &c.,  3d  edit.,  p.  234,  London,  1836. 

'  Carpenter,  Principles  of  Human  Physiology,  2d  Anier.  edit.,  p.  125,  Philad.,  1845. 

♦  Dr.  Reid,  op.  cit.,  Jan.,  1838,  p.  175. 


644 


SENSIBILITY. 


lumbar;  and  the  five  or  six  sacral, — that  is,  thirty-one  or  thirtj-two  per- 
fect, regular,  or  double  nerves, — including,  to  state  more  briefly,  all  the 
spinal  nerves,  and  one  encephalic — the  fifth  pair.  The  fifth  pair  is  found 
to  arise  from  the  encephalon  by  two  roots,  and  to  have  a  ganglion  upon 
the  posterior  root.  It  is,  accordingly,  classed  with  the  spinal  nerves ;  and, 
like  them,  according  to  Sir  Charles  Bell,  conveys  both  motion  and  sen- 
sibility to  the  parts  to  which  it  is  distributed.  These  regular  nerves 
are  common  to  all  animals,  from  the  zoophyte  to  man.  They  run  out 
laterally ;  or  in  a  direction  perpendicular  to  the  longitudinal  division  of 
the  body ;  and  never  take  a  course  parallel  to  it.  The  other  class  is 
called  irregular  or  swperadded.  The  different  nervous  cords,  proceeding 
from  it,  are  distinguished  by  a  simple  fasciculus  or  single  root.  All 
these  are  simple  in  their  origins ;  irregular  in  their  distribution;  and 
deficient  in  that  symmetry  which  characterizes  those  of  the  first  class. 
They  are  superadded  to  the  original  class ;  and  correspond  to  the 
number  and  complication  of  the  superadded  organs.  Of  these,  there 
are  the  ihird^  fourth^  and  sixth^  distributed  to  the  eye;  the  seventh,  to 
the  face;  the  ?m^^A,  to  the  tongue;  the  glosso-pharyngeal,  to  the  pha- 
rynx; the  vagvs,  to  the  larynx,  heart,  lungs,  and  stomach  ;  the  phrenic, 
to  the  diaphragm  ;  the  spinal  accessory,  to  the  muscles  of  the  shoulders; 

and  the  external  respiratory,  to  the 


Fig.  203, 


Roots  of  a  Dorsal  Spinal  Nerve,  and  its  union 
with  the  Sympathetic. 

c,  c.  Anterior  fissure  of  the  spinal  cord.  a.  Ante- 
rior root.  p.  Posterior  root,  with  its  ganglion,  a'. 
Anterior  branch,  p'.  Posterior  branch,  s.  Sympa- 
thetic, e.  Its  double  junction  with  the  anterior 
branch  of  the  spinal  nurve  by  a  white  and  a  gray  fila- 
ment. 


outside  of  the  chest.  The  reason 
of  the  seeming  confusion  in  this 
latter  class  is  to  be  looked  for  in 
the  complication  of  the  superadd- 
ed apparatus  of  respiration,  and 
in  the  variety  of  offices  it  has  to 
perform  in  the  higher  classes  of 
animals. 

4,  Great  Sympathetic.  —  This 
nerve,  called  also  trisplanchnic, 
splanchnic,  ganglionic,  great  inter- 
costal, vegetative,  and  organic  is 
constituted  of  a  series  of  gan- 
glions, joined  to  each  other  by  a 
nervous  trunk,  and  extending 
down  the  side  of  the  spine,  from 
the  base  of  the  cranium  to  the 
OS  coccygis  or  lowest  bone.  It 
communicates  with  each  of  the 
spinal  nerves,  and  with  several 
of  the  encephalic ;  and  from  the 
ganglions,  formed  by  such  com- 
munication, sends  ofl'  nerves, 
which  accompany  the  arteries, 
and  are  distributed  particularly 
to  the  organs  of  involuntary 
functions.  At  its  upper  part,  it 
is  situate  in  the  carotid  canal, 
where  it  appears  under  the  form 
of  a  ganglionic  plexus;  two  fila- 


GEEAT   SYMPATHETIC. 


645 


merits  of  wliicli  proceed  to  join  Fig.  204. 

the  sixth  pair  of  encephalic 
nerves,  and  another  to  meet  the 
Vidian  twig  of  the  fifth  pair. 
By  means  of  the  fifth  pair,  it 
communicates  also  with  the  oph- 
thalmic ganglion,  which  Bichat 
considered  to  belong  to  it.  On 
issuing  from  the  carotid  canal, 
the  nerve  passes  downwards, 
along  the  side  of  the  spine,  to 
the  sacrum;  presenting  a  series 
of  ganglions; — three  in  the  neck, 
— the  sujperior^  middle^  and  in- 
ferior cervical;  twelve  in  the 
back, — the  thoracic;  five  in  the 
loins, — the  lumbar;  and  three 
or  four  in  the  sacrum, — the  sa- 
cral. When  it  reaches  the  coc- 
cyx, it  terminates  by  a  small 
ganglion,  called  coccygeal;  or  by 
uniting  with  the  great  sympa- 
thetic of  the  opposite  side. 

The  ganglions  are  of  an  irre- 
gular, but  generally  roundish, 
shape.  They  consist  of  nervous 
filaments,  surrounded  by  a  red- 
dish-gray, pulpy,  albuminous,  or 
gelatinous  substance,  which  dif- 
fers from  the  gray  matter  of  the 
brain.  Sir  E.  Home'  considers 
their  structure  to  be  intermediate 
between  that  of  brain  and  nerves ; 
the  brain  being  composed  of 
small  globules  suspended  in  a 
transparent  elastic  jelly ;  the 
nerves  made  up  of  single  rows  of 
globules,  and  the  ganglions  con- 
sisting of  a  congeries  of  nervous 
fibres  compacted  together.^  Volk- 

Great  Sympathetic  Nerve. 
1.  Plexus  on  the  carotid  artery  in  tlie  carotid  foramen.  2.  Sixth  nerve  (motor  externus).  3.  First 
branch  of  the  fifth,  or  ophthalmic  nerve.  4.  A  branch  on  the  septum  narium  going  to  the  inci.sive  fora- 
men. 5.  Recurrent  branch  or  Vidian  nerve  dividing  into  the  carotid  and  petrosal  branches.  6.  Poste- 
rior palatine  branches.  7.  Lingual  nerve  joined  by  the  chorda  tympani.  8.  Portio  dura  of  the  seventh 
pair.  9.  Superior  cervical  ganglion.  10  Middle  cervical  ganglion.  11.  Inferior  cervical  ganglion.  12. 
Roots  of  the  great  splanchnic  nerve  arising  from  the  dorsal  ganglia.  13.  Lesser  splanchnic  nerve.  14. 
Renal  plexus.  15.  Solar  plexus.  16.  Mesenteric  plexus.  17.  Lumbar  ganglia.  18.  Sacral  ganglia.  19. 
Vesical  plexus.  20.  Rectal  plexus.  21.  Lumbar  plexus  (cerebro-spinal).  22.  Rectum.  2.3.  Bladder. 
24.  Pubis.  2.5.  Crest  of  the  ilium.  26.  Kidney.  27.  Aorta.  28.  Diaphragm.  29.  Heart.  .30.  Larynx. 
3l!  Submaxillary  gland.  32.  Incisor  teeth.  33.  Nasal  septum.  34.  Globe  of  the  eye.  3o,  36.  Cavity  of 
the  cranium. 

'  Lect.  on  Comp.  Anat.,  v.  194,  Lond.,  1828. 

'^  See,  on  the   Histology  of  the  Organic  or  Sympathetic  Nervous  Fibres,  Mr.  Paget, 
Brit,  and  For.  Med.  Rev.,  July,  1842,  p.  279. 


QiQ  SENSIBILITY. 

man  and  Bidder,  and  Reichert/  consider  the  sympathetic  nerve-fibres 
to  be  distinct  in  size  and  strncture  from  the  cerebro-spinal ;  but  Valen- 
tin and  others  maintain  there  is  no  difterence. 

Authors  are  by  no  means  agreed  with  regard  to  the  uses  of  these 
ganglions.  Willis,^  Haller,^  and  others,  considered  them  to  be  small 
brains  for  the  secretion  of  the  nervous  fluid  or  animal  spirits;  an 
opinion,  which  was  embraced  by  Richerand,''  and  Cuvier;*  the  latter 
of  whom  remarks,  that  the  ganglia  are  larger  and  more  numerous 
when  the  brain  is  deficient  in  size.  Lancisi,^  and  Vicq  d'Azyr,  re- 
garded them  as  a  kind  of  heart  for  the  propulsion  of  these  spirits,  or 
as  reservoirs  for  keeping  them  in  deposit.  Scarpa^  treats  them  as 
synonymous  with  plexuses;  but  plexuses  with  the  filaments  in  close 
approximation;  and  plexuses  he  regards  as  ganglions,  the  filaments  of 
which  are  more  separated.  He  consequently  believes,  with  many 
physiologists,  that  their  office  is  to  commingle  and  unite  various 
nervous  filaments  with  each  other.  Dr.  Wilson  Philip*  thinks,  that 
they  are  secondary  sources  of  nervous  influence ;  that  they  receive 
supplies  of  it  from  all  parts  of  the  brain  and  spinal  marrow,  and  trans- 
mit the  united  influence  to  the  organs  to  which  the  nerves  are  distri- 
buted; whilst  some  conceive,  that  at  least  one  office  is  to  communicate 
irritability  to  the  tissues.^  Johnstone, '°  Reil,"  Bichat,'^  and  others, 
are  of  opinion  that  their  use  is  to  render  the  oi'gans,  which  derive 
their  nerves  from  them,  independent  of  the  will. 

These  views  are  sufficiently  discordant;  and  well  indicate  the  intrin- 
sic obscurity  of  the  subject.  That  of  Dr.  Philip  is  the  most  probable. 
Containing  the  vesicular  or  gray  matter,  which  seems  to  be  everywhere, 
perhaps,  concerned  in  the  production  of  nerve-power,  the  ganglia  may 
be  regarded  as  agents  of  nervous  reinforcement;  although  we  may 
remain  uncertain  as  to  the  mode  in  which  their  office  is  executed,"  It 
is  affirmed  by  M.  Robin,  in  a  communication  made  by  him  to  the 
Acadcmie  des  Sciences,  of  Paris,  in  June,  18-i7,  that  the  ganglia  of  the 
great  sympathetic  and  of  the  cerebro-spinal  nerves  enclose  the  same 

'  ISIuUer's  Archiv.,  1844,  cited  bvMr.  Pa<ret,ln  Brit,  and  For.  Med.  Rev.,  April,  1845, 
p.  572. 

■*  Cerebri  Anatome  cui  accessit  Nervorum  Descriptio,  &:c.,  cap.  sxvi.,  Lond.,  16fi4. 

^  De  Vera  Nervi  Intercostalis  Origine,  Gotting.,  1793;  Collect.  Dissei't.  Auat.,ii.  939; 
and  Oper.  Minor,  i.  503. 

*  See  Appendix  to  Ernx-  edit.,  by  Dr.  Copland. 

*  Lei,'ous  d'Anatomie  Compar.  Introd..  p.  2G. 

^  Dissert,  de  Structura  Usuque  Gangliorum  ad  J.  B.  Morgagnium,  in  Morgagni  Ad- 
ver.  Anat.,  v.  101,  Lugd.  Bat.,  1741. 
^  De  Nervis  Comment.,  cap.  ii.  320. 

*  Philosopli.  Transact,  for  1829;  and  Inquiry  into  the  Nature  of  Sleep  and  Death, 
Lond.,  1834,  p.  14, 

9  Fletcher,  Rudiments  of  Physiology,  P.  ii.  a.  p.  68,  Edinb.,  1836. 

'"  Philosopliical  Transactions,  vols,  54,  57,  and  60 ;  Essays  on  the  Use  of  the  Gan- 
glions  of  the  Nerves,  Shre\y5bury,  3  771 ;  and  Medical  Essays  and  Observations  relating 
to  the  Nervous  System,  Evesham,  1795, 

"  Archiv.  fur  die  Physiol.,  S.  226,  vii.,  Halle,  1807. 

'^  Anatomie  Generale,  torn.  i.  200,  and  ii.  405. 

"^  See  the  excellent  article  by  Wagner,  entitled  Sympathischer  Nerv,  Ganglienstruc- 
tur  und  Nervenendigungen,  in  his  Handwiirterbuch  der  Physiologie,  17te  Lieferung,  S. 
360,  Braunschweig,  1847  ;  another  by  Budge,  on  the  Sympathetic,  with  special  relation 
to  the  Heart's  action,  Ibid.,  S.  406;  and  on  the  Sympathetic  Ganglia  of  the  Heart  by 
Wagner,  Ibid.,  S.  450. 


GREAT   SYMPATHETIC.  447 

kind  of  ganglionary  globules,  and  of  elementary  tubes,  but  in  differ- 
ent proportions;  and  hence  he  does  not  regard  them  as  separate 
nervous  systems. 

Although  connected  with  the  brain  by  the  branches  of  the  fifth  and 
sixth  pairs  of  encephalic  nerves,  and  with  the  spinal  cord  by  the  spinal 
nerves,  the  sympathetic  does  not  appear  to  be  directly  influenced  by 
either;  as  the  functions  of  the  parts  to  which  its  ramifications  are  dis- 
tributed continue  for  some  time  after  both  brain  and  spinal  marrow 
have  been  separated;  nay,  as  in  the  case  of  the  heart  and  intestines, 
after  they  have  been  removed  from  the  body.  Yet  many  discussions 
have  been  indulged  regarding  the  origin  of  this  important  part  of  the 
nervous  system;  some  assigning  it  to  the  brain,  others  to  the  spinal 
marrow;  whilst  others  again  esteem  it  a  distinct  nerve,  communicating 
with  the  brain  and  spinal  cord,  but  not  originating  from  either ;  re- 
ceiving, according  to  M.  Broussais,'  by  the  cerebral  nerves,  the  excit- 
ant influence,  and  applying  it  to  movements  that  are  independent  of 
the  centre  of  perception.  In  like  manner,  he  affirms,  when  irritation 
predominates  in  the  viscera,  it  is  conveyed  by  the  ganglionic  to  the 
cerebral  nerves,  which  transmit  it  to  the  brain.  Eeil  and  Bichat, 
esteeming  the  sympathetic  to  be  the  great  nervous  centre  of  involun- 
tary functions,  have  termed  it  the  organic  nervous  system,  in  contradis- 
tinction to  the  animal  nervous  system,  which  presides  over  the  animal 
functions ;  whilst  Lobstein,^  who  has  published  an  ex  professo  work  on 
the  subject,  assigns  three  functions  to  it.  1.  To  preside  over  nutrition, 
secretion,  the  action  of  the  heart,  and  the  circulation  of  the  blood ; 
2.  To  maintain  a  communication  between  different  organs  of  the  body; 
and  3.  To  be  the  connecting  medium  between  the  brain  and  abdominal 
viscera.  Remak,^  who  believes  that  the  animal  economy  possesses 
two  sensoriums, — the  one  in  the  cerebro-spinal  axis,  the  other  in  the 
ganglionic  system, — considers,  that  as  in  the  cerebro-spinal  system  of 
nerves  two  orders  of  phenomena  occur, — the  perception  of  sensation, 
and  the  reaction  or  reflection  of  volition;  so,  in  the  organic  nervous 
system,  two  analogous  actions  take  place, — organic  perception,  or,  as 
it  has  been  called,  Hallerian  irritability,  and  reaction  or  organic  reflec- 
tion, as  shown  by  J.  jMiiller.'' 

From  the  result  of  his  own  researches.  Dr.  Carpenter^  inferred,  that 
the  sympathetic  system  does  not  exist  in  the  lowest  classes  of  animals 
in  a  distinct  form ; — that  the  nervous  system  of  the  invertebrata,  taken 
as  a  whole,  bears  no  analogy  to  it,  and  that  as  the  divisions  of  this 
become  more  specialized,  some  appearance  of  a  separate  sympathetic 
presents  itself,  but  it  is  never  so  distinct  as  in  the  vertebrata;  hence 
he  deduces,  and  with  probability,  that  as  the  sympathetic  system  is 

'  A  Treatise  on  Physiology  applied  to  Pathology,  translated  by  Drs.  John  Bell,  and 
R.  La  Roche,  p.  257,  Philad.,  1832. 

^  De  Nervi  Sympath.  Human.,  &c.,  translated  by  Dr.  Pancoast,  Philad.,  1831. 

3  Amnion's  Monatschrift,  June,  1840;  and  Edinb.  Med.  and  Surg.  Journal,  Jan.,  1841, 
p.  a49. 

*  Elements  of  Physiology,  by  Baly,  i.  73t),  Lond.,  1838. 

*  Dissertation  on  "the  Pliysiological  Inferences  to  l)e  deduced  from  the  Structure  of 
the  Nervous  System  in  the  Invertebrated  Classes  of  Animals,  Edinb.,  1839;  reprinted 
in  Dunglison's  Meil.  Library,  Philad.,  1839;  also,  his  Principles  of  Human  Physiology, 
p.  Ill,  London,  1842. 


6-18  SENSIBILITY. 

not  developed  in  proportion  to  the  predominant  activity  of  the  func- 
tions of  organic  life,  but  in  proportion  to  the  developement  of  the 
higher  division  of  the  nervous  system,  its  office  is  not  to  preside  over 
the  former,  but  to  bring  them  in  relation  with  the  latter;  so  that  the 
actions  of  the  organs  of  vegetative  life  are  not  dependent  upon  it,  but 
influenced  by  it  in  accordance  with  the  operations  of  the  system  of 
animal  life. 

Again,  the  great  sympathetic  has  been  esteemed  to  be  the  visceral 
nerve  j)ar  excellence^  or  the  one  that  supplies  the  different  viscera  with 
their  nervous  influence, — a  part  of  its  office  as  the  presumed  nervous 
system  of  organic  functions.  On  examining  its  course,  we  find  many 
filaments  proceeding  from  the  cervical  and  thoracic  ganglions,  interlac- 
ing and  forming  the  cardiac  plexus,  from  which  the  nerves  of  the  heart 
and  great  vessels  arise.  The  same  thoracic  ganglions  furnish  a  branch 
to  each  intercostal  artery.  A  nerve  of  the  great  sympathetic — called 
the  qreat  splanchnic  or  visceral — proceeding  from  some  of  the  thoracic 
ganglions,  passes  through  the  pillars  of  the  diaphragm  into  the  abdo- 
men, and  terminates  in  the  large  plexus  or  ganglion,  called  the  semi- 
lunar;  and  this  by  uniting  with  its  fellow  of  the  opposite  side,  consti- 
tutes the  still  more  extensive  interlacing, — the  solar  plexus.  From  this, 
numerous  filaments  proceed,  which — by  accompanying  the  coronaria 
ventriculi,  hepatic,  splenic,  spermatic,  renal,  superior  and  inferior 
mesenteric,  and  hypogastric  arteries — are  distributed  to  the  parts  sup- 
plied with  blood  by  these  arteries, — the  stomach,  liver,  spleen,  testes, 
kidneys,  intestines,  &c.  Weber,^  however,  who  examined  the  great 
sympathetic  in  different  animals,  affirms,  that  the  splanchnic  may  not 
be  the  sole  visceral  nerve,  but  that  the  eighth  pair  may  share  in  the 
function.  He  states,  that  the  great  sympathetic  is  less  developed,  the 
lower  the  animal  is  in  the  scale ;  whilst  the  eighth  pair  is  more  and 
more  developed  as  we  descend,  and  at  length  is  the  only  visceral  nerve 
in  some  of  the  mollusca.  Sir  A.  Cooper's^  experiments  satisfied  him, 
that  this  nerve  is  essential  to  the  digestive  process;  but  of  this  we  shall 
have  to  speak  hereafter.  In  the  prosecution  of  those  experiments  he 
found,  that  when  the  great  sympathetic  was  tied  on  a  dog,  but  little 
effect  was  produced;  the  animal's  heart  appeared  to  beat  more  quickly 
and  feebly  than  usual;  but  of  this  circumstance  he  could  not  be  posi- 
tive, on  account  of  the  natural  quickness  of  its  action.  The  animal 
was  kept  seven  days,  at  which  time  one  nerve  was  ulcerated  through, 
and  the  other  nearly  so,  at  the  situation  of  the  ligatures.  Another  ani- 
mal on  which  the  sympathetic  had  been  tied  nearly  a  month  before, 
was  still  living  when  he  wrote.  When  the  pneumogastric  or  eighth 
pair,  the  phrenic,  and  the  great  sympathetic  were  all  tied  on  each  side, 
"  the  animal  lived  little  more  than  a  quarter  of  an  hour,  and  died  of 
dyspnoea."^ 

These  experiments  would  appear  to  show,  either  that  the  great  sym- 
pathetic is  not  so  indispensable  to  the  economy  as  has  been  imagined; 
or  that  it  is,  in  every  part,  a  generator  of  nervous  influence,  so  that 
if  its  connexion  with  the  brain  or  any  other  viscus  be  destroyed,  the 
divided  portions  may  still  possess  the  power  of  generating  nervous 

'  Anatom.  Coraparat.  Nerv.  Sjmpath.,  Lips.,  1817. 

*  Guy's  Hospital  Reports,  voL  i.  p.  457,  London,  1836.  »  Ibid.,  p.  471. 


EEFLEX  NERVOUS   SYSTEM.  649 

agency.  But  if  we  admit  this  as  regards  the  system  of  the  great  sym- 
pathetic, we  shall  find,  that  it  is  difficult  to  extend  it  to  detached  por- 
tions of  the  nervous  system  of  animal  life. 

It  must  be  confessed,  that  our  knowledge  of  the  uses  of  this  great 
division  of  the  nervous  system  is  far  from  being  precise;  for  whilst 
some  physiologists  believe  it  to  be  concerned  in  every  involuntary  and 
organic  action ;  Dr.  Proctor^  thinks,  that  the  nearest  approach  to  a 
positive  determination  of  its  use  that  we  can  arrive  at  with  our  present 
limited  knowledge  is,  that  "it  is  for  the  purpose  of  regulating  the  tonic 
contraction  of  the  arterial  system,  and  for  nothing  else."  One  distin- 
guished observer,  M.  Magendie,^  inquires  whether  we  have  sufficient 
reason  for  the  belief,  that  it  is  a  nerve  at  all!  and  a  writer  of  distinc- 
tion. Dr.  J.  C.  B.  Williams,^  admits,  that  nothing  is  definitely  known 
as  to  the  properties  communicated  by  ganglionic  nerves;  and  he  adds: 
''Before  the  influence  of  the  ganglionic  system  can  be  employed  as  an 
element  in  pathology,  its  existence  must  be  proved,  and  its  properties 
defined  in  physiology;  this  has  not  been  done." 

The  experiments  of  M.  Flourens,''  exhibited  that  the  semilunar  is 
the  only  ganglion  that  shows  any  great  sensibility ;  and  hence  it  has 
been  considered  as  a  sort  of  intervention  to  connect  the  viscera  with 
the  encephalon. 

5.  True  /Spinal,  Excito-Motory  or  Reflex  Nervous  System. — Until  of 
late  years,  the  nervous  system  was  commonly  divided  into  the  cerebro- 
spinal and  the  sympathetic;  although  there  were  numerous  functions 
of  a  reflex  character,  which  could  not  be  well  explained  by  them  ;  and 
which  had  attracted  the  attention  of  investigators  into  the  actions  of 
the  nervous  system.*  We  are  indebted  to  Dr.  Marshall  HalP  for  an 
additional  division,  which  throws  light  on  many  of  the  obscure  phe- 
nomena that  had  not  previously  received  elucidation.  He  has  pro- 
posed to  divide  all  the  nerves  into  1.  The  cerebral  or  sentient  and 
voluntary.  2.  The  true  spinal  or  excito-motory.  8.  The  ganglionic 
or  nutrient  and  secretory. 

If  the  sentient  and  voluntary  functions  be  destroyed  by  a  blow  on 
the  head,  the  sphincter  muscles  still  contract  when  irritated,  because 
the  irritation  is  conveyed  to  the  spine,  and  the  reflex  action  takes 
place  to  the  muscle  so  as  to  throw  it  into  contraction.  But  if  the 
spinal  marrow  be  now  destroyed,  the  sphincters  remain  entirely  mo- 
tionless ;  because  the  centre  of  the  sj'stem  is  destroyed.  Dr.  Hall 
thinks,  that  a  peculiar  set  of  nerves  constitute,  with  the  true  spinal 
marrow  as  their  axis,  the  second  subdivision  of  the  nervous  system ; 
and  as  those  of  the  first  subdivision  are  distinguished  into  sentient 

'  Merlico-Chirurg.  Eev.,  Jan.,  1845,  p.  182. 

2  Precis  de  Physiologie,  2de  edit.,  i.  171,  Paris,  1825. 

'  Principles  of  Medicine,  3d  Amer.  edit.,  by  Dr.  Clymer,  p.  200,  note,  Philad.,  1848. 

*  Reeherches  Experimentales  sur  les  Proprietes  et  les  Fonotions  du  Systeme  Nerveux, 
&c.,  2de  edit.,  p.  229,  Paris,  1842. 

^  Whytt,  An  Essay  on  the  Vital  and  other  Involuntary  Functions  of  Animals,  Edinb., 
1751 ;  The  Principles  of  Physiology,  by  John  Augustus  Unzer ;  and  A  Dissertation  on 
tlie  Functions  of  the  Nervous  System,  by  George  Prochaska ;  translated  and  edited  by 
Thomas  Laycock,  M.  D.,  Sydenliam  Society's  edit.,  London,  1851. 

^  Lectures  on  the  Nervous  System,  Loud.,  1836,  or  Amer.  edit.,  Philad.,  183G;  also, 
his  Lectures  on  the  Theory  and  Practice  of  Medicine,  in  London  Lancet,  Feb.  3  and 
Feb.  7,  1838. 


650  SENSIBILITY. 

and  voluntary,  these  may  be  distinguished  into  excitor  and  motory. 
The  first,  or  excitor  nerves,  pursue  their  course  principally  from  in- 
ternal surfaces,  characterized  by  peculiar  excitabilities,  to  the  vesicular 
centre  of  the  medulla  oblongata  and  medulla  spinalis;  the  second  or 
motor  nerves  pursue  a  reflex  course  from  the  medulla  to  the  muscles, 
having  peculiar  actions  concerned  principall}^  in  ingestion  and  egestion. 
The  motions  connected  with  the  first  or  cerebral  subdivision  are  some- 
times— indeed  frequently — spontaneous;  those  connected  with  the  true 
spinal  are,  he  believes,  always  excited.  Dr.  Hall  thinks  that  there  is 
good  reason  for  viewing  the  fifth,  and  posterior  spinal  nerves  as  con- 
stituting an  external  ganglionic  system  for  the  nutrition  of  the  external 
organs;  and  he  proposes  to  divide  the  ganglionic  subdivision  of  the 
nervous  system  into  1,  the  internal  ganglionic,  which  includes  that 
usually  denominated  the  sympathetic,  and  probably  filaments  of  the 
pneumogastric ;  and  2,  the  external  ganglionic,  embracing  the  fifth  and 
posterior  spinal  nerves.  To  the  cerebral  system  he  assigns  all  diseases 
of  sensation,  perception,  judgment,  and  volition, — therefore  all  pain- 
ful, mental,  and  comatose,  and  some  paralytic  diseases.  To  the  true 
spinal  or  excito-motory  or  refiex  system  belong  all  spasmodic  and  certain 
paralytic  diseases.  He  adds,  that  these  two  parts  of  the  nervous  sys- 
tem influence  each  other  both  in  health  and  disease,  as  they  both 
influence  the  ganglionic  system.^  This  reflex  faculty  is  regarded  by 
Dr.  Brown-Sequard^  as  a  vital  property  belonging  to  the  spinal  cord; 
and  its  source  he  refers  to  the  nutrition,  which  maintains  the  organiza- 
tion of  that  nervous  centre. 

The  views  of  Dr.  Hall  on  the  excito-motory  function  have  been 
embraced  by  Miiller,^  Grainger,*  Carpenter,*  and  indeed,  with  more  or 
less  modification,  by  almost  all  physiologists.^  The  last  named  gentle- 
man inferred  from  his  inquiries,  that  the  actions  most  universally  per- 
formed by  a  nervous  system  are  those  connected  Avith  the  introduction 
of  food  into  the  digestive  cavity,  and  that  we  have  reason  to  regard 
this  class  of  actions  as  every  where  independent  of  volition,  and  per- 
haps also  of  sensation, — the  propulsion  of  food  along  the  cesophagus, 
in  man,  being  of  this  character; — that  for  the  performance  of  any 
action  of  this  nature,  a  nervous  circle  is  requisite,  consisting  of  an 
afferent  nerve,  on  the  peripheral  extremities  of  which  an  impression  is 
made, — a  ganglionic  centre,  where  the  white  fibres  of  which  that  nerve 
consists  terminate  in  gray  matter,  and  those  of  the  efi'erent  nerve  ori- 
ginate in  like  manner;  and  an  efferent  trunk  conducting  to  the  contrac- 
tile structure  the  motor  impulse,  which  originates  in  some  change 
between  the  gray  and  white  matter ; — that  in  the  lowest  animals  such 
actions  constitute  nearly  the  entire  function  of  the  nervous  system, — 
the  amount  of  those  involving  sensation  and  volition  being  very  small ; 

'  Principles  of  the  Theory  aud  Practice  of  Medicine,  by  Marshall  Hall,  M.  D.,  F.  R.  S., 
p.  243,  London,  1837,  and  American  edit,  by  Drs.  Bigelow  and  Holmes,  Best.,  1839. 

2  Medical  Examiner,  August,  1852,  p.  483. 

3  Handbuch  der  Physiologie,  S.  333,  and  S.  688,  Coblenz,  1835,  1837,  or  the  English 
translation  by  Dr.  Baly,  i.  707,  London,  1838. 

*  On  the  Structure  and  Functions  of  the  Spinal  Cord,  London,  1837. 
»  Op.  cit. 

^  Todd  and  Bowman,  the  Physiological  Anatomy  and  Physiology  of  Man,  p.  312, 
London, 1845. 


FUNCTIONS   OF   NERVOUS   SYSTEM.  651 

but  as  we  ascend  the  scale,  the  evidence  of  the  participation  of  true 
sensation  in  the  actions  necessary  for  acquiring  food,  as  shown  by  the 
developement  of  special  sensory  organs,  is  much  greater;  but  that  the 
movements  immediately  concerned  with  the  introduction  of  food  into 
the  stomach  remain  under  the  control  of  a  separate  system  of  nerves 
and  ganglia,  to  the  action  of  which  the  influence  of  the  cephalic  gan- 
glia— the  special  if  not  the  only  seat  of  sensibility  and  volition — is 
not  essential;  that,  in  like  manner,  the  active  movements  of  respira- 
tion are  controlled  by  a  separate  system  of  nerves  and  ganglia,  and  are 
not  dependent  upon  that  of  sensation  and  volition,  although  capable 
of  being  influenced  by  it; — that  whilst  the  actions  of  these  systems 
are,  in  the  lower  tribes,  almost  entirely  of  a  simply  reflex  character, 
■we  find  them,  as  we  ascend,  gradually  becoming  subordinate  to  the 
will ;  and  that  this  is  effected  by  the  mixture  of  fibres  proceeding 
directly  from  the  cephalic  ganglia  with  those  arising  from  their  own 
centres; — that  the  locomotive  organs,  in  like  manner,  have  their  own 
centres  of  reflex  action,  which  are  independent  of  the  influence  of 
volition,  perhaps  also  of  sensation: — that  the  influence  of  the  will  is 
conveyed  to  them  by  separate  nervous  fibres,  proceeding  from  the 
cephalic  ganglia,  and  that  similar  fibres  probably  convey  to  the  cephalic 
ganglia  the  impressions  destined  to  produce  sensations; — that  the  sto- 
mato-gastric,  respiratory,  and  locomotive  centres  are  all  united  in  the 
spinal  cord  of  the  vertebrata,  where  they  form  one  continuous  gan- 
glionic mass,  and  that  the  nerves  connected  with  all  these  likewise 
receive  fibres  derived  immediately  from  the  cephalic  ganglia ; — and 
lastly,  that  whenever  peculiar  consentaneousness  of  action  is  required 
between  different  organs,  their  ganglionic  centres  are  united  more  or 
less  closely;  and  that  the  trunks  themselves  are  generally  connected 
by  bands  of  communication. 

On  the  whole,  in  the  present  state  of  our  knowledge,  we  are  justi- 
fied, perhaps,  in  adopting  the  systematic  summary  of  the  functions  of 
the  nervous  system,  and  the  general  purposes  to  which  it  is  inservient, 
as  originally  given  by  the  writer  last  cited,^  1.  The  nervous  system 
receives  impressions,  which,  being  conveyed  by  its  afferent  fibres  to 
the  sensorium,  are  there  communicated  to  the  conscious  mind ;  and 
are  inservient,  in  some  manner,  to  the  acts  of  that  mind.  As  the  re- 
sult of  these  acts,  a  motor  impulse  is  transmitted  along  efferent  nerves 
to  particular  muscles,  which  excites  them  to  contraction.  Of  these 
acts  the  encephalon,  and  nerves  communicating  with  it,  are  the  organs. 
2.  Certain  parts  of  the  nervous  system  receive  impressions,  which  are 
propagated  along  afferent  fibres  that  terminate  in  ganglionic  centres 
distinct  from  the  sensorium.  In  these,  a  reflex  motor  impulse  is  thus 
excited,  which  is  transmitted  along  efferent  trunks  proceeding  from 
those  centres,  and  excites  muscidar  contraction  without  any  necessary 
intervention  of  sensation  or  volition.  The  organs  of  this  function  are 
the  gray  matter  of  the  spinal  cord,  which  is  not  continuous  with  the 
fibrous  structure  of  the  brain,  and  the  trunks  connected  with  it.  It  is 
the  true  spinal  or  excito-motory  system  of  Dr.  Hall,  3.  There  is  yet  a 
division  of  the  nervous  system,  which  appears  to  have  for  its  object  to 

■  Human  Pliysiology,  p,  79,  London,  1842;  see  also  Amer.  edit.,  Philad.,  1854. 


652  SENSIBILITY. 

combine  and  harmonize  the  muscular  movements  immediately  con- 
nected with  the  maintenance  of  organic  life.  It  may  likewise  influ- 
ence, and  connect  with  each  other  the  functions  of  nutrition,  secretion, 
&c. ;  although  these — like  the  muscular  movements  immediately  con- 
nected with  the  maintenance  of  organic  life — are  doubtless  essentially 
independent  of  it ;  and — as  has  been  shown — can  be  carried  on  where 
it  does  not  exist.  The  organ  of  these  acts  is  the  great  sympathetic. 
Of  late — as  will  be  seen  hereafter — Dr.  Carpenter^  has  contended  with 
much  force  for  the  existence  of  a  series  of  sensory  ganglia,  separate 
and  distinct  from  those  that  compose  the  cerebrum  and  cerebellum — • 
"  ganglia  of  the  nerves  of  sensation,  common  and  special,  which  are 
superposed,  as  it  were,  on  the  medulla  oblongata,"  and  which,  together, 
constitute  the  real  sensorium. 

It  has  been  urged  by  Dr.  Laycock,^  in  a  paper  read  before  the 
British  Association  at  York,  in  accordance  with  views  published  by 
him  four  years  previously,  that  the  brain,  although  the  organ  of  con- 
sciousness, is  subject  also  to  the  laws  of  reflex  action  ;  and  that  in  this 
respect  it  does  not  differ  from  other  ganglia  of  the  nervous  sj^stcin. 
He  regards  the  cerebral  nerves,  and  especially  the  optic,  auditory,  and 
olfactory,  as  afferent  excitor  nerves,  along  which  impressions  pass  to 
the  central  axis;  thence  to  be  communicated  to  the  motor  nerves,  and 
thus  give  rise  to  combined  muscular  acts,  or  to  irregular  spasmodic 
movements.  Hydrophobia  is  adduced  by  him  as  a  good  illustration 
of  these  cerebral  refiex  movements.  The  acknowledged  excito-motoiy 
phenomena  in  that  disease  may  be  induced. — First.  Through  the  nerviis 
of  touch,  as  by  the  contact  of  water  with  the  surface  of  the  head, 
hands,  chest,  lips,  and  pharynx.  Secondly.  By  a  current  of  air  im- 
pinging on  the  face  or  chest.  Thirdly.  By  a  bright  surface,  as  a  mir- 
ror. Fourthly.  By  the  sight  of  water;  and  Fifthly.  By  the  idea  <>f 
water,  as  when  it  is  suggested  to  the  patient  to  drink.  The  author 
has  been  in  the  habit  of  offering  as  an  example  of  the  same  kind, 
vomiting  induced  by  the  sight  of  a  disgusting  object.  Here  the  im- 
pression is  first  made  upon  the  brain  through  an  organ  of  sense,  and 
the  reflex  motor  phenomena  concerned  in  vomiting  are  instantaneously 
excited; — facts,  which  at  least  prove,  that  although  the  gray  matter  of 
the  spinal  marrow  may  continue  to  execute  its  functions,  when  those 
of  the  cerebro-spinal  nervous  system  are  suspended, — as  during  sleep 
or  an  attack  of  epilepsy, — it  is  capable  of  being  excited  to  action  by 
impressions  made  through  the  latter,  in  the  same  manner  as  by  im- 
pressions made  on  the  afferent  spinal  nerves  themselves. 

From  all  that  has  been  said,  it  will  be  understood,  that  each  nerve 
as  it  issues  from  the  spinal  canal  must  be  composed  of  various  fasci- 
culi : — one,  sensory  or  of  sensation,  connected  with  the  posterior  me- 
dullary tract,  and  continuous  with  the  medullary  matter  of  the  brain; 
another,  connected  with  the  anterior  medullary  tract,  and  conveying 
the  influence  of  volition  from  the  brain  along  the  spinal  cord  and 
nerves  to  the  muscles ;  a  third,  consisting  of  excitor  fibres,  terminating 

'  Human  Physiology,  4th  Amer.  edit.,  p.  320,  Philad.,  1850,  and  new  edit.,  p.  488, 
Philad.,  1855. 

^  British  and  Foreign  Medical  Review,  Jan.,  1845,  p.  298  ;  see  also  an  interesting 
essay  by  him  on  the  Functions  of  the  Brain,  iu  Brit,  and  For.  Med.-Cliir.  Rev.,  July, 
1855,  p.  155. 


SPINAL   NERVES. 


653 


Fig.  205. 


in  tlie  gray  or  ganglionic  matter  of  the  cord,  and  conve3n'ng  impres- 
sions to  it;  and  a  fourth,  consisting  of  motor  fibres,  arising  from  the 
gray  matter  of  the  cord,  and  conveying  the  nervous  influence  reflected 
to  the  muscles. 

It  would  appear  that  a  part  of  each  root 
enters  the  gray  matter  of  the  cord;  whilst  a 
part  is  continuous  with  the  white  or  medul- 
lary matter;  and  Dr.  Stilling^  affirms — as 
the  result  of  his  researches — that  of  the  fibres 
of  the  posterior  roots  some  form  loops  in  the 
gray  matter,  and  become  continuous  with 
those  of  the  anterior  roots  of  the  same  side; 
whilst  others  cross  the  gray  matter,  and  be- 
come continuous  with  those  of  the  anterior 
roots   of    the   opposite   side.      It   has   been 

Fig.  206. 


Transverse  Section  of  the  Medulla. 
The  transverse  gray  fibres  are  the  continuation  of  the  roots 
of  the  nerves ;  the  longitudinal  white  and  gray  fibres  are  indi- 
cated by  points. 


Structure  of  the  Spinal  Cord,  ac- 
cording to  Stilling. 

A.  Posterior  fibres  continuous  with 
the  anterior  of  the  same  side, 
through  the  nucleus  of  the  cord. 
B.  Posterior  fibres  continuous  with 
the  anterior  of  the  opposite  side. 


shown,  too,  by  Mr.  Newport,^  that  there  are  other  fibres,  which  pass 
from  the  posterior  into  the  anterior  roots  of  other  nerves,  above  and 
below,  both  on  the  same  and  the  opposite  side. 

It  has  been  a  matter  of  daily  observation,  that  hemorrhage  into  one 
hemisphere  of  the  brain  produces  loss  of  sensation  in  the  opposite  side 
of  the  body  ;  and  the  decussation  of  the  sensory  fibres  has  generally, 
perhaps,  been  considered  to  take  place  in  the  medulla  oblongata ;  whilst 
some  physiologists  have  referred  it  to  the  pons  varolii,  tubercula  quad- 
rigemina,  and  crura  cerebri.  Dr.  Brown-Sequard,-^  however,  found, 
from  experiments  on  guinea-pigs,  dogs,  cats,  sheep  and  rabbits,  that  in 
the  case  of  a  lesion  of  one  side  of  the  spinal  cord,  a  diminution  or  loss 
of  sensibility  is  produced  on  the  opposite  side  of  the  body,  whence  he 
infers,  that  most  of  the  impressions  made  on  one  side  of  the  body  are 
transmitted  to  the  sensorium  by  the  opposite  side  of  the  spinal  cord. 
This  is  the  reverse  of  what  occurs  in  regard  to  motion ;.  for  a  lesion  of 
the  right  side  of  the  spinal  cord  causes  a  loss  or  diminution  of  voluntary 
movements  in  the  same  side  of  the  body;  and  this  is  explained  by  the 

'  Untersucliungen  iiber  die  Textur  des  Riickenmarks,  von  Dr.  B.  Stilling  und  Dr. 
J.  Wallach,  S.  51,  Leipz.,  1842. 

2  Pliilosopliical  Transactions,  1843,  and  Dr.  Carpenter,  2d  Amer.  edit.,  p.  125, 
Philad.,  1845. 

*  Medical  Examiner,  Nov.  1852,  p.  708,  and  his  Experimental  and  Clinical  Re- 
searches on  the  Physiology  and  Pathology  of  the  Spinal  Cord  and  some  other  parts  of 
the  nervous  centres,  Richmond,  1855. 


654  SEXSIBILITY. 

motor  fibres  decussating  in  the  medulla  oblongata  only ;  whilst  the 
decussation  of  the  sensorj^  occurs  in  every  part  of  the  spinal  cord. 

Much,  doubtless,  still  remains  to  be  accomplished,  before  we  can 
consider  views  in  regard  to  the  nervous  system  established.  Like  many 
important  questions  of  physiology,  they  may  be  regarded  as  in  a  tran- 
sition state;  but  the  zeal  and  activity  of  physiological  inquirers  are 
dail}^  throwing  light  upon  many  points ;  and  of  these  there  are  none  sur- 
rounded with  more  obscurity  than  those  that  appertain  to  this  subject. 

All  the  parts  described  as  constituting  the  nervous  system — brain, 
cerebellum,  medulla  spinalis,  and  nerves — are  formed  of  the  primary 
nervous  fibre,  the  nature  of  which  has  been  already  described.  The 
neurine  or  substance  of  which  they  are  constituted  is  soft  and  pulpy; 
but  the  consistence  varies  in  different  portions,  and,  in  the  whole,  at 
different  ages.  In  the  foetus  it  is  almost  fluid ;  in  youth  of  greater 
firmness;  and  in  the  adult  still  more  so.  This  softness  of  structure  in 
the  encephalon  of  the  foetus  is  by  no  means  inutile.  It  admits  of  the 
pressure,  which  takes  place,  to  a  greater  or  less  extent  in  all  cases  of 
parturition,  whilst  the  head  is  passing  through  the  pelvis,  without  the 
child  sustaining  any  injury.  On  examining,  however,  the  consistence 
of  different  brains,  it  is  necessary  to  inquire  into  the  period  that  has 
elapsed  since  the  death  of  the  individual,  as  the  brain  loses  its  firm- 
ness by  being  kept;  and  ultimately  becomes  semi-fluid.  It  is  likewise 
rendered  fluid  by  disease,  constituting  ramollissement  du  cerveau  or 
moUescence  of  the  brain,  to  which  the  attention  of  pathologists  has  been 
directed  of  comparatively  late  years,  but  without  much  important 
advantage  to  science. 

When  the  encephalon  is  fresh,  it  has  a  faint,  spermatic,  and  some- 
what tenacious  smell.  This,  according  to  M.  Chaussier,  has  persisted 
for  years  in  brains  that  have  been  dried. 

Neurine  has  been  subjected  to  analysis  by  M.  Yauquelin,'  and  found 
to  contain,  water,  80'00 ;  white  fatty  matter,  4*58  ;  red  fatty  matter, 
called  cerebrin,  O'TO ;  osmazome,  1"12 ;  albumen,  7*00 ;  phosphorus, 
1*50  ;  sulphur,  and  acid  phosphates  of  potassa,  lime,  and  magnesia,  5"15. 
M.  Couerbe's  analysis  of  that  of  the  brain^  gives,  1.  A  pulverulent 
yellow  fat,  stearconote ;  2.  An  elastic  yellow  fat,  cerancephahte ;  3.  A 
reddish -yellow  oil,  eleancephol ;  4.  A  white  fatty  matter,  cerebrate,  the 
white  fatty  Tyiatter  of  Vauquelin,  the  wyelocone  of  Klihn  ;  5.  Cerebral 
cholesterin — cholesterote;  and  the  salts  found  b}'-  Vauquelin, — lactic 
acid,  sulphur,  and  phosphorus,  which  form  a  part  of  the  fats  above 
mentioned.^  In  the  spinal  cord,  there  is  more  fatty  matter,  and  less 
osmazome,  albumen,  and  water.  In  the  nerves,  albumen  predominates, 
and  fatty  matters  are  less  in  quantity.  Eesearches  by  M.  Lassaigne 
show,  that  water  constitutes  ^Qths  of  the  nerves ;  and  -^^t\\&  of  the 
brain ;  whilst  the  proportion  of  albumen  in  the  former  is  ,^0^0^^^  !  i^ 
the  latter,  y^^ths.  He  found  the  neurine  of  different  parts  of  the  brain 
to  be  compcjsed  as  follows: 

'  Annales  de  Cliim.,  Ixxxi.  37 ;  and  Annals  of  Philosophy,  i.  332. 

*  Annales  de  Chimie  et  de  Physique,  Ivi.  160. 

'  For  John's  Analysis  of  the  white  and  gray  cerebral  matter,  see  Journal  de  Chimie 
Medicale,  Aout,  1835.  See,  also,  Simon's  Medical  Chemistry,  p.  81,  Lond.,  Is45  ;  or 
Amer.  edit.,  Philad.,  1846. 


NERVOUS 

TISSUE 

• 

65 

The  whole  B 

rain. 

White  portion. 

Gray  portion. 

Water, 

77-0 

73-0 

'85-0 

Albumen, 

9-6 

9-9 

7-5 

White  fatty  matter, 

7-2 

13-9 

1-0 

Red  fatty  matter, 

3-1 

0-9 

3-7 

Osmazome,  lactic  acid, 

and  salts,       2*0 

1-0 

1-4 

Earthy  phosphate, 

1-1 

1-3 

1-2 

100-0  100-0  100-0' 

M.  EaspaiP  has  pointed  out  two  other  differences.  First^  when  a 
nerve  is  left  upon  a  plate  of  glass  in  dry  air,  it  becomes  dry,  without 
putrefying,  whilst  cerebral  neurine  putrefies  in  twenty-four  hours;  and 
secondly^  the  dried  nerve  has  all  the  physical  characters  of  the  corneous 
substances, — nails,  hair,  and  other  analogous  bodies ;  and  in  their 
chemical  relations,  these  bodies  do  not  differ  sufficiently  to  repel  the 
analogy.  Neither  the  chemical  analysis  of  neurine,  nor  inquiry  into 
its  minute  structure  by  the  aid  of  the  microscope,  has,  however,  thrown 
light  upon  the  wonderful  functions  executed  by  this  elevated  part  of 
the  organism. 

It  would  seem,  that  neurine  is,  in  composition,  intermediate  between 
fat  and  the  compounds  of  protein ;  it  contains  nitrogen,  which  is  not 
present  in  fats,  but  in  smaller  proportion  than  in  protein ;  and,  on  the 
other  hand,  it  is  much  richer  in  carbon  than  protein  or  its  compounds. 
Phosphorus,  too,  is  an  essential  ingredient.  According  to  researches 
by  M.  Fremy,  there  is  in  cerebral  neurine  a  peculiar  acid,  analogous 
to  the  fatty  acids,  which  he  calls  cerehric  acid,  and  which  contains  nitro- 
gen and  phosphorus ;  this  is  mixed  with  an  albuminous  substance; 
with  an  oily  acid — oleo-phosphoric ;  with  cholesterin  ;  and  with  small 
quantities  of  olein  and  margarin,  and  oleic  and  margaric  acids.^ 

As  Lehmann,''  however,  has  remarked,  the  analysis  of  the  nervous 
tissue  is  still  very  imperfect.* 

To  the  naked  eye,  neurine  appears  under  two  forms; — the  one  gray 
and  of  a  softer  consistence;  the  other  white,  and  more  compact.  The 
former  is  called  the  vesicular,  gray,  cortical,  cirieritious,  or  puljyy  sub- 
stance; the  latter,  the  tubnlar,  white,  Tnedullary,  or  fibrous,  called 
"tubular"  in  consequence  of  its  consisting  of  tubes  of  great  minute- 
ness, which  are  filled  with  a  kind  of  granular  albuminous  pith  that  can 
be  squeezed  from  them, — a  view  adopted  by  most  histologists.  Dr. 
James  Stark  has,^  however,  affirmed,  as  the  result  of  his  examination, 
— and  Mulder  and  Bonders  accord  with  him — that  the  matter  which 
fills  the  tubes  is  of  an  oily  nature,  differing,  in  no  essential  respect, 
from  butter  or  soft  fat,  and  remaining  of  a  fluid  consistence  during  the 

'  Journal  de  Chim.  Medic. ;  and  Pharmaceutisches  Central  Blatt,  Nov.  19,  1836,  S. 
765. 

^  Cliiraie  Organique,  p.  217,  Paris,  1833. 

'  Journ.  des  Coiniais.  Med.-Chir.,  Jan.,  1841;  also  Turuer  and  Liebig's  Chemistry, 
7th  edit.,  p.  1195,  Lend.,  1842. 

''  Lehrbuch  der  Physiologischen  Chemie,  iii.  123,  Leipzig,  1851  ;  and  Amer.  edit,  of 
Dr.  Day's  translation,  by  Dr.  Robert  E.  Rogers,  ii.  266,  Pliilad.,  1855. 

^  For  the  recent  analyses  of  the  neurine  of  man  and  the  mammalia,  by  Von  Bibra, 
Schlossberger,  and  others,  see  an  excellent  resume  by  Dr.  Dav,  in  Brit,  and  For.  Med.- 
Chir.  Rev.,  July,  1855,  p.  223. 

^  Proceedings  of  the  Royal  Society,  No.  56,  Lond.,  1843. 


656 


SENSIBILITY. 


life  of  the  animal,  or  whilst  it  retains  its  natural  temperature ;  but  be- 
coming granular  or  solid  when  the  animal  dies. 

Lehmann'  is  of  opinion,  that  although  it  is  difficult  to  obtain  direct 
proof  from  microscopical  observations,  or  rather  to  form  a  judgment 
from  them,  the  descriptions  of  the  alterations  experienced  by  the  me- 
dulla or  nerve-pulp  on  the  addition  of  different  reagents — in  becoming 
coarsely  or  finely  granular  or  crystalline — seem  to  indicate,  that  the 
nerve-pulp  contains  a  soluble  protein  substance,  in  the  closest  admix- 
ture'with  a  fat  dissolved  by  easily  decomposable  soaps,  and  that  the 
visibility  of  the  pulp  is  owing  less  to  the  coagulation  of  this  albuminous 
body  than  to  the  separation  of  the  fat  from  the  decomposing  soaps  and 
the  albuminous  substance.  The  pitli  that  fills  the  tubes  or  the  axis 
cylinder  he  regards  as  a  protein  substance  presenting  many  resem- 
blances to  the  sub- 
Fig.  207.  stance  of  the  muscu- 
lar fibrils — syntonin ; 
and  he  dissents,  there- 
fore, from  the  view  of 
those — as  Mulder  and 
Bonders — who  regard 
it  to  be  composed  of 
fat,  or  at  all  events  of 
a  very  fatty  substance. 
The  tubular  nervous 
matter,  wherever  it  is 
found,  seems  to  consist 
of  fibres,  which  have  a 
definite  arrangement. 
Two  kinds  of  primi- 
tive fibre,  according 
to  the  researches  of 
Messrs.  Todd  and 
Bowman,^  are  present 
in  the  nervous  sys- 
tem, which  they  dis- 
tinguish as  the  tubular 

A.  Tubular  nerve-fibres,  showing  the  sinuous  outline  and  double    Jlbre  OT  lierve  tubc,  and 
contours. 

B.  Diagram  to  show  the  parts  of  a  tubular  fibre,  viz. :  1,  1.  Mem- 
branous ttiAe.  2,2.  White  sitbstance  or  medullary  sheath.  Z.  Axis  ox 
primitive  band. 

c.  Figure  (imaginary)  intended  to  represent  the  appearances  occa- 
sionally seen  in  the  tubular  fibres.     1,  1.  Membrane  of  the  tube  seen 
at  parts  where  the  wliite  substance  has  separated  from  it.     2.  A  part 
where  the  white  substance  is  interrupted.     3.  Axis  projecting  beyond      r»Viipfl\;-  in     tliA    Qirmnri 
the  broken  end  of  the  tube.     i.  Part  of  the  contents  of  the  tube  es-     '-'"i^^J    ^"    ''^«   by  mpd- 

caped.  thetic    system.      The 

tubular  fibres  vary  in 
diameter  from  i-s'stj^^  even  to  toooo^^i  of  an  inch;  but  their  average 
width  is  from  ao'ootl^  to  4o'o?)th  of  an  inch.  The  gelatinous  fibre  is 
devoid  of  the  whiteness  that  characterizes  the  tubular  fibre;  and  the 
gray  colour  of  certain  nerves,  it  has  been  thought,  is  dependent  chiefly 

'  Op.  cit. 

*  Dr.  Todd,  Art.  Nervous  Centres,  in  Cyclop,  of  Anat.  and  Pliys.,  Pt.  xxvi.,  p.  707  ; 
and  The  Physiological  Anatomy  and  Physiology  of  Man,  p.  208,  Loudon,  1845. 


Tubular  Nerve-fibres. 


the  gelatinous  fibre, — 
the  former  infinitely 
the  more  numerous, 
and  the  latter  found 


CIRCULATIOISr  IN  THE   ENCEPHALON. 


657 


Gelatinous  Nerve-fibres. 

a  and  ftmagnifiod  340  diameters,  after  Han- 
nover :  c  and  d  after  Kemak. 


upon  the  presence  of  a  large  proportion  of  gelatinous  fibres.     Hence 
they  have  been  sometimes  termed  gray  fibres.     These  are  in  general 
smaller  than  the  tubular  fibres, — their 
average  diameter  ranging  between  the 
gjj'ofjth  and  the  4o'oo^^^  of  an  inch.^ 

The  central  portion  of  each  nerve- 
fibre  dii^ers  from  the  peripheral :  the 
former  has  been  termed  by  Rosenthal 
and  Purkinje  the  axis-cylinder;  the 
latter  is  the  medullary  or  loliite  sub- 
stance of  Schwann,  and  to  it  the  white 
colour  of  the  cerebro-spinal  nerves  is 
chiefly  due. 

The  researches  of  histologists  have 
shown  that  vesicles  or  cells  containing 
nuclei  and  nucleoli,  and  called  also 
7ierve  corpuscles  and  globules  and  gnn- 
glion  corpuscles  and  globules,  are  the  es- 
sential elements  of  gray  or  vesicular  matter.  These  are  found  in  the 
nervous  centres,  mingled  with  nerve-fibres,  and  imbedded  in  a  dimly 
shaded  or  granular  substance.  They  give  to  the  ganglia  and  to  certain 
parts  of  the  brain  and  spinal  cord  the  peculiar  urayish  or  reddish-gray 
appearance  by  which  they  are  characterized.  They  are  large  nucleated 
cells,  filled  with  a  finely  granular  material; 
some  of  which  is  often  dark,  like  pigment; 
— the  nucleus,  which  is  vesicular,  contain- 
ing a  nucleolus.  The  marginal  figure  (Fig. 
209)  represents  some  that  have  a  regular 
outline.  Others,  as  in  Fig,  210,  are  caudate 
or  stellate,  and  have  tubular  processes  issu- 
ing from  them,  filled  with  the  same  kind 
of  granular  matter  as  is  contained  in  the 
corpuscle. 

The  gray  substance  is  not  always  at  the 
exterior,  nor  the  medullary  in  the  interior. 
Ill  the  medulla  spinalis,  their  situation  is 
the  reverse  of  what  it  is  in  the  brain.     In 

the  invertebrata,  the  gray  matter  forms  the  nuclei  of  the  ganglia,  which 
are  the  centres  of  the  nervous  system ;  and  the  true  spinal  system, 
which  occupies  the  interior  of  the  spinal  cord,  has  been  regarded  as  a 
chain  of  similar  ganglia.  It  is  the  organ,  as  already  shown,  of  the 
spinal  excito-motory  nervous  function.  Ruyscjh  considered,  that  the 
gray  portion  owes  its  colour  to  the  bloodvessels  that  enter  it;^  and,  in 
this  opinion,  Haller,  Adelon,^  and  others,"  concur ;  but  this  is  not  pro- 
bable, and  it  has  not  been  by  any  means  demonstrated,  nor  has  the 

'  See  on  the  disputes  in  regard  to  the  two  sets  of  nerve  fibres,  and  especially  on  the 
so  called  fibres  of  Remak  or  gelatinous  fibres,  Dr.  J.  Drummond,  Art.  Sympathetic  Nerve, 
in  Cyclop,  of  Anat,  and  Physiol,,  Ft.  xlvii.  p.  433,  London,  August,  1855. 

^  bper.,  Amstel.,  1727. 

3  Physiologie  de  I'llomme,  2de  edit.,  i.  208,  Paris,  1829. 

*  Carpenter,  Human  Physiology,  p.  81,  Lond,,  1842. 
VOL.  I. — 42 


Ganglion  Corpuscles. 

In  one  a  second  nucleus  is  visible. 
The  nucleus  of  several  contains  one  or 
two  nucleoli. 


658 


SENSIBILITY. 


210. 


nature  of  the  pigmental  matter  been  detected.^  The  medullary  portion 
has  the  appearance  of  being  fibrous ;  and  it  has  been  so  regarded 
by  Leeuenhoek,^  Yieussens,  Steno,  and  Gall  and  Spurzheim.^  Mal- 
pighi''  believed  the  gray  cortical  substance  to  be  an  assemblage  of 

small  follicles,  intended  to 
secrete  the  nervous  fluid;  and 
the  white  medullary  sub- 
stance to  be  composed  of  the 
excretory  vessels  of  these 
follicles ;  and  an  analogous 
view  is  entertained  by  many 
physiologists  of  the  present 
day, — the  gray  matter  at 
least  being  regarded  as  the 
generator  of  the  nervous  in- 
fluence; the  white  matter  as 
chiefly  concerned  in  its  con- 
duction. Gall  and  Spurz- 
heim  conjecture,  that  the  use 
of  the  gray  matter  is  to  be 
the  source  or  nourisher  of 
the  white  fibres.  The  facts, 
on  which  they  support  their 
view,  are,  that  the  nerves 
appear  to  be  enlarged  when 
they  pass  through  a  mass  of 
gray  matter,  and  that  masses 
of  this  substance  are  dej^osit- 
ed  in  all  parts  of  the  spinal 
cord  where  it  sends  out 
nerves;  but  Tiedemann*  has 
remarked,  that  in  the  foetus 
the  medullary  is  developed 
before  the  cortical  portion,  and  he  conceives  the  use  of  the  latter  to  be 
— to  convey  arterial  blood,  which  may  be  needed  by  the  medullary 
portion  for  the  due  execution  of  its  functions.  After  all,  however,  it 
must  be  admitted  with  Dr.  Allen  Thomson,^  that  the  general  conclusion 
deducible  from  all  the  facts  would  seem  to  be,  that  whilst  the  gray 
fibres  predominate  in  the  organic  or  sympathetic  nerves,  and  the  tubu- 
lar fibres  in  the  cerebro-spiual  nerves,  these  two  elements  are  mixed, 
in  various  proportions,  in  the  great  divisions  of  the  nervous  system; 
and  that,  therefore,  these  divisions,  although,  in  a  great  measure,  struc- 
turally different,  are  not  altogether  distinct  from,  or  independent  of, 
each  other.  "But" — he  properly  adds — "in  regard  to  the  whole  sub- 
ject of  the  structures  and  nature  of  the  different  varieties  of  the  nerv- 


Stellate  or  Caudate  Xerve  Corpuscles. 

a,  a.  From  the  deeper  part  of  the  gray  matter  of  the  con- 
volutions of  the  cerebellum.  The  larger  processes  are  di- 
rected towards  the  surface  of  the  organ.  6.  Another  from 
the  cerebellum,  c,  d.  Others  from  the  post-horn  of  gray 
matter  of  the  dorsal  region  of  the  cord.  These  contain  pig- 
ment, which  surrounds  the  nucleus  in  c.  In  all  the  speci- 
mens the  processes  are  more  or  less  broken.  Magnified  200 
diameters. 


'  Todd,  Cvclop.  of  Anat.  and  Thysiol.,  Pt.  xxv.  p.  647,  Lond.,  1844. 

2  Philo.-?.  Transact.,  1677,  p.  899. 

^  Recherches  sur  le  Systeme  Nerveux  en  general,  et  sur  celui  du  Cerveau  en  parti- 
culier,  avec  figures,  Paris,  1809. 

*  Oper.  Malpighii,  and  Mangeti  Bibl.  Anat.,  i.  321. 

*  Anatomie  und  Bildungsgeschichte  des  Gehirns,  mit  Tafeln,  Niimberg,  1816. 
6  Outlines  of  Physiology,  Pt.  i.  p.  155,  Edinb.,  1848. 


CIRCULATION   IN   THE   ENCEPHALON. 


659 


ous  texture,  it  is  unquestionable  that  mucli  still  remains  to  be  ascer- 
tained by  laborious  investigation." 

Of  the  mode  in  which  the  tubular  neurine  communicates  with  the 


Fig.  211. 


Fig.  212. 


Microscopic  Ganglion  from  Heart  of  Frog.         Bipolar  Ganglionic  Cells  and  Nerve-fibres  from 
Unipolar  Ganglionic  Cell.  ganglion  of  5th  Pair  in  Lamprey. 

vesicular  we  know  nothing,  as  yet,  that  is  very  definite;  that  a  direct 
communication  must  exist  appears  to  be  evident.     Histologists  have 

Fig.  213. 


Connection  between  nerve-fibres  and  nerve  corpuscles ;  from  the  roots  of  a  spinal  nerve  of  the  ray. 
A.  A  nerve-corpuscle,  escaped  by  pressure  from  the  capsule  formed  around  it  by  the  dilated  slieath  of 
the  nerve-tubule;  it  shows  also  the  gradual  disappearance  of  the  outer  portion  of  the  substance  of  the 
nerve  as  it  comes  into  relation  with  tJie  corpuscles,  b.  A  nerve-corpuscle  inclosed  within  a  dilated  por- 
tion of  the  sheath  of  a  nerve:  part  of  the  granular  material  of  the  corpuscle  is  continuous  with  the  cen- 
tral substance  of  the  nerve  in  the  course  of  which  it  is  inserted. 

detected  it,  and  it  has  been  noticed,  that  a  vesicle  or  cell  gives  off  at 
times,  a  single  prolongation,  in  which  case  the  ganglionic  cell  is 
termed — unipolar ;  whilst  at  others,  a  ganglion  cell  seems  to  be  con- 
tained in  a  nerve-tube,  having  each  of  its  extremities  prolonged  into 
a  fibre  or  tubule,  when  the  cell  is  termed — bipolar.  The  former  is  said 
to  be  more  common  in  man  and  the  higher  vertebrata, — the  latter  in 
fishes.  In  certain  parts  of  the  nervous  centres  of  man,  stellate  gan- 
glionic cells  send  out  radiating  prolongations,  some  of  which  luive 
been  observed  communicating  with  the  axis  cylinder  of  nerve  tubes.' 
Bidder  noticed  the  transition  of  primitive  fibre  cells  of  the  roots  of  the 
spinal  nerves,  as  well  as  the  longitudinal  fibres  of  the  white  substance 


'  Ecker,  in  Carpenter's  Principles  of  Human  Physiology,  Amer.  edit.,  p.  431,  Philad. 
1855. 


660 


SENSIBILITY. 


into  cells  of  the  gray,  in  great  abundance.'  Vesicles  or  corpuscles 
are  seen,  however,  that  do  not  seem  to  be  immediately  connected 
with  nerves.^ 

Sir  Charles  BelP  affirms,  that  he  has  found,  at  different  times,  all  the 

internal   parts   of    the   brain 
Fig-  214.  diseased,  without  loss  of  sense; 

but  he  has  never  seen  disease 
general  on  the  surface  of  the 
hemispheres  without  derange- 
ment or  oppression  of  mind 
during  the  patient's  life  ;  and 
hence  he  concludes,  that  the 
vesicular  matter  of  the  brain 
is  the  seat  of  the  intellect,  and 
the  tubular  of  the  subservient 
parts.^  A  similar  use  has  been 
ascribed  to  the  vesicular  por- 
tion, from  pathological  ob- 
servations, by  MM.  Foville 
and  Pinel  Grandchamp.*  This 
view  would  afford  consider- 
able support  to  the  opinions  of 
Gall,  Spurzheim,  and  others, 
who  consider  the  organs  of 
the  cerebral  faculties  to  be  con- 
stituted of  expansions  of  the 
columns  of  the  spinal  marrow 
and  medulla  oblongata,  and  to 
Circle  of  Willis.  terminate  by  radiating  fibres 

1.  Vertebral  arteries.  2.  Two  anterior  spinal  branches  qjj  t,he  periphery  of  the  brain  ; 
uniting  to  form  a  single  vessel.    3.  One  of  the  posterior  r        /       -i  "^  n  ->•-    -r>. 

spinal  arteries.     4.  Posterior  meningeal.     5.  Interior  cere-  aS   Weli  aS  tO  tllOSC  Ol    iVl.  JJCo- 

bellar.    6.  Basilar  arterygiving  off  its  transverse  branches  ^  _,,!  •     q  <>   nnrl     nthpTS  who    TH- 

to  either  .side.     7.  Superior  cerebellar  artery.    8.  Posterior  mOUlins,      aUQ    OlUClhWIlO    i  O- 

cerebral.     9.   Po.sterior  communicating  branch  of  the  in-  g-ard  thc    COUVOlutioUS    aS    the 

ternal  carotid.     10.  Internal  carotid,  showing  the  curva-  S"^^     „      ■,  .      i  ttt      i 

tures  it  makes  within  the  skull.  11.  Ophthalmic  artery  gg^t  of  the  UllUd.  We  haVC, 
divided  across.     12.  Middle  cerebral  artery.     13.  Anterior  J    4.1     4. 

cerebral  arteries  connected  by,  l-l.  Anterior  communicat-  nOWCVCr,  CaSCS  OU   TeCOrQ,  lUat 

^"s  '^''•''■y-  signally  conflict  with  this  view 

of  the  subject;  in  which  the  cortical  substance  has  been  destroyed,  and 
yet  the  moral  and  intellectual  manifestations  have  been  little,  if  at  all, 
injured.  Many  years  ago,  the  author  dissected  the  brain  of  an  indi- 
vidual of  rank  in  the  British  army  of  India,  in  the  anterior  lobes  of 
which  neither  medullary  nor  cortical  portion  could  be  distinguished, — 
both  one  and  the  other  appearing  to  be  broken  down  into  a  semi-puru- 

'  Dr.  J.  W.  Ogle,  Report  of  Micrology,  in  Brit,  and  For.  Med.-Chir.  Rev.,  Oct.,  1855, 
T)   525. 

"*  See,  on  all  this  subject,  KoUiker,  Mikroskopische  Anatomie,  ii.  508,  Leipzic,  1850, 
or  Amer.  edit,  of  Sydenham  Society's  edition  of  his  Manual  of  Histology,  p.  35ti,  Phila- 
delphia, 1854;  and" Drumniond,  Cyclop,  of  Anat.  and  riiysiol.,  loc.  cit. 

3  Anatomy  and  Physiology,  5th  Amer.  edit.,  by  J.  D.  (Jodman,  p.  29,  New  York, 
1827 

<  See  two  interesting  pathological  cases,  confirming  this  view  of  the  function  of  the 
gray  matter,  by  Dr.  Cowan,  in  Provincial  Medical  and  Surgical  Journal,  April  16, 1845. 

*  Sur  le  Systeme  Nerveux,  Paris,  1820.  _ 

6  Anatomie  des  Systemes  Nerveux  des  Animaux  a  Vertebres,  p.  599,  Pans,  1825. 


CIRCULATION   IN   THE   BRAIN.  661 

lent,  amorphous  substance ;  yet  tlie  intellectual  faculties  had  been 
nearly  unimpaired,  although  the  morbid  process  must  have  been  of 
some  duration. 

The  encephalon  affords  many  striking  instances  of  the  different 
effects  produced  by  sudden,  and  by  gradual  interference  with  its  func- 
tions. Whilst  a  depressed  portion  of  bone  or  an  extravasation  of  blood 
may  suddenly  give  rise  to  the  abolition  of  the  intellectual  and  moral 
faculties,  gradual  compression  by  a  tumour  may  scarcely  interfere  with 
any  of  its  manifestations. 

The  circulation  of  blood  in  the  encephalon  requires  i|otice.  The 
arteries  are  four  in  number, — two  i7iternal  carotids,  and  two  vertehrals : 
to  these  may  be  added  the  spinal  or  middle  artery  of  the  dura  water, — 
arteria  meningcea  media.  The  carotid  arteries  enter  the  head  through 
the  carotid  canals,  which  open  on  each  side  of  the  sella  turcica,  or  of 
the  chiasma  of  the  optic  nerves.  The  vertebral  arteries  enter  the  head 
through  the  foramen  magnum  of  the  occipital  bone ;  unite  on  the 
medulla  oblongata  to  form  the  basilary  artery,  which  passes  forward 
along  the  middle  of  the  pons  Varolii ;  and,  at  the  anterior  part  of  the 
pons,  gives  off  lateral  branches,  which  inosculate  with  corresponding 
branches  of  the  carotids,  and  form  a  kind  of  circle  at  the  base  of  the 
brain,  which  has  been  called  circulus  arteriosus  of  Willis.  The  passage 
of  the  bloodvessels  is  extremely  tortuous,  so  that  the  blood  does  not 
enter  the  brain  with  great  impetus;  and  they  become  capillary  before 
they  penetrate  the  organ, — an  arrangement  of  importance,  when  we 
regard  the  large  amount  of  blood  sent  to  it.  This  has  been  estimated 
as  high  as  one-eighth  of  the  whole  fluid  transmitted  from  the  heart. 
The  amount  does  not  admit  of  accurate  appreciation,  but  it  is  consider- 
able. It  of  course  varies  according  to  circumstances.  In  hypertro- 
phy of  the  heart,  the  quantity  is  sometimes  increased;  as  well  as  in 
ordinary  cases  of  what  are  called  determinations  of  blood  to  the  head. 
Here,  too  large  an  amount  is  sent  by  the  arterial  vessels;  but  an  equal 
accumulation  may  occur,  if  the  return  of  the  blood  from  the  head  by 
the  veins  be  in  any  manner  impeded, — as  when  we  stoop,  or  compress 
the  veins  of  the  neck,  by  a  tight  cravat,  or  by  keeping  the  head  turned 
for  a  length  of  time.  Congestion  or  accumulation  of  blood  may  there- 
fore arise  from  very  different  causes. 

Sir  Astley  Cooper'  found  by  experiment,  that  the  vertebral  arteries 
are  more  important  vessels  as  regards  the  encephalon  and  its  functions 
in  certain  animals,  as  the  rabbit,  than  the  carotids.  The  nervous  power 
is  lessened  by  tying  them ;  and,  in  his  experiments,  the  animals  did 
not,  in  any  case,  survive  the  operation  more  than  a  fortnight.  In  the 
dog,  he  tied  the  carotids  with  little  effect,  but  the  ligature  of  the  verte- 
hrals had  a  great  influence.  The  effect  of  the  operation  was  to  render 
the  breathing  immediately  difficult  and  laborious ;  owing,  in  Sir  Astley's 
opinion,  to  the  supply  of  blood  to  the  phrenic  nerves,  and  the  whole 
tradus  respiratorius  of  Sir  Charles  Bell,  being  cut  off".  The  animal 
became  dull,  and  indisposed  to  make  use  of  exertion ;  or  to  take  food. 
Compression  of  the  carotids  and  the  vertebrals  at  the  same  moment, 
in  the  rabbit,  destroyed  the  nervous  functions  immediately.  This  was 
effected  by  the  application  of  the  thumbs  to  both  sides  of  the  neck,  the 

'  Guy's  Hospital  Reports,  i.  472,  London,  1836. 


662 


SENSIBILITY. 


Fig.  215. 


trachea  remaining  free  from  pressure.  Eespiration  ceased  entirely, 
witli  the  exception  of  a  few  convulsive  gasps.  The  same  fact  was 
evinced  in  a  clearer  and  more  satisfactory  manner  by  the  application 
of  ligatures  to  the  four  vessels,  all  of  which  were  tightened  at  the  same 
instant.     Stoppage  of  respiration  and  death  immediately  ensued. 

The  cerebral,  like  other  arteries,  are  accompanied  by  branches  of 

the  great  sympathetic.  The  researches  of 
of  Purkinje,^  Volkmann,^  and  Kainey,^ 
have  shown  the  existence  of  a  large  num- 
ber of  nerves  in  connection  with  the  en- 
cephalic and  spinal  arachnoid.  They  do 
not  seem  to  communicate  with  the  roots  of 
the  spinal  nerves,  but  belong  exclusively 
to  the  sympathetic*  The  encephalic  veins 
are  disposed  as  already  described,  termi- 
nating in  sinuses  formed  by  the  dura  mater, 
and  conveying  their  blood  to  the  heart  by 
means  of  the  lateral  sinuses  and  internal 
jugulars;  but  of  the  peculiarities  of  the 
circulation  in  the  encephalon,  mention  will 
be  made  in  the  appropriate  place.  No 
lymphatic  vessels  have  been  detected  in 
the  encephalon  ;  yet,  that  absorbents  exist 
there  is  proved  by  the  dissection  of  apo- 
plectic and  paralytic  individuals.  In  these 
cases,  when  blood  has  been  effused,  the 
red  particles  are  gradually  taken  up,  with 
a  portion  of  the  fibrinous  part  of  the  blood, 
leaving  a  cavity  called  an  apoplectic  cell, 
which  is  at  the  same  time  the  evidence  of 
previous  extravasation  and  subsequent 
absorption. 

The  whole  of  the  nervous  system  is  well 
supplied  with  bloodvessels.     In  the  vesi- 
cular neuriue  of  the  nervous  centres,  the 
capillaries  surround  the  ganglion  cells  or 
bules;   and  in  the  tubular  they  pass 
een  the  nerve-tubes,  being  connected 
ntervals  by  transverse  branches, 
hen  the  skull  of  the  new-born  infant, 
hich,  at  the  fontanelles,  consists  of  mern- 
e  only — or  the  head  of  any  one  who 
has  received  an  injury,  that  exposes  the 
brain — is  examined,  two  distinct  move- 
ments are   perceptible.      One,  which   is 
generally  obscure,  is  synchronous  with  the  pulsation  of  the  heart  and 


Sinuses  of  the  Base  of  the  Skull. 

1.  Ophthalmic  veins.  2.  Cavernous 
sinus  of  one  side.  .3.  Circular  sinus : 
the  figure  occupies  the  position  of  the 
pituitary  gland  in  the  sella  turcica.  4. 
Inferior  petrosal  sinus.  5.  Transverse 
or  anterior  occipital  sinus.  6.  Superior 
petrosal  sinus.  7.  Internal  jugular  vein. 
8.  Foramen  magnum.  9.  Occipital  si- 
nuses. 10.  Torcular  Herophili.  11,  11. 
Lateral  sinuses. 


Fiff.  216. 


Capillary    Network    of  Xervoas 
Centres. 


'  Miiller's  Arcliiv.  fiir  Anatomie,  p.  281,  Berlin,  1845. 

2  Art.  Nerveuphysiologie,  Wagner's  Hand\r6rterbnch  der  Physiologie,  lOte  Lieferung, 
S.  494,  Braunschweig,  1845. 

^  Meiiico-Chirurgical  Transactions  for  the  ye^r  1845. 

••  Brinton,  Art.  Serous  and  Synovial  Meiubraues,  in  Cyclop,  of  Anat.  and  Physiol., 
Pt.  xxxiv.  p.  525,  Loud.,  Jan.,  1849. 


CEPHALO-SPINAL   FLUID.  663 

arteries;  the  otlier,  much  more  apparent,  is  connected  with  respiration, 
the  organ  seeming  to  sink  at  the  time  of  inspiration,  and  to  rise  during 
expiration.  This  phenomenon  is  not  confined  to  the  cerebrum,  but 
exists  likewise  in  the  cerebellum  and  spinal  marrow.  The  motion  of 
the  encephalon,  synchronous  with  that  of  the  heart,  admits  of  easy 
explanation.  It  is  owing  to  the  pulsation  of  the  circle  of  arteries  at 
the  base  of  the  brain  elevating  the  organ  at  each  sj^stoie  of  the  heart. 
The  other  movement  is  not  so  readily  intelligible.  It  has  been  attri- 
buted to  the  resistance,  experienced  by  the  blood  in  its  passage  through 
the  lungs  during  expiration,  owing  to  which  an  accumulation  of  blood 
takes  place  in  the  right  side  of  the  heart ;  this  extends  to  the  veins  and 
to  the  cerebral  sinuses,  and  an  augmentation  of  bulk  is  thus  occasioned. 
It  has  been  elsewhere  remarked,  that  one  of  the  forces  conceived  to  pro- 
pel the  blood  along  the  vessels  is  atmospheric  pressure.  According  to 
that  view,  the  sinking  down  of  the  brain  during  inspiration  is  expli- 
cable ;  the  blood  is  rapidly  drawn  to  the  heart ;  the  quantity  in  the 
veins  is  consequently  diminished  ;  and  sinking  of  the  brain  succeeds. 

On  dissection,  we  find  that  the  encephalon  fills  the  cavity  of  the  cra- 
nium; during  life,  therefore,  it  must  be  pressed  upon,  more  or  less,  by 
the  blood  in  the  vessels,  and  by  the  serous  fluid  exhaled  by  the  pia 
mater  into  the  subarachnoid  tissue.  Thence  it  penetrates  into  the 
ventricles, — according  to  M.  Magendie,  at  the  lower  end  of  the  fourth 
ventricle,  at  the  calamus  scriptorius.  The  quantity  varies  according  to 
the  age  and  size  of  the  patient,  and  usually  bears  an  inverse  propor- 
tion to  the  size  of  the  encephalon.  It  is  seldom,  however,  less  than 
two  ounces,  and  often  amounts  to  five.  M.  Magendie  is  of  opinion, 
that  the  fluid  is  secreted  by  the  pia  mater,  and  states,  that  it  may  be 
seen  transuding  from  it  in  the  living  animal.  The  results  of  chemical 
analysis  appear  to  show,  that  it  differs  from  mere  serum.  It  is  ob- 
viously, however,  almost  impracticable — if  not  wholly  so — to  separate 
the  consideration  of  this  fluid  from  that  met  with  in  the  cavity  of  the 
arachnoid. 

The  spinal  marrow  does  not,  as  we  have  seen,  fill  the  vertebral 
canal;  the  cephalo-spinal  fluid  exerts  upon  it  the  necessary  pressure; 
added  to  which,  the  pia  mater  seems  to  press  more  upon  this  organ 
than  upon  the  rest  of  the  cerebro-spinal  system.  A  certain  degree  of 
pressure  appears,  indeed,  necessary  for  the  due  performance  of  its 
functions ;  and  if  this  be  either  suddenly  and  considerably  augmented, 
or  diminished,  derangement  of  function  is  the  result.  M.  Magendie,^ 
however,  asserts,  that  he  has  known  animals,  from  which  the  fluid 
had  been  removed,  survive  without  any  sensible  derangement  of  the 
nervous  functions.  It  is  this  fluid,  which  is  drawn  ofl"  by  the  surgeon 
when  he  punctures  in  a  case  of  spina  bifida. 

When  the  brain  is  examined  in  the  living  body,  it  exhibits  proper- 
ties, which,  some  years  ago,  it  would  have  been  esteemed  the  height  of 
hardihood  and  ignorance  to  ascribe  to  it.  The  opinion  has  universally 
prevailed,  that  all  nerves  are  exquisitely  sensible.     Many  opportuni- 

'  Precis  El  mentaire,  secoiide  i^dit.,  i.  192;  and  Rocherclies  Physiologiques  et 
Cliiiiques  sur  le  Liquide  Cei>lialo-racliidieii  ou  Cerebro  spinal,  Paris,  1842.  Dr.  Todd, 
Cyclopajdia  of  AnatouiV  and  Physiology,  Pt.  xxv.  p.  (531),  London,  1844 ;  and  Foltz, 
Schmidt's  Jahrb,  xxxvi.  292,  and  Brit,  and  For.  Med.-Chir.  Rev.,  Jan.,  1850,  p.  234. 


664  SENSIBILITY. 

ties  will  occur  for  showing,  that  this  sentiment  is  not  founded  on  fact; 
even  the  encephalon  itself, — the  organ  in  which  perception  takes 
place, — is  insensible,  in  the  common  acceptation  of  the  term;  that  is, 
we  may  prick,  lacerate,  cut,  and  even  cauterize  it,  yet  no  painful  im- 
pression will  be  produced.  Experiment  leaves  no  doubt  regarding 
the  truth  of  this,  and  we  find  the  fact  frequently  confirmed  by  patho- 
logical cases.  Portions  of  brain  may  be  discharged  from  a  wound  in 
the  skull,  and  yet  no  pain  be  evinced.  In  his  "  Anatomy  and  Phy- 
siology," Sir  C.  BelP  remarks,  that  he  cannot  resist  stating,  that  on  the 
morning  on  which  he  was  writing,  he  had  had  his  finger  deep  in  the 
anterior  lobes  of  the  brain;  when  the  patient,  being  at  the  time  acutely 
sensible,  and  capable  of  expressing  himself,  complained  only  of  the 
integument.  A  pistol-ball  had  passed  through  the  head,  and  Sir 
Charles,  having  ascertained,  that  it  had  penetrated  the  dura  mater  by 
forcing  his  finger  into  the  wound,  trephined  on  the  opposite  side  of 
the  head,  and  extracted  it. 

By  the  experiments,  instituted  by  M^f.  Magendie,'  Flourens  and 
others,  it  has  been  shown,  that  an  animal  may  live  days,  and  even 
weeks,  after  the  hemispheres  have  been  removed;  nay,  that  in  certain 
animals,  as  reptiles,  no  change  is  produced  in  their  habitudes  by  such 
abstraction.  They  move  about  as  if  unhurt.  Injuries  of  the  surfiice 
of  the  cerebellum  exhibit,  that  it  also  is  not  sensible;  but  deeper 
wounds,  and  especially  such  as  interest  the  peduncles,  have  singular 
results, — to  be  mentioned  hereafter.  The  spinal  cord  is  not  exactly 
circumstanced  in  this  manner.  Its  sensibility  is  exquisite  on  the  pos- 
terior surface;  much  less  on  the  anterior,  and  almost  null  at  the  centre. 
Considerable  sensibility  is  also  found  within,  and  at  the  sides  of,  the 
fourth  ventricle;  but  this  diminishes  as  we  proceed  towards  the  ante- 
rior part  of  the  medulla  oblongata,  and  is  very  feeble  in  the  tabercula 
quadrigemina  of  the  mammalia. 

It  has  been  shown,  that  the  spinal  nerves,  by  means  of  their  poste- 
rior roots,  convey  general  sensibility  to  the  parts  to  which  they  are 
distributed.  But  there  are  other  nerves,  which,  like  the  brain,  are 
themselves  entirely  devoid  of  general  sensibility.  This  has  given 
occasion  to  a  distinction  of  nerves  into  those  of  general  and  of  specinl 
sensibility.  Of  nerves,  which  must  be  considered  insensible  or  devoid 
of  general  sensibility,  we  may  instance  the  optic,  olfactory,  and  audi- 
tory. Each  of  these  has,  however,  a  special  seiisihility;  and  although 
it  may  exhibit  no  pain  when  irritated,  it  is  capable  of  being  impressed 
by  appropriate  stimuli — by  light,  in  the  case  of  the  optic  nerve;  by 
odours,  in  that  of  the  olfactory ;  and  by  sound,  in  that  of  the  auditory. 
Yet  we  shall  find,  that  most  of  the  nerves  of  special  sensibility  seem  to 
require  the  influence  of  a  nerve  of  general  sensibility, — the  fifth  pair. 

Many  nerves  appear  devoid  of  sensibility,  as  the  third,  fourth,  and 
sixth  pairs;  the  portio  dura  of  the  seventh  ;  the  ninth  pair  of  encephalic 
nerves;  and,  as  has  been  shown,  all  the  anterior  roots  of  the  spinal 
nerves. 

The  parts  of  the  encephalon,  concerned  in  muscular  motion,  will 
fall  under  consideration  hereafter. 

'  Fifth  Anier.  edit,  by  J.  D.  Godman,  ii.  6,  New  York,  1827. 
*  Precis  Elementaire,  i.  325. 


SENSATIONS.  665 


2.   PHYSIOLOGY  OF  SENSIBILITY. 

Animal  sensibility  we  have  defined  to  be — the  function  by  which 
we  experience  feeling,  or  have  the  perception  of  an  impression.  It  in- 
cludes two  oTeat  sets  of  phenomena;  the  sensations^  properly  so  called, 
and  the  intelkctunl  and  moral  manifestations.  These  we  shall  investi- 
gate in  succession. 

a.   Sensations. 

A  sensation  is  the  perception  of  an  impression  made  on  a  living 
tissue; — or,  in  the  language  of  Gall,  it  is  the  perception  of  an  irrita- 
tion. By  the  sensations  we  receive  a  knowledge  of  what  is  passing 
within  or  without  the  body;  and,  in  this  way,  our  notions  or  ideas  of 
them  are  obtained.  When  these  ideas  are  reflected  upon,  and  com- 
pared with  each  other,  we  exert  thouglit  and  judgment;  and  they  can 
be  recalled  with  more  or  less  vividness  and  accuracy  by  the  exercise 
of  mem.ory. 

The  sensations  are  numerous,  but  they  may  all  be  comprised  in  two 
divisions, — the  external  and  the  internal.  Vision  and  audition  afford  us 
examples  of  the  former,  in  which  the  impression  made  upon  the  organ 
is  external  to  the  part  impressed.  Hunger  and  thirst  are  instances  of 
the  latter,  the  cause  being  internal,  necessary,  and  depending  upon 
influences  seated  in  the  economy  itself.  Let  us  endeavour  to  discover 
in  what  they  resemble  each  other. 

In  the  first  place,  every  sensation,  whatever  may  be  its  nature, — ex- 
ternal, or  internal, — requires  the  intervention  of  the  encephalon.  The 
distant  organ — as  the  eye  or  ear — may  receive  the  impression,  but  it  is 
not  until  this  irnpression  has  been  communicated  to  the  encephalon,  that 
sensation  is  effected.  The  proofs  of  this  are  easy  and  satisfactory.  If 
we  cut  the  nerve  proceeding  to  any  sensible  part,  put  a  ligature  around 
it,  or  compress  it  in  any  manner, — it  matters  not  that  the  object,  which 
ordinarily  excites  a  sensible  impression,  is  applied  to  the  part, — no 
sensation  is  experienced.  Again,  if  the  brain,  the  organ  of  percep- 
tion, be  prevented  in  any  way  from  acting,  it  matters  not  that  the  part 
impressed,  and  the  nerve  communicating  with  it,  are  in  a  condition 
necessary  for  the  due  performance  of  the  function,  sensation  is  not 
effected.  We  see  this  in  numerous  instances.  In  pressure  on  the  brain, 
occasioned  by  fracture  of  the  skull;  or  in  apoplexy,  a  disease  generally 
dependent  upon  pressure,  we  find  all  sensation,  all  mental  manifestation, 
lost;  and  they  are  not  regained  until  the  compressing  cause  has  been 
removed.  The  same  thing  occurs  if  the  brain  be  stupefied  by  opium; 
and,  to  a  less  degree,  in  sleep,  or  when  the  brain  is  engaged  in  intel- 
lectual meditations.  Who  has  not  found,  that  in  a  state  of  reverie  or 
brown  study,  he  has  succeeded  in  threading  his  way  through  a  crowded 
street,  carefully  avoiding  every  obstacle,  yet  so  little  impressed  by  the 
objects  around  as  not  to  retain  the  slightest  recollection  of  them!  On 
the  other  hand,  how  vivid  are  the  sensations  when  attention  is  directed 
to  them!  Again,  we  have  numerous  cases  in  which  the  brain  itself 
engenders  the  sensation,  as  in  dreams,  and  in  insanity.  In  the  former, 
we  see,  hear,  speak,  use  every  one  of  our  senses  apparently;  yet  there 
has  been  no  impression  from  without.     Although  we  may  behold  in 


666  SENSIBILITY. 

our  dreams  the  figure  of  a  friend  long  since  dead,  tliere  can  obviously 
be  no  impression  made  on  the  retina  from  without.^  Such  are  called 
subjective  sensations,  to  distinguish  them  from  those  caused  by  impres- 
sions made  by  objects  on  the  peripheral  extremities  of  the  nerves  of 
sense,  and  hence  termed  objective  sensations. 

The  whole  history  of  spectral  illusions,  morbid  hallucinations,  and 
maniacal  phantasies,  is  to  be  accounted  for  in  this  manner.  Whether, 
in  such  cases,  the  brain  reacts  upon  the  nerves  of  sense,  and  produces 
an  impression  upon  them  from  within,  similar  to  what  they  experience 
from  without  during  the  production  of  a  sensation,  will  form  a  subject 
for  future  inquiry.  Pathology  also  affords  several  instances  where  the 
brain  engenders  the  sensation,  most  of  which  are  precursory  signs  of 
cerebral  derangement.  The  appearance  of  spots  flying  before  the  eyes, 
of  spangles,  depravations  of  vision,  hearing,  &c.,  and  a  sense  of  numb- 
ness in  the  extremities,  are  referable  to  this  cause;  as  well  as  the  singu- 
lar fact  well  known  to  the  operative  surgeon,  that  pain  is  often  felt  in 
the  stump  of  a  limb,  months  after  it  has  been  removed  from  the  body. 

These  facts  prove,  that  every  sensation,  although  referred  to  some 
organ,  must  be  perfected  in  the  brain.  The  impression  is  made  upon 
the  nerve  of  the  part,  but  the  appreciation  takes  place  in  the  common 
sensorium. 

There  are  few  organs  which  could  be  regarded  insensible,  were  we 
aware  of  the  precise  circumstances  under  which  their  sensibility  is 
elicited.  The  old  doctrine — as  old  indeed  as  Hippocrates^ — was,  that 
the  tendons  and  other  membranous  parts  are  among  the  most  sensible 
of  the  body.  This  opinion  was  implicitly  credited  by  Boerhaave,  and 
his  follower  Van  Swieten;^  and  in  many  cases  had  a  decided  influence 
on  surgical  practice  more  especially.  As  the  bladder  consists  princi- 
pally of  membrane,  it  was  agreed  for  ages  by  lithotomists,  that  it  would 
be  improper  to  cut  or  divide  it;  and,  therefore,  to  extract  the  stone  di- 
lating instruments  were  used,  which  caused  the  most  painful  lacerations 
of  the  parts.  Haller"*  considered  tendons,  ligaments,  periosteum,  bones, 
meninges  of  the  brain,  different  serous  membranes,  arteries  and  veins, 
entirely  insensible;  yet  we  know,  that  they  are  exquisitely  sensible 
when  attacked  with  inflammation.  One  of  the  most  painful  affections 
to  which  man  is  liable  is  the  variety  of  whitlow  that  implicates  the 
periosteum;  and  in  all  affections  of  the  bone  which  inflame  or  press 
forcibly  upon  that  membrane,  there  is  excessive  sensibility.  It  would 
appear,  that  the  possession  of  vessels  or  vascularity  is  a  necessary  con- 
dition of  the  sensibility  of  any  tissue. 

Many  parts,  too,  are  affected  by  special  irritants;  and,  after  they  have 
appeared  insensible  to  a  multitude  of  agents,  show  great  sensibility 
when  a  particular  irritant  is  applied.  Bichat  endeavoured  to  elicit  the 
sensibility  of  ligaments  in  a  thousand  ways,  without  succes-;;  but 
when  he  subjected  them  to  distension  or  twisting,  they  immediately 
gave  evidence  of  it.  It  is  obvious,  that  before  we  determine  that  a  part 
is  insensible,  it  must  have  been  submitted  to  every  kind  of  irritation. 

'  Adelon,  .art.  Encepliale  (Physiolostie),  in  Diet,  de  Med.,  vii.  514,  Paris,  1823 ;  and 
Physiol,  de  rHomme,  torn.  1.  p.  239,  2de  edit.,  Paris,  1829. 

^  Foesii  fficonom.  Ilippocr.  "NsLpsv."         ^  Aphorism.  1(34  and  1G5,  and  Comment. 
'  *  Oper.  Minor.,  torn.  i. 


SENSATIONS   ACCOMPLISHED   IN   THE   ENCEPHALON.       667 

M.  Adelon  affirms,  that  there  is  no  part  but  what  may  become  painful 
by  disease.  From  this  assertion  the  cuticle  might  be  excepted.  If  we 
are  right,  indeed,  in  our  view  of  its  origin  and  uses,  as  described  here- 
after, sensibility  would  be  of  no  advantage  to  it;  but  the  contrary.  In 
the  present  state,  then,  of  our  knowledge,  we  are  justified  in  asserting, 
that  bones,  cartilages,  and  membranes  are  not  sensible  to  ordinary  ex- 
ternal irritants,  when  in  a  state  of  health, — or  in  other  words,  that  we  are 
not  aware  of  the  irritants,  which  are  adapted  to  elicit  their  sensibility. 

That  sensibility  is  due  to  the  nerves  distributed  to  a  part  is  so  gene- 
rally admitted  as  not  to  require  comment.  Dr.  Todd'  has  affirmed,  that 
the  anatomical  condition  necessary  for  the  developement  of  the  greater 
or  less  sensibility  of  an  organ  or  tissue  is  the  distribution  in  it  of  a 
greater  or  less  number  of  sensitive  nerves;  and  that  the  anatomist  can 
determine  the  degree  to  which  this  property  is  enjoyed  by  any  tissue  or 
organ  by  the  amount  of  nervous  supply,  which  his  research  discloses. 
It  may  well  be  doubted,  however,  whether  sach  sensibility  be  by  any 
means  in  proportion  to  the  number  of  nerves  received  by  a  part.  Nay, 
some  parts  are  acutely  sensible  in  disease  into  which  nerves  cannot  be 
traced.  To  explain  these  cases,  Reil'^  supposed  that  each  nerve  is  sur- 
rounded at  its  termination  by  a  nervous  atmosphere,  by  which  its  action 
is  extended  beyond  the  part  in  which  it  is  seated.  This  opinion  is  a 
mere  creation  of  the  imagination.  We  have  no  evidence  of  any  such 
atmosphere;  and  it  is  more  philosophical  to  presume,  that  the  reason  we 
do  not  discover  nerves  may  be  owing  to  the  imperfection  of  our  vision. 

We  may  conclude,  that  the  action  of  impression  occurs  in  the  nerves 
of  the  part  to  which  the  sensation  is  referred.  As  to  the  mode  in 
which  this  impression  affects  them  we  are  ignorant.  Microscopic  ex- 
amination of  the  nerves  connected  with  sensory  organs  would  seem  to 
show,  that  they  come  into  relation  with  a 
substance  very  analogous  to  the  gray  mat- 
ter of  the  encephalon,  although  its  elements 
are  somewhat  differently  arranged.  The 
nervous  fibres,  too,  appear  to  terminate  in 
close  approximation  with  a  vascular  plexus ; 
and  a  granular  structure  is  present,  which — 
as  in  the  vesicular  portion  of  the  brain — 
seems  to  be  intermediate.  This  point  has 
been  regarded  as  the  origin  of  the  afferent 
fibres;  and  as  the  seat  of  changes  made  by    i»'^';;'""i';."  "''  ^:'piiia,ies  at  .ho 

'  .  ,  ^  "^        surface  ol  the  skiu  ol  the  linger. 

external  impressions.^ 

The  facts  mentioned  show,  that  the  action  of  perception  takes  place 
in  the  encephalon;  and  that  the  nerve  is  merely  the  conductor  of  the 
impression  between  the  part  impressed  and  that  organ.  If  a  ligature 
be  put  round  a  nerve,  sensation  is  lost  below  the  ligature;  but  it  is 
uninjured  above  it.  If  two  ligatures  be  applied,  sensibility  is  lost  in 
the  portion  included  between  the  ligatures ;  but  it  is  restored  if  the 
upper  ligature  be  removed.  The  spinal  marrow  is  sensible  along  the 
whole  of  its  posterior  column,  but  it  also  acts  only  as  a  conductor  of 

'  Art.  Sensation,  Cycloprpdia  of  Anat.  and  Physiology,  pt.  xxxiv.  p.  511,  Jan.,  1849. 
*  Exercitat.  Anatom.  Fascic,  i.  p.  28;  and  Archiv.  filr  die  Physiologie,  B.  lit. 
'  Carpenter,  Human  Physiology,  p.  85,  Loud.,  1842. 


668  SENSIBILITY. 

tlie  impression.  M.  Flourens  destroyed  tlie  spinal  cord  from  below,  by 
slicing  it  away ;  and  found,  tliat  sensibility  was  gradually  extinguished 
in  the  parts  corresponding  to  the  destroyed  medulla,  but  that  the  parts 
above  evidently  continued  to  feel.  Perception,  therefore,  occurs  in  the 
encephalon ;  and  not  in  the  whole,  but  in  some  of  its  parts.  Many 
physiologists — Haller,  Lorr}^,  Rolando,  and  Flourens' — sliced  away  the 
brain,  and  found  that  the  sensations  continued  until  the  knife  reached 
the  level  of  the  corpora  quadrigemina ;  and,  again,  it  has  been  found, 
that  if  the  spinal  cord  be  sliced  away  from  below  upwards,  the  sensa- 
tions persist  until  we  reach  the  medulla  oblongata.  It  is,  then,  between 
these  parts,  that  we  must  place  the  cerebral  organs  of  the  senses,  and 
it  is  with  this  part  of  the  cephalo-spinal  axis,  tliat  the  nerves  of  the 
senses  are  actually  found  to  communicate.  Mr.  Lawrence^  saw  a  child 
with  no  more  encephalon  than  a  bulb,  which  was  a  continuation  of  the 
medulla  spinalis,  for  about  an  inch  above  the  foramen  magnum,  and  with 
which  all  the  nerves  from  the  fifth  to  the  ninth  pair  were  connected. 
The  child's  breathing  and  temperature  were  natural ;  it  discharged 
urine  and  fseces ;  took  food,  and  at  first  moved  very  briskly.  It  lived 
four  days. 

If  we  divide  the  posterior  roots  of  the  spinal  nerves  and  the  fifth 
pair,  general  sensibility  is  lost ;  but  if  we  divide  the  nerves  of  the 
senses,  we  destroy  only  their  functions.  We  can  thus  understand 
why,  after  decapitation,  sensibility  may  remain  for  a  time  in  the  head. 
It  is  instantly  destroyed  in  the  trunk,  owing  to  the  removal  of  all  com- 
munication with  the  encephalon ;  but  the  fifth  pair  is  entire,  as  well  as 
the  nerves  of  the  organs  of  the  senses.  Death  must  of  course  follow 
almost  instantaneously  from  loss  of  blood;  but  there  is  doubtless  an 
appreciable  interval  during  which  the  head  may  continue  to  feel;  or, 
in  other  words,  during  which  the  external  senses  may  act.^  M.  Julia 
Fontanelle'*  has  indeed  concluded,  from  a  review  of  all  the  observa- 
tions made  on  this  matter,  that,  contrary  to  the  common  opinion,  death 
by  the  guillotine  is  one  of  the  most  painful ;  that  the  pains  of  decolla- 
tion are  horrible,  and  endure  even  until  there  is  an  entire  extinction 
of  animal  heat !  It  need  scarcely  be  said,  that  all  these  inferences  are 
imaginative,  and  perhaps  equally  fabulous  with  the  oft-told  story  of 
Charlotte  Corday  scowling  at  the  executioner,  after  her  head  was 
removed  from  her  body  by  the  guillotine ;  and  this  conclusion  is 
strongly  confirmed  by  the  results  of  experiments  on  a  robber — who 
was  beheaded  with  the  sword — by  Drs.  Bischoff",  Heerman,  and  Jolly, 
who  inferred  that  consciousness  must  have  ceased  instantaneousl3^* 
But  if  such  be  the  case  with  man,  it  most  assuredly  is  not  so  with  the 
inferior  animals.  Ample  evidence  will  be  aflbrded  hereafter  to  show, 
that  both  sensation  and  volition  may  persist,  apparently,  in  the  rattle- 

'  Rolaniio,  Saggio  sopra  la  vera  Struttura  del  Cervello,  Sassari,  1809  ;  and  Flourens, 
Recherclies  Experimentales  sur  les  Proprietes  et  les  Fonctions  du  Systeme  Nerveux, 
&c.,  2de  edit.,  Paris,  1842. 

*  Medico-Chirurg.  Transact.,  v.  166. 

'  Berard,  Rapports  du  Phvsique  et  du  Moral,  p.  93,  Paris,  1823. 

*  Plicebus,  Art.  Enthauptung,  in  Encyclopad.  Woilerb.  der  Medicin.  Wissenchaft. 
xi.  204,  Berlin,  1835. 

^  A  condensed  account  of  Dr.  Bischoff 's  Remarks,  from  Miiller's  Archiv.,  by  S.  L.  L. 
Bigger,  is  in  the  Dublin  Journal  of  Medical  Science,  Sept.,  1839,  p.  1. 


SENSOKY   GANGLIA.  669 

snake  and  alligator,  long  after  the  head  has  been  removed  from  the 
body,.  Singular  facts  in  regard  to  the  latter  animal  have  been  recorded 
by  Dr.  Leconte,'  and  by  Dr.  Dowler,^  of  New  Orleans. 

It  has  been  remarked,  that  the  cerebral  hemispheres  may  be  sliced 
away  without  abolishing  the  senses.  The  experiments  of  Eolando  and 
Flourens,  which  have  been  repeated  by  M,  Magendie,  show,  however, 
that  the  sight  is  an  exception  ; — that  it  is  lost  by  their  removal.  If  the 
right  hemisphere  be  sliced  away,  the  sight  of  the  left  eye  is  lost;  and 
conversely ; — one  of  the  facts  that  prove  the  decussation  of  the  optic 
nerves.  The  experiments  of  these  gentlemen  show,  that  vision,  more 
than  the  other  senses,  requires  a  connection  with  the  organ  of  the  intel- 
lectual faculties — the  cerebral  hemispheres ;  and  this,  as  M.  Magendie 
has  ingeniously  remarked,  because  vision  rarely  consists  in  a  single 
impression  made  by  light,  but  is  connected  with  an  intellectual  process, 
by  which  we  judge  of  the  distance,  size,  shape,  &c.,  of  bodies.  It  has 
been  well  suggested  and  maintained  by  Dr. 
Carpenter,^  that  whilst  the  cerebral  ganglia  Fig.  218. 

are  the  organs  of  the  higher  intellectual  and 
moral  acts ;  there  is  a  series  of  ganglia,  con- 
nected with  the  reception  of  impressions 
from  without,  which  are  seated  near  the  base 
of  the  brain,  and  are  hence  termed  by  him 
sensory  ganglia.  As  we  descend  in  the  ani- 
mal scale,  these  gangl  ia  become  more  marked; 
whilst  the  cerebral  hemispheres  become  less 
and  less ;  until  ultimately  the  animal  appears 
to  have  its  encephalic  organs  limited  almost 
wholly  to  those  that  are  concerned  in  the 
reception  of  impressions  from  without,  and 

the    originating    of  motor   impulsioiis  from  Brain  of  Squirrel,  laid  open. 

within.     These  ganglia  are  seated  at  the       The  hemispheres,   b,  drawn  to 

T  o    ,^         1         •  (•  ,1  •     •  o    .^  either    side    to    show    the    subjacent 

base  or  the  bram,  Irom  the  origm  of  the  parts,  c.  The  optic  lobes.  d.  cere- 
auditory  nerves  to  those  of  the  olfactory,  colpu'^stttatum!'''"""'"^""''-  '*• 
Dr.  Carpenter  is  disposed  to  regard  the  optic 

thalami  as  ganglia  for  the  reception  of  tactile  impressions,  and  the 
corpora  striata  as  ganglia  connected  with  motion.  He  esteems  them 
to  be,  moreover,  the  centre  of  consensual  or  instinctive  movements,  or 
of  automatic  movements  involving  sensation. 

Having  arrived  at  a  knowledge  that  in  man  and  the  upper  class  of 
animals  perception  is  eftected  in  a  part  of  the  encephalon.  our  acquaint- 
ance with  this  mysterious  process  ends.  We  know  not,  and  we  proba- 
bly never  shall  know,  the  action  of  the  brain  in  accomplishing  it.  It 
is  certainly  not  allied  to  any  physical  phenomenon ;  and  if  we  are 
ever  justified  in  referring  functions  to  the  class  of  organic  and  vital,  it 
may  be  those,  that  belong  to  the  elevated  phenomena,  which  have  to 
be  considered  under  the  head  of  animal  functions.     We  know  them 

'  New  York  Journal  of  Medicine,  for  Nov.,  1845,  p.  335,  and  Sir  Charles  Lyell,  Travels 
in  North  America,  Amer.  edit.,  i.  237.     New  York,  1849. 

2  Contributions  to  Physiology,  New  Orleans,  1849,  from  New  Orleans  Journal  of  Me- 
dicine. 

"  Principles  of  Human  Physiology,  Amer.  edit.,  p.  437,  Philad.,  1855. 


670 


SENSIBILITY. 


only  by  their  results ;  yet  we  are  little  better  acquainted  with  many  topics 
of  physical  inquiry  ; — with  the  nature  of  the  electric  fluid  for  example. 


Fig.  219. 


Fig.  220. 
Pike. 


Fig.  221. 

Cod. 


J 


:  ■:§: 


Brain  of  Turtle. 

A.  Olfactive  ganglia,     b.  Cerebral  hemi- 
spheres,   c.  Optic  gauglia.    d.  Cerebellum. 


Brains  of  Fishes. 

A.  Olfactive  lobes  or  ganglia,     b.  Cerebral  hemi- 
sphere.s.     c.  Optic  lobes.     D.  Cerebellum. 


The  organs,  then,  that  form  the  media  of  communication  between 
the  parts  impressed  and  the  brain,  are  the  nerves  and  spinal  marrow. 
M.  Broussais,Mndeed,  affirmed,  that  every  stimulation  capable  of  causing 
perception  in  the  brain,  runs  through  the  whole  of  the  nervous  system 
of  relation;  and  is  repeated  in  the  mucous  membranes,  whence  it  is 
again  returned  to  the  centre  of  perception,  which  judges  of  it  according 
to  the  view  of  the  viscus  to  which  the  mucous  membrane  belongs ;  and 
adapts  its  action  as  it  perceives  pleasure  or  pain. 

AVe  are  totally  unacquainted  with  the  mattrial  character  of  the  fluid, 
which  passes  M"ith  the  rapidity  of  lightning  along  nervous  cords;  and 
it  is  as  impossible  to  describe  its  mode  of  transmission,  as  it  is  to  depict 
that  of  the  electric  fluid  along  a  conducting  wire.  As  in  the  last  case, 
we  are  aware  of  such  transmission  only  by  the  result.  Still,  hypotheses, 
as  on  every  obscure  matter  of  inquiry,  have  not  been  wanting.^  Of 
these,  three  are  chiefly  deserving  of  notice.  The  y?rs^,  of  greatest  anti- 
quity, is,  that  the  brain  secretes  a  subtile  fluid,  which  circulates  through 
the  nerves,  called  onimaJ  spirits^  and  Avhich  is  the  medium  of  commu- 
nication between  the  dilYerent  parts  of  the  nervous  system;  the  second 
regards  the  nerves  as  cords,  and  the  transmission  as  efi'ected  by  means 
of  the  vibrations  or  oscillations  of  these  cords ;  whilst  the  third  ascribes 
it  to  the  operation  of  electricity. 

1.  The  hj'potheses  of  animal  spirits  has  prevailed  most  extensively. 
It  was  the  doctrine  of  llippocrates,  Galen,  the  Arabians,  and  of  most 

'  Trrate  de  Physiolocie,  &c.,  Paris,  1822 ;  or  translation  bv  Drs.  Bell  and  La  Roche, 
3d  Amer.  edit.,  p.  63,  Philad.,  1832. 

'  Fletcher's  Rudiments  of  Physiology,  P.  ii.  b.  p.  68,  Edinb.,  1836. 


INNERVATION — HYPOTHESIS   OF   VIBRATIONS.  671 

of  the  physicians  of  the  last  centuries.  Des  Cartes'  adopted  it  energe- 
tically; and  was  the  cause  of  its  more  extensive  diffusion.  The  great 
grounds  assigned  for  the  belief  were ; — first^  that  as  the  brain  receives 
so  much  more  blood  than  is  necessary  for  its  own  nutrition,  it  must  be 
an  organ  of  secretion;  secondly^  that  the  nerves  seem  to  be  a  continua- 
tion of  the  tubular  matter  of  the  brain ;  and  it  has  already  been  re- 
marked, that  Malpighi  considered  the  cortical  neurine  to  be  follicular, 
and  the  medullary  to  consist  of  secretory  tubes.  It  was  not  unnatural, 
therefore,  to  regard  the  nerves  as  vessels  for  the  transmission  of  these 
spirits.  As,  however,  the  animal  spirits  had  never  been  met  with  in  a 
tangible  shape,  ingenuity  was  largely  invoked  in  surmises  regarding 
their  nature;  and,  generally,  opinions  settled  down  into  the  belief  that 
they  were  of  an  ethereal  character.  For  the  various  views  that  have 
been  held  upon  the  subject,  the  reader  is  referred  to  Haller,^  who  was 
himself  an  ardent  believer  in  their  existence,  and  has  wasted  much  time 
and  space  in  an  unprofitable  inquiry  into  their  nature.  The  truth  is, 
that  we  have  not  sufficient  evidence,  direct  or  indirect,  of  the  existence 
of  any  nervous  fluid  of  the  kind  described.  Allusion  has  been  already 
made  to  the  views,  in  regard  to  the  tubular  structure  of  the  white  neu- 
rine, admitted  by  most  observers  ;  Berres'  affirms  that  the  forms,  which 
the  nervous  substance  assumes  under  the  magnifying  glass,  can  only  be 
compared  to  those  of  canals  and  vesicles;  but  whether  they  be  hollow 
he  does  not  attempt  to  decide.  M.  RaspaiP  has  concluded,  that  the 
opinion  of  their  being  hollow,  and  containing  a  fluid,  is  unsupported 
by  facts ;  for  although  he  admits,  that  M.  Bogros  succeeded  in  inject- 
ing the  nerves  with  mercury,  he  thinks  that  the  passage  of  the  metal 
along  them  was  owing  to  its  having  forced  its  way  by  gravity.  Modern 
histologists  accord  with  great  unanimity  as  to  the  tubular  structure  of 
the  medullary  neurine  ;  but  we  have  no  reason  for  considering  the 
brain  the  organ  of  any  ponderable  secretion.  Yet  the  term  "animal 
spirits,"  although  their  existence  is  not  now  believed,  is  retained  in 
popular  language.  We  speak  of  a  man  who  has  a  great  flow  of  animal 
spirits,  but  without  regarding  the  hypothesis  whence  the  expression 
originated. 

The  term  nervous  fluid  is  still  used  by  phj^siologists.  By  this,  how- 
ever, they  simply  mean  the  medium  of  communication  or  of  convey- 
ance, by  which  the  nervous  influence  is  carried  with  the  rapidity  of 
lightning  from  one  part  of  the  system  to  another ;  but  without  com- 
mitting themselves  as  to  its  character ; — so  that,  after  all,  the  idea  of 
animal  spirits  is  in  part  retained,  although  the  term,  as  applied  to  the 
nervous  fluid,  is  generally  exploded.  Dr.  Good^  directly  admits  them 
under  the  more  modern  title;  Mr.  J.  W.  Earle^  firmly  believes  in  the 
existence  of  a  circulation  in  the  nervous  sj^stem, — and  it  is  not  easy  to 
conceive,  that  the  brain  does  not  possess  the  function  of  elaborating 

'  Tractatus  de  Homine,  p.  17,  Lugd.  Bat.,  16C4. 

*  Elementa  Physiologite,  x.  8. 

'^  Oesterreicli.  Med.  Jahrbuch.,  B.  ix.,  cited  in  Brit,  and  Foreign  Med.  Review,  Janu- 
ary, 1838,  p.  219. 

*  Chimie  Organique,  p.  218,  Paris,  1833. 

^  Study  of  Medicine,  witli  Notes  by  S.  Cooper,  Doane's  Amer.  edit.,  vol.  ii.,  in 
Proem  to  Class  iv.  Neurotica,  New  York,  1835. 

*  New  Exposition  of  tlie  Functions  of  the  Nerves,  Part  I.,  London,  1833. 


672  SENSIBILITY. 

some  fluid, — galvanoid  or  other, — whicli  is  tbe  great  agent  in  the 
nervous  function. 

2.  The  hypothesis  of  vibrations  is  ancient,  but  has  been  by  no 
means  as  generally  admitted  as  the  last.  Among  the  moderns,  it  has 
received  the  support  of  Condillac,'  Hartley,^  Blumenbach,^  and  others; 
some  supposing,  that  the  nervous  matter  itself  is  thrown  into  vibra- 
tions; others,  that  an  invisible  and  subtile  ether  is  diffused  through  it, 
which  acts  the  sole  or  chief  part.  As  the  latter  is  conceived,  by  many, 
to  be  the  mode  in  which  electricity  is  transmitted  along  conducting 
wires,  it  is  not  liable  to  the  same  objections  as  the  former.  Simple 
inspection  of  a  nerve  at  once  exhibits,  that  it  is  incapable  of  being 
thrown  into  vibrations.  It  is  soft;  never  tense;  always  pressed  upon 
in  its  course;  and,  as  it  consists  of  filaments  destined  for  very  differ- 
ent functions, — sensation,  voluntar}^  and  involuntary  motion,  &c. — we 
cannot  conceive  how  one  of  these  filaments  can  be  thrown  into  vibra- 
tion without  the  effect  being  extended  laterally  to  others ;  and  great 
confusion  being  thus  induced.  The  view  of  Dr.  James  Stark,**  in  re- 
gard to  the  structure  of  the  tubes  of  the  nerves,  has  led  him  to  adopt 
a  modification  of  the  theory  of  vibrations.  Believing,  that  the  matter 
which  fills  the  tubes  is  of  an  oily  nature, — and  as  oily  substances  are 
known  to  be  non-conductors  of  electricity;  and  farther,  as  the  nerves 
have  been  shown  by  the  experiments  of  Bischoff'  to  be  amongst  the 
worst  possible  conductors  of  electricity, — he  contends,  that  the  nerv- 
ous energy  can  be  neither  electricity  nor  galvanism,  nor  any  property 
related  to  them;  and  he  conceives,  that  the  phenomena  are  best  ex- 
plained on  the  hypothesis  of  undulations  or  vibrations  propagated 
along  the  course  of  the  tubes  by  the  oily  globules  which  as  before 
remarked — he  considers  they  contain.  Others,  as  Dr.  Brown  Sequard^ 
— who  observed,  in  experiments  on  animals,  that  nerve  fibres  acted 
nearly  as  well  when  their  contents  were  coagulated  as  when  they  were 
still  liquid — are  of  opinion,  that  the  communication  is  through  the 
sheath  of  the  nerve, — the  membranous  tube  (Fig.  207). 

3.  The  last  hypothesis  is  of  later  date, — subsequent  to  the  disco- 
veries in  animal  electricity.  The  rapidity  with  which  sensation  and 
volition  are  communicated  alonsr  the  nerves  could  not  fail  to  suorgest 
a  resemblance  to  the  mode  in  which  the  electric  and  galvanic  fluids  fly 
along  conducting  wires.  Yet  the  great  support  of  the  opinion  was  in 
the  experiments  of  Dr.  Wilson  Philij)''  and  others,  from  which  it  ap- 
peared, that  if  the  nerve  proceeding  to  a  ])art  be  destroyed, — and  the 
secretion,  which  ordinarily  takes  place  in  the  part  be  thus  arrested, — 
the  secretion  may  be  restored  by  causing  the  galvanic  fluid  to  pass 
from  one  divided  extremity  of  the  nerve  to  the  other.  The  experi- 
ments, connected  with  secretion,  will  be  noticed  more  at  length  here- 
after.    It  will  likewise  be  shown,  that  in  the  effect  of  galvanism  upon 

'  ffiuvres,  Paris,  1822.  ^ 

^  Observations  on  Man,  &c.,  chap.  i.  sect.  1.  London,  1791. 
^  Institntiones  Physiologicfle,  ?;  22(J. 
*  Proceedings  of  the  Royal  Society,  No.  56,  Lond.,  1S43. 
^  Medical  Examiner,  April,  1852,  p.  564. 

^  Philosoph.  Traus.  for  1815,  and  Lond.  Med.  Gazette  for  March  18,  and  March  25, 
1837. 


EXTERNAL   SENSATIONS.  673 

the  muscles,  there  is  a  like  analogy  ; — that  the  muscles  may  be  made 
to  contract  for  a  length  of  time  after  the  death  of  the  animal,  and 
even  when  a  limb  is  removed  from  the  body,  on  the  application  of  the 
galvanic  stimulus ;  and  that  comparative  anatomy  exhibits  to  us  great 
development  of  nervous  structure  in  electrical  animals,  which  astonish 
us  by  the  intensity  of  the  electric  shocks  they  are  capable  of  commu- 
nicating. 

Physiologists  of  the  present  day  generally,  we  think,  accord  with 
the  electrical  hypothesis.  The  late  Dr.  Young,*  so  celebrated  for  his 
knowledge  in  numerous  departments  of  science,  adopted  it  prior  to 
the  interesting  experiments  of  Dr.  Philip  ;  and  Mr.  Abernethy,^  whilst 
he  is  strongly  opposing  the  doctrines  of  materialism,  goes  so  far  as  to 
consider  some  subtile  fluid,  not  merely  as  the  agent  of  nervous  trans- 
mission but  as  forming  the  essence  of  life  itself.  By  putting  a  liga- 
ture, however,  around  a  nervous  trunk,  its  functions,  as  a  conductor 
of  nervous  influence,  are  paralyzed,  whilst  it  is  still  capable  of  convey- 
ing electricity ;  and,  moreover,  when  wires  are  inserted  into  an  ex- 
posed nerve,  and  their  opposite  extremities  are  attached  to  the  galva- 
nometer, no  movement  of  the  needle  has  been  observed  by  Person, 
Miiller,  Matteucci,  Todd  and  Bowman,^  and  others.  Dr.  Bostock,** 
too,  has  remarked,  that  before  the  electrical  hypothesis  can  be  con- 
sidered proved,  two  points  must  be  demonstrated;  first,  that  every 
function  of  the  nervous  system  may  be  peiformed  by  the  substitution 
of  electricity  for  the  action  of  nerves ;  and  secondly,  that  all  nerves 
admit  of  this  substitution.  This  is  true  as  concerns  the  belief  in  the 
identity  of  the  nervous  and  electrical  fluids ;  but  we  have,  even  now, 
evidence  sufficient  to  show  their  similarity;  and  that  we  are  justified 
in  considering  the  nervous  fluid  to  be  electroid  or  galvanoid  in  its  na- 
ture, emanating  from  the  brain  by  some  action  unknown  to  us,  and 
transmitted  to  the  different  parts  of  the  system  to  supply  the  expendi- 
ture, which  must  be  constantly  taking  place. 

ReiV  Senac,''  Prochaska,  Scarpa,^  and  others  are  of  opinion,  that  the 
nervous  agency  is  generated  throughout  the  nervous  system;  and  that 
every  part  derives  sensation  and  motion  from  its  own  nerves.  We 
have  satisfactorily  shown,  however,  that  a  communication  with  the 
nervous  centres  is  absolutely  necessary  in  all  cases,  and  that  we  can 
immediately  cut  off  sensation  in  the  portion  of  a  nerve  included  be- 
tween two  ligatures,  and  as  instantly  restore  it  by  removing  the  upper 
ligature,  and  renewing  the  communication  with  the  brain. 

a.  External  Sensations. 

The  external  sensations  are  those  perceptions  which  are  occasioned 
by  the  impressions  of  bodies  external  to  the  part  impressed.  They  are 
not  confined  to  impressions  made  by  objects  external  to  us.    The  hand 

'  Med.  Literature,  p.  93.  Lond.,  J813. 

^  Physiological  Lectures,  exhibiting  a  view  of  Mr.  Hunter's  Physiology,  &c.  Lond., 
1817. 

"  The  Physiological  Anatomy  and  Physiology  of  Man,  p.  242.  Lond.,  1845. 

*  Aw  Elementary  System  of  Physiology,  3d  edit.,  p.  148.  Lond.,  183(5. 

*  De  Structura  Nervorum,  Hal.,  17915. 

*  Traite  de  la  Structure  du  Cceur,  &c.,  liv.  iv.  chap.  8.     Paris,  1749. 
'  Tabulfe  Neurologicse.     Ticin.,  1794,  §  22. 

VOL.  I. — 43 


674  SENSIBILITY. 

applied  to  any  part  of  the  body ;  any  two  of  its  parts  brought  into 
contact ;  or  the  presence  of  its  own  secretions  or  excretions  may  equally 
excite  them.  M.  Adelon/  has  divided  them  into  two  orders — first^  the 
senses^  properly  so  called,  by  the  aid  of  which  the  mind  acquires  its 
notion  of  external  bodies,  and  of  their  different  qualities ;  and  secondly^ 
those  sensations  which  are  still  caused  by  the  contact  of  some  body, 
and  yet  afford  no  information  to  the  mind. 

It  is  by  the  external  senses,  that  we  become  acquainted  with  the 
bodies  that  surround  us.  They  are  the  instruments  by  which  the  brain 
receives  its  knowledge  of  the  universe  ;  but  they  are  only  instruments, 
and  cannot  be  considered  as  the  sole  regulators  of  the  intellectual 
sphere  of  the  individual.  This  we  shall  see  is  dependent  upon  another 
and  still  higher  nervous  organ, — the  brain. 

The  external  senses  are  generally  considered  to  be  five  in  number; 
for,  although  others  have  been  reckoned,  they  may  perhaps  be  reduced 
to  some  modification  of  these  five, — tact  or  touchy  taste,  smell,  hearing, 
and  vision.  All  these  have  some  properties  in  common.  They  are 
situate  at  the  surface  of  the  body,  so  as  to  be  capable  of  being  acted 
upon  with  due  facility  by  external  bodies.  They  all  consist  of  two 
parts; — the  one,  physical,  which  modifies  the  action  of  the  body,  that 
causes  the  impression ;  the  other  nervous  or  vital,  which  receives  the 
impression,  and  conveys  it  to  the  brain.  In  the  e3'e  and  the  ear,  we 
have  better  exemplifications  of  this  distinction  than  in  the  other  senses. 
The  physical  portion  of  the  eye  is  a  true  optical  instrument,  which 
modifies  the  light,  before  it  impinges  upon  the  retina.  A  similar  modi- 
fication is  produced  by  the  physical  portion  of  the  ear  on  the  sonorous 
vibrations  before  they  reach  the  auditory  nerve ;  whilst,  in  the  other 
senses,  the  physical  portion  forms  a  part  of  the  common  tegument  in 
which  the  nervovis  portion  is  seated,  and  cannot  be  easily  distinguished. 
Some  of  them,  again,  as  the  skin,  tongue,  and  nose,  are  symmetrical, 
that  is,  composed  of  two  separate  and  similar  halves,  united  at  a  median 
line.  Others,  as  the  eye  and  ear,  are  in  pairs ;  and  this,  partly  per- 
haps, to  euable  the  distances  of  external  objects  to  be  appreciated.  We 
shall  find,  at  least,  that  there  are  certain  cases,  in  which  both  the  organs 
are  necessary  for  accurate  appreciation. 

Two  of  the  senses — vision  and  audition — have,  respectively,  a  nerve 
of  special  sensibility;  and,  until  of  late  years,  the  smell  was  universally 
believed  to  be  similarly  situate.  In  the  present  state  of  our  knowledge, 
we  cannot  decide  upon  the  precise  nerve  of  taste,  although  it  will  be 
seen  that  a  plausible  opinion  may  be  indulged  on  the  subject.  The 
general  sense  of  touch  or  feeling  is  certainly  seated  in  the  nerves  of 
general  sensibility  connected  with  the  posterior  roots  of  the  spinal 
nerves,  and  the  fifth  encephalic  pair ;  and  according  to  some,^  in  the 
glosso-pharyngeal  and  pneumogastric  nerves.  The  other  senses  seem 
intimately  connected  with  one  nerve  of  general  sensibility, — the  fifth 
pair.  This  is  especiall}^  the  case  with  those  senses  that  possess  nerves  ' 
of  special  sensibility  ;  for,  if  the  fifth  pair  be  cut,  the  function  is  abo- 
lished or  impaired,  although  the  nerve  of  special  sensibility  may 
remain  entire. 

'  Pliysiologie  de  I'llomme,  torn.  i.  p.  250,  2de  edit.     Paris,  1829. 
*  Louget,  Traite  de  Physiologie,  ii.  17tJ,  uote.     Paris,  1850. 


EXTERNAL   SENSATIONS.  675 

Being  instruments  by  which  the  mind  becomes  acquainted  with 
external  bodies,  it  is  manifestly  of  importance,  that  the  senses  should 
be  influenced  by  volition.  Most  of  them  are  so.  The  touch  has  the 
pliable  upper  extremity,  admirably  adapted  for  the  purpose.  The 
tongue  is  movable  in  almost  every  direction.  The  eye  can  be  turned 
by  its  own  immediate  muscles  towards  objects  in  almost  all  positions. 
The  ear  and  the  nose  possess  the  least  individual  motion ;  but  the  last 
four,  being  seated  in  the  head,  are  capable  of  being  assisted  by  the 
muscles  adapted  for  its  movements. 

All  the  senses  may  be  exercised  passively  and  actively.  By  directing 
the  attention,  we  can  render  the  impression  more  vivid ;  and  hence  the 
difference  between  simply  seeing  or  passive  vision,  and  looking  atten- 
tively ;  between  hearing  and  listening;  smelling  and  snuffing;  touching 
and  feeling  closely.  It  is  to  the  active  exercise  of  the  senses,  that  we 
are  indebted  for  many  of  the  pleasures  and  comforts  of  social  existence. 
Yet,  to  preserve  the  senses  in  the  vigour  and  delicacy,  which  they  are 
capable  of  acquiring  by  attention,  the  impressions  must  not  be  too 
constantly  or  too  strongly  made.  The  occasional  use  of  the  sense  of 
smell,  under  the  guidance  of  volition,  may  be  the  test  on  which  the 
chemist,  perfumer,  or  wine-merchant,  may  rely  in  the  discrimination 
of  the  numerous  odorous  characteristics  of  bodies ;  but,  if  the  olfactory 
nerves  be  constantly,  or  too  frequently,  stimulated  by  excitants,  of  this 
or  any  other  kind,  dependence  can  no  longer  be  placed  upon  them  as 
a  means  of  discrimination.  The  maxim  that  "habit  blunts  feeling,"' 
is  true  only  in  such  dases  as  the  last.  Education  can,  indeed,  render 
it  extremely  acute.'  Volition,  on  the  other  hand,  enables  us  to  deaden 
the  force  of  sensations.  By  corrugating  the  eyebrows,  and  approxi- 
mating the  eyelids,  we  can  diminish  the  quantity  of  light  when  it  is 
too  powerful.  We  can  breathe  through  the  mouth,  when  a  disagree- 
able odour  is  exhaled  around  us ;  or,  with  the  aid  of  the  upper  ex- 
tremity, can  completely  shut  off  its  passage  by  the  nostrils.  Over  the 
hearing  we  have  less  command  as  regards  its  individual  action:  the 
upper  extremity  is  here  always  called  into  service,  when  we  desire  to 
diminish  the  intensity  of  any  sonorous  impression. 

Lastly.  It  is  a  common  observation,  that  the  loss  of  one  sense  occa- 
sions greater  vividness  in  others.  This  is  only  true  as  regards  tlie  senses 
that  administer  chiefly  to  the  intellect, — those  of  touch,  audition,  and 
vision,  for  example.  Those  of  smell  and  taste  may  be  destroyed;  and 
yet  the  more  intellectual  senses  may  be  uninfluenced.  In  the  singular 
condition  of  artificial  somnambulism  or  hypnotism,  the  author  has  seen 
the  various  senses  rendered  astonishingly  acute. 

The  cause  of  the  superiority  of  the  remaining  intellectual  senses, 
when  one  has  been  lost,  is  not  owing  to  any  superior  organization  in 
those  senses;  but  is  another  example  of  the  influence  of  education. 
The  remaining  senses  are  exerted  attentively  to  compensate  for  the 
privation ;  and  they  become  surprisingly  delicate. 

"We  proceed  to  the  consideration  of  the  separate  senses,  beginning 
with  that  of  tact  or  toucli^  because  it  is  most  generally  distributed,  and 

'  Burard,  Rapport  du  Physique  et  du  Moral,  p.  245  ;  Pans,  1823. 


676  *  SENSIBILITY. 

may  be  regarded  as  that  from  whicli  the  others  are  derived.  They  are 
all,  indeed,  modifications  of  the  sense  of  touch.  In  the  taste,  the  sapid 
body;  in  the  smell,  the  odorous  particle;  in  the  hearing,  the  sonorous 
vibration ;  and  in  the  sight,  the  particle  of  light,  must  impinge  upon 
or  touch  the  nervous  part  of  the  organ,  before  sensation  can,  in  any  of 
the  cases,  be  effected. 

A.  SENSE  OF  TACT  OR  TOUCH— PALPATION. 

The  sense  of  tact  or  touch  is  the  general  feeling  or  sensibility,  pos- 
sessed by  the  skin  especially,  which  instructs  us  regarding  the  tempe- 
rature and  general  qualities  of  bodies.  By  some,  touch  is  restricted 
to  the  sense  of  resistance  alone;  and  hence  they  have  conceived  it 
necessary  to  raise  into  a  distinct  sense  one  of  the  attributes  of  tact  or 
touch.  The  sense  of  heat,  for  example,  has  been  separated  from  tact ; 
but  although  the  appreciation  of  external  bodies  by  tact  or  touch  diflers 
— as  will  be  seen — in  some  respects  from  our  appreciation  of  their 
temperature,  its  consideration  properly  belongs  to  the  sense  we  are 
considering,  in  the  acceptation  here  given  to  it,  and  adopted  by  all  the 
French  physiologists.  According  to  them,  tact  is  spread  generally  in 
the  organs,  and  especially  in  the  cutaneous  and  mucous  surfaces.  It 
exists  in  all  animals;  whilst  touch  is  exercised  only  by  parts  evidently 
destined  for  that  purpose,  and  is  not  present  in  every  animal.  It  is 
nothing  more  than  tact  joined  to  muscular  contraction  and  directed 
by  volition.  So  that,  in  the  exercise  of  tact,  we  may  be  esteemed  jjas- 
sive ;  in  that  of  touch,  active. 

The  organs  concerned  in  touch,  execute  other  functions  besides;  and 
in  this  respect  touch  differs  from  the  other  senses.  Its  chief  organ, 
however,  is  the  skin;  and  hence  it  is  necessary  to  inquire  into  its  struc- 
ture, so  far  as  is  requisite  for  our  purpose. 

1.    ANATOMY  OF  THE  SKIN,  HAIR,  NAILS,  ETC. 

The  upper  classes  of  animals  agree  in  possessing  an  outer  envelope 
or  skin,  through  which  the  insensible  perspiration  passes ;  a  slight  de- 
gree of  absorption  takes  place;  the  parts  beneath  are  protected  ;  and 
the  sense  of  touch  is  accomplished.  In  man,  the  skin  is  generally 
considered  to  consist  of  four  parts, — the  cuticle,  rete  mucosuin,  corpus 
papillare,  and  corium;  but  when  reduced  to  its  simplest  expression,  the 
whole  of  the  integument,  with  the  mucous  membrane,  which  is  an  ex- 
tension of  it,  may  be  regarded  as  a  continuous  membrane,  more  or  less 
involuted,  more  or  less  modified  by  the  elementary  tissues  which  com- 
pose it  or  are  in  connexion  with  it,  and  within  which  all  the  rest  of  the 
animal  is  contained.  It  consists  of  two  elements — a  hasement  tksue 
or  inemhrane,  composed  of  simple  membrane,  uninterrupted,  homo- 
geneous, and  transparent;  covered  by  an  epithelium  or  pavement  of 
nucleated  particles.' 

1.  The  epidermis  or  cuticle  is  the  outermost  layer.  It  is  a  dry,  mem- 
branous structure,  devoid  of  vessels  and  nerves;  yet  it  is  described  by 
some  modern  investigators  as  a  tissue  of  a  somewhat  complex  organiza- 

'  Todd  and  Bowman,  Tlie  Physiological  Anatomy  and  Physiology  of  Man,  p.  404, 
London,  1845. 


ORGANS   OF  TOUCH.  *  677 

tion,  connected  with  the  functions  of  exhalation  and  absorption;  but  its 
vitality  is  regarded  to  be  on  a  par  with  that  of  vegetables.  The  absence 
of  nerves  proper  to  it  renders  it  insensible;  it  is  coloured;  and  exhales 
and  absorbs  in  the  manner  of  vegetables.  It  is,  so  far  as  we  know, 
entirely  insensible;  resists  putrefaction  for  a  long  time,  and  may  be 
easily  obtained  in  a  separate  state  from  the  other  layers  by  maceration 
in  water.     It  is  the  thin  pellicle  raised  by  a  blister. 

The  cuticle  is  probably  a  secretion  or  exudation  from  the  true  skin, 
which  concretes  on  the  surface ;  becomes  dried,  and  aftbrds  an  efi&cient 
protection  to  the  corpus  papillare  beneath.  It  is  composed,  according 
to  some,  of  concrete  albumen ;  according  to  others,  of  mucus ;  and  is 
j^erced  by  oblique  pores  for  the  passage  of  hairs,  and  for  the  orifices  of 
exhalant  and  absorbent  vessels.  MM.  Breschet  and  Roassel  de  Vau- 
zeme^  affirm,  that  there  is  a  special '"'' hlennogenous  or  mucijic  apparatus''' 
for  the  secretion  of  this  mucous  matter,  composed  of  a  glandular  paren- 
chyma or  organ  of  secretion  situate  in  the  substance  of  the  derma,  and 
of  excretory  ducts,  which  issue  from  the  organ,  and  deposit  the  mucous 
matter  between  the  papillce ;  but  such  an  apparatus  is  not  admitted. 

It  is  probable,  that  the  cuticle  is  placed  at  the  surface  of  the  body, 
not  simply  to  protect  the  corpus  papillare;  but  to  prevent  the  constant 
imbibition  and  transudation  that  might  take  place  did  no  such  envelope 
exist.  It  exfoliates,  in  the  form  of  scales,  from  the  head;  and  in  large 
pieces,  from  every  part  of  the  body,  after  certain  cutaneous  diseases. 

M.  Flourens,^  who  has  closely  and  accurately  investigated  the  ana- 
tomy of  the  cutaneous  envelope,  considers  that  the  skin  of  the  coloured 
races  has  an  apparatus,  which  is  wanting  in  the  white  variety  of  the 
species.  This  apparatus  he  names  pigmental, — appareil  pigmental.  It 
is  composed  of  a  layer  {lame)  or  membrane  which  bears  the  pigment, 
and  of  the  pigment  itself.  Above  it  are  two  cuticles.  In  the  white 
variety  the  pigmental  apparatus  is  wanting,  and  consequently  the  skin 
is  more  simple  than  that  of  the  coloured  races.  The  skin  of  the  white 
variety  approaches  that  of  the  coloured  in  some  remarkable  points. 
First. — The  superficial  layer  or  lame  of  the  derma  is  everywhere  of  a 
peculiar  appearance,  which  is  different  from  that  of  the  rest  of  the 
derma.  Secondly. — Around  the  nipple  of  the  white  woman,  the  super- 
ficial layer  of  the  derma  presents  the  same  granular  appearance  as  the 
pigmental  memlrarte  of  the  coloured  races.  And  tliirdly. — The  pAgmental 
layer  around  the  nipple  of  the  white  woman  is  placed,  as  in  the  coloured 
races,  under  the  two  cuticles. 

Modern  histologists  consider  the  epidermis  to  be  composed  of  a  series 
of  flattened,  scale-lilce  cells,  epidermic  cells^  which,  when  first  formed,  are 
of  a  spheroidal  shape;  but  gradually  dry  up.  These  form  various  layers. 
According  to  M.  Kaspail,^  it  consists  of  a  collection  of  vesicles  deprived 
of  their  contents,  closely  applied  together,  dried  and  thrown  off'  in  the 
form  of  branny  scales.    He  regards  it  as  the  outer  layer  of  the  corium. 

The  epidermoid  tissues  have  the  simplest  structure  of  any  solids. 

Analysis  has  shown,  that  the  chemical  constitution  of  the  mem- 

'  Nouvelles  Reclierches  sur  la  Structure  de  la  Peau,  par  M.  Breschet,  Paris,  1835. 
^  Anatomic  Generale  de  la  Peau  et  d(^s  Membraiied  Muqueuses,  p.  34,  Paris,  1843. 
'  Chimie  Orgauique,  p.  245,  Paris,  1833. 


678 


SENSIBILITY 


Fig.  222. 


Scrotum  of  a  Negro. 

a.  Deep  cells,  loaded  with  pigment,  h.  Cells 
at  a  higher  level,  paler  and  nrnre  flattened,  c. 
Cells  at  the  surface,  scalv  and  oolourles.s  as  in 
the  white  races. — Magnified  300  diameters. 


==^^=.- 


branous  epidermis  of  tbe  sole  of  the  foot  is  the  same  as  that  of  the 
compact  horny  matter  of  which  nails,  hair,  and  wool  are  composed. 

2.  The  corpus  or  rete  mncosum,  rete 
Jfalpic/hn,  mucous  web,  is  generally 
reorarded  as  constituting?  the  next 
layer.  It  was  considered  by  Mal- 
pighi  to  be  mucus,  secreted  by  the 
papillas,  and  spread  on  the  surface 
of  the  corpus  papillare,  to  preserve 

Vertical  Section    of   the  Cuticle,  from    the     it    ill    the    State    of  SUppleueSS    UeCCS- 

"""'         '  sary  for  the  performance  of  its  func- 

tions. In  this  rete  mucosum,  the 
colouring  matter  of  the  dark  races 
seems  to  exist.  It  is  black  in  the 
African,  or  rather  in  the  Ethiopian ; 
and  copper-coloured  in  the  mulatto.' 
Gaultier^  considers  it  to  be  composed 
of  four  layers;  but  this  notion  is  not 
admitted  by  anatomists,  and  scarcely 
concerns  the  present  inquiry.  M. 
Breschet  affirmed,  that  there  is  a  spe- 
cial ^^ chromalogenous  or  colorific  appn- 
ratus,''^  for  producing  the  colouring 
matter,  composed  of  a  glandular  or 
secreting  parenchyma,  situate  a  little 
below  the  papilhis,  and  presenting 
special  excretory  ducts,  which  pour 
out  the  colouring  matter  on  the  sur- 
face of  the  derma.  Modern  observers 
deny,  that  there  is  any  such  distinct 
layer.  Some  regard  it  as  the  deepest 
or  most  recently  formed  part  of  the 
cuticle.  M.  Flourens''  considers,  that 
the  term  corpus  mucosum  ought  to 
be  replaced  by  that  of  pigmental 
apparatus, — appareil  pigmental ;  and 

s  seen  in  the  palm" of  the  hand  or 'sole  Jf     that  thc  tCrm  TCte   OT   COriJUS  Veticulave 
nt;  they  are  CDniposed  of  minute  conical      .  ,  .         .  „  .  „     -'  .    , 


^■ 


---^ 


.■^■fl 


Section  of  the  Skin. 


1.  Cuticle,  showing  the  oblique  laminjE  of 
■which  it  i.s  composed,  and  the  imbricated  dispo- 
sition of  the  ridges  upon  its  surface.  2.  Rete  mu- 
cusum.  3.  Two  of  the  quadrilateral  papillary 
masses 

the  foo,,   ...._,  „ ,,„..,.  ., ^  ...      .  .         .„  .  „  .    , 

papilla;.  4.  Deeper  layer  of  the  cutis,  the  corium.  m  the  Signification  of  a  SpCCial  net 
r>.  Adipose  vesicles;  showing  their  appearance  i        -^        j       n      ^  ,i         i  i 

beneath  the  microscope.  6.  Perspiratory  gland  WOrlC  SltUatC  bCtWeen  the  dcrma  aUQ 
with  its  s])iral  duct,  as  seen  in  the  palni  of  the  +l-,p  f^^  pntiplpd  nno-lit  tr>  Kp>  'hnniQliPfl 
hand  or  sole  of  the  foot.   7.  Another  perspiratory     ^^le  IWO  OUllCitS,  OU g  ni  10  DC  OaUlbnea 

giandwith  astraighterduct.suchasseeniuthe   from  auatomv.     The  naturc  of  the 

scalp.     8.  Two  hairs  from  the  scalp,  enclosed  in         .  -n  i  pit  p 

their  follicles;  their  relative  depth  in  the  skin  pigment  Will  DC  rCierred  tO  hereaiter, 
preserved.     9,  A  pair  of.sebaceous  glands  open-     ^^^^^^^  SECRETION. 

The  rete  mucosum  is  considered 
to  be  the  last  formed  portion  of  the  cuticle. 

3.  The  corpus  piajjillare,  or  what  M.  Breschet  calls  the  ^'■neurothelic  or 
mammillary  nervous  apparatus,^^  \s  seated  next  below  the  rete  mucosum. 
It  consists  of  a  collection  of  small  papillae,  formed  by  the  extremities 


ing  by  short  duets  into  the  follicle  of  the  hair. 


'  Sir  E.  Home,  Lect.  on  Comp.  Anat.,  v.  278. 

'^  Recherches  Anatomiques  sur  le  Systeme  Cutani^  de  rHomme,  Paris,  1811. 

'  Op.  cit.,  p.  38. 


ORGANS   OF   TOUCH.  •  679 

of  nerves  and  vessels,  winch,  after  having  passed  through  the  corium 

beneath,  are  grouped  in  small  pencils  or  villi  on  a  spongy,  erectile 

tissue.   These  pencils  are  disposed  in  pairs,  and, 

when  not  in  action,  are  relaxed,  but  become  Fig.  224. 

erect  when  employed  in  the  sense  of  touch. 

They  are  very  readily  seen,  when  the  cutis  vera 

is  exposed  by  the  action  of  a  blister;  and  are 

always  evident  at  the  palmar  surface  of  the 

hand,  and  especially  at  the  tips  of  the  fingers,      i-^^Mp^'^-^'^T;-)^ 

where   they  have   a   concentric   arrangement.  — -—         -_j--j 

These  villi  are  sometimes  called  vamllce.   They      rnpiHasof  thePaim.the  Cu- 

,.  ,  .  nil-  1      tide  being  detached. — Mag- 

are,  m  reality,  prolongations  ot  the  skm;  and    nified  35  diameters. 

consequently — as  M.  Flourens^  has  remarked — 

"the  pretended  corjms  pajnllare^  taken  as  a  body,  apart  and  distinct 

from  the  derma,  is  but  an  idle  name." 

In  parts  that  are  endowed  with  much  tactile  sensibility,  the  cutaneous 
nerve  fibres — as  of  the  papillae  of  the  palm  of  the  hand — terminate  in 
the  corpuscles  of  touch  already  mentioned.^ 

4.  The  corium^  cutis  vera^  derma  or  true  slan,  is  the  innermost  layer  of 
the  skin.  It  consists  of  a  collection  of  dense  fibres,  intersecting  each 
other  in  various  directions;  and  leaving  between  them  holes  for  the 
pafisage  of  vessels  and  nerves.  It  forms  a  firm  stratum,  giving  the 
whole  skin  the  necessary  solidity  for  accomplishing  its  various  ends; 
and  consists  chiefly  of  gelatin; — hence  it  is  used  in  the  manufacture  of 
glue.  Gelatin,  when  united  with  tannic  acid,  forms  a  substance  which 
is  insoluble  in  water;  and  it  is  to  this  combination  that  leather  owes 
the  properties  it  possesses.  The  hide  is  first  macerated  in  lime-water 
to  remove  the  cuticle  and  hairs,  and  leave  the  corium  or  gelatin.  This 
is  then  placed  in  an  infusion  of  oak  bark,  which  contains  tannic  acid. 
The  tannic  acid  and  the  skin  unite;  and  leather  is  the  product. 

These  four  strata  constitute  the  skin,  as  it  is  commonly  called;  yet 
all  are  comprised  in  the  thickness  of  two  or  three  lines.  The  cutis 
vera  is  united  to  the  structures  below  by  areolar  tissue;  and  this,  with 
the  layers  external  to  it,  forms  the  common  integument.  In  certain  parts 
of  the  body,  and  in  animals  more  particularly,  the  cutis  vera  is  ad- 
herent to  muscular  fibres,  inserted  more  or  less  obliquely.  These  form 
the  muscular  weh,  mantle,  or  pannicuhis  carnosus.  The  layer  is  well  seen 
in  the  hedgehog  and  porcupine,  in  which  it  rolls  up  the  body,  and 
erects  the  spines;  and  in  birds  raises  the  feathers.  In  man,  it  can 
hardly  be  said  to  exist.  Some  muscles,  however,  execute  a  similar 
function.  By  the  occipito-frontalis,  many  persons  can  move  the  hairy 
scalp ;  and  by  the  dartos  the  skin  of  the  scrotum  can  be  corrugated. 
These  two  parts,  therefore,  act  as  pariniculi  carnosi. 

The  skin  itself  also  possesses  smooth  muscular  fibres,  which  give 
occasion  to  its  contractility,  as  seen  in  the  corrugation  of  the  scrotum, 
the  erection  of  the  nipple,  and  the  phenomena  of  the  cutis  anserina. 

'  Op.  cit.,  p.  38. 

2  Page  t)40.  Seo,  on  the  nature  of  these  bodies,  Wagner,  in  Miiller's  Archiv.,  1852, 
Heft  4;  Kolliker,  Mikioskopische  Anatomie,  Bd.  ii.  S.  24;  and  Amer.  edit,  of  Sy- 
denham Society':*  edition  of  his  Human  Histology,  by  Dr.  Ua  Costa,  p.  129,  Philad., 
1854;  and  Mr.  Huxley,  Quarterly  Journal  of  Microscopical  Science,  ii.  1. 


680 


SENSIBILITY. 


These  have  been  found  by  Froriep,  Brown-Sequard,  and  Kcilliker  to 
contract  on  the  application  of  electricity.-'  The  cutis  anserina  consists 
in  local  contractions  of  the  portions  of  the  skin  around  the  hair  fol- 
licles, by  which  their  apertures  are  protruded  conically,  by  muscular 
fibres  discovered  by  Kcilliker,  which  pass  obliquely  from  the  super- 
ficial part  of  the  cutis  down  to  the  follicles,  and,  when  they  contract, 
protrude  the  follicles,  and  retract  those  portions  of  the  skin  whence 
they  arise. 

In  the  skin  are  situate  numerous  sebaceous  follicles  or  crypts,  which 
separate  an  oily  fluid  from  the  blood,  and  pour  it  over  the  surface  to 
lubricate  and  defend  it  from  the  action  of  moisture.  They  are  most 
abundant,  where  there  are  folds  of  the  skin,  or  hairs,  or  where  the  sur- 
face is  exposed  to  friction.  We  can  generally  see  them  on  the  pavilion 
of  the  ear,  and  their  situation  is  often  indicated  by  small  dark  spots  on 

the  surface,  which,  when  pressed  between 
Fig-  225.  the  fingers,  may  be  forced  out  along  with 

the  sebaceous  secretion,  in  the  form  of 
small  worms.  By  the  vulgar,  indeed, 
they  are  considered  to  be  worms.  The 
follicular  secretions  have  engaged  atten- 
tion  elsewhere. 


The  consideration  of  the  hair  belongs 
naturally  to  that  of  the  slcin.  The  roots 
are  in  the  form  of  bulbs ;  taking  their 
origin  in  small  follicles  or  open  sacs, 
hair  follicles,  formed  by  the  inversion  of 
the  cutis,  and  lined  by  a  reflexion  of  the 
epidermis.  Around  each  bulb  there  are 
two  capsules,  the  innermost  of  which  is 
vascular  and  a  continuation  of  the  co- 
rium.  The  hair  itself  consists  of  a  horny, 
external  covering,  and  a  central  part, 
called  medulla  or  pith.  When  we  take 
hold  of  a  hair  by  the  base,  with  the  thumb 
and  forefinger,- and  draw  it  through  them 
from  tlie  root  towards  the  point,  it  feels 
smooth  to  the  touch ;  but  if  we  draw  it 
through  from  the  point  to  the  root,  we 
feel  the  surface  rough;  and  it  offers  con- 
siderable resistance.  It  is,  therefore, 
concluded,  that  the  hair  is  bristled,  im- 
bricated, or  consists  of  eminences  point- 


Sections  of  Hair. 

a.  Transverse  section  of  a  hair  of  the  head, 
sliowing  the  exterior  cortex,  the  meilulla  or 
pith  with  its  scattered  pigment,  and  a  cen- 
tral space  filled  with  pigment,  b.  A  similar 
section  of  a  hair,  at  a  point  where  no  aggre- 
gation of  pigment  in  the  axis  exists.  c. 
Longitudinal  section,  without  a  central  ca- 
vity, showing  the  imbrication  of  the  cortex, 
and  the  arrangement  of  the  pigment  in  the 
Hbrous  part.  d.  Surface  showing  the  sinu- 
ous transverse  lines  formed  by  the  edges  of 
the  cortical  scales,  d'.  A  portion  of  the 
margin,  showing  their  imbrication. — Mag- 
nified 150  diameters. 


ing  towards  its  outer  extremity,  and  it  is 
upon  this  structure,  that  the  o{)eration  of  felting  is  dependent — the 
hairs  being  mechanically  entangled  and  retained  in  that  state  by  the 

» 

'  Ki'iUiker,  Experiments,  &c.,  on  the  Body  of  an  Executed  Criminal,  in  Goodsir's  Annals 
of  Anatomy  and  Patholosiy,  for  Maj^  1852,  No.  2,  p.  109  ;  and  Mikroskopische  Anato- 
niie ;  or  Amer.  edit.,  by  Dr.  Da  Co.sta,  of  Sydenham  Society's  edition  of  his  Manual  of 
Hiatology,  by  Messrs.  13usk  and  Huxley,  p.  1'66,  Philad.,  1854. 


TOUCH — HAIR. 


681 


inequalities  of  tlieir  surface.  Certain  observers  have,  however,  failed 
in  detecting  this  striated  appearance  by  the  aid  of  the  microscope;  and 
Dr.  Bostock'  affirms,  that  he  had  an  opportunity  of  viewing  the  human 


Fig.  227. 


Thin  Layer  from  the  Scalp. 


a,  a.   Sebaceous 
with  its  follicle,  c. 


glands.      6.    Hair, 


Magnified  view  of  the  Root  of  the  Hair. 

a.  Stem  or  shaft  of  hair  cut  across,  h.  Inner,  and  c,  outer 
layer  of  the  epidermic  lining  of  the  hair  follicle,  called  also  the 
root-sheath,  d.  Dermic  or  external  coat  of  the  hair  follicle, 
shown  in  part.  e.  Imbricated  scales  about  to  form  a  cortical 
layer  on  the  surface  of  the  hair. 


hair,  and  the  hair  of  various  kinds  of  animals,  with  the  excellent  micro- 
scope of  Mr.  Bauer,  but  without  being  able  to  observe  it.  Bichat,^ 
however,  and  more  recently.  Dr.  Goring,^  and  most  histologists,  have 
assigned  this  as  their  structure;  and  the  author  has  had  repeated  op- 
portunities for  confirming  it. 

Modern  observers  believe,  that,  as  in  other  structures,  growth  takes 
place  from  cells,  which  are  a  modification  of  those  of  the  epidermis. 
The  primary  cells  become  elongated,  and  generate  within  themselves 
fasciculi  of  fibres  or  secondary  cells,  which  interlace  to  form  the  hair 
cylinder.  The  walls  of  these  fibre-cells  are  at  first  soft  and  permeable; 
and  the  lower  part  of  the  hair,  which  is  composed  of  them,  seems  to 
admit  the  passage  of  fluid  without  much  difficulty.  At  a  short  dis- 
tance from  the  base,  the  horny  character  of  the  hair,  caused  by  the 
deposit  of  horny  matter  in  the  interior  of  the  fibres,  becomes  appa- 
rent. "There  is  then,  at  the  base,  a  continual  formation  of  soft  fibrous 
tissue,  by  which  the  length  of  the  cylinder  is  increased;  whilst  at  a 
short  distance  above  it,  there  is  a  continual  consolidation  of  this  (as  it 
progressively  arrives  at  that  point)  by  the  deposit  of  a  peculiar  secre- 
tion in  its  substance."* 

The  shape  of  the  hair  is  different  in  different  races.     It  is  described 


Pliysiology,  p.  52,  3d  edit.,  Lond.,  183G". 
.Tournal  of  Science,  New  Series,  vol.  i.  433. 


2  Anat.  General.,  torn.  iv.  §  2. 


*  Carpenter,  Human  Physiology,  §  (537.     Lond.,  1842. 


682  SENSIBILITY. 

as  cylindrical  in  the  American  Indian;  oval  in  the  white  man,  and 
eccentrically  elliptical  or  flat  in  the  negro.^  Its  colour  also  differs  in 
different  races  and  individuals.  By  some,  this  is  considered  to  depend 
upon  the  fluids  contained  in  the  pith.  M.  Vauquelin^  analyzed  the 
hair  attentively,  and  found  it  to  consist  chiefly  of  an  animal  matter, 
united  to  a  portion  of  oil,  which  appeared  to  contribute  to  its  flexi- 
bility and  cohesion.  Besides  this,  there  is  another  substance,  of  an 
oily  nature,  from  which  he  considers  the  colour  of  the  hair  is  derived. 
The  animal  matter,  according  to  that  chemist,  is  a  species  of  mucus; 
but  other  chemists  believe  it  to  be  chiefly  albumen.  Vauquelin  found, 
that  the  colouring  matter  is  destroj^ed  by  acids;  and  he  suggests,  that 
when  it  has  suddenly  changed  colour  and  become  gray,  in  consequence 
of  any  mental  agitation,  this  may  be  owing  to  the  production  of  an 
acid  in  the  system,  which  acts  upon  the  colouring  matter.  The  expla- 
nation is  hypothetical,  and  is  considered,  and  characterized  as  such  by 
Dr.  Bostock ;  but  it  must  be  admitted,  that  the  same  objection  applies 
to  the  view  he  has  substituted  for  it.  He  conceives  it  "  more  probable 
that  the  effect  depends  upon  a  sudden  stagnation  in  the  vessels,  which 
secrete  the  colouring  matter;  while  the  absorbents  continue  to  act, 
and  remove  that  which  already  exists."  There  is,  however,  no  more 
real  evidence  of  "  stagnation  of  vessels"  than  there  is  of  the  formation 
of  an  acid.  Our  knowledge  is  limited  to  the  fact,  that  a  sudden  and 
decided  change  in  the  whole  pileous  system  may  occur  after  great  or 
prolonged  mental  agitation. 

"  My  hair  is  gray,  but  not  with  years, 
Nor  grew  it  white  in  a  single  night, 
As  men's  have  grown  from  sudden  fears." 

Byron's  ^'Prisoner  of  Chillon." 

"  Danger,  long  travail,  want  and  wo, 
Soon  change  the  form  that  best  we  know  : 
For  deadly  fear  can  time  outgo, 

And  blanch  at  once  the  hair. 
Hard  toil  can  roughen  form  and  face, 
And  want  can  quench  the  eye's  bright  grace, 
Nor  does  old  age  a  wrinkle  trace 

Moi-e  deeply  than  despair." 

Scott's  '■'■Mannion." 

It  is  stated,^  that  such  a  change  occurred  in  a  single  night  to  the 
queen  of  Louis  the  16th — the  unfortunate  Marie  Antoinette — when 
the  royal  party  was  arrested  at  Varennes,  in  1791.'' 

But  a  similar,  though  more  gradual  change  is  produced  by  age. 
We  find  some  persons  entirely  gray  at  a  very  early  period  of  life ; 
and,  in  old  age,  the  change  happens  universally.  It  is  not  then  dif- 
ficult to  suppose,  that  some  alteration  in  the  nutrition  of  the  hair  may 

'  P.  A.  Browne,  The  Classification  of  Mankind  by  the  Hair  and  Wool  of  their  Heads, 
p.  4,  Philad.,  1850,  and  Trichologia  Mammaliura,  p.  51.     Philad.,  1853. 

^  Annales  de  Chiinie,  tom.  Iviii.  p.  41,  Paris,  1806. 

3  "  La  reine  ne  dormit  pas.  Toutes  ses  passions,  de  femme,  de  mere,  de  reine,  la 
colere,  la  terreur,  la  desespoir,  se  livrerent  un  tel  assaut  dans  son  a,me,  que  ses  che- 
veux,  blonds  la  vieille,  furent  blancs  le  lendemaiu." — De  Lamartine,  Histoire  des 
Girondins,  i.  116.     Paris,  1847. 

*  Several  cases  are  recorded  in  Mr.  Erasmus  Wilson,  Healthy  Skin,  Amer.  edit.,  p. 
114,  Philad.,  1854. 


TOUCH — HAIR.  683 

supervene,  resembling  that  whicli  occurs  in  the  progress  of  life.  Dr. 
Bostock  doubts  the  fact  of  such  sudden  conversions;  but  the  instances 
are  too  numerous  for  us  to  consider  them  entirely  fabulous.  Still,  it 
is  difficult  to  comprehend  how  parts,  which,  like  the  extremities  of  the 
hair,  are  foreign  to  nutrition,  can  change  so  rapidly.  M.  Lepelletier^ 
ascribes  it  to  two  very  different  causes.  First^  to  defective  secretion 
of  the  colouring  fluid,  without  any  privation  of  nutrition.  In  this 
case,  the  hairs  may  live  and  retain  their  hold,  as  we  observe  in  young 
individuals: — and  secondly^  to  the  canals,  which  convey  the  fluid  into 
the  hair  being  obliterated,  as  in  old  age.  The  same  cause,  acting  on 
the  nutritious  vessels  of  the  bulb,  produces  successively,  privation  of 
colour,  death,  and  loss  of  those  epidermoid  productions.  A  case  re- 
lated by  M.  Faget^ — and  which  he  esteems  authentic — is,  as  he  pro- 
perly remarks,  in  near  relation  to  those  in  which  the  hair  grows 
quickly  gray  in  mental  anguish.  A  lady,  who  is  subject  to  attacks  of 
what  are  called  nervous  headaches,  always  finds  in  the  morning,  after 
one  of  them,  that  some  patches  of  her  hair  are  white,  as  if  powdered 
with  starch.  "  The  change  is  effected  in  a  night,  and  in  a  few  days 
after,  the  hairs  gradually  regain  their  dark  brownish  colour." 

According  to  other  physiologists,  the  seat  of  colour  is  in  the  horny 
covering  of  the  hair ;  and  in  the  largest  hairs  or  spines  of  the  porcu- 
pine this  seems  to  be  the  case,  the  pith  being  white,  and  the  horny 
covering  coloured.  There  is  often  an  intimate  relationship  observed 
between  the  colour  of  the  hair  and  that  of  the  skin.  A  fair  complex- 
ion is  accompanied  with  light  hair ;  a  swarthy  with  dark  ; — and  we 
see  the  connexion  still  more  signally  displayed  in  those  animals  that 
are  spotted, — the  colour  of  the  hair  being  variegated  like  that  of  the 
skin. 

Hairs  differ  materially  according  to  the  part  of  the  body  on  which 
they  grow.  In  some  parts  they  are  short,  as  in  the  armpits ;  whilst 
on  the  head  it  is  not  easy  to  say  what  would  be  the  precise  limit  to  the 
growth,  were  they  left  entirely  to  nature.  In  the  Malay,  it  is  by  no 
means  uncommon  to  see  them  touch  the  ground. 

The  hair  has  various  names  assigned  to  it,  according  to  the  part  on 
which  it  appears, — heard,  ivhislcers,  mustachios,  eyebrows,  eyelashes,  &c. 
In  many  animals  it  is  long  and  straight;  in  others  crisped,  when  it  is 
called  luool.  If  stiff",  it  is  termed  a  bristle;  if  inflexible,  a  spine.  It  is 
entirely  insensible,  and,  excepting  in  the  bulbous  portion,  is  not  liable 
to  disease.  Dr.  Bostock  affirms,  that  under  certain  circumstances 
hairs  are  subject  to  a  species  of  inflammation,  when  vessels  may  be 
detected,  at  least  in  some  of  them,  and  they  become  acutely  sensitive. 
Their  sensibility  under  'any  known  circumstance  may  be  doubted. 
They  appear  to  be  anorganic,  except  at  the  root ;  and,  like  the  cuticle, 
resist  putrefaction  for  a  length  of  time.  The  parts  that  do  not  receive 
vessels  are  nourished  by  transudation  from  those  that  do.  Bichat  and 
Gaultier  were  of  the  opinion  of  Di\  Bostock, — misled,  apparently,  by 
erroneous  reports  concerning  plica  polonica ;  but  Baron  Larrey^  has 


'  Traits  de  Physiologie  MMioale  et  Philosophiqiie,  torn.  iii.  p.  42,  Paris,  1832. 
2  Lectures  on  Surgical  Pathology,  Amer.  edit.,  ]>.  44,  Philad.,  1854. 
'  Memoires  de  Chirurgie  Militaire,  t,  iii.  108,  Paris,  1812. 


684 


SENSIBILITY. 


satisfactorily  shown  that  plica  is  confined  to  the  bulbs :  the  hairs  them- 
selves continue  devoid  of  sensibility. 

It  is  diffiofilt  to  assign  a  plausible  use  for  the  hair.  That  of  the 
head  has  already  engaged  attention ;  but  the  hair,  which  appears  on 
certain  parts  at  the  age  of  puberty  and  not  till  then,  and  that  on  the 
chin  and  upper  lip  of  the  male  sex  only,  set  our  ingenuity  at  defiance. 
In  this  respect,  the  hair  is  not  unique.  Many  physiologists  regard 
certain  parts,  which  exist  in  one  animal,  apparently  without  function, 
but  which  answer  useful  purposes  in  another,  to  be  vestiges  indicating 
the  harmony  that  reigns  through  nature's  works.  The  generally  use- 
less nipple  and  mamma  of  one  sex  might  be  looked  upon  in  this  light; 
but  the  tufts  of  hair  on  various  parts  cannot,  in  any  way,  be  assimi- 
lated to  the  hairy  coating  that  envelopes  the  bodies  of  animals ;  and 
is,  in  them,  manifestly  intended  as  a  protection  against  cold. 

There  is  another  class  of  bodies  connected  with  the  skin,  and  ana- 
logous in  nature  to  the  last  described, — the  nails.  These  serve  a 
useful  purpose  in  touch,  and  consequently  require  notice  here.     In 

Fig.  229. 


Section  of  the  Skin  on  the  end  of  the  Finger. 

The  cuticle  and  nail,  n,  detached  from  the  cutis 
and  matrix,  m. 


A  transverse  Section  of  a  Finger-Nail,  showing 
the  manner  in  which  it  is  connected  with  the 
sensitive  skin  by  its  under  surface. 

a.  The  nail  laminated  in  texture,  h  6.  The  vor- 
tical plates  of  its  under  surface,  c  e.  The  sensitive 
skin,  which  sends  up  folds  hetween  the  plates  of  the 
nail.  d.  A  small  bloodvessel  supplying  the  sensitive 
skin  and  its  folds. 


the  system  of  De  Blainville,  they  constitute  a  subdivision  of  the  haii'.s, 
which  he  distinguishes  into  simple  and  com.poi(7id, — simple,  when  eae-h 
bulb  is  separated,  and  has  a  distinct  hair ; — compound,  when  several 
pileous  bulbs  are  agglomerated,  so  that  the  different  hairs,  as  they  are 
formed,  are  cemented  together  to  constitute  a  solid  body  of  greater  or 
less  size, — nail,  scale,  horn,  &c.  In  man,  the  nail  alone  exists ;  the 
chief  and  obvious  use  of  which  is  to  support  the  pulp  of  the  finger, 
whilst  it  is  exercising  touch.  Animals  are  provided  with  horns, 
beaks,  hoofs,  nails,  spurs,  scales,  &c.  All  these,  like  the  hair,  gi-ow 
from  roots;  and  are  considered  to  be  analogous  in  their  physical  and 
vital  properties.  Meckel,  De  Blainville,  Bonn,  Walther,  Lavagna,  and 
others,  are  of  opinion,  that  the  teeth  are  of  the  same  class;  and  that 
they  belong,  originally,  to  the  skin  of  the  mouth. 

The  nails,  near  their  origin,  are  seen,  under  the  microscope,  to  con- 
sist of  primary  cells,  almost  identical  with  those  of  the  epidermis ;  these 
gradually  dry  into  scales;  and  the  growth  of  the  nail  appears  to  be 
effected  by  the  constant  generation  of  cells  at  its  root  and  under  sur- 
face; and  as  successive  layers  are  pushed  forward,  each  cell  becomes 


TOUCH  —  MUCOUS   MEMBRANES. 


685 


larger,  flatter,  and  drier,  and  more  firmly  fixed  than  those  around  it.^ 
The  chemical  composition  of  the  epidermis  and  the  nails  is  similar  to 
that  of  the  hair:  yet  according  to  Mulder,^  there  are  material  differ- 
ences in  their  properties; — the  latter,  being  almost  insoluble  in  strong 
acetic  acid,  in  which  the  other  two  are  readily  soluble:  hence — he 
infers — the  composition  of  hair  and  of  horn  and  whalebone  must  differ 
materially ;  and,  that,  accordingly,  Scherer's  conclusion,  that  they  are 
all  identical  is  incorrect.  The  following  are  the  results  of  the  analysis 
of  each  of  these  bodies. 


Epidermis. 

Horn. 

Whalebone. 

Hair. 

c. 

50-28      ■ 

51-03 

51-86 

50-65 

H. 

6-76 

6-80 

6-87 

6-36 

N. 

17-21 

16-24 

15-70 

17-14 

0. 

25-01 

22-51 

■21-97 

20-85 

s. 

0-74 

3-42 

3-60 

5-00 

For  physiological  purposes,  the  above  description  is  sufficient. 

Mucous  Memhranes. — A  few  words  will  be  necessary  regarding  the 
mucous  membranes,  which  resemble  the  skin  so  much  in  their 
properties,  as  to  be,  with  propriety,  termed  dermoid.  If  we  trace 
the  skin  into  the  various  outlets,  we  find,  that  a  continuous,  soft, 
velvety  membrane  exists  through  their  whole  extent ;  and,  if  the 
channel  has  two  outlets,  as  in  the  alimentary  canal,  this  membrane,  at 
each  outlet,  commingles  with  the  skin ;  and  appears  to  differ  but 
slightly  from  it.  So  much,  indeed,  do  they  seem  to  form  part  of  the 
same  organ,  that  physiologists  have  described  the  absorption,  that 
takes  place  from  the  intestinal  mucous  membrane,  as  external.  They 
cannot,  however,  in  the  higher  order  of  animals,  be  considered  com- 
pletely identical ;  nor  is  the  same  membrane  alike  in  its  whole  extent. 
They  have  all  been  referred  to  two  great  surfaces; — the  gastro-'pulmo- 
nary — comprising  the  membranes  of  the  outer  surface  of  the  eye, 
ductus  ad  nasum,  nose,  mouth,  and  respiratory  and  digestive  passages; 
and  the  geniio-urinary — which  line  the  whole  of  the  genital  and  uri- 
nary apparatuses.  In  addition  to  these,  a  membrane  of  similar  cha- 
racter lines  the  meatus  auditorius  externus,  and  the  excretory  ducts 
of  the  mammae. 

A  Fig.  230.  B 


Separated  Epitheliurn  Cell?  from 

mucous  membrane  of  mouth. 
h.  With  nuclei,     c.  And  nucleoli. 


Pavement-Epithelium  of  the  Mucous 
Membrane  of  the  sm.iller  bronchinl  tubes. 
a.  Nuclei  with  double  nucleoli. 


The  analogy  between  the  skin  and  mucous  membranes  is  farther 
shown  by  the  fact,  that  if  we  invert  the  polypus,  the  mucous  membrane 

'  Henle,  edit,  cit.,  i.  289,  Paris,  1843. 

*  The  Chemistry  of  Vegetable  and  Animal  Physiology,  translated  by  Fromberg,  p. 
527.  Edinb.  and  Loudon,  1849. 


686  SENSIBILITY. 

gradually  assumes  the  cliaracters  of  skin ;  and  the  same  circumstance 
is  observed  in  habitual  descents  of  the  rectum  and  uterus. 

In  the  mucous  membranes — especially  at  their  extremities,  which 
appear  to  be  alone  concerned  in  the  sense  of  touch — the  same  super- 
position of  strata  is  generally  considered  to  exist  as  in  the  skin — 
viz.,  epidermis  or  epithelium,  rete  mucosum,  corpus  papillare,  and 
cutis  vera.  They  have,  likewise,  similar  follicles,  called  mucous ;  but 
nothing  analogous  to  the  hairs ;  unless  we  regard  the  teeth  to  be  so, 
in  correspondence  with  the  views  of  Meckel,  De  Blainville,  and  others. 
The  attention  of  anatomists  has  been  closely  directed  to  the  ultimate 
structure  of  the  mucous  system.  In  the*mucous  tissues  two  structures 
have  been  separately  described, — especially  by  Mr.  Bowman,^  who  has 
thrown  much  light  on  the  subject.  These  are  the  hasement  membrane  — 
as  he  terms  it — and  the  epithelium.  The  former  is  a  simple,  homoge- 
neous expansion,  transparent,  colourless,  and  of  extreme  tenuity,  situate 
on  its  parenchymal  surface,  and  giving  it  shape  and  strength.  This 
serves  as  a  foundation  on  which  the  epithelium  rests.  It  may  fre- 
quently be  demonstrated  with  very  little  trouble  in  the  tubuli  of  the 
glands,  especially  of  the  kidney,  which  are  but  very  slightly  adherent, 
by  their  external  surface,  to  the  surrounding  tissue. 

M.  Flourens^  considers  that  every  mucous  membrane  is  composed  of 
three  laminas  or  layers, — the  derma,  epidermis,  and  corpus  mucosum 
situate  between  the  derma  and  epidermis.  The  corpus  mucosum  of 
mucous  membranes  is  continuous  at  all  the  outlets  of  the  body,  and  is 
identical  with  the  second  epidermis  ;  differing,  therefore,  from  the 
corpus  mucosum  of  the  skin,  a  term  which — as  elsev/here  remarked — 
he  thinks  ought  to  be  abolished. 

Histological  examination  exhibits  the  epithelium  to  consist  of  cells, 
which  are  termed  epithelial^  and  have  various  shapes.     The  two  chief 
are  tesselated  or  pjavenient  epithelium^  and  cylinder  or  cortical  epithelium. 
Epithelium  is  not,  however,  confined  to  mucous  membranes,  but,  of 
late  years,  has  been  found  to  exist  elsewhere ;  it 
is  always  in  contact  with  fluids,  and  of  a  soft, 
pliant    character.      Tesselated  epithelium    covers 
the  serous  and  synovial  membranes,  the  lining 
membrane  of  the  blood-vessels,  and  the  mucous 
membranes,  except  where  cylinder  epithelium 
exists.     It  is  spread  over  the  mouth,  pharynx 
and   oesophagus,  conjunctiva,  vagina,   and  en- 
trance of  the  female  urethra.     The  cells  com- 
posing it  are  usually  polj^gonal;  and  are  well 
seen  in  the  marginal  figure.    Cylinder  epithelium 
v^'"^  is  found  in  the  intestinal  canal,  beyond  the  car- 

Tesseiated  Epithelium.       diac  orificc,  in  the  larger  ducts  of  the  salivary 
Extremity  of  one  of  the  tu-    glauds,  in  the  ductus  couimunis  choledochus, 

bun  unniten,  from  the  kidney     <-'  '         _^  i  ^         ^  ■        ^  •        i 

of  an  adult ;  ^huwing  its  tes-    prostatc,  Cowpcr  s  glands,  vesicula3  seminales, 

selated  epithelium. — Magnified  ^    ^    c  i.    i      t  .     . ,,      .  -■  ■,  r  .  i 

2oo  diameters.  vas  deiereus,  tuDuli  urmiien,  and  urethra  oi  the 

male ;    and  lines  the  urinary  passages  of  the 

female  from  the  orifice  of  the  urethra  to  the  beginning  of  the  tubuli 

'  Cyclopaedia  of  Anat.  and  Plivsioloffv,  pt.  xxiii.  p.  486,  April,  1842. 
^  Op.  cit.,p.  80. 


PHYSIOLOGY   OF   TOUCH. 


•687 


uriniferi  of  the  kidnej.     In  all  these  situations,  it  is  continuous  with 
tesselated  epithelium,  which  lines  the  more  delicate  ducts  of  the  various 

Fig.  232. 


Scales  of  Tesselated  Epithelium. 

A.  Section  of  epithelium  of  conjunctiva  with  some  scales  loosened,    b.  Scales  from  surface  of  cheek,    c. 
The  more  deeply  seated  scales  from  the  human  conjunctiva. 

glands.  The  cells  have  the  form  of  long  cylinders  or  truncated  cones, 
arranged  side  by  side,  the  apices  attached  to  the  mucous  membrane  or 
to  flat  epithelial  cells  lying  upon  it ;  the  base  being  free.  Each  cell, 
nearly  midway  between  the  base  and  apex,  encloses  a  flat  nucleus  with 

Fig.  233. 


/ 


Cylinders  of  Intestinal  Epithelium,     (After  Henle.) 

A.  From  the  cardiac  region  of  the  human  stomach.     B.  From  jejunum,     c.  Cylinders  seen  when  look- 
ing on  their  free  extremities,     d.  Ditto,  as  seen  in  a  transverse  section  of  a  villus.  » 

nucleoli.  Epithelium  is  sometimes  furnished  with  cilia^  or  is  said  to 
be  ciliated.  The  nature  and  uses  of  these  cilia,  as  well  as  the  different 
varieties  of  mucous  membrane,  will  be  described  hereafter. 

2.  PHYSIOLOGY  OF  TACT  AND  TOUCH. 

In  describing  the  physiology  of  the  sense  of  touch,  it  will  be  conve- 
nient to  revert  to  the  distinction  already  made  between  the  sense  when 
passively  and  actively  exerted  ;  or  between  tod,  and  touch.  The  mode, 
however,  in  which  the  impression  is  made  is  in  each  case  alike,  and 
equally  simple.  It  is  merely  necessary,  that  the  substance,  which 
causes  it,  should  be  brought  in  contact  with  what  may  be  termed  the 
physical  part  of  the  organ — the  cuticle ;  the  nervous  part  is  seated  in 
the  corpus  papillare,  for  if  the  nerves  proceeding  to  this  layer  of  the 
skin  be  cut,  the  sense  is  destroyed.  In  the  exercise  of  touch,  each  of 
the  layers  seems  to  have  its  appropriate  office:  the  corium,  the  inner- 
most layer,  the  base  on  which  the  others  rest,  offers  the  necessary 
resistance,  when  bodies  are  applied  to  the  surface ;  the  rete  mucosum  is 
unconcerned  in  the  function :  the  erectile  tissue,  on  which  the  papillas 
are  grouped,  probably  aids  them  in  their  appreciation  of  bodies ;  and 
the  epidermis  modifies  the  tactile  impression  which  might  become  too 
intense,  or  be  painful,  did  this  anorganic  envelope  not  exist.  The 
degree  of  perfection  of  the  sense  is  greatly  influenced  by  the  state  of 


688 


SENSIBILITY. 


the  cuticle.  Where  thin — as  upon  the  lips,  glans  penis,  clitoris,  &c. — 
the  sense  is  very  acute ;  where  thick  and  hard,  it  is  obtuse ;  and  where 
removed — as  by  blistering — the  contact  of  bodies  gives  pain,  but  does 
not  occasion  the  appropriate  impression  of  touch. 

Professors  Weber^  and  Valentin^  have  shown  that  the  tactile  power 
of  the  skin  is  not  proportionate  to  its  sensibility.  The  mammae,  for 
example,  are  easily  tickled,  and  susceptible  of  great  pain  when  irritated; 
yet  they  are  moderately  endowed  with  the  sense  of  touch.  The  difterent 
parts  of  the  skin,  too,  vary  in  their  tactile  power.  The  left  hand,  in 
most  persons,  is  more  sensible  to  temperature  than  the  right,  probably 
owing  to  the  epidermis  being  thinner  from  less  use. 

Weber  made  various  experiments  for  the  purpose  of  determining 
the  relative  sensibility  of  difterent  portions  of  the  skin,  by  touching 
the  surface  with  the  legs  of  a  pair  of  compasses,  the  points  of  which 
were  inserted  into  pieces  of  cork.  The  person's  eyes  being  closed  at 
the  time,  the  legs  were  brought  together  so  as  to  be  separated  by 
difterent  distances.  The  following  are  some  of  the  results  of  his  ex- 
periments. 

Point  of  middle  finger 
Point  of  tongue    . 

Palmar  surface  of  third  finger     .  1 

Red  surface  of  lips            .              .  2 

Palmar  surface  of  middle  finger  .  2 

Dorsal  surface  of  third  finger      •  3 

Tip  of  the  nose     ...  3 

Dorsum  and  edge  of  tongue         .  4 

Part  of  lips  covered  by  skin         .  4 

Palm  of  hand       ...  5 

Skin  of  cheek       ...  5 

Extremity  of  great  toe     .              .  5 

Hard  palate          ...  6 

Dorsal  surface  of  fore  finger        .  7 
Dorsum  of  hand  . 


Weber  found,  that  the 
seemed  to  be  greater,  alt 


Lines. 

Mucous  membrane  of  gums 

9 

Lower  part  of  forehead  . 

10 

Lower  part  of  occiput     . 

12 

Back  of  hand 

14 

Neck,  under  lower  jaw  . 

15 

Vertex   . 

15 

Skin  over  patella 

16 

Skin  over  sacrum 

18 
18 
18 

acromion       . 

Dorsum  of  foot 

Skin  over  sternum 

20 

Skin  beneath  occiput     . 

24 

Skin  over  sjiine,  in  back 

30 

Middle  of  the  arm 

30 

thigh 

303 

listance  between  the  legs  of  the  compasses 
hough  it  was  really  less,  when  they  were 
placed  upon  more  sensitive  parts. 

It  has  been  supposed,  that  some  of  the  recorded  instances  of  great 
resistance  to  heat  have  been  caused  by  unusual  thiclvness,  and  com- 
pactness of  cuticle,  together  with  a  certain  degree  of  insensibility  of 
the  skin.  The  latter  may  be  an  important  element  in  the  explanation; 
but  some  of  the  feats,  executed  by  persons  of  the  character  alluded  to, 
could  hardly  have  been  influenced  by  the  former,  as  the  resistance 
seemed  almost  equally  great  in  the  delicately  organized  mucous  mem- 
branes. A  Madame  Girandelli, — who  was  exhibited  in  Great  Britain 
many  years  ago, — was  in  the  habit  of  drawing  a  box  with  a  dozen 

'  Art.  Tastsinn  und  das  Gemeingefiihl,  in  Wagner's  HandwiJrterbuch  der  Physi- 
ologie,  22ste  Lieferung,  S.  539.  Braunschweig,  1849.  His  earlier  experiments  are 
detailed  and  confirmed  by  Dr.  Allen  Thomson,  in  Edinb.  Med.  and  Surg.  Journal,  for 
July,  1833. 

^  Lehrbuch  der  Physiologic  des  Menschen,  ii.  565.  Braunschweig,  1844 ;  and 
Grundriss  der  Physiologie,  S.  331.     Braunschweig,  1846. 

'  A  full  table  of  the  results  of  the  observations  of  Professors  "Weber  and  Valentin  is 
given  by  Dr.  Carpenter,  in  Art.  Touch,  Cyclop,  of  Anat.  and  Physiol.,  iv.  1169,  Lon- 
don, 1852. 


TOUCH — APPRECIATION   OF   TEMPERATURE.  689 

lighted  candles  along  her  arm,  putting  her  naked  foot  upon  melted 
lead,  and  of  dropping  melted  sealing-wax  upon  her  tongue,  and  im- 
pressing it  with  a  seal,  without  appearing  to  experience  uneasiness; 
and  several  years  ago  (1832),  a  man  of  the  name  of  Chabert  excited  in 
this  country  the  surprise  which  followed  his  exhibitions  in  London  a 
year  or  two  previously,  and  gave  him  the  appellation  of  the  "  Fire 
King,"  In  addition  to  the  experiments  performed  by  Madame  Giran- 
delli,  Chabert  swallowed  forty  grains  of  phosphorus;  washed  his  fin- 
gers in  melted  lead;  and  drank  boiling  Florence  oil  with  perfect  im- 
punity. For  the  phosphorus  he  professed  to  take  an  antidote,  and 
doubtless  did  so.  It  is  probable,  also,  that  agents  were  used  by  him 
to  deaden  the  painful  impressions  ordinarily  produced  by  hot  bodies 
applied  to  the  surface.  A  solution  of  borax  or  alum  spread  upon  the 
skin  is  said  to  exert  a  powerful  effect  of  the  kind;  but,  in  addition  to 
the  use  of  such  agents,  there  must  be  a  degree  of  insensibility  of  the 
corpus  papillare;  otherwise  it  is  difficult  to  understand  why  those  hot 
substances  did  not  painfully  inflame  the  surface.  We  see,  daily, 
striking  differences  in  individuals  in  the  degree  of  sensibility  of  the 
mucous  membrane  of  the  mouth  and  gullet,  and  are  frequently  sur- 
prised at  the  facility  with  which  certain  persons  swallow  fluids  of  a 
temperature  that  would  excite  the  most  painful  sensations  in  others. 
In  this,  habit  has  unquestionably  much  to  do. 

The  surprising  feats  of  dipping  the  hand  into  melted  lead,  laying 
hold  of  a  red-hot  iron,  &c.,  were  explained  by  M.  Boutigny  at  the 
meeting  of  the  British  Association  at  Ipswich  in  1851  as  follows.  In 
all  such  cases,  a  thin  film  of  aqueous  fluid  in  the  spherical  state  inter- 
venes between  the  skin  and  the  heated  surflice;  and  a  hand,  which  is 
naturally  damp,  or  which  has  been  slightly  moistened,  may,  it  is 
affirmed,  be  safely  passed  into  the  stream  of  melted  iron  as  it  flows 
from  the  surface,  as  was  shown  by  M.  Boutigny  at  the  meeting.' 

In  the  mucous  membranes,  tact  is  effected  in  the  same  way  as  in  the 
skin.  The  layers,  of  which  it  is  constituted,  participate  in  like  man- 
ner; but  the  sense  is  more  exercised  at  the  extremities  of  the  mem- 
brane than  internally.  The  food,  received  into  the  mouth,  is  felt 
there ;  but  after  it  has  passed  into  the  gullet  it  excites  hardly  any  tac- 
tile impression;  and  it  is  not  until  it  has  reached  the  lower  part  of  the 
membrane,  in  the  shape  of  excrement,  that  its  presence  is  again  indi- 
cated by  this  sense. 

Pathologically,  we  have  some  striking  instances  of  this  difference  in 
different  parts  of  the  mucous  membrane.  If  an  irritation  exists  within 
the  intestinal  canal,  the  only  indication  we  may  have  of  it  is  itching  of 
the  nose,  or  at  one  extremity  of  the  membrane.  In  like  maimer,  a 
calculus  in  the  bladder  is  indicated  by  itching  of  the  glans  penis ;  and 
a  similar  exemplification  is  offered  during  the  passage  of  a  gall-stone 
through  the  ductus  communis  choledochus.  On  its  first  entrance,  the 
pain  experienced  is  of  the  most  violent  character;  this,  after  a  time 
subsides, — as  soon,  indeed,  as  the  calculus  has  got  fairly  into  the  canal, 

'  Eeport  on   the  21st  Meeting  of  the  British  Association  for  tlie   Advancement  of 
Science,  Lend,,  1852;  and  Carpenter,  rrincijiles  of  Human  Physiology,  Amor,  edit.,  p. 
411  (note),  Philad.,  1855. 
VOL,  I. — 4-1: 


690  SENSIBILITY. 

One  of  tlie  great  purposes  of  the  seuse  of  tact  is  to  enable  us  to 
judge  of  the  temperature  of  bodies.  This  office  it  executes  alone.  No 
other  sense  participates  in  it.  It  requires  no  previous  exercise;  is  felt 
equally  by  the  infant  and  the  adult,  and  requires  only  the  proper  de- 
velopment of  its  organs.  The  relative  temperature  of  bodies  is  accu- 
rately designated  by  the  instrument  called  the  therrriometer ;  but  very 
inaccurately  by  our  own  sensations;  and  the  reason  of  this  inaccuracy 
is  sufficiently  intelligible.  In  both  cases,  the  effect  is  produced  by  the 
disengagement  of  a  subtile  fluid,  called  caloric  or  the  matter  of  heat, 
which  pervades  all  bodies,  and  is  contained  in  them  to  a  greater  or 
less  extent.  This  caloric  is  constantly  passing  and  repassing  between 
bodies,  either  by  radiation  or  by  conduction,  until  there  is  an  equili- 
brium of  caloric  and  all  have  the  same  temperature  as  indicated  by 
the  thermometer.  Hence,  objects  in  the  same  apartment  will  exhibit, 
cceteris  jjarihus,  a  like  temperature  by  this  test.  From  this  law,  how- 
ever, the  animal  body  must  be  excepted.  The  power  which  it  pos- 
sesses of  generating  its  own  heat,  and  of  counteracting  the  external 
influences  of  temperature,  preserves  it  constantly  at  the  same  point. 

Although,  however,  all  objects  may  exhibit  the  same  temperature, 
in  the  same  apartment,  when  the  thermometer  is  applied  to  them;  the 
sensations  communicated  by  them  may  be  very  different.  Hence  the 
difficulty,  which  the  uninstructed  have  in  believing,  that  they  are 
actually  of  identical  temperature; — that  a  hearth-stone,  for  instance, 
is  of  the  same  degree  of  heat  as  the  carpet  in  the  same  chamber. 
The  cause  of  the  different  sensations  experienced  in  the  two  cases 
is,  that  the  hearthstone  is  a  much  better  conductor  of  the  matter  of  heat 
than  the  carpet.  The  consequence  is,  that  caloric  is  more  rapidly  ab- 
stracted by  it  from  the  part  of  the  body  which  comes  in  contact 
with  it,  and  the  stone  appears  to  be  the  colder  of  the  two.  For 
the  same  reason,  when  these  two  substances  are  raised  in  temperature 
above  that  of  the  human  body,  the  hearth-stone  will  appear  the  hotter 
of  the  two;  because,  it  conducts  caloric  and  communicates  it  more 
rapidly  to  the  body  than  the  carpet. 

When  the  temperature  of  the  surrounding  air  is  higher  than  98°, 
we  receive  caloric  from  the  atmosphere,  and  experience  the  sensation 
of  heat.  The  human  body  is  capable  of  being  penetrated  by  the  caloric 
of  substances  exterior  to  it,  precisely  like  those  substances  themselves; 
but,  within  certain  limits,  it  possesses  the  faculty  of  consuming  the 
heat,  and  retaining  the  same  temperature.  When  the  temperature  of 
the  atmosphere  is  only  as  high  as  our  own — an  elevation  which  it  not 
unfrequently  attains  in  many  parts  of  the  United  States — we  still  ex- 
perience the  sensation  of  unusual  warmth ;  yet  no  caloric  is  commu- 
nicated to  us.  The  cause  of  this  feeling  is,  that  we  are  accustomed  to 
live  in  a  medium  of  a  less  elevated  temperature,  and  consequently  to 
give  off'  caloric  habitually  to  the  atmosphere. 

Lastly,  in  an  atmosphere  of  a  temperature  much  lower  than  that  of 
the  body,  heat  is  incessantly  abstracted  from  us;  and,  if  rapidly,  we 
have  the  sensation  of  cold.  From  registers,  kept  by  the  illustrious 
founder  of  the  University  of  Virginia,  Mr.  Jefterson,  at  his  residence 
at  Monticello,^  lat.  87°  bS\  long.  7b°  40',  it  appears  that  the  mean 

'  Virginia  Literary  Museum,  p.  36,  Charlottesville,  1830. 


TOUCH — APPRECIATION   OF   TEMPERATURE.  691 

temperature  of  that  part  of  Virginia,  is  about  55i°  or  56° ;  and  that 
the  thermometer  varies  from  5J°  in  the  coldest  month,  to  94°  in  the 
warmest.  Now,  the  temperature  of  the  human  body  being  98°,  it 
follows,  that  heat  must  be  incessantly  parting  from  us,  and  that  we 
ought,  therefore,  to  experience  constantly  a  sensation  of  cold ;  and 
this  we  should  unquestionably  do,  were  we  not  protected  by  clothing, 
and  aided  by  artificial  temperature  during  the  colder  seasons.  Yet, 
accustomed  as  the  body  is  to  give  oft'  caloric,  there  is  a  temperature, 
in  which,  clothed  as  we  are,  we  do  not  feel  cold,  although  we  may  be 
disengaging  heat  to  some  extent.  This  temperature  ma}^  perhaps  be 
fixed  somewhere  between  70°  and  80°  in  the  climate  of  the  middle 
portions  of  the  United  States.  So  much,  however,  are  our  sensations 
in  this  respect  dependent  upon  the  temperature  which  has  previouslv 
existed,  that  the  comfortable  point  varies  at  dift'erent  seasons.  If  the 
thermometer,  for  instance,  has  ranged  as  high  as  98°,  and  has  main- 
tained this  elevation  for  a  few  days,  a  depression  of  15°  or  20°  will  be 
accompanied  by  feelings  of  discomfort;,  whilst  a  sudden  elevation  from 
30°  to  75°  may  occasion  an  oppressive  feeling  of  heat.  In  northern 
Siberia,  M,  von  Wrangel'  found,  that  only  a  few  degrees  of  frost  was 
currently  denominated  "  warm  weather;"  and  that  after  having  been 
accustomed  to  the  winter  temperature  of  that  climate,  it  seemed  to 
him,  that  10°  of  cold,  22°  below  the  freezing  point  of  Fahrenheit,  was 
a  mild  temperature.  During  the  voyages  made  by  Captain  Parry  and 
others  to  discover  a  northwest  passage,  it  was  found,  that  after  having 
lived  for  some  days  in  a  temperature  of  15°  or  20°  below  0,  it  felt 
comfortable  when  the  thermometer  rose  to  zero. 

These  are  the  great  sources  of  the  deceptive  nature  of  our  sensations 
as  to  warmth  and  cold  which  enable  us  to  judge  merely  of  the  com- 
parative conditions  of  the  present  and  the  past;  and  hence  it  is,  that  a 
deep  cellar  appears  warm  in  winter  and  cold  in  summer.  At  a  certain 
distance  below  the  surface,  the  temperature  of  the  earth  indicates  the 
medium  heat  of  the  climate;  3'et,  although  this  may  be  stationary,  our 
sensations  on  descending  to  it  in  winter  and  summer  would  be  by  no 
means  the  same.  If  two  men  were  to  meet  on  the  middle  of  the 
South  American  Andes, — the  one  having  descended,  and  the  other 
ascended, — their  sensations  would  be  very  different.  The  one,  who 
had  descended,  coming  from  a  colder  to  a  warmer  atmos})here,  would 
experience  warmth;  whilst  the  other,  who  had  ascended,  would  feel 
correspondently  cool.  An  experiment,  often  performed  in  the  chemi- 
cal lecture-room,  exhibits  the  same  physiological  fact.  If,  after  having 
held  one  hand  in  iced,  and  the  other  in  warm  water,  we  plunge  both 
into  water  of  a  medium  heat,  it  will  seem  warm  to  the  one  hand,  and 
cold  to  the  other. 

But  our  sensations  are  not  guided  solely  by  bodies  surrounding  us. 
They  are  often  greatly  dependent,  especially  in  disease,  on  the  state  of 
the  animal  economy  itself.  If  the  power,  which  the  system  possesses, 
of  forming  heat,  be  morbidly  depressed, — or  if,  in  consequence  of  old 
age,  or  of  previous  sickness,  calorification  does  not  go  on  regularlv 

'  Reise  des  kaiserlicli  Russischen  Flotten  Lieutenants  F.  v.  Wrangel  Kings  derNord- 
kiiste  vou  Siberien,  u.  s.  w.,  Berlin,  Ib^D,  translated  in  Harper's  Family  Library. 


692  SENSIBILITY. 

and  energetically,  a  temperature  of  the  air,  wliicli  to  the  vigorous  is 
agreeable,  may  produce  an  unpleasant  impression  of  cold.  Under 
opposite  circumstances,  a  feeling  of  heat  exists. 

In  regard  to  the  mode  in  which  the  temperature  of  bodies  is  appre- 
ciated, there  are  peculiarities,  which  would  favour  the  idea  of  the  sense 
of  heat  being  distinct  from  that  of  tact  or  touch.  Professor  Weber, 
for  example,  found  that  the  left  hand  is  more  sensitive  than  the  right, 
although  the  sense  of  touch  is  more  acute  in  the  latter;  and  that  if  the 
two  hands,  at  the  time  of  like  temperature,  be  plunged  into  separate 
basins  of  water,  the  one  in  which  the  left  hand  is,  will  appear  to  be 
the  warmer,  even  although  its  temperature  may  be  somewhat  lower 
than  that  of  the  other.  It  would  seem,  too,  from  Weber's  experiments, 
that  in  regard  to  sensations  of  heat  and  cold,  a  weaker  impression 
made  upon  a  large  surface  appears  more  powerful  than  a  stronger 
made  upon  a  small  surface;  and,  accordingly,  to  judge  of  nice  shades 
of  difference  in  the  temperature  of  a  fluid,  the  whole  hand  will  enable 
a  variation  to  be  detected,  that  would  be  inappreciable  to  the  finger. 
A  dilference  of  one-third  of  a  degree,  it  is  affirmed,  may  be  easily  de- 
tected, when  the  same  hand  is  placed  successively  in  two  vessels  of 
water,  or  any  other  fluid.^ 

These  and  other  phenomena  of  an  analogous  kind  have  led  to  the 
suggestion,  thift  every  nerve  of  sensation  is  composed  of  several  nerves, 
each  of  which  may  have  its  special  function ;  and  that  the  nerves  of 
touch  comprise  some  which  appreciate  temperature;  others,  which  per- 
ceive the  resistance  of  bodies,  and  others  which  effect  touch  properly 
so  called.  In  pi'oof  of  this  a  recent  writer  urges  that  either  of  these 
faculties  may  be  lost,  without  the  other  being  so.  Thus,  when  the  arm 
has  been  '"asleep,"  and  sensibility  is  returning  to  it,  the  hand  first  per- 
ceives temperature,  then  the  resistance  of  bodies,  and  it  is  not  until 
some  time  afterwards  that  the  faculty  of  touch,  properly  so  called,  is 
exercised.  In  the  lower  extremities  the  contrary  takes  place;  the  sense 
of  touch  first  returns;  then  a  sensation  of  pricking  is  experienced,  fol- 
lowed by  the  perception  of  temperature,  and  the  power  of  appreciating 
resistance  returns  last.  It  may  be  added,  that  many  cases  are  recorded, 
in  which  the  sense  of  temperature  has  been  lost,  whilst  the  ordinary 
sense  of  tact  remained;  and,  as  remarked  by  Dr.  Carpenter,'^  it  is  an 
additional  evidence  in  favour  of  the  distinctness  of  nervous  fibres  to 
convey  the  impressions  of  temperature,  that  these  are  frequently 
affected, — a  person  being  sensible  of  heat  or  of  chilliness  in  some  part 
of  the  body, — without  any  real  alteration  of  its  temperature,  whilst 
there  is  no  corresponding  affection  of  the  tactile  sensations. 

By  tact  we  are  lilvcwise  capable  of  forming  a  judgment  of  many  of 
the  qualities  of  bodies,— such  as  their  size,  consistence,  weight,  distance, 
and  motion.  This  faculty,  however,  is  not  possessed  exclusively  by 
the  sense  in  question.  We  can  judge  of  the  size  of  bodies  by  the 
sight;  of  distance,  to  a  certain  extent,  by  the  ear,  &c.  To  appreciate 
these  characters,  it  is  necessary,  that  the  sense  should  be  used  actively ; 
that  we  should  call  into  exercise  the  admirable  instrument  with  which 

'  E.  H.  Weber,  art.  Tastsinn  und  das  Cremeiii,G;efuhl,  in  Wagner's  Handworterbucli 
der  Physiologie,  22te  Lieferung,  S.  549,  Braunschweig,  1849. 

^  Princix'les  of  Physiology,  2d  Amer.  edit.,  j).  229,  Philad.,  1845. 


TOUCH  —  THE  HAND  THE  GREAT  ORGAN". 


69S 


we  are  provided  for  that  purpose;  and  in  many  of  them  we  are  greatly 
instructed  by  the  muscular  sense. 

In  treating  of  the  external  senses  generally,  it  was  remarked,  that 
we  are  capable  of  judging,  by  their  aid,  of  impressions  made  on  us  by 
portions  of  our  own  body.  By  the  sense  of  touch  we  can  derive  infor- 
mation regarding  its  temperature,  shape,  consistence,  &c.  An  opinion 
has,  indeed,  been  advanced,  that  this  sense  is  best  adapted  for  proving 
our  own  existence,  as  every  time  that  two  portions  of  the  body  come 
in  contact,  two  impressions  are  conveyed  to  the  brain,  whilst  if  we 
touch  an  extraneous  body,  there  is  but  one. 

The  tact  of  mucous  membranes  is  extremely  delicate.  The  great 
sensibility  of  the  lips,  tongue,  tunica  conjunctiva,  Schneiderian  mem- 
brane, lining  membrane  of  the  trachea  and  urethra,  is  familiar  to  all. 
Excessive  pain  is  produced  in  them  by  the  contact  of  extraneous  bodies; 
yet,  in  many  cases,  they  signally  exemplify  the  effect  of  habit  in  blunt- 
ing sensation.  The  first  introduction  of  a  bougie  into  the  urethra 
generally  produces  intense  irritation ;  but  after  a  few  repetitions  the 
sensation  may  become  scarcely  disagreeable. 

To  appreciate  accurately  the  shape  and  size  of  objects,  it  is  neces- 
sary, that  they  should 

be  embraced  by  a  part  Fig-  234. 

of  the  body,  which  can 
examine  their  surfaces, 
and  be  applied  to  them 
in  every  direction.  In 
man,  the  organ  well 
fitted  for  this  purpose 
is  the  hand.  This  is 
situate  at  the  free 
extremity  of  a  long 
and  flexible  member, 
which  admits  of  its 
being  moved  in  every 
direction,  and  renders 
it  not  only  well  adapt- 
ed for  the  organ  of 
touch,  but  for  that  of 
prehension.  Man  alone 
possesses  a  true  hand;  for  although  other  animals  have  organs  of  pre- 
hension very  similar  to  his,  they  are  much  less  complete.  Aristotle 
and  Galen  termed  it  the  iyistruvynt  of  instrumeiits^  and  its  construction 
was  considered  worthy  of  forming  the  subject  of  one  of  the  ^'■Bridge- 
water  Treatises'''  "On  the  Power,  Wisdom,  and  Goodness  of  God,  as 
manifested  in  the  Creation," — a  task  assigned  to  Sir  Charles  Bell. 

The  chief  superiority  of  the  hand  consists  in  the  size  and  strength 
of  the  thumb,  which  stands  out  from  the  fingers,  and  can  be  brought 
in  opposition  to  them,  so  as  to  enable  us  to  grasp  bodies,  and  to  execute 
various  mechanical  processes  under  the  guidance  of  the  intellect.  So 
important  was  the  thumb  esteemed  by  Albiuus,^  that  he  called  it  a 
lesser  hand  to  assist  the  larger — "  manus  parva  majori  adjutrixr 


Hand  of  Man,  compared  with  anterior  extremity  of  Oranj 


'  De  Sceleto,  p.  465. 


694  SENSIBILITY. 

In  addition  to  the  advantages  referred  to,  the  hand  is  furnished  with 
a    highly    sensible    integument.      The    pa- 
Fis.  235.  pillae  are  largely  developed,  especially  at  the 

extremities  of  the  fingers,  where  they  are 
ranged  in  concentric  circles,  and  rest  upon 
a  spongy  tissue,  by  many  considered  to  be 
erectile,  and  serving  as  a  cushion,  and  are 
well  supplied  with  capillary  vessels.  (See 
Figs.  217,  and  235.)  At  the  posterior  ex- 
tremity of  the  fingers,  are  the  nails,  which 
support  the  pulps  of  the  fingers  behind;  and 
Capillary  Neiw,,rk  at  margin  Tender  the  coutact  with  external  bodies 
of  lips.  more  immediate.     This  happy  organization 

of  the  soft  parts  of  the  hand  alone  concerns 
the  sense  of  touch  directly.  The  other  advantages,  which  it  possesses, 
relate  to  the  power  of  applying  it  under  the  guidance  of  volition. 

Of  the  mode  in  which  touch  is  effected  it  is  not  necessary  to  treat. 
Being  nothing  more  than  tact,  exerted  by  an  appropriate  instrument, 
the  physiology  of  the  two  must  be  identical. 

Metaphysicians  have  differed  widely  regarding  the  services  thatought 
to  be  attributed  to  the  touch.  Some  have  greatly  exaggerated  them, 
considering  it  the  sense  par  excellence^  the  first  of  the  senses.  It  is  an 
ancient  notion  to  ascribe  the  superiority  of  man  over  animals  and  his 
pre-eminence  in  the  universe — his  intelligence,  in  short — to  the  hand. 
Anaxagoras  asserted,  and  Ilelvetius'  revived  the  idea,  "that  man  is  the 
wisest  of  animals  because  he  possesses  hands."  The  notion  has  been 
embraced  and  expanded  by  Condillac,^  Buffon,^  and  many  modern  phy- 
siologists and  metaphysicians.  Biiffon  assigned  so  much  importance 
to  the  touch,  that  he  believed  the  cause  why  one  person  has  more  intel- 
lect than  another  is  his  having  made  a  more  prompt  and  repeated  use 
of  his  hands  from  early  infancy.  Hence,  he  recommended,  that  infants 
should  use  them  freely  from  the  moment  of  birth.  Other  metaphysi- 
cians have  considered  the  hand  the  source  of  mechanical  capabilities ; 
but  the  same  answer  applies  to  all  these  views.  It  can  only  be  re- 
garded as  an  instrument  by  which  information  of  particular  kinds  is 
conveyed  to  the  brain ;  and  by  which  other  functions  are  executed, 
under  the  direction  of  the  will.  The  idiot  often  has  the  sense  more 
delicate  than  the  man  of  genius  or  than  the  best  mechanician,  whilst 
the  most  ingenious  artists  have  by  no  means  the  most  delicate  touch. 
We  have,  indeed,  some  striking  cases  to  show,  that  the  hand  is  not  en- 
titled to  this  extravagant  commendation.  Not  many  years  ago,  a  Miss 
Biffin  was  exhibited  in  London,  who  was  totally  devoid  of  upper  and 
lower  extremities;  yet  she  was  unusually  intelligent  and  ingenious.  It 
was  surprising  to  observe  the  facility  with  which  she  hem-stitched; 
turning  the  needle  with  the  greatest  rapidity  in  her  mouth,  and  insert- 
ing it  by  means  of  the  teeth.  She  painted  miniatures  faithfulh^,  and 
beautifully;— holding  the  pencil  between  her  head  and  neck.     All  her 

'  De  I'Homme,  &c.,  torn.  i.  ^  Traite  des  Sensations,  P.  i. 

*  Histoire  Naturelle,  torn.  vi. 


TOUCH  —  THE    GEOMETRICAL    SENSE.  695 

motions  were,  in  fact,  confined  to  tlie  tongue  and  lips,  and  to  the  muscles 
of  the  neclv.  M.  Magendie^  alludes  to  a  similar  case.  lie  says,  that 
there  was,  in  Paris,  at  the  time  he  wrote,  a  young  artist,  who  had  no 
signs  of  arm,  forearm,  or  hand,  and  whose  feet  had  one  toe  less  than 
usual — the  second ;  yet  his  intelligence  was  in  no  respect  inferior  to 
that  of  boys  of  his  age;  and  he  even  gave  indications  of  distinguished 
ability.  He  sketched  and  painted  with  his  feet.  Not  many  years  ago, 
a  Miss  Honeywell,  born  without  arms,  travelled  about  this  country. 
She  had  acquired  so  much  dexterity  in  the  use  of  the  scissors,  as  to  be 
able,  by  holding  them  in  her  mouth,  to  cut  likenesses,  watch-papers, 
flowers,  &c.  She  also  wrote,  drew,  and  executed  all  kinds  of  needle- 
work with  the  utmost  ease  and  despatch.  How  fatal  are  such  authentic 
examples  to  the  views  of  Helvetius  and  others! 

But,  it  has  been  said,  that  touch  is  the  least  subject  to  error  of  all 
the  senses :  it  is  the  regulating — the  geometrical  sense.  In  part  only 
is  this  accurate.  It  certainly  possesses  the  advantage  of  allowing  the 
organ  of  sense  to  be  brought  into  immediate  contact  with  the  body 
that  excites  the  impression;  whilst,  in  the  case  of  olfaction,  the  organ 
receives  the  impression  of  an  emanation  from  the  body ;  and,  in  vision 
and  audition,  only  the  vibration  of  an  intervening  medium.  Yet 
some  of  the  errors  into  which  touch  falls  are  as  grievous  as  those  that 
happen  to  the  other  senses.  How  inaccurate  is  its  appreciation  of  the 
temperature  of  bodies !  We  have  attempted  to  show,  that  it  affords 
merely  relative  knowledge, — the  same  substance  appearing  hot  or 
cold  to  us,  according  to  the  temperature  of  the  substance  previously 
touched.  Nay,  infallibility  so  little  exists,  that  we  have  the  same  sen- 
sation communicated  by  a  body  that  rapidly  abstracts  caloric  from  us, 
as  by  one  that  rapidly  supplies  it.  By  touching  frozen  mercury, 
which  requires  a  temperature  of  — 40°  of  Fahrenheit  to  be  congealed, 
we  experience  the  sensation  of  a  burn.  Again,  if  we  cross  the  fingers 
and  touch  a  rounded  body — a  marble,  for  instance — with  two  of  the 
pulps  at  the  same  time:  instead  of  experiencing  the  sensation  of  one 
body,  we  feel  as  if  there  were  two, — an  illusion  produced  by  the 
lateral  portions  of  fingers  being  brought  in  apposition,  which  are 
naturally  in  a  different  situation,  and  at  a  distance  from  each  other; 
and,  as  these  two  parts  habitually  receive  distinct  impressions  when 
separated,  they  continue  to  do  so  when  applied  to  opposite  sides  of  the 
rounded  body. 

It  has  been  asserted,  that  the  touch  is  the  great  corrector  of  the 
errors  into  which  the  other  senses  fall.  But  let  us  inquire,  whether, 
in  this  respect,  it  possesses  any  decided  superiority  over  them.  For 
this  purpose,  the  distinction  of  the  sensory  functions  into  immediate 
and  mediate  has  been  adopted.  Each  sense  has  its  immediate  func- 
tion, which  it  possesses  exclusively ;  and  for  which  no  other  can  be 
substituted.  The  touch  instructs  us  regarding  resistance;  the  taste 
appreciates  savours;  the  smell,  odours;  audition,  sound;  and  vision, 
colours.  These  are  the  immediate  functions  of  the  senses,  each  of 
which  can  be  accomplished  by  its  own  organs,  but  by  no  other.  As 
concerns  the  immediate  functions  of  the  senses,  therefore,  the  touch 

'  Precis  Elementaire,  2de  edit.,  i.  154,  Paris,  1825. 


696  SENSIBILITY. 

can  afford  no  correction.  Its  predominance,  as  regards  the  mediate 
functions  of  the  senses,  is  likewise  exaggerated.  The  mediate  functions 
are  those  that  furnish  impressions  to  the  mind;  and  by  aid  of  which 
it  acquires  its  notions  of  bodies.  The  essential  difference  between 
these  two  sets  of  functions  is,  that  the  mediate  can  be  effected  by 
several  senses  at  once,  and  may  be  regarded  as  belonging  to  the  cere- 
brum. Vision,  olfaction,  and  audition  participate  with  touch  in 
enabling  us  to  judge  of  distances;  the  sight  instructs  us  regarding 
shape,  &c.  It  has  been  affirmed  by  metaphysicians,  that  touch  is 
necessary  to  several  of  the  senses  to  give  them  their  full  power,  and 
that  we  could  form  no  notion  of  the  size,  shape,  and  distance  of  bodies, 
unless  instructed  by  this  sense.  The  remarks  already  made  have 
proved  the  inaccuracy  of  this  opinion.  The  farther  examination  of  it 
will  be  resumed  under  Vision.  The  senses  are,  in  truth,  of  mutual 
assistance.  If  the  touch  falls  into  error,  as  in  the  case  of  inaccurate 
appreciation  of  temperature,  the  sight,  aided  by  appropriate  instru- 
ments, dispels  it.  If  the  crossed  fingers  convey  to  the  brain  the  sen- 
sation of  two  rounded  bodies,  when  one  only  exists,  the  sight  apprises 
us  of  the  error ;  and  if  the  sight  and  touch  united  impress  us  with  a 
belief  in  the  identity  of  two  liquids,  the  smell  or  the  taste  will  often 
detect  the  erroneous  inference. 

But,  it  has  been  said  by  some,  touch  is  the  only  sense  that  gives  us 
any  notion  of  thf  existence  of  bodies.  M.  Destutt-Tracy'  has  satis- 
factorily opposed  this,  by  showing  that  such  notion  is  a  work  of  the 
mind,  in  acquiring  which  the  touch  does  not  assist  more  immediately 
than  any  other  sense.  "The  tactile  sensations,"  he  observes,  "have 
not  of  themselves  an}'-  prerogative  essential  to  their  nature,  which  dis- 
tinguishes them  from  others.  If  a  body  affects  the  nerves  beneath  the 
skin  of  my  hand,  or  if  it  produces  certain  vibrations  in  those  distri- 
buted on  the  membranes  of  my  palate,  nose,  eye,  or  ear,  it  is  a  pure 
impression  which  I  receive;  a  simple  affection  which  I  experience; 
and  there  seems  to  be  no  reason  for  believing  that  one  is  more  in- 
stinctive than  another ;  that  one  is  more  adapted  than  another  for 
enabling  me  to  judge  that  it  proceeds  from  a  body  exterior  to  me. 
Why  should  the  simple  sensation  of  a  puncture,  burn,  titillation,  or 
jjressure,  give  me  more  knowledge  of  the  cause,  than  that  of  a  colour, 
sound,  or  internal  pain?  There  is  no  reason  for  believing  it."  There 
are,  indeed,  numerous  classes  of  bodies,  regarding  whose  existence  the 
touch  affords  us  no  information,  but  which  are  detected  by  the  other 
senses. 

On  the  whole,  then,  we  must  conclude,  that  the  senses  mutually  aid 
each  other  in  the  execution  of  certain  of  their  functions ;  that  each 
has  its  province,  which  cannot  be  invaded  by  others ;  and  that  too 
much  preponderance  has  been  ascribed  to  the  touch  by  metaphysicians 
and  physiologists.  Ministering,  however,  as  it  does,  so  largely  to  the 
mind,  it  has  been  properly  ranked  with  vision  and  audition  as  an  in- 
tellectual sense.^ 

By  education,  the  sense  of  touch  is  capable  of  acquiring  extraordi- 

'  l-ltniens  d'lrltologie,  lere  Partie,  p.  114,  2de  edit.     Paris,  1S04. 
^  Gall,  Sur  les  Foiic-tious  du  Cerveau,  i.  99,  I'arid,  1S25. 


TOUCH  IMPROVED  BY  EDUCATION".  697 

narj  acuteness.  To  this  circumstance  must  be  ascribed  the  surprising 
feats  we  occasionally  meet  with  in  the  blind.  For  all  their  reading 
and  writing  they  are,  indeed,  indebted  to  this  sense,  and  modelling  in 
clay,  wax,  &c.,  and  sculpture,  carving  in  wood,  and  even  engraving 
have  been  accomplished  by  them.' 

Dr.  Saunderson — who  lost  his  eyesight  in  the  second  year  of  his 
life,  and  was  Professor  of  Mathematics  at  Cambridge,  England — could 
discern  false  from  genuine  medals;  and  had  a  most  extensive  acquaint- 
ance with  numismatics.^  As  an  instance  of  the  correct  notions,  which 
may  be  conveyed  to  the  mind  of  the  forms  and  surfaces  of  a  great 
variety  of  objects,  and  of  the  sufficiency  of  these  notions  for  accurate 
comparison.  Dr.  Carpenter'  mentions  the  case  of  a  blind  friend,  who 
has  acquired  a  very  complete  knowledge  of  conchology,  both  recent 
and  fossil;  and  who  is  not  only  able  to  recognize  every  one  of  the 
numerous  specimens  in  his  own  cabinet,  but  to  mention  the  nearest 
alliances  of  a  shell  previously  unknown  to  him,  when  he  has  tho- 
roughly examined  it  by  the  touch.  Baczko,  referred  to  by  Eudolphi,"* 
who  describes  his  own  case,  could  discriminate  between  samples  of 
woollen  cloth  of  equal  quality  but  of  different  colours.  The  black 
appeared  to  him  among  the  roughest  and  hardest:  to  this  succeeded 
dark  blue  and  dark  brown,  which  he  could  not,  however,  distinguish 
from  each  other.  I'he  colours  of  cotton  and  silk  stuffs  he  was  unable 
to  discriminate;  and  he  properly  enough  doubts  the  case  of  a  Count 
Lynar,  blind,  who,  it  was  said,  was  capable  of  judging  of  the  colour  of 
a  horse  by  the  feel.  The  only  means  the  blind  can  possess  of  discri- 
minating colours  must  be  through  the  physical  differences  of  surface, 
which  render  it  capable  of  reflecting  one  ray  or  combination  of  rays, 
whilst  it  absorbs  the  rest;  and  if  these  differences  were  insufficient  to 
enable  Baczko  to  detect  the  differences  between  cotton  and  silk  fabrics, 
it  is  not  probable,  that  the  sleek  surface  of  the  horse  would  admit  of 
such  discrimination.*  Education  or  sustained  and  discriminating!: 
attention  gives  the  same  facility  in  the  appreciation  of  temperature. 
It  is  affirmed,  that  Dr.  Saunderson,  when  some  of  his  pupils  were  en- 
gaged in  taking  the  altitude  of  the  sun,  could  tell  by  the  slight  modi- 
fication in  the  temperature  of  the  air,  Avhen  very  light  clouds  were 
passing  over  the  sun's  disk. 

The  deaf  have  no  perce|ition  of  the  vibrations  of  sonorous  bodies ; 
yet  by  the  sense  of  touch  they  can  judge  of  tangible  percussions  from 
bodies  that  are  thrown  into  powerful  vibration ;  and  Dr.  Kitto'' — him- 
self deaf — has  given  a  vivid  representation  of  the  impression  made 
upon  him  by  different  forms  of  percussive  vibrations. 

'  Rev.  Wm.  Taylor,  F.  R.  S.,  in  Notices  of  tlie  Meetings  of  the  Roval  Institution, 
1853. 

*  Abercrombie's  Inquiries  concerning  the  Intellectual  Powers ;  Anier.  edit.,  p.  55, 
New  York,  1832. 

^  Principles  of  Human  Physiology,  American  edit.,  p.  657,  Philad.,  1854;  and  art. 
Touch,  Cyclop,  of  Anat.  and  Physiol.,  iv.  1180,  Lond.,  1852. 

■•  Gtrundriss  der  Physiologie,  2er  Band,  S.  85,  Berlin,  1823. 

5  For  an  interesting  account  of  the  blind  and  deaf  James  Mitchell,  Laura  Bridgman, 
and  others,  referred  to  hareafter — and  of  blind  travellers,  blind  i)0(:'ts,  blind  musicians, 
blind  divines  and  blind  philosophers,  see  The  Lost  Senses,  by  John  Kitto,  D.  D., 
F.  S.  A.,  Series  II.,  Blindness,  Lond.,  1845. 

^  Op.  cit.,  Series  I.,  Deafness,  Lond.,  1853. 


698  SEXSIBILITY. 

lu  animals  the  organ  of  touch  varies.  The  monkey's  resembles 
that  of  man.  In  other  quadrupeds,  it  is  seated  in  the  lips,  snout,  or 
proboscis.  In  molluscous  animals,  the  tentacula;  and  in  insects,  the 
antenna  or  feelers,  are  organs  of  touch,  possessing,  in  some,  very  great 
sensibility.  Bats  appear  to  have  this  to  an  unusual  degree.  Spallan- 
zani  observed  them,  even  after  their  eyes  had  been  destroyed  and  the 
ears  and  nostrils  closed,  flying  through  intricate  passages,  without 
striking  the  walls,  and  dexterously  avoiding  cords  and  lines  placed  in 
the  way.  The  membrane  of  the  wings  is,  in  the  opinion  of  Cuvier 
and  many  others,^  the  organ  that  receives  an  impression  produced  by 
a  change  in  the  resistance  of  the  air,  M,  Jurine  concludes,  that  nei- 
ther hearing  nor  smell  is  the  channel  through  which  they  obtain  per- 
ception of  the  presence  and  situation  of  surrounding  bodies.  He 
ascribes  this  extraordinary  faculty  to  the  great  sensibility  of  the  skin 
of  the  upper  jaw,  mouth,  and  external  ear,  which  are  furnished  with 
large  nerves;  whilst  Sir  Anthony  Carlisle  attributes  it  to  the  extreme 
delicacy  of  hearing  possessed  by  the  animal  f  a  view  which  is  con- 
firmed by  experiments  instituted  by  the  author's  friend.  Professor  J. 
K.  Mitchell.  Certain  experiments  by  Mr.  Broughton'  sanction  the 
idea  that  this  may  be,  in  part,  dependent  upon  their  whiskers.  These, 
which  are  found  on  the  upper  lip  of  feline  and  other  animals,  are  plen- 
tifully supplied  with  nerves,  which  seem  to  proceed  from  the  second 
branch  of  the  fifth  pair,  and  are  lost  in  the  substance  of  the  hairs.  In 
an  experiment,  made  by  Mr.  Broughton  on  a  kitten,  he  found  that 
whilst  the  whiskers  were  entire,  it  was  capable  of  threading  its  way, 
blindfold,  from  a  labyrinth  in  which  it  was  designedly  placed;  but  it 
was  totally  unable  to  do  so  when  the  whiskers  were  cut  off.  It  struck 
its  head  repeatedly  against  the  sides;  ran  against  all  the  corners;  and 
tumbled  over  steps  placed  in  the  way,  instead  of  avoiding  them,  as  it 
did  prior  to  the  removal  of  the  whiskers. 

From  facts  like  these  Mr.  Broughton  drew  the  conclusion,  that  cer- 
tain animals  are  supplied  with  whiskers  for  the  purpose  of  enabling 
them  to  steer  clear  of  opposing  bodies  in  the  dark. 

B.   SENSE  OF  TASTE  OR  GUSTATIOX. 

The  sense  of  taste  teaches  us  the  quality  of  bodies  called  sapidity. 
It  is  more  nearly  allied  to  touch  in  its  mechanism  than  any  other  of 
the  senses,  as  it  requires  the  immediate  contact  of  the  body  with  the 
organ,  and  the  organ  is,  at  the  same  time,  capable  of  receiving 
tactile  impressions  distinct  from  those  of  taste.  Of  this  we  have  a 
striking  example,  if  we  touch  various  portions  of  the  tongue  with  the 
point  of  a  needle.  "We  find  two  distinct  perceptions  occasioned.  In 
some  parts  the  sensation  of  a  pointed  body  without  savour;  and  in 
others,  a  metallic  taste  is  experienced.  Pathological  cases,  too,  exhibit, 
that  the  sense  of  taste  may  be  lost,  whilst  general  sensibility  remains, 
— and  conversely.  The  organ  of  gustation  is  not,  therefore,  restricted 
to  that  sense,  but  participates  in  touch.  Yet  so  distinct  are  those 
functions,  that  touch  can,  in  no  wise,  supply  the  place  of  its  fellow 

'  Carpenter,  Human  Physiology,  p.  253,  Lond.,  1842. 

^  See  Roget's  Animal  and  Vegetable  Physiology,  ii.  399,  Amer.  edit.,  Pliilad.,  1836. 

'  Loudon  Medical  and  Physical  Journal,  for  1823. 


ORGANS   OF   TASTE. 


699 


sense,  in  detecting  the  sapidity  of  bodies, 
instruction  afforded  by  gustation. 


This  last  is  the  immediate 


1.   ANATOMY  OF  THE  ORGANS  OF  TASTE. 


The  chief  organ  of  taste  is 
membrane  covering  the  upper 
The  lips,  inner  surface  of  the 
cheeks,  palate,  and  fauces,  par- 
ticipate in  the  function,  espe- 
cially when  particular  savours 
are  concerned.  M.  Magendie^ 
includes  the  oesophagus  and 
stomach;  but  we  know  not  on 
what  grounds :  his  subsequent 
remarks,  indeed,  controvert  the 
idea.  The  lingual  branch  of 
the  fifth  pair  is,  according  to 
him,  incontestably  the  nerve  of 
taste;  and,  as  this  nerve  is  dis- 
tributed to  the  mouth,  we  can 
understand,  why  gustation 
should  be  effected  there;  but 
not  how  it  can  be  accomplished 
in  the  oesophagus  and  stomach. 
The  tongue  consists  almost  en- 
tirely of  muscles,  which  give  it 
great  mobility,  and  enable  it  to 
fulfil  the  various  functions  as- 
signed to  it ;  for  it  is  not  only 
an  organ  of  taste,  but  of  masti- 
cation, deglutition,  and  articu- 
lation. The  muscles  being  un- 
der the  influence  of  volition, 
enable  the  sense  to  be  executed 
passively  or  actively. 

As  regards  gustation,  the  mu- 
cous membrane  is  the  portion 
immediately  concerned.  This 
is  formed,  like  the  mucous  mem- 
branes in  general,  of  the  differ- 
ent layers  already  described. 
The  corpus  papillare  requires 
farther  notice.  If  the  surflxce 
of  the  tongue  be  examined,  it 
will  be  found  to  consist  of  my- 
riads of  fine  papillae  or  villi, 
that  give  the  organ  a  velvety 
appearance.  These  papillas  are, 
doubtless,  like  those  of  the  skin, 


the  tongue,   or   rather  the   mucous 
surface,   and  sides    of    that  organ. 

Fig.  236. 


Front  View  of  the  Upper  Surface  of  the  Tongue, 
as  well  as  of  the  Palatine  Arch. 
1,  1.  Posterior  lateral  half  arches,  with  the  palato- 
pharyngei  muscles,  and  tonsils.  2.  Epiglottic  cartilage, 
seen  from  hefore.  3,  3.  Ligament  and  mucous  mem- 
brane, extending  from  the  root  of  the  tongue  to  the 
base  of  the  epiglottic  cartilage.  4.  One  of  the  pouchp.s 
on  the  .side  of  the  posterior  frjenum,  in  which  food 
sometimes  lodges.  5.  Foramen  cjecum.  6.  Papillje 
capitata;  seu  maxima;.  7.  The  white  point  at  the  end 
of  the  line,  and  all  like  it,  are  the  papilla  fungiformes. 

8.  Side  of  the  tongue,  and  rugre  transversa;  of  Albinus. 

9.  Papillse  filiformes.     10.  Point  of  the  tongue. 

Fig.  237. 


View  of  a  Papilla  of  the  smallest  class,  magnified 
25  diameters. 
The  loops  o    blood-vessels  are  hero  shown,  each,  loop 
containing  usually  only  one  vessel. 


Precis  de  Physiol.,  i.  139. 


700 


SENSIBILITY. 


Fig.  23S.  formed  of  the  final  ra- 

mifications of  nerves, 
and  of  the  radicles  of 
exhalant  and  absorbent 
vessels,  united  by  means 
of  a  spongy  erectile  tis- 
sue. Great  confusion 
exists  among  anato- 
mists in  their  descri])- 
tions  of  the  papillse  of 
the  tongue.    Those  cer- 

Vertical  Section  of  one  of  the  (iustatory  Papilla;  of  the  Inrgest  tainly  Concerned  in  the 

fY^'   showing   its  corneal  form,  its   sides,  and   the  fissure  ggj^gg  ^f  ^^g^^  ^iOW- 

between  the  different  Papillae.  ,  .       ,     ■;     , 

The  length  of  soTie  of  the   divided  blood-vessels,   a  transverse  CVCr, 

section  of  others,  and  the  vessels  which  rise  up  from  the  surface  t\VO 

like  loops  or  meshes,  are  also  shown. 


Fig.  239. 


msssmM 


be  included  in 
divisions: —  1st, 
the  conical  ov  pyramid- 
al,— the  finest  sort  by 
some  called  filifonn; 
and  2dly,  lh.Q  fvjvj  if  arm. 
The  former  are  broader 
at  the  base  than  at  the 
top;  and  are  seen  over 
the  Avhole  surface  of  the 
tongue,  from  the  ti])  to 
the  root.  The  latter, 
which  are  larger  at  the 
top  than  the  base,  and 
resemble  the  mushroom, 
— whence  their  name, 
— are  spread  about, 
here  and  there,  on  the 
surface  of  the  orgjin. 
These  must  be  distin- 
guished from  a  third 
set,  the  painllcB  capHaloR 
or  circumvallatce,  which 
are  situate  near  the 
base  of  the    ton  one  in 


The  Hypoglo.=sal ;   Lingual  branch  of  fifth  pair;  fJlosso-Pha- 
rvntceal  and  deep-seated  Nerve.*  of  the  Neck. 

1.  The  hypoglossal  nerve.     2.  Branches  communicating  with  the 
lingual  branch.     3.  A  branch  to    the  origin  of  the  hyoid  muscles. 
4.  The  desceudens  noni  nerve,     o.  The  loop  formed  with  the  branch 
from  the  cervical  nerves.     6.  Muscular  branches  to  the  depressor     tWO    V  shapcd    llllCS    at 
muscles  of  the   larynx.     7.  A  lilament   from   the   second    cervical      j.i  v,  ^1 

nerve,  and  8.  a  filament  from  the  third  cervical,  uniting  to  form  the     tllC     OaSC    OI    tllC    Orgail. 
communicating  branch  with  the  loop   from   the   descendens  noni.      fpi-io-,,-     o  ro    <-> i  vi^i n  1  o r       .lo 
9.  The   auricular   nerve.      10.  The   inferior   dental   nerve.     11.  Its       -*- ^^J     "■'^^    CirCUidT     Cie- 
mylo-hyoidean  branch.     12.  The  lingual  branch.     1.3.  The  chorda- 
tympani  passing   to  the  lingual  branch.     14.  The  chorda-tympani 
learing  the   lingual   branch  to  join   the   sub-maxillary  ganglion. 
1.5.  The  sub-raaxillary  ganglion.     16.  Filaments  of  communication 
with  the  lingual    nerve.      17.  The   glosso-pharyngeal    nerve.      18. 
The  pneumogastric  or  par  vagum  nerve.     19.  The  three  upper  cer- 
vical nerves.     20.  The  four  inferior  cervical  nerves.     21.  The  first 
dorsal   nerve.     22,  23.  The  brachial   plexus.     24,  2.5.  The   phrenic 
nerve.    26.  The  carotid  artery.     27.  The  internal  jugular  vein.  ,  .  -         ,,        i   ■    , 

at  the  outside  oi  which, 
again,  is  a  slightly  elevated  ring,  the  central  elevation  and  the  ring 
being  formed  of  close  set  simple  papillse.  The  epithelium  of  the 
tongue  is  of  the  tesselated  variety,  like  that  of  the  epidermis.  Over 
the  fungiform  pajDilte,  it  forms  a  thinner  layer  than  elsewhere;  so  that 


vations  from  g'^th  to 
^'.,th  of  an  inch  wide, 
each  with  a  central  de- 
pression, and  surround- 
ed by  a  circular  fissure, 


TASTE — SAVOURS.  701 

they  stand  out  more  prominently  tlian  the  rest.  That  which  covers 
the  conical  papillae,  according  to  Messrs.  Todd  and  Bowman,^  has  a 
singular  arrangement;  being  extremely  dense  and  thick,  and  project- 
ing from  their  sides  and  tops  in  the  form  of  long,  stiff",  hair-like  pro- 
cesses ;  many  of  which  bear  a  strong  resemblance  in  structure  to  hairs ; 
and  some  actually  contain  hair  tubes. 

All  the  nerves  that  pass  to  the  parts  whose  office  it  is  to  appreciate 
savours,  must  be  considered  to  belong  to  the  gustatory  apparatus. 
These  are  the  inferior  maxillary ;  several  branches  of  the  superior ; 
filaments  from  the  spheno-palatine  and  naso-palatine  ganglions;  the 
lingual  branch  of  the  fifth  pair,  commonly  called  the  gustatory  nerve ; 
the  whole  of  the  ninth  pair  or  hypoglossal ;  and  the  glosso-pharyngeal. 
To  which  of  these  must  be  assigned  the  function  of  gustation,  we 
shall  inquire  presently. 

Like  tlie  skia  and  mucous  membranes  in  general,  that  of  the  tongue 
and  mouth  contains,  in  its  substance,  numerous  mucous  follicles,  which 
secrete  a  fluid  that  lubricates  the  organ,  and  keeps  it  in  a  condition 
adapted  for  the  accomplishment  of  its  functions.  The  fluids,  exhaled 
from  the  mucous  membrane  of  the  mouth,  and  the  secretion  of  the 
different  salivary  glands,  likewise  aid  in  gustation;  but  they  are  more 
concerned  in  mastication  and  insalivation,  and  will  require  notice 
under  another  head.^ 

2.   SAVOURS. 

Before  proceeding  to  explain  the  physiology  of  gustation,  it  may  be 
necessary  to  inquire  briefly  into  the  nature  of  bodies  as  connected  with 
their  sapidity ;  or,  in  other  words,  into  savours,  which  are  the  cause  of 
sapidity. 

The  ancients  were  of  opinion,  that  the  cause  of  sapidity  is  a  peculiar 
principle,  which,  according  to  its  combination  with  the  constituents  of 
bodies,  gives  rise  to  various  savours.  This  notion  has  been  long  aban- 
doned; and  chiefly,  because  we  observe  no  general  or  common  charac- 
ters amongst  sapid  bodies,  which  ought  to  be  were  they  pervaded  by 
the  same  principle ;  and  because  bodies  may  be  deprived  of  their 
sapidity  by  subjecting  them  to  appropriate  processes.  Many  of  our 
culinary  processes  have  been  instituted  for  this  purpose :  the  infusion 
of  tea  is  indebted  for  all  its  attractions  to  the  power  we  possess  of 
separating,  by  boiling  water,  the  savoury  from  the  insipid  portions  of 
the  plant.  A  sapid  principle  must,  therefore,  be  esteemed  an  integrant 
molecule  of  a  body ;  not  the  same  in  all  cases,  but  as  heterogeneous 
in  its  nature  as  the  impressions  made  upon  the  organ  of  taste. 

When  the  notion  was  once  entertained,  that  a  sapid  principle  is  an 
integrant  molecule,  sapidity  was  attempted  to  be  explained  by  its 
shape.  It  was  said,  for  instance,  that  if  the  savour  be  sweet,  the  mole- 
cule must  be  round;  if  sharp,  angular;  and  so  forth.  Sugar  was  said 
to  possess  a  spherical, — acids,  a  pointed,  or  angular  molecule.     We 

'  The  Physiological  Anat.  and  Physiology  of  Man,  i.  439,  Lond.,  1848,  or  Amer.  edit., 
p.  382.  See,  also,  H.  Hyde  Salter,  art.  Tongue  in  Cycloj).  of  Anat.  and  Physiol.,  iv. 
1120,  Lond.,  1852. 

^  For  an  elaborate  account  of  the  Anatomy  of  the  Organ  of  Gestation,  see  H.  Hyde 
Salter,  op.  cit. 


702  SENSIBILITY. 

know,  however,  that  substances  which  resemble  each  other  in  the 
primitive  shape  of  their  crj^stal,  impress  the  organ  of  taste  differently; 
and  that  solution,  which  must  destroy  most — if  not  all — the  influence 
from  shape,  induces  no  change  in  the  savour. 

Others  have  referred  sapidity  to  a  kind  of  chemical  action  between 
the  molecules,  and  the  nervous  fluid.  This  view  has  been  suggested 
by  the  fact,  that,  as  a  general  rule,  sapid,  like  chemical  bodies,  act 
only  when  in  a  state  of  solution;  that  the  same  savours  usually  belong 
to  bodies  possessed  of  similar  chemical  properties,  as  is  exemplified  by 
the  sulphates  and  nitrates;  and  that,  in  the  action  of  acids  on  the 
tongue  and  mouth,  we  witness  a  state  of  whiteness  and  constriction, 
indicative  of  a  first  degree  of  combination.  All  these  circumstances, 
however,  admit  of  another  explanation.  There  are  unquestionably 
many  substances,  which  do  combine  chemically, — not  with  a  nervous 
fluid,  of  whose  existence  we  know  nothing, — but  with  the  mucus  of 
the  mouth ;  and  the  sapidity  resulting  from  such  combination  is  appre- 
ciated by  the  nerves  of  taste ;  but  there  are  many  bodies,  which  are 
eminently  sapid,  and  yet  attbrd  us  instances  of  very  feeble  powers  of 
chemical  combination ;  nay,  in  numerous  cases,  we  have  not  the  least 
evidence  that  such  powers  exist.  Vegetable  infusions  or  solutions  are 
strong  6^xamples  of  the  kind, — of  which  syrup  maj^  be  taken  as  the 
most  familiar.  The  effect  of  solution  is  easily  intelligible ;  the  par- 
ticles of  the  sapid  body  are  in  this  way  separated,  and  come  succes- 
sively into  contact  with  the  gustatory  organ  ;  but  there  is  some  reason 
to  believe,  that  solution  is  not  always  requisite  to  give  sapidity.  Metals 
have  generally  a  peculiar  taste,  which  has  been  denominated  metallic; 
and  this,  even  if  the  surface  be  carefull}^  rubbed,  so  as  to  free  it  from 
oxide,  which  is  more  or  less  soluble.  Birds,  too,  whose  organs  of  taste 
are  as  dry  as  the  corn  they  select  from  a  mass  of  equally  arid  sub- 
stances, are  probably  able  to  appreciate  savours.  The  taste  produced 
b}^  touching  the  wires  of  a  galvanic  pile  with  the  tongue  has  been 
offered  as  another  instance  of  sapidity  exhibited  by  dry  bodies.  This 
is,  more  probably,  the  eftect  of  chemical  action  on  the  fluids  covering 
the  mucous  membrane  of  the  tongue,  which  always  follows  such 
contact.  Such  chemical  change  must,  however,  be  confined  to  these 
fluids;  and,  when  once  produced,  the  nerve  of  taste  is  impressed  by 
the  savour  developed  in  the  same  manner  as  it  is  in  cases  of  morbid 
alterations  of  the  secretion  of  the  mucous  membrane.  In  both  cases, 
a  body  possessing  considerable  and  peculiar  sapidity  may  fail  to  impress 
the  nerves  altogether,  or  may  do  so  inaccurately.  The  notion  of  any 
chemical  combination  with  the  nervous  fluid  must  of  course  be  dis- 
carded, as  there  is  not  the  slightest  evidence  in  favour  of  the  hypo- 
thesis; yet  the  epithet  cAem/ca?  was  once  applied  to  this  sense  on  the 
strength  of  it;  in  opposition  to  the  senses  of  touch,  vision,  and  audition, 
which  were  called  mechanical^  and  supposed  to  be  produced  by  vibra- 
tions of  the  nerves  of  those  senses. 

The  savours,  met  with  in  the  three  kingdoms  of  nature,  are  innu- 
merable. Each  body  has  its  own,  by  which  it  is  distinguished  :  few 
instances  occur  in  which  any  two  can  be  said  to  be  identical.  This  is 
the  great  source  of  difficulty,  when  we  attempt  to  throw  them  into 
classes,  as  has  been  done  by  physiologists.     Of  these  classifications, 


TASTE  —  CLASSIFICATION   OF   SAVOURS.  703 

the  one  by  Linnaeus'  is  best  known:  it  will  elucidate  the  unsatisfactory 
character  of  the  whole.  He  divides  sapid  bodies  into  sicca^  aquosa, 
viscosa^  salsa,  acida,  styptica,  dulcia,  pinguia,  amara,  acria,  and  nanseosa. 
He  gives  also  examples  of  mixed  savours,  acido-acria,  acido-amara, 
amaro-acria,  amnro-acerba,  amaro- dulcia,  duhi-st>/2)tica,  didci-acida,  dulci- 
ac7-ia,  and  acri-viscida ;  and  remarks,  that  the  majority  are  antitheses  to 
each  other,  two  and  two, — as  dulcia  and  acria ;  pinguia  and  styftica  ; 
viscosa  and  salsa;  and  aquosa  and  sicca.  Boerhaave^  again  divides 
them  into  primary  and  compound;  the  former  including  the  so^ir,  siveet, 
hitter,  saline,  acrid,  alkaline,  vinous,  sjjirituovs,  aromatic,  and  acerb; — the 
latter  resulting  from  the  union  of  certain  primary  savours.  There  is 
no  accordance  amongst  physiologists  as  to  those  that  should  be  esteemed 
primary,  and  those  secondary  and  compound;  although  the  division 
appears  to  be  admissible.  The  acerb,  for  example — which  is  considered 
primary  by  Boerhaave — is  by  others,  with  more  propriety,  classed 
among  secondary  or  compound,  and  believed  to  consist  of  a  combination 
of  the  acrid  and  acid.  We  understand,  however,  sufficiently  well  the 
character  of  the  acid,  acrid,  bitter,  acerb,  sweet,  &c. ;  but  when,  in  common 
language,  we  have  to  depict  other  savours,  we  are  frequently  compelled 
to  take  some  well-known  substance  as  a  standard  of  comparison. 

According  to  M.  Adelon,^  the  only  distinction  we  can  make  amono-st 
them  is, — into  the  agreeable  and  disagreeable.  Yet  of  the  unsatisfactory 
nature  of  this  classification  he  himself  adduces  numerous  proofs.  It 
can  only,  of  course,  be  applicable  to  one  animal  species,  often  even  to 
an  individual  only ;  and  often  again  only  to  such  individual  when  in  a 
given  condition.  Some  animals  feed  upon  substances,  that  are  not 
only  disagreeable  but  noxious  to  others.  The  most  poisonous  plants 
have  an  insect  which  devours  them  greedily  and  with  impunity :  the 
southern  planter  is  well  aware,  that  this  is  the  case  with  his  tobacco, 
unless  the  operation  of  worming  be  performed  in  due  season.  The  old 
adage,  that  "  one  man's  meat  is  another  man's  poison"  is  metaphori- 
cally accurate.  Each  individual  has,  by  organization  or  association, 
dislikes  to  particular  articles  of  food,  or  shades  of  difference  in  his 
appreciation  of  tastes,  which  may  be  esteemed  peculiar ;  and,  in  cer- 
'tain  cases,  these  peculiarities  are  signal  and  surprising. 

Of  the  strange  differences,  in  this  respect,  that  occur  in  the  same 
individual  under  different  circumstances,  we  have  a  forcible  instance  iu 
the  pregnant  female,  who  often  ardently  desires  substances,  that  were 
previously  perhaps  repugnant  to  her,  or,  at  all  events,  not  relished. 
The  sense,  too,  in  certain  diseases — especially  of  a  sexual  character,  or 
such  as  are  connected  with  the  state  of  the  sexual  functions — becomes 
strangely  depraved,  so  that  substances,  which  can  in  no  way  be  ranked 
as  eatables,  are  greedily  sought  after.  A  young  lady  was  under  the 
care  of  the  author,  whose  honne  bouche  was  slate  pencils.  In  other 
cases,  we  find  chalk,  brickdust,  ashes,  dirt,  &c.,  preferred.  Habit,  too, 
has  considerable  etl'ect  in  our  decisions  regarding  the  agreeable.  The 
Roman  liquamen  or  garum,  the  most  celebrated  sauce  of  antiquity,  was 
prepared  from  half  putrid  intestines  of  fiah  ;  and  one  of  the  varieties 

'  Amoenit.  Academ.,  ii.  335.  ^  Prnelect.  Academ.,  torn.  iv. 

^  riiysiologie  de  rHomuie,  aeconde  edit.,  i.  301,  Paris,  Ib'l'd. 


704:  SENSIBILITY. 

of  the  Ort05  'Eo.'piov,  laserpitivm,  is  supposed  to  have  been  assafcjotida.' 
Even  at  this  day,  certain  orientals  are  fond  of  the  flavour  of  this  nau- 
seous substance.  Putrid  meat  is  the  delioht  of  some  nations;  and  a 
rotten  egg,  especially  if  accompanied  with  the  chick,  is  esteemed  by 
the  Siamese.  In  civilized  countries,  we  find  game,  in  a  putrescent 
state,  eaten  as  a  luxury :  this,  to  those  unaccustomed  to  it,  requires  a 
true  education.  The  same  may  be  said  of  the  pickled  olive,  and  of 
several  cheeses — -froma<je  de  Qriiyh-e^  for  example — so  much  esteemed 
by  the  inhabitants  of  continental  Europe. 

M.  Magendie^  asserts,  that  the  distinction  of  savours  into  agreeable 
and  disagreeable  is  the  most  important, — as  substances  whose  taste 
appears  agreeable  to  us  are  generally  useful ;  whilst  those  Avhose  taste 
is  disagreeable  are  commonly  noxious.  As  a  general  rule  this  is  true, 
but  there  are  many  signal  exceptions  to  it. 

3.   PHYSIOLOGY  OF  TASTE. 

The  physiology  of  taste  being  so  nearly  allied  to  that  of  touch 
effected  by  mucous  membranes,  it  will  not  be  necessary  to  repeat  the 
uses  of  the  various  laj'crs  of  which  the  membrane  of  the  mouth  con- 
sists. In  order  that  taste  may  be  satisfactorily  executed,  it  is  neces- 
sary that  the  membrane  should  be  in  a  state  of  integrity ;  for  if  the 
cuticle  be  removed,  gustation  is  not  effected  ;  and  the  morbid  sensation 
of  pain  is  substituted.  It  is  also  indispensable  that  the  fluids  poured 
into  the  cavity  of  the  mouth  should  be  in  necessary  quantity,  and  pos- 
sess proper  physical  characteristics.  We  can  farther  appreciate  the 
advantages  of  mastication  and  insalivation,  by  which  solid  bodies  are 
divided  into  minute  portions;  dissolved  when  soluble,  and  brought 
successively  in  contact  with  the  organ  of  taste.  The  gustatory  nerves 
thus  receive  the  impression,  and  by  them  it  is  transmitted  to  the  brain. 
These  nerves  go  to  the  formation  of  the  papillie,  which,  we  have  seen, 
are  situated  in  a  spongy,  erectile  tissue.  As  in  the  sense  of  tact  and 
touch,  it  is  probable  that  this  erectile  tissue  is  not  passive  during  the 
exercise  of  taste ;  and  that  the  papillae,  through  it,  assume  a  kind  of 
erection.  M.  Magendie^  believes  this  view  to  be  void  of  foundation ;, 
but  Sir  C.  Bell"*  has  properly  remarked,  that  if  we  take  a  pencil,  dip  it 
in  a  little  vinegar,  and  touch,  or  even  rub  it  strongly  on  the  surl'ace 
of  the  tongue,  where  these  papillas  do  not  exist,  the  sensation  of  the 
presence  of  a  cold  liquid  is  alone  experienced;  but  if  we  touch  one  of 
the  papillas  with  the  point  of  the  brush,  and,  at  the  same  time,  use  a 
magni tying  glass,  it  is  seen  to  stand  erect,  and  the  acid  taste  is  felt  to 
pass,  as  it  were,  backward  to  the  root  of  the  tongue.  This  experiment 
confirms  the  one  with  the  point  of  the  needle  before  referred  to,  and 
shows  that  the  parts  of  the  tongue  which  possess  the  power  of  receiving 
tactile  impressions  are  distinct  from  those  concerned  in  gustation.  The 
fine  conical  papillae,  by  some  calledyzZ(/br77i,  seated  at  the  sides  and  tip 
of  the  tongue,  have  been  generallj^  esteemed  the  most  exquisitely^  sen- 
sible. 

'  See  an  article  on  the  Gastronomy  of  the  Romans,  hy  the  author,  in  Amer.  Quar- 
terly Review,  ii.  422,  Philad.,  1827. 

^  Precis  Eleinentaire,  i.  139.  ^  Precis,  &c.,  i.  141. 

<  Anatomy  and  Phjsiol.,  Godman's  5th  Amer.  edit.,  ii.  283,  New  Yoik,  1827. 


PHYSIOLOGY   OF   TASTE.  705 

The  sense  of  taste  is  almost  wholly  accomplished  in  the  membrane 
covering  the  tongue.-"  M.  A.  Yerniere^  found,  in  experiments  which  he 
instituted,  the  mucous  membrane  of  the  palatine  arch,  gums,  cheeks, 
lips,  and  middle  and  dorsal  region  of  the  tongue  constantly  insensible 
to  savours;  whilst  gustatory  sensibility  was  possessed  by  the  membrane 
covering  the  sublingual  glands,  the  inferior  surface,  point,  edges  and 
base  of  the  tongue ;  the  pillars  and  two  surfaces  of  the  velum  palati, 
the  tonsils  and  pharynx.  Subsequently,  MM.  Guyot  and  Admyrauld'' 
found,  from  a  series  of  experiments  made  upon  themselves,  that  the 
lips,  inner  surface  of  the  cheeks,  palatine  arch,  pharynx,  pillars  of  the 
velum  palati,  and  dorsal  and  inferior  surface  of  the  tongue  are  inca- 
pable of  appreciating  savours;  and  that  the  seat  of  gustation  is  at  the 
posterior  and  deep-seated  part  of  the  tongue,  beyond  a  curved  line, 
whose  concavity  anteriorly  passes  through  the  foramen  ca3cum,  and 
joins  the  two  margins  of  the  tongue  anterior  to  the  pillars; — at  the 
edges  of  the  tongue;  and  on  a  surface  of  about  two  lines  uniting  them 
with  the  dorsal  surface; — at  the  apex  with  an  extension  of  four  or  five 
lines  on  the  dorsal,  and  of  one  or  two  on  the  inferior  surface;  and 
lastly,  at  a  small  space  of  the  velum  palati  situate  nearly  at  the  centre 
of  its  anterior  surface.  M.  Guyot,  moreover,  found,  that  the  same  sapid 
body  does  not  produce  the  same  sensation  on  every  part  of  the  gusta- 
tory organ.  We  find,  indeed,  that  certain  bodies  affect  one  part  of  the 
mouth,  and  others  another.  Acids  act  more  especially  on  the  lips  and 
teeth ;  acrid  bodies,  as  mustard,  on  the  pharynx.  These  experiments 
were  repeated  by  M.  Longet,"  with  every  precaution  pointed  out  by 
MM.  Verni^re,  Guyot,  and  Admyrauld.  The  results  agreed  generally 
with  those  of  M.  Verniere.  He  could  not,  however,  discover  any  gus- 
tatory sensibility  in  the  mucous  membrane  covering  the  superior  sur- 
face of  the  velum  palati,  the  sublingual  glands,  and  inferior  surface  of 
the  tongue ;  and  he  does  not  regard  the  superior  and  middle  region  of 
the  tongue  as  absolutely  devoid  of  gustatory  sensibility. 

That  the  sense  is  not  restricted  to  the  tongue  we  have  direct  evidence 
in  those  cases  in  which  the  tongue  has  been  wanting.  M.  Roland,  of 
Saumur,^  gives  the  case  of  a  child,  six  years  of  age,  who  lost  the  organ 
in  smallpox ;  and  yet  could  speak,  spit,  chew,  swallow,  and  taste.  De 
Jussieu^  exhibited  to  the  Acadtmie  des  Sciences  of  Paris,  in  1718,  a 
Portuguese  girl,  born  without  a  tongue,  who  also  possessed  these  facul- 
ties. In  a  case  mentioned  by  M.  Berdot,  and  cited  by  Rudolphi,^  in 
which  no  part  of  the  tongue  existed,  the  individual  could  appreciate 
the  bitterness  of  sal  ammoniac;  and  the  sweetness  of  sugar;  and  Blu- 
menbach^  refers  to  that  of  a  young  man,  who  was  born  without  a 

'  Bidder,  art.  Schmecken,  in  Wagner's  Handworterbuch  der  Pliysiologie,  13ste  Lio- 
ferung,  S.  2,  Braunschweig,  184G. 

^  Journal  des  Progres,  &c.,  iii.  208,  and  iv.  219,  Paris,  1827. 

'  Memoire  sur  la  Siege  du  Gout  cliez  rHomme,  Paris,  1830,  and  Archives  Generates 
de  Medeciue,  Janvier,  1837. 

*  Traite  de  Phjsiologie,  torn.  ii.  p.  166,  Paris,  1850. 
^  Aglossostomographie,  Paris,  1630. 

^  Mem.  de  I'Academ.  des  Sciences,  p.  6,  Paris,  1718. 

'  Gruiidriss  der  Physiologic,  2ter  liand,  Iste  Abtheil.,  S.  92,  Berlin,  1823. 

*  Comparative  Anatomy,  by  Lawrence,  p.  323,  London,  1807. 

VOL.  I. — 45 


706  SENSIBILITY. 

tongue;  and  yet,  when  blindfolded,  could  distinguish  between  solu- 
tions of  salt,  sugar,  and  aloes,  put  upon  the  palate.^ 

Certain  bodies  leave  their  taste  in  the  mouth  for  a  length  of  time 
after  they  have  been  swallowed.  This  arrihe-gout — Nachgeschniack 
of  the  Germans — is  sometimes  felt  in  the  whole  mouth;  at  others,  in  a 
part  only;  and  is  probably  owing  to  the  papillse  having  imbibed  the 
savour, — for  the  substances  producing  the  effect  belong  principally  to 
the  class  of  aromatics.  This  imbibition  frequently  prevents  the  savour 
of  another  substance  from  being  duly  appreciated;  and,  in  the  adminis- 
tration of  nauseous  drugs,  we  avail  ourselves  of  the  knowledge  of  the 
fact,  either  by  previously  giving  an  aromatic  so  as  to  forestall  the 
nauseous  impression,  or,  by  combining  powerful  aromatics  with  it, 
which  strongly  impress  the  nerves,  and  produce  a  similar  result. 

There  is  a  common  experiment,  which  has  been  the  foundation  of 
numerous  wagers,  and  elucidates  this  subject;  or  at  least  demonstrates, 
that  the  effect  produced  upon  the  nerve  by  the  special  irritant  con- 
tinues, as  in  the  case  of  the  other  senses,  for  some  time  after  it  has 
made  its  impression,  so  that  the  nerve  becomes,  for  a  time,  compara- 
tively insensible  to  the  action  of  other  sapid  bodies.  It  consists  in 
giving  to  one — blindfold — brandy,  rum,  and  gin,  or  other  spirituous 
li(^uors  in  rapid  succession,  and  seeing  whether  he  can  discriminate 
one  from  another,  A  few  contacts  are  sufhcient  to  impregnate  the 
nerve  so  completely  that  distinction  becomes  confounded. 

It  has  been  remarked,  that  numerous  nerves  are  distributed  to  the 
organ  of  taste:  tlie  ninth  pair,  the  lingual,  and  other  branches  of  the 
fifth,  and  the  glosso-pharyngeal.  (See  Fig.  289.)  An  interesting  ques- 
tion arises — which  of  these  is  the  nerve  of  taste;  or  are  mure  than 
one,  or  the  whole,  concerned?  Of  old,  the  lingual  nerve  of  the  fifth 
pair  was  universally  considered  to  acconq)lish  tlie  function;  the  other 
nerves  being  looked  upon  as  simple  motors.  Boerhaave  and  others 
assigned  the  office  to  the  ninth,  and  considered  the  others  to  be  motors. 
The  filaments  of  the  fifth  have  been  described  as  ti'aceable  even  in  the 
papilke;  but  others  have  denied  this.  Opinions  have  generally  settled 
down  upon  the  lirigual  branch  of  the  fifth  pair.  Such  is  the  view  of 
Sir  Charles  Bell,  who  considers  the  ninth  pair,  whiph  arises  from  the 
anterior  column  of  the  spinal  marrow,  the  nerve  of  motion  for  the 
tongue;  the  lirKjual  branch  of  the  jifth,  a  nerve  having  a  posterior  root, 
the  nerve  of  taste;  and  the  gloi^sopliaryngeal,  tlie  nerve  by  which  the 
tongue  is  associated  with  the  phai'ynx  in  the  function  of  deglutition. 
Bellingeri^  thinks  the  last  nerve  gives  the  organic  and  involuntary 
character  to  the  tongue.  In  this  it  is  aided  by  branches  of  the  fifth 
pair  and  pneumogastric.  The  hype^glossal  he  regards  as  the  nerve  of 
the  voluntary  n)otions  of  the  organ  for  articulate  speech,  and  modu- 
lated sound  in  singing — an  inference  which  has  seemed  to  be  confirmed 
by  the  fact,  that  in  fishes  i^'pisces  muli)  it  is  wanting.  It  is  likewise 
maintained,  tliat  the  fifth  is  the  fir.^t  encephalic  nerve,  which  appears 
in  the  lower  classes  of  animated  nature;  as  the  taste  is  the  first  of  the 

'  Brillat  Savarin,  Physiologie  du  Gout,  p.  38,  Paris,  1843. 

*  Dissert.  Inaugural.  Turini,  1823,  noticed  in  Edinburgh  Med.  and  Surg.  Journal  for 
July,  1834,  p.  129. 


NERVE   OF   TASTE.  707 

special  senses  noticed  in  them;  that,  at  first,  the  nerve  consists  onl}^  of 
the  lingual  branch;  and  farther,  that  its  size,  in  animals,  is  generally 
in  a  ratio  with  that  of  the  organs  of  taste  and  mastication. 

Certain  experiments  by  M.  Magendie*  would  seem  to  settle  the 
question  definitely.  On  dividing  the  lingual  branch  of  the  fifth  pair 
on  animals,  he  found  that  the  tongue  continued  to  move,  but  that  they 
lost  the  faculty  of  appreciating  savours.  The  palate,  gums,  and  internal 
surface  of  the  cheeks,  however,  preserved  the  faculty,  because  supplied 
with  other  branches  of  the  fifth.  But  when  the  trunk  of  the  nerve 
was  cut  within  the  cranium,  the  power  of  recognising  savours  was 
completely  lost  in  every  part  of  the  mouth, — even  in  the  case  of  highly 
acrid  and  caustic  bodies.  He  found,  too,  that  the  loss  of  sense  occurred 
in  all  those  who  had  the  fifth  pair  morbidly  aftected, — a  fact,  which 
has  been  confirmed  by  observations  of  others.^ 

Experiments  on  dogs  by  Professor  Panizza,  of  Pavia,  led  him  to  infer, 
that  the  hypoglossal  is  the  nerve  of  motion  for  the  tongue  ;  the  lingual 
branch  of  the  fifth  pair,  the  nerve  of  general  sensibility ;  and  the 
glosso  pharyngeal,  the  nerve  of  gustation.^  The  views  of  Panizza 
have  been  embraced  by  Messrs.  Elliotson,''  Wagner,*  Valentin,  Bruns, 
Broughton,^  and  others,^  and  have  been  confirmed  by  the  experiments 
and  observations  of  Stannius;^  and  Mr.  Brougliton  has  summed  up 
what  he  considers  to  be  the  final  results  of  all  the  comparative  inqui- 
ries. The  communicating  nerve  of  the  face  (portio  dura),  and  the  fifth 
pair,  arising  by  distinct  roots,  send  off  branches  as  they  emerge  from 
the  bed  of  the  parotid  gland,  some  of  which  unite  in  parallel  lines, 
and  others  do  not,  each  ramification  retaining  the  original  propeity  of 
its  own  root  unmixed;  the  one  destined  to  govern  certain  motions  of 
different  parts  of  the  face;  the  other  devoted  to  tactile  sensibility,  as 
far  as  regards  the  superficial  parts  of  the  face.  Thus  far,  there  is  no 
disagreement:  the  whole  developement  has  been  arrived  at  by  repeated 
experiments  b}^  different  persons.  In  the  next  place,  it  a{)pears,  that 
the  hypoglossal  governs  the  motions  of  the  tongue;  deglutition;  and 
mastication,  without  interfering  with  common  sensation  and  taste.  The 
instinctive  and  voluntary  motions  of  the  tongue  are  all  destroyed  by 
dividing  this  nerve.  The  next  position  is,  that  the  lingual  branches  of 
the  fifth  pair  are  devoted  to  tactile  sensibility,  or  the  common  sensation 
of  the  tongue.     Their  division  does  not  affect  the  motions  of  that  organ 

'  Precis.,  i.  144,  .and  Journal  de  Physiologie,  t.  i^. 

^  Mr.  Bisliop,  in  Lond.  Med.  Gazette  for  Dec.  12,  lb35  ;  and  Romberg,  Miiller's  Arcliiv., 
1838,  H.  iii. 

*  Riclierche  Sperimentali  soprai  Nervi,  translated  in  Edinb.  Med.  and  Snrg.  .Tonrnal, 
for  Jan.,  183(5,  p.  70  ;  see  also,  Amer.  .Journal  of  the  Med.  Sciences,  May,  183(J,  p.  188  ; 
and  Mayo,  Outlines  of  Human  Physiology,  4th  edit.,  p.  314,  London,  1837. 

"  Human  Physiology,  p.  536,  Lond.  1840. 

^  Trait  •  de  Nevrologie,  trad,  par  Jourdan,  p.  433,  Paris,  1843,  and  Lehrbuch  der 
Physiologie  des  Menschen,  ii.  679.     Bivvunschweig,  1844. 

■*  Edinburgh  Medical  and  Surgical  .Journal,  April,  1836,  p.  431.  A  case  in  which  there 
was  complete  insensibility  of  every  part  supplied  by  the  fifth  pair,  and  the  sense  of 
taste  was  perfect,  is  given  in  Bullet,  dell  Scienz.  Medich.,  Aprile,  1841,  cited  in  Brit, 
and  For.  Med.  Rev.,  Oct.,  1842,  p.  545.  See,  also,  Bidder,  Art.  Schmecken,  in  Wagner's 
Handwilrterbuch  der  Physiologie,  loc.  cit. 

"  Funke,  Lehrbuch  der  Physiologie  des  Menschen,  von  A.  F.  Giinther,  B.  ii.,  Abth. 
2,  S.  3.0!),  Leipz.,  1853. 

»  Mailer's  Archiv.,  S.  13^138,  Berlin,  1848. 


708  SENSIBILITY. 

or  its  power  of  taste ;  both  remain  entire.  Lastly,  wlien  the  glosso- 
pharyngeal nerve  is  divided,  the  sense  of  taste  is  lost ;  whilst,  the  other 
nerves  being  uninjured,  motion  and  tactile  sensibility  remain.  Pro- 
fessor Panizza  found,  that  when  the  glosso-pharyngeal  nerve  was 
divided,  the  animal  could  not  taste  coloquintida. 

From  a  series  of  experiments,  however,  similar  to  those  of  Panizza 
and  Mr.  Broughton,  Mr,  Mayo  inferred,  in  conformity  with  an  opinion 
previously  expressed  by  him,'  that  the  lingual  branch  of  the  fifth  is  the 
jiroper  nerve  of  taste,  and  that  it  possesses  also  general  sensibility ; 
that  the  ninth  or  hypoglossal  is  the  nerve  of  voluntary  motion  ;  whilst 
the  glosso-pharyngeal  is  in  part  a  nerve  of  voluntary  motion  and  in 
part  of  general  sensibility,  but  not  of  taste.^  Again  :  the  experiments 
and  researches  of  Dr.  John  Reid,^  have  satisfied  him,  that  after  the 
perfect  section  of  the  glosso-pharyngeal  nerves  on  both  sides,  the  sense 
of  taste  is  sufficiently  acute  to  enable  the  animal  to  recognise  bitter 
substances ;  and  his  inference  is,  that  this  nerve  may  participate  with 
others  in  the  function  of  taste ;  but  that  it  assuredly  is  not  the  special 
nerve  of  that  sense.  Prof.  J.  Miiller^  esteems  it  certain,  both  from  his 
own  experiments  and  those  of  M.  ]S[agendie  and  others,  as  well  as  from 
pathological  observations,  that  the  lingual  branch  of  the  fifth  is  the 
principal  nerve  of  taste  of  the  tongue ;  but  he  does  not  regard  it  proved, 
that  the  glosso-pharyngeal  has  no  share  in  the  perception  of  taste  at 
the  posterior  part  of  the  tongue,  and  in  the  fauces.  Dr.  Carpenter,* 
from  a  consideration  of  how  nearly  the  sense  of  taste  is  allied  to  that 
of  touch,  and  bearing  in  mind  the  distribution  of  the  two  nerves,  thinks 
it  not  difficult  to  arrive  at  the  conclusion,  that  both  nerves  are  concerned 
in  the  function ;''  and  that  there  seems  good  reason  to  believe  the 
glosso-pharyngeal  to  be  exclusively  that  through  which  the  impressions 
made  by  disagreeable  substances  taken  into  the  mouth  are  propagated 
to  the  medulla  oblongata,  so  as  to  produce  nausea,  and  excite  eftbrts  to 
vomit ; — whilst  M.  Longet^  regards  the  lingual  branch  of  the  fifth  and 
the  glosso-pharyngeal  as  necessary  for  the  general  and  special  sensibility 
of  the  gustatory  organs,  "  the  action  of  the  one  perfecting  that  of  the 
other,  both  as  respects  the  general  sensibility  and  the  gustatory  sensi- 
bility of  the  tongue."  It  may  be  proper  to  add,  that  experiments  seem 
to  show,  that  the  glosso-pharyngeal  possesses  also  a  direct  motor  influ- 
ence. Such  is  the  inference  of  Messrs.  J.  Mliller,  Yolkmann,  and  Hein. 
The  last  observer,  whose  experiments  were  carefully  performed,  states 
that  his  results  accord  completely  with  those  of  Volkmann.  When  the 
roots  of  the  glosso-pharyngeal  nerve  were  irritated  in  the  recently 
cut-off"  heads  of  calves  and  dogs,  after  removing  the  brain  and  medulla 

'  Anatomical  and  Physiological  Commentaries,  p.  2,  Lond.,  1822. 

2  IJostock's  Physiology,  3d  edit.,  p.  732,  Lond.,  1836  ;  and  Mayo,  Outlines  of  Physi- 
ology, 4th  edit.,  p.  314,  Lond.,  1837. 

^  Edinburgh  Medical  and  Surg.  Journal,  for  Jan.,  1838,  p.  129.  See,  on  this  disputed 
topic,  Alcock,  in  Dublin  Journal,  for  iN'ov.,  183t!,  and  J.  Guyot,  Archives  Geui  rales  de 
Medecine,  Janvier,  1837. 

^  Elements  of  Physiology,  by  Baly,  P.  v.  p.  1321,  Lond.,  1839. 

*  Human  Physiology,  p.  173,  and  p.  253,  Lond.,  1842,  and  Art.  Taste,  in  Todd's 
Cyclop,  of  Anat.  and'Physiol.,  iv.  858,  Lond.,  1852. 

•>  Todd  and  Bowman,  The  Physiological  Anatomy  and  Physiology  of  Man,  p.  442, 
London, 1845. 

^  Traite  de  Physiologic,  ii.  297,  Paris,  1850. 

\ 


IMMEDIATE   FUNCTION   OF   TASTE.  709 

oblongata,  and  separating  tlieir  roots  from  those  of  the  pneumogastric, 
contractions  always  ensued  in  the  stylo-pharyngeus  muscle.  From  all 
the  facts  adduced  by  recent  observers,  Mr.  Paget'  thinks  it  probable, — ■ 
First.  That  the  glosso-pharyngeal  is  chiefly  the  nerve  of  taste,  and,  in 
a  less  degree,  a  nerve  of  common  sensation ;  and  Secondly.  That, 
according  to  tlie  experiments  of  MM.  Mliller  and  Ilein,  it  is  the  motor 
nerve  of  the  stylo-pharyngeus,  and  probably  also  of  the  palato-glossus. 

Lastly,  M,  de  Blainville  supposes,  that  the  sense  of  taste  is,  perhaps, 
neither  sufficiently  special  nor  sufficiently  limited  in  extent  to  have  a 
separate  nervous  system ;  and  therefore  that  all  the  afferent  nerves  of 
the  tongue  are  equally  inservient  to  the  sense,  as  the  different  nerves 
of  the  skin,  which  proceed  from  numerous  pairs,  are  equally  inservient 
to  touch  or  tact.^ 

Such  is  the  existing  state  of  uncertainty  regarding  this  interesting 
point  of  physiology ;  the  view  of  Panizza  appears,  however,  to  the 
author,  to  be  most  in  accordance  with  analogy ;  and  in  all  respects 
most  worthy  of  adoption. 

From  the  experiments  and  observations  of  Bellingeri,  Montault, 
Diday,  C.  Bernard,  and  Verga,^  it  would  appear,  that  the  filaments  of 
the  chorda  tympani,  which  are  united  and  confounded  with  those  of 
the  lingual  branch  of  the  fifth  pair,  are  in  an  inexplicable  manner  con- 
nected with  gustation.  When  the  facial  nerve  has  been  paralyzed,  or 
divided  above  tlie  origin  of  the  tympanic  branch,  the  sense  of  taste 
has  been  impaired.  The  functions  of  the  chorda  tympani  are  by  no 
means  determined ; — some  esteeming  it  as  a  sensory,  others  as  a  motor 
nerve;  whilst  others,  again,  believe  it  to  possess  both  sensory  and 
motor  properties. 

The  immediate  function  of  taste,  as  has  been  remarked,  is  to  give 
the  sensation  of  savours.  This  function,  like  touch,  is  instinctive ; 
requires  no  education;  cannot  be  supplied  by  any  of  the  other  senses, 
and  is  accomplished  as  soon  as  the  tongue  has  acquired  the  necessary 
degree  of  development.  To  this  it  may  be  replied,  that  the  very  young 
infant  is  not  readily  affected  by  savours.  In  all  cases,  however,  certain 
sapid  bodies  excite  their  usual  impression ;  and,  in  the  course  of  a  few 
months,  when  the  organ  becomes  developed,  the  sense  acquires  a  high, 
and  often  inconvenient,  degree  of  acuteness. 

The  mediate  or  auxiliary  offices  of  gustation  are  few,  and  limited  in 
extent.  It  does  not  afford  much  instruction  to  the  mind.  The  chemist 
and  mineralogist  occasionally  gain  information  through  it;  but  it  is 
never  considered  to  merit  the  rank  of  an  intellectual  sense:  on  the  con- 
trary, it  is  classed  with  olfaction  as  a  corporeal  sense. 

To  appreciate  a  savour  accurately,  the  sapid  substance  must  remain 
for  a  time  in  the  mouth ;  when  rapidly  swallowed,  the  impression  is 
feeble,  and  almost  null.  Of  this  fact  we  take  advantage  when  com- 
pelled to  swallow  nauseous  substances ;  whilst  we  retain  a  savoury  arti- 
cle long  in  the  mouth,  in  order  that  we  may  extract  its  sweets.  IIow 
different,  too,  is  the  consent  of  the  auxiliary  organs  under  these  two 

'  Brit,  and  For.  Mefl.  Rev.,  April,  1845,  p.  fiSO. 

2  Adelou,  op.  cit.,  i.  309.  ^  Cited  hy  M.  Longet,  op.  cit.,p.  305,  Paris,  1850. 


710  SEXSIRILITY. 

circumstances!  Whilst  a  luscious  body  augments  tlie  secretion  of  the 
salivary  glands,  or  causes  the  "  mouth  to  water,''  as  it  has  been  called 
— projecting  the'  saliva,  at  times,  to  a  distance  of  some  feet  from  the 
mouth,  and  disposing  every  part  to  approach  or  mingle  with  it — a 
nauseous  substance  produces  constriction  of  every  secretory  organ  ;  an 
elYect  which  extends  even  to  the  stomach  itself,  so  that  it  often  rejects 
the  offending  article,  as  soon  as  it  reaches  the  cavity.  We  can  thus 
understand  how,  ccettris  jMribus,  an  article,  that  is  pleasing  to  the 
palate,  may  be  more  digestible  than  one  that  excites  disgust;  and  con- 
versely. Of  the  "  consent  of  parts,"  exerted  between  the  stomach  and 
the  organ  of  taste,  we  have  a  familiar  illustration  in  the  fact, — that 
whatever  may  be  the  gout,  with  which  we  conmience  a  meal  on  a 
favourite  article  of  diet,  we  find  that  the  relish  is  blunted  as  the  stomach 
becomes  filled;  and  hence  the  Komans  were  in  the  habit  of  leaving  the 
table  once  or  twice  during  a  meal,  and,  after  having  unloaded  the 
organ,  of  returning  again  to  the  charge — ^^vornwit  ut  edant,  edunt  ut 
vomantP 

If  we  place  a  sapid  substance  in  the  mouth,  and  then  close  the  nos- 
trils, the  taste  is  diminished, — a  fact,  which  has  given  rise  to  the  gene- 
rally prevalent  and  correct  opinion,  that  an  intimate  relation  exists 
between  the  smell  and  taste.  They  are,  however,  distinct.  Most 
sapid  substances  have  an  odour  or  "flavour,"  which  is  not  appreciated 
when  we  prevent  the  air  from  passing  through  the  nasal  fossae.  This 
renders  the  impression  on  the  gustatory  nerves  still  less  marked,  but  it 
exists.  Gustation  is  likewise  diminished  by  the  new  sensation  produced 
in  the  nostrils  by  their  closure;  so  that  the  same  amount  of  attention 
is  not  directed  to  the  sense  of  taste. 

A  curious  case  of  deprivation  and  modification  of  the  senses  of  taste 
and  smell  has  been  related  by  Mr.  Justice,^  of  Philadelphia.  It  shows 
the  intimate  relation  between  them.  Nine  months  previously,  a  person 
of  his  acquaintance  was  thrown  from  his  carriage;  and  in  the  fall,  his 
head  came  first  in  contact  with  the  ground,  and  concussion  of  the  brain 
was  produced.  The  injury  appeared  to  have  been  received  behind,  but 
above  the  ear.  He  was  laid  in  bed  in  a  state  of  total  insensibility,  and 
thus  remained  for  nearly  a  month,  about  which  time  he  revived,  and, 
to  his  surprise,  found  that  he  had  entirely  lost  both  the  sense  of  taste 
and  the  sense  of  smell.  In  this  situation  he  remained  at  the  time  when 
Mr.  Justice  detailed  the  particulars  of  the  case.  It  was  equally  indif- 
ferent to  him  what  he  took  as  food  so  far  as  regarded  taste, — Cayenne 
pepper  or  sawdust  as  he  expressed  it  being  alike  tasteless; — but  as  a 
compensation  for  this  privation,  he  had  a  constant  sensation  of  a  most 
delightful  character,  which  he  could  only  compare  to  that  of  the  most 
delicious  cordial  flowing  through  his  mouth.  This  continues  night  and 
day,  and  is  especially  perceptible  when  the  lips  are  apart,  and  he  in- 
hales the  air  through  his  mouth ; — the  only  intermission  to  this  plea- 
surable sensation  being  whilst  he  is  taking  his  food. 

Yet  although  closely  related  the  senses  of  taste  and  smell  are  dis- 
tinct. A  case  has  been  related  by  Dr.  J.  C.  Hutchinson^  in  which  the 
olfactory  nerve  appeared  to  be  entirely  paral3'zed,  whilst  the  branches 

'  Proceedings  of  the  American  Philosopliical  Society,  vi.  52,  Oct.  6,  1854. 
^  American  Journal  of  the  Medical  Sciences,  Jan.,  1852. 


ACUTENESS   OF   TASTE.  711 

of  tlie  fifth  pair  retained  their  integrity.  Smell  was  lost;  yet  a  pun- 
gent sensation  was  excited  by  irritating  vapours,  and  when  snuft'  was 
taken  sneezing  was  induced.  The  sense  of  taste,  however,  did  not  seem 
to  be  modified ;  inasmuch  as  substances,  which  were  possessed  of  neither 
smell  nor  pungency  could  be  readily  distinguished  from  each  other, 
even  when  their  tastes  were  not  very  different. 

Among  animals  we  see  great  diversities  in  this  sense.  Whilst  none 
possess  the  refined  taste  of  man,  there  are  many,  which  are  capable, 
by  taste  or  smell,  of  knowing  plants  that  are  nutritive  from  those  that 
are  noxious  to  them;  and  it  is  unusual  for  us  to  find  that  an  animal  has 
died  from  eating  such  as  are  unquestionably  poisonous  to  it.  Yet,  as 
we  have  remarked,  a  substance,  that  is  noxious  to  one,  may  be  eaten 
with  impunity  by  another;  and,  if  we  select  animals,  and  place  them  in 
a  field  containing  plants,  all  of  which  are  ranked  as  poisons,  and  are 
poisonous  to  a  majority  of  them,  we  find  that  not  only  has  a  selection 
been  made  by  each  animal  of  that  which  is  innocuous  to  it,  but  that 
the  substance  has  furnished  nourishment  to  it,  whilst  it  might  have 
proved  fatal  to  others.  All  this  must  be  dependent  upon  peculiar,  and 
inappreciable  organization. 

The  sense  of  taste  is  more  under  the  influence  of  volition  than  any 
other.  It  is  provided  with  a  muscular  apparatus,  by  which  it  can  be 
closed  or  opened  at  pleasure;  and,  in  addition,  ordinarily  requires  the 
assistance  of  the  upper  extremity  to  convey  the  sapid  substance  to  the 
mouth.  The  sense  can,  therefore,  be  exercised  either  |x/s5iY-eZ?/  or 
actively  ;  and,  by  cultivation,  it  is  capable  of  being  largely  developed. 
The  spirit  taster  to  extensive  commercial  establishments  exhibits  the 
truth  of  this  in  a  striking  manner.  In  his  vocation,  he  has  not  only  to 
taste  numerous  samples,  but  to  appreciate  the  age,  strength,  flavour, 
and  other  qualities  of  each  ;  and  the  practised  individual  is  rarely  wrong 
in  his  discrimination.  With  almost  all,  if  not  all,  these  "tasters,"  the 
custom  is  to  take  a  small  quantity  of  the  liquor  into  the  mouth  ;  throw 
it  rajiidly  around  that  cavity,  and  eject  it.  A  portion,  in  this  way, 
comes  in  contact  with  every  part  of  the  membrane ;  and  of  course  im- 
presses the  glosso-pharyngeal  as  well  as  the  lingual  and  other  ramifica- 
tions of  the  fifth  pair. 

The  gourmet  of  the  French — somewhat  more  elevated  in  the  scale 
than  our  ordinary  epicure — prides  himself  upon  his  discrimination  of 
the  nicest  shades  of  difference  and  excellence  in  the  materials  set  be- 
fore him.  Many  gourmtts  profess  to  be  able  to  pronounce,  by  sipping 
a  few  drops  of  wine,  the  country  whence  it  comes,  and  its  age ;  and, 
according  to  Stelluti,  can  tell,  by  the  taste,  whether  birds  put  upon 
the  table  are  domesticated  or  wild, — male  or  female.^  Dr.  Kitchener' 
asserts,  that  many  epicures  are  cajiable  of  saying  in  what  precise  reach, 
or  stretch  of  the  Thames  the  salmon  on  the  table  has  been  caught;  and 
Sir  Astley  Cooper  was  in  the  habit  of  relating  the  remarkable  case  of 
a  professional  friend,  who  could  discriminate  by  the  taste  the  beef  fur- 
nished by  a  particular  London  butcher.^     This  acuteness  of  sense  is 

'  American  Quarterly  Review,  ii.  427. 
2  Cook's  Oracle,  3d  edit.,  p.  22f),  Lond.,  1821. 

^  Life  of  Sir  Astley  Cooper,  Bart.,  by  Brausby  Blake  Cooper,  Esq.,  F.  R.  S.,  ii.  137, 
Lond.,  1843. 


712  SENSIBILITY. 

by  no  nrcans  desirable.  Doomed  to  meet,  in  his  progress  tlirongli 
life,  with  such  a  preponderance  of  what  demands  obtuseness  rather 
than  acuteness  of  feeling,  the  epicure  must  be  liable  to  continual 
annoyances  and  discomforts,  which  the  less  favoured  can  never  expe- 
rience. 

In  disease,  gustation  often  becomes  greatly  depraved;  and  the 
various  morbid  tastes  have  been  accounted  for  by  depraved  secretions 
in  the  mouth,  acting  as  foreign  sapid  substances  on  the  papillas.  Cer- 
tain tastes,  however,  cannot  be  explained  in  this  way,  and  must  be 
regarded  as  nervous  phenomena — subjective  sensations.  If  the  epithe- 
lium be  covered  with  a  fur,  taste  may  be  lost  or  impaired,  and  be 
instantaneously  restored  as  soon  as  the  coating  is  removed.  M.  Ma- 
gendie  observed,  that  dogs,  after  the  injection  of  milk  into  their  veins, 
liclvcd  their  lips,  and  gave  other  evidences  of  tasting.  When  Dr.  E. 
Hale,  in  an  experiment  referred  to  in  another  part  of  this  work,  in- 
jected castor  oil  into  one  of  his  veins,  he  distinctly  tasted  the  oil  a 
short  time  afterwards.  Messrs.  Todd  and  Bowman'  suggest  that  such 
phenomena,  if  uniformly  present,  might  be  occasioned  by  the  transu- 
dation of  the  fluid  from  the  vessels  to  the  nerves  of  the  papillaa ;  and 
this  may  be  the  true  explanation,  although  it  is  not  so  easy  to  see 
that  such  transudation  could  readily  occur  in  the  case  of  castor  oil. 

C.  SENSE  OF  SMELL  OR  OLFACTION. 

The  object  of  this  sense  is  to  appreciate  the  odorous  properties  of 
bodies.  It  differs  from  the  last  in  the  circumstance  that  the  body  does 
not  come  into  immediate  contact.  It  is  only  necessary  that  an  odorous 
emanation  from  it  shall  impinge  upon  the  organ  of  sense.  Still,  it 
does  not  essentially  vary  in  its  physiology  from  the  sense  of  taste. 

1.  ANATOMY  OF  THE  ORGAN  OF  SMELL. 

The  organ  of  smell  is  a  mucous  membrane,  which  lines  the  nasal 
cavities,  and  is  called  Schneiderian  or  'pituitary.  It  resembles  that 
which  covers  the  organ  of  taste,  except  that  the  nervous  papilhe  are 
more  delicate,  to  correspond  with  the  greater  tenuity  of  the  body  that 
has  to  make  the  impression.  The  membrane  lines  the  whole  of  the 
bony  cavities  called  nasal  fossce^  which  are  constantly  open  anteriorly 
and  posteriorly,  to  permit  the  air  that  traverses  them  to  proceed  to  the 
lungs.  The  anterior  aperture  is  covered  by  a  kind  of  pent-house  or 
capital,  for  the  purpose  of  collecting  the  odorous  particles.  This 
capital  is  called  the  nose.  The  essential  part  of  the  organ  is  the  pitui- 
tary or  olfactory  membrane, — the  other  parts  being  superadded  to 
perfect  the  sense. 

The  bony  portions  of  the  nose  are  separated  from  each  other  by  the 
vomer.  This  bony  septum  is  prolonged,  by  means  of  cartilage,  to  the 
anterior  extremity  of  the  nose,  so  that  the  nasal  fossae  are  divided  into 
like  parts,  which  have  no  communication  with  each  other,  but  open 
together,  posteriorly,  into  the  top  of  the  pharynx.  Within  each  of 
the  nares  are  two  convoluted  or  turbinated  hones — generally  called  ossa 
spongiosa  sen  turhinata;  and,  by  the  French,  cornets.     These  are  situate 

'  Tlie  Physiological  Anatomy  and  Physiology  of  Man,  p.  448,  Loud.,  1845. 


ORGAN   OF   SMELL. 


713 


Fig.  240. 


one  above  tlie  other ;  the  superior  formed  of  a  plate  of  the  ethmoid 
bone — the  inferior  a  distinct  bone.  They  divide  the  general  cavit}^  of 
each  nostril  into  three  passages  or 
meatus.  The  inferior  meatus  is  broad 
and  long ;  the  least  oblique,  and  least 
tortuous;  the  middle  is  narrow,  al- 
most as  long,  but  more  extensive 
from  above  to  below ;  and  the  su2:je- 
rior  is  much  shorter,  more  oblique, 
and  still  narrower.  The  narrowness 
of  these  passages  in  the  living  sub- 
ject is  so  great,  that  the  slightest 
tumefaction  of  the  membrane  renders 
the  passage  of  air  through  the  fossae 
extremely  difficult.  This  is  the  cause 
of  the  difficulty  of  breathing  through 
the  nose,  that  attends  "  a  cold  in  the 
head."  Into  the  two  upper  passages, 
cavities  in  certain  bones  open,  which 
considerably  enlarge  the  extent  of 
the  foss[B.  These  are  called  sinuses  ; 
and  are  the  maxillary,  ixdat'me^  fron- 
tal^ sphenoidal,  ethmoidal, — the  last 
being  sometimes  termed  etlimoidal 
cells. 

All  the  cavities  are  lined  by  the 
delicate  pituitary  membrane,  or  by 
a  prolongation  of  it.  In  the  nasal 
fossEe  it  augments  the  thickness  of 
the  turbinated  bones.     It  resembles 

the  mucous  membranes  in  general  in  its  composition ;  and  adheres 
firmly  to  the  bones  and  cartilages,  which  it  covers.  Its  aspect  is  vel- 
vety," owing  to  a  multitude  of  minute  papilUe;  and  it  receives  a  great 
number  of  vessels  and  nerves.  The  sinuses  are  lined  by  a  prolonga- 
tion apparently  of  the  same  membrane,  diflering,  however,  in  some 
respects  from  the  other.  The  whole  of  the  membrane  is  the  seat  of 
the  secretion  of  nasal  mucus,  which,  doubtless,  performs  a  part  in 
olfaction  as  important  as  the  secretion  from  the  mucous  membrane  of 
the  mouth  does  in  gustation. 

The  same  nerve  is  not  distributed  over  the  whole  of  this  membrane. 
In  some  parts,  the  olfactory,  ethmoidal,  or  first  pair  can  be  traced;  in 
others,  we  see  only  filaments  of  the  fifth  pair.  The  first  of  these  have 
not  always  been  regarded  as  the  nerves  of  smell.  Anciently,  they 
were  presumed  to  be  canals  for  the  passage  of  pituita  or  phlegm,  which 
was  supposed  to  be  secreted  by  the  brain.  At  the  present  day,  anato- 
mists are  doubtful  only  as  regards  their  origin  ;  some  .deriving  them 
from  the  anterior  lobes  of  the  brain;  others  from  the  corpora  striata, 
which  have,  in  consequence,  been  called  thalami  nervorum  ethmo'ida- 
lium ;  and  others,  again,  with  Willis  and  GalV  and  with  probability, 

'  Eeclierches  sur  le  Systeme  Nervimx  en  general  et  sur  celui  du  Cerveau  eu  parti- 
culier,  par  F.  J.  Gall  et  G.  tspurzUeiui,  Taris,  1809. 


Vertical  Section  of  the  Middle  Part  hf  the 
Nasal  Fossa?,  giving  a  Posterior  View  of 
the  Arrangement  of  the  Ethmoidal  Cells, 
&c. 

1.  Anterior  fossa  of  the  cranium.  2.  The 
same  covered  by  the  dura  mater.  3.  Dura  mater 
turned  up.  i.  Crista  galli  of  the  ethmoid  bone. 
5.  Its  cribriform  phite.  6.  Its  nasal  himella. 
7.  Middle  spongy  bones.  8.  Ethmoidal  cells. 
9.  Os  planum.  10.  Inferior  spongy  bones.  11. 
Vomer.  12.  Superior  maxillary  bone.  13.  Its 
union  with  the  ethmoid.  14.  Anterior  parietes 
of  the  antrum  Higbmoriauum,  covered  by  its 
membrane.  15.  Its  fibrous  layer.  16.  Its  mu- 
cous membrane.  17.  Palatine  process  of  the  su- 
perior maxillary  bone.  18.  Roof  of  the  mouth, 
covered  by  the  mucou.s  membrane.  19.  Section 
of  this  membrane.  A  bristle  in  the  orifice  of  the 
antrum  Highmorianum. 


714 


SENSIBILITY. 
Fig,  241. 


Outer  wall  of  the  Nasal  Fossa,  with   the  Three  Spongy  Bones  and  Meatus  :  the  Nerves  lieing 
shown  as  thej'  would  appear  through  the  membrane  if  it  were  transparent. 

a.  Olfactory  process.  &.  Olfactory  bulb  (represented  rather  too  short)  resting  on  the  cribriform  plate. 
Below  is  seen  the  plexiform  arrangement  of  the  olfactory  filaments  on  the  upper  and  middle  spungy 
bones,  c.  Fifth  nerve  within  the  cranium  with  its  Gasserian  ganglion,  d.  Its  superior  maxillary  divi- 
sion, sending  branches  to  Meckel's  ganglion,  and  through  tliat  to  the  three  spongy  bones,  where  they 
anastomose  with  the  olfactory  filaments,  and  with  ^f,  branches  of  the  nasal  division  of  the  ophthalmic 
nerve,  o.  Posterior  palatine  tvrigs  from  Meckel's  ganglion,  .supplying  the  soft  and  hard  palate,  t.  Orifice 
of  the  Eustachian  tube  on  the  side  of  the  pharynx,  behind  the  lower  spongy  bone. — Two-thirds  dia- 
meter. 

referring  them,  like  every  other  nerve  of  sense,  to  the  medulla  oblon- 
gata.    M.  Beclard  affirms,  that  in  a  hydrocephalic  patient,  where  a 

part  of  the  brain  had  been  destroyed 
Fig.  242.  by   disease,    he   actually   saw    this 

origin.^  The  nerve  proceeds  di- 
rectly forwards  until  it  reaches  the 
upper  surface  of  the  cribriform 
plate  of  the  ethmoid  bone,  where  it 
divides  into  a  number  of  filaments, 

JF^^^^^M^iiH^  ^''^^^^^  ^^^^^  V^^^  through  the  foramina  in 

.A^P/  *^  ^^^^  the  plate,  and  attain  the  nasal  fossae; 

where  they  are  dispersed  on  the 
upper  and  middle  part  of  the 
Schneiderian  membrane;  but  can- 
not be  traced  on  the  lower.  Most 
anatomists  are  of  opinion,  that  here 
they  constitute,  with  vessels  of  ex- 
halation and  absorption,  the  pa- 
pilke ;  whilst  others,  as  Scarpa,  not 
havino"  been  able  to  trace  them 
thither,  have  been  of  opinion,  that 
the  filaments  interlace  to  constitute 
a  kind  of  proper  membrane.  Our 
means  of  observation  cannot  be 
considered  sufficient  to  enable  us  to 


Nerves  of  the  Septum  of  the  Nose. 


a.  Olfactory  bulb  resting  on  the  cribriform 
plate,  below  which  its  branches  may  be  tracod 
on  the  septum,  abou<  half  way  down.  Behind, 
the  naso-palatine  nerve  from  Meckel's  ganglion 
is  seen  descending  to  the  naso-palatine  canal.  In 
front,  the  nasal  twig  of  the  ophthalmic  nerve  de- 
scends towards  the  tip  of  the  nose,  dividing  into 
two  principal  branches,  p.  Roof  of  the  mouth, 
e.  Orifice  of  the  Eustachian  tube. — One-half  dia- 
meter. 


Adelon,  Physiologie  de  rHomine,  edit,  cit,,  i,  330. 


ORGAN   OF   SMELL. 


715 


decide  tliis  question  positively.  The  nerve  has  not  been  traced  on  the 
OS  spongiosum  inferius;  on  the  inner  surface  of  the  middle  spongy 
bone,  or  in  any  of  the  sinuses. 

Fig.  243. 


A  portion  of  the  Pituitary  Membrane  of  the 
Na?fil  Septum,  magnified  9  times,  showing 
the  jN'umher,  Sizes,  and  Arrangement  of  the 
Mucous  Crypts. 


A  portion  of  the  Pituitary  Membrane  with  its 
Arteries  and  Veins  injected.— Magnified  ]5 
diameters. 

The  natural  size  of  this  piece  is  seen  at  the  bot- 
tom of  the  cut. 

1,  1,  1.  Orifices  of  three  mucous  crypts  sur- 
rounded by  veins  and  arteries. 


Fig.  245. 


The  olfactory  filaments,  according  to  Messrs.  Todd  and  Bowman,^ 
form  a  considerable  part  of  the  entii'e  thickness  of  the  Schueiderian 
membrane,  and  differ  widely  from  the 
ordinary  encephalic  nerves  in  struc- 
ture. They  contain  no  ivhite  substance 
of  Schwann ;  are  not  divisible  into 
elementary  fibrilloa ;  are  nucleated  and 
finely  granular  in  texture,  and  invest- 
ed with  a  sheath  of  homogeneous 
membrane ;  and  are  regarded  by  those 
gentlemen  as  direct  continuations  of 
the  vesicular  matter  of  the  olfactory 
bulb  or  ganglion;  and  they  "venture 
to  hint,"  that  the  amalgamation  of  the 
elements  of  the  peripheral  part  of 
the  nervous  apparatus  in  the  larger 
branches,  and  probably  in  the  most 
remote  distribution,  as  well  as  the 
nucleated  character  indicative  of  an 
essential  continuity  of  tissue  with  the 
vesicular,  matter  of  the  lobe,  are  in 
accordance  with  the  oneness  of  the  sensation  resulting  from  simulta- 
neous impressions  on  different  parts  of  this  organ  of  sense,  and  seem 
to  show,  that  it  would  be  most  correct  to  spealc  of  the  first  pair  of 
nerves  as  a  portion  of  the  nervous  centre  put  forward  beyond  the  cra- 


Olfactory  Filaments  of  the  Dog. 

b.  In  acetic  acid. — Magnified 


a.  In  water. 
2.50  diameters. 


'  Op.  cit.,  ii.  5-11. 


716  SENSIBILITY. 

nium,  in  order  that  it  ma}''  there  receive,  as  at  first  hand,  the  impres 
sions  of  which  the  mind  is  to  become  cognizant. 

Besides  the  first  pair  of  nerves,  the  pituitary  membrane  receives 
several  branches  from  the  fifth  encephalic  pair;  for  example,  the  nasal 
twig  of  the  ophthalmic  branch  of  the  fifth,  and  filaments  from  the  frontal 
branch  of  the  same ;  from  the  spheno-palatine  ganglion ;  the  palatine 
nerve ;  the  vidian  nerve ;  and  from  the  anterior  dental  branch  of  the 
superior  maxillary.  One  of  these  twigs  enters  the  anterior  naso-pala- 
tine  canal ;  and,  in  its  course  to  the  roof  of  the  mouth,  passes  through 
a  small  ganglion,  which  has  been  described  by  M.  H.  Cloquet  under 
the  name  naso-jjalatine,  and  which  he  conceives  to  be  the  organ  of  sym- 
pathy between  the  senses  of  smell  and  taste. 

The  pituitary  membrane  is  kept  moist  by  nasal  mucus,  as  well  as  by 
the  exhalation  that  constantly  takes  place  from  it.  It  receives  the 
superfluous  tears  by  means  of  the  ductus  ad  nasum, — a  duct  passing 
from  the  inner  canthus  of  the  e3'e,  and  opening  into  the  nasal  fossae 
below  the  lower  spongy  bone.  The  constant  evaporation  which  must 
take  place  from  the  membrane,  owing  to  the  passage  of  the  air  during 
respiration,  requires  that  the  secretion  should  be  continuous  and  copious, 
otherwise  the  membrane  would  become  dry. 

The  nasal  fossee  communicate  externally  by  means  of  the  nostrils, 
the  shape,  size,  and  direction  of  which  vary,  so  as  to  give  rise  to  the 
aquiline,  Roman,  inig,  and  other  varieties  of  nose.  At  the  extremity 
of  the  nostrils  long  hairs  are  situate — technically  called  vihrissce — whose 
function,  it  is  conceived,  may  be  to  sift,  as  it  were,  the  air  passing 
through  during  respiration,  and  thus  prevent  extraneous  bodies  from 
entering  the  fossa3.  The  nostrils  are  also  capable  of  being  expanded 
or  contracted  by  appropriate  muscles. 

In  this  sense,  there  is  a  more  clear  separation  between  the  physical 
and  nervous  part  of  the  apparatus  than  in  either  of  those  alread}^  con- 
sidered ; — the  nose  proper  forming  the  physical  portion ;  and  the  nerves 
of  smell  the  organic  or  nervous. 

2.    ODOUES. 

The  comprehension  of  the  physiology  of  olfaction  will  not  be  complete 

■without  an  inquiry  into  odours  or  those  emanations  from  odorous  bodies, 
that  give  them  their  character,  and  impress  the  organ  of  smell. 

It  was  long  maintained,  as  in  the  case  of  savours,  that  odours  are 
dependent  upon  a  peculiar  principle,  which,  according  to  its  particular 
combination  with  the  constituents  of  bodies,  gives  rise  to  various  odours. 
To  this  principle  the  terms  aroma  and  spiritus rector  hsive  been  assigned; 
but  the  notion  has  been  long  abandoned,  because  no  general  or  common 
characters  are  observable  amongst  odorous  bodies,  which  should  be 
expected  were  they  indebted  for  their  odour  to  the  same  principle. 
Walther,  a  German  physiologist,  expresses  the  opinion,  that  an  odorous 
body  is  such  by  virtue  of  a  vibratory  motion,  analogous  to  that  made 
by  a  sonorous  body.  We  have,  however,  the  most  satisfactory  evidence, 
that  there  are  special  odours,  as  there  are  special  savoury  molecules. 
We  can  prevent  an  odorous  body  from  impressing  our  olfactory  nerves 
by  covering  it  with  a  glass  receiver.  Odours  can  be  separated  By  in- 
fusion and  distillation.    The  fact,  moreover,  has  been  directly  proved  by 


ODOURS.  717 

an  experiment  of  M.  Bertbollet.  On  nearly  filling  a  tube  with  mercury, 
and  placing  a  piece  of  camphor  at  the  top  of  the  tube,  he  found  that, 
after  a  time,  the  mercury  descended,  the  camphor  had  diminished  in  size, 
and  the  space  above  the  metal  was  occupied  by  an  odorous  gas.* 

But  what  is  the  cause  of  the  diseno;a2:ement  of  these  odorous  mole- 
cules?  By  most  writers  on  this  subject  it  has  been  considered  to  be 
owing  to  the  solvent  action  of  caloric  on  the  odorous  body.  The  opinion 
that  all  bodies  are  odorous  is  as  old  as  Theophrastus;  and  it  is  one  which 
it  is  difficult  not  to  embrace,  if  we  add — provided  they  are  subjected 
to  the  appropriate  agents  for  disengaging  the  odorous  particles ;  and 
the  probability  is,  that  the  reason  we  esteem  particular  bodies  inodor- 
ous is,  that  our  olfactory  nerves  are  not  organized  with  sufficient  deli- 
cacy to  enable  us  to  distinguish  their  odorous  properties.  Heat  assists 
the  escape  of  odorous  particles  from  a  variety  of  bodies ;  and  hence 
it  has  been  maintained,  that  every  body  which  is  volatile  must  be  odor- 
ous. M.  Adelon^  asserts,  that  this  is  not  the  case;  but  it  is  difficult  to 
accord  with  him.  The  fact  of  our  not  appreciating  the  odour  is  no 
proof  of  its  non-existence.  In  truth,  bodies  that  are  inodorous  to  one 
animal  or  individual  may  not  be  so  to  another.  In  cases,  too,  in  which 
smell  is  morbidly  acute,  a  substance  may  appear  overwhelmingly  odor- 
ous, which  may  seem  devoid  of  smell  to  a  healthy  individual.  M. 
H.  Cloquet^  refers  to  the  case  of  a  celebrated  Parisian  physician,  who 
was  subject  to  violent  attacks  of  hemicrania  or  megrim,  and  who  was 
dreadfully  tormented,  during  one  of  the  paroxysms,  by  the  smell  of 
copper,  exhaled  from  a  pin  that  had  been  dropped  on  the  bed ! 

Caloric  seems  to  be  only  one  of  the  causes  of  the  disengagement  of 
odours.  Some  are  retained  by  so  feeble  a  degree  of  affinity,  that  they 
appear  to  be  exhaled  equally  at  all  temperatures.  Light  influences 
their  escape  in  particular  cases;  some  plants  giving  off' their  fragrance 
during  the  day ;  others  perfuming  the  air  only  at  night.  Dampness, 
in  many  instances,  assists  their  escape, — hence  the  fragrance  of  a  gar- 
den after  a  summer's  shower ;  and  the  smell  afforded  by  all  argillaceous 
substances  when  breathed  upon, — a  fact,  the  knowledge  of  which  is 
of  importance  to  the  chemist. 

Lastly; — substances,  that  appear  to  us  devoid  of  odour,  may  exhale 
a  strong  one,  when  rubbed  together.  All  these  circumstances  tend 
greatly  to  prove,  that  every  substance  is  possessed  of  odorous  quali- 
ties, although  we  may  not  be  aware  of  the  precise  mode  for  causing 
their  emanation,  or  our  olfactory  nerves  may  not  be  sufficiently  deli- 
cate to  appreciate  them. 

Ai'ouud  odorous  bodies,  the  molecules,  as  they  escape,  form  an  atmo- 
sphere, which,  of  course,  will  be  denser,  the  nearer  it  is  to  the  body. 
These  particles  are  diffused  around, — not,  probably,  in  the  same  man- 
ner as  light  or  sound,  but  as  one  fluid  mixes  with  another;  and,  when 
the  air  is  still,  it  is  conceived,  their  strength  will  be  inversely  as  the 
square  of  the  distance  from  the  substance  that  exhales  them.  There 
is  a  great  difference,  however,  in  odours  as  regards  their  diftusibility  in 

'  Cloquet,  Art.  Odeurs,  Diet,  des  Sciences  Medicales,  torn.  xxxvii.,p.  89,  Paris,1819. 

«  Op  cit.,  i.  322. 

3  Ospliresiologie  ou  Traite  des  Odeurs,  Paris,  1821. 


713  SENSIBILITY. 

the  atmosphere.  Some  extend  to  a  great  distance,  whilst  others  are 
confined  ^s'ithin  a  small  compass.  The  odours  of  many  flowers  are  so 
delicate  as  not  to  be  appreciated,  unless  they  are  brought  near  the 
olfactory  organs;  whilst  that  of  cinnamon  is  said  to  have  been  detect- 
ed at  sea,  at  the  distance  of  twenty-five  miles  from  Ceylon.  Lord 
Valentia^  affirms,  that  he  himself  distinctly  smelt  the  aromatic  gale 
at  nine  leagues'  distance; — but  Dr.  Kuschenberger^  was  not  equally 
fortunate.  The  author  was  informed  by  Commodore  Stewart,  of  the 
Navy,  that  he  had  discovered  the  spicy  emanations  when  two  hun- 
dred miles  from  Ceylon,  and  the  terebinthinate  odours  of  the  pines 
of  Virginia,  when  one  hundred  miles  from  the  coast;  and  Dr.  Wil- 
cocks,  of  Philadelphia,  when  at  sea  in  1844,  and  two  hundred  miles  to 
the  westward  of  the  coast  of  Ireland,  observed,  as  did-  many  others  of 
the  passengers,  a  smoky  odour,  which  lasted  for  several  days  in  suc- 
cession. On  appealing  to  the  captain  for  the  cause  of  the  phenomenon, 
he  informed  them  that  he  had  frequently  remarked  it  before;  and 
that  it  was  owing  to  the  long  continuance  of  easterly  winds,  which 
carried  the  odour  of  burning  peat  from  Ireland  far  out  to  sea.^  Facts 
of  this  kind  are  employed  by  the  natural  philosopher  to  exhibit  the 
excessive  divisibility  of  matter.  Scales,  in  which  a  few  grains  of 
musk  have  been  weighed,  have  retained  the  smell  for  twenty  years 
afterwards,  although  they  must  have  been  constantly  exhaling  odorous 
molecules  during  the  whole  of  this  pericjd.  Ilaller'*  kept  some  pa})ers, 
for  more  than  forty  years,  which  had  been  perfumed  by  a  single  grain 
of  amber;  and,  at  the  end  of  that  time,  they  did  not  appear  to  have 
lost  any  of  their  odour.  That  distinguished  physiologist  and  mathe- 
matician calculated,  that  every  inch  of  their  surface  had  been  im- 
pregnated by  osyro'sToiio^^''  ^^  ^  grain  of  amber,  and  yet  they  had 
scented  for  14,600  days  a  stratum  of  air  at  least  a  foot  in  thici<ness. 
But  how  much  larger  must  these  molecules  be  than  those  of  light — 
provided  we  regard  it  as  consisting  of  molecules — seeing  that  glass  is 
capable  of  arresting  the  former,  but  suffers  the  other  to  penetrate  it  in 
every  direction. 

Nor  need  we  be  so  much  surprised  at  the  excessive  diflfusibility  of 
odorous  particles,  when  we  call  to  mind  the  facts  on  record  in  regard 
to  the  transmission  through  the  air  of  fine  particles  of  sand.  Gene- 
rally, according  to  Mr.  Darwin,*  the  atmosphere  of  the  Cape  Verd 
Islands  is  hazy;  and  this  is  caused  by  the  falling  of  impalpably  fine 
dust,  which  was  found  to  have  sliglitly  injured  the  astronomical  instru- 
ments. The  morning  before  they  anchored  at  Porto  Praya,  he  col- 
lected a  little  packet  of  this  brown-coloured  fine  dust,  which  appeared 
to  have  been  filtered  from  the  wind  by  the  gauze  of  the  vane  at  the 
mast-head.  Sir  Charles  Lyell  also  gave  him  four  packets  of  dust  which 
fell  on  a  vessel  a  few  hundred  miles  northward  of  these  islands.     Pro- 

'  Voyages  and  Travels  in  India,  London,  1S09. 

2  Embassy  to  the  courts  of  Muscat  and  Siam,  &c.,  p.  154,  Philad.,  1838. 

'  Medical  Examiner,  Marcli,  184tJ,  p.  159. 

*  Elementa  Physiolog.,  torn.  v.  lib.  xiv.  sect.  2,  p.  157,  Lausann.,  17b'9. 

^  .Journal  of  Researches  into  tlie  Natural  History  and  Geology  of  the  countries  visited 
during  the  voyage  of  H.  M.  S.  Beagle  round  the  world,  &c.  Amer.  edit.,  i.  5.  New  York, 
184(j. 


ODOURS.  719 

fessor  Ehrenberg  found,  that  this  dnst  consisted,  in  great  part,  of  infu- 
soria with  silicious  siiields,  and  of  the  silicious  tissue  of  plants.  In  five 
little  packets  which  Mr.  Darwin  sent  him,  he  ascertained  no  less  than 
sixty-seven  difierent  organic  forms  !  The  infusoria,  with  the  exception 
of  two  marine  species,  were  all  inhabitants  of  fresh  water. 

]\Ir.  Darwin  has  found  no  less  than  fifteen  different  accounts  of  dust 
having  fallen  on  vessels  when  far  out  in  the  Atlantic.  From  the  direc- 
tion  of  the  wind  whenever  it  has  fallen,  and  from  its  having  always 
been  observed  during  those  months  when  the  harmattan  is  known  to 
raise  clouds  of  dust  high  in  the  atmosphere,  it  is  prettj''  certain  that  it 
must  proceed  from  Africa.  It  is,  however — as  Mr.  Darwin  remarks — 
a  singular  fact,  that,  although  Professor  Ehrenberg  is  acquainted  with 
many  species  of  infusoria  peculiar  to  Africa,  he  found  none  of  these 
in  the  dust  sent  him;  but,  on  the  other  hand,  discovered  in  it  two 
species  which  he  knew  as  living  only  in  South  America.  "  The  dust," 
says  Mr.  Darwin — "falls  in  such  quantity  as  to  dirty  everything  on 
board,  and  to  hurt  people's  eyes;  vessels  even  have  run  on  shore  owing 
to  the  obscurity  of  the  atmosphere.  It  has  often  fallen  on  ships  when 
several  hundred,  and  even  more  than  a  thousand  miles  from  the  coast 
of  Africa,  and  at  points  sixteen  hundred  miles  distant  in  a  north  and 
south  direction.  In  some  dust,  which  was  collected  on  a  vessel  three 
hundred  miles  from  the  land,  I  was  much  surprised  to  find  particles  of 
stone  above  the  thousandth  of  an  inch  square,  mixed  with  finer  matter. 
After  this  fixct,  one  need  not  be  surprised  at  tlio  diffusion  of  the  far 
lighter  and  smaller  sporules  of  cryptogamic  plants.  Dr.  Kane'  exhi- 
bited to  the  American  Philosophical  Society  tihunents  of  mosses  suffi- 
ciently large  to  be  recognized  as  such  by  the  unassisted  eye,  which  he 
had  collected  on  the  ice  off  Cape  Adair,  in  the  Arctic  Seas,  in  the 
month  of  February,  1851,  upwards  of  sevent}''  mih^s  from  the  shore. 

The  air  is  not  the  only  vehicle  for  odours.  It  has  been  seen,  that 
they  adhere  to  solid  bodies;  and  that,  in  many  cases,  they  can  be  sepa- 
rated by  aqueous  or  spirituous  distillation.  The  art  of  the  perfumer 
consists  in  fixing  and  preserving  them  in  the  most  agreeable  and  con- 
venient vehicles.  Yet,  it  was  at  one  time  strenuously  denied,  that  they 
could  be  conducted  through  water;  and,  as  a  natural  consequence  of 
this,  that  fishes  could  smell.  M.  Dumeril,  for  example,  maintained, 
that  odours,  being  essentially  of  a  volatile  or  gaseous  nature,  cannot 
exist  in  fluids; — and,  moreover,  that  fishes  have  no  proper  olfactory 
organ  ; — that  the  part  which  is  commonly  considered  in  them  to  be 
such  is  the  organ  of  taste.  This  opinion  is  entertained  by  few.  We 
have  seen  that  odours  can  be  retained  in  fluids,  and  not  many  natural- 
ists of  the  present  day  will  be  hardy  enough  to  den}'-  that  fishes  have 
an  organ  or  sense  of  smell.  At  all  events,  few  anglers,  who  have  used 
the  oil  of  rhodium,  or  other  attractive  bait,  will  be  disposed  to  give  up 
the  results  of  their  experience  without  stronger  grounds  than  any  that 
have  been  assigned  by  the  advocates  of  that  view  of  the  subject.  Be- 
sides, air  is  contained  in  considerable  quantity  in  water,  so  that  odorous 
substances  might  reach  the  olfactory  organs  tlwough  it. 

'  The  IT.  S.  Grinnell  Expodition  in  soarcli  of  Sir  John  Franklin  :  a  personal  narrative, 
by  Elislia  Kent  Kane,  M.  D.,  U.  S.  N.,  p.  139.     Kow  York,  lfc53. 


720  SENSIBILITY. 

"When  it  was  determined,  that  odours  consist  in  special  molecules 
given  off  from  bodies,  it  was  attempted  to  explain  their  action  on  the 
pituitar}'-  membrane  in  the  same  manner  as  that  of  savours  on  the 
membrane  of  the  tongue.  It  was  conceived  that  the  shape  of  the  mole- 
cules of  a  pungent  odour  is  pointed,  that  of  an  agreeable  one,  round. 
Others,  again,  were  of  opinion,  that  olfaction  is  owing  to  some  chemi- 
cal union  between  the  odorous  molecule  and  the  nervous  fluid,  or, 
between  it  and  the  nasal  mucus.  None,  however,  have  attempted  to 
specify  the  precise  chemical  composition  that  renders  a  body  odorous. 
The  sensations  do  not  present  the  most  fivourable  occasions  for  exhi- 
biting chemical  agency ;  and,  in  this  particular  sense,  it  is  probably  no 
farther  concerned  than  in  the  sense  of  touch ;  and  not  so  much  as  in 
that  of  taste.  It  is  sufficient  for  the  odorous  particle — animal,  vege- 
table, or  mineral — to  come  in  contact  with  the  olfactory  nerves,  in 
order  that  the  odour  shall  be  appreciated ;  and  we  may,  in  vain,  look 
for  chemical  action  in  many  of  those  animal  and  vegetable  perfumes, — 
as  musk,  amber,  camphor,  vanilla,  &c. — which  astonish  us  by  their 
intensity  and  diffusibility. 

The  same  remarks,  that  were  made  on  the  classification  of  savours, 
are  applicable  to  that  of  odours.  They  are  not  less  numerous  and 
varied ;  and  each  substance,  as  a  general  rule,  has  its  own,  by  which 
it  is  distinguished.  Numerous  attempts  have  been  made  to  group 
them;  but  all  have  been  unsatisfactory.  The  classification  proposed 
by  Linnaeus,*  was — into  Odores  aromatici^  those  of  the  flowers  of  the 
pink,  bay  leaves,  &c.:  0.  fragr antes ^  those  of  the  lily,  jessamine,  &c.; 
0.  amhrosiaci^  those  of  amber,  musk,  &c. ;  0.  aUiacei,  those  of  garlic, 
assafoetida,  &;c. ;  0.  hircini^  (like  that  of  tlie  goat,)  those  of  the  Orchis  hir- 
cina,  Ghe^iopodium  vulvar ia,  &c. ;  0.  tetri,  repulsive  or  virous  odours^ — those 
of  the  greater  part  of  the  family  solanece;  and  lastly,  0.  nauseosi,  those 
of  the  flowers  of  the  veratrum,  &c.  A  simple  glance  at  this  division 
will  exhibit  its  glaring  imperfections.  No  two  persons  could  agree  to 
which  of  any  two  of  the  cognate  classes  a  particular  odour  should  be 
referred.  None  of  the  other  classifications,  that  have  been  proposed, 
are  more  satisfactory.  jVI.  Fourcroy  divided  them  into  extractive  or 
mucous,  fugaceous  oili/,  volatile  oily,  aromatic  and  acid,  and  hydrosulpJiu- 
reous; — and  Lorry  into  camphorated,  narcotic,  ethereal,  volatile  acid,  and 
alkaline.  The  distinction  into  animal,  vegetable,  and  m,ineral,  is  not 
more  commendable.  Musk  is  the  product  of  an  animal  of  the  rumi- 
nant family;  but  the  odour  is  not  confined  to  that  animal.  It  is  con- 
tained in  the  civet;  in  the  flesh  of  the  crocodile;  and  in  the  musk-rat. 
Haller  asserts,  that  his  own  perspiration  smelt  of  it.  It  is  met  with, 
likewise,  in  the  vegetable  kingdom : — in  Erodium  moschatum,  in  the 
seeds  of  Ahelmaschus,  the  flowers  of  Rosa  moschata,  and  Adoxa  m,oscha- 
tellina,  and  in  some  of  the  varieties  of  the  melon  and  pear;  and,  what 
is  perhaps  more  surprising,  in  mineral  substances; — as  in  certain  pre- 
parjitions  of  gold;  and  in  some  earths  of  which  tea-pots  are  made  in 
China  and  Japan.  The  odour  of  garlic,  again,  is  found  not  only  in 
that  vegetable,  but  in  assafoetida ;  in  arsenic,  when  thrown  upon  hot 
coals ;  and  in  Bufo  pluvialis,  a  species  of  toad. 

'  Amoenitat.  Academic,  Eriang.,  17S7,  1790. 


ODOURS.  721 

In  bj  far  the  majority  of  cases,  we  can  only  designate  an  odonr  by 
comparing  it  with  that  of  some  well-known  substance ;  hence  the  epi- 
thets musky ^  alliaceous^  S2:)ennaif'c,  &c.  M.  Adelon  asserts,  that  the  sole 
classification  which  can  be  adopted  is  into  the  agreeable  and  disagreea- 
hle.  But  even  the  miserably  imperfect  division  proposed  by  Haller^ 
is  better  than  this:  he  made  three  classes — Odores  suaveolentes^  0.  medii^ 
and  0.  fcetores.  The  truth  is,  that  all  the  objections,  made  to  the  divi- 
sion of  savours  into  agreeable  and  disagreeable^  are  equally  applicable 
to  odours.  Assafoetida,  we  have  seen,  was  employed  by  the  ancients 
as  a  condiment;  and,  although  with  us  it  has  the  name  deviVs  dung^  it 
is,  by  many  of  the  Asiatics,  called /ooJ  of  the  gods.  We  find,  too,  cer- 
tain animals  that  are  almost  enchanted  by  particular  odours.  The  cat, 
for  example,  if  catmint — Nepeta  cataria, — or  the  root  of  valerian — 
Valeriana,  officinalis — be  placed  in  its  way.  Again,  odours,  generally 
thought  agreeable,  are  to  some  persons  intolerable.  To  many,  as  to 
Professor  Miiller,^  mignonette  has  but  an  herb-like  odour.  The  smell 
of  the  calycanthus  is  to  most  individuals  pleasant;  but  exceedingly 
disagreeable  to  some;  and,  according  to  Arnold,^  whilst  the  flower  of 
Iris  Persica  was  pronounced  to  possess  an  agreeable  odour  by  forty- 
one  out  of  fifty -four  persons,  four  considered  it  to  have  little  scent;  by 
eight  it  was  declared  to  be  devoid  of  odour,  and  by  one  to  be  disagree- 
able. These  difierences,  like  those  in  the  appreciation  of  savours  by 
animals,  must  be  referred  to  minute  and  inappreciable  difierences  of 
organization. 

Odours  have  been  considered  to  be  possessed  of  medicinal  and  even 
of  poisonous  properties.  Some  individuals,  whose  peculiarity  of  con- 
stitution renders  them  very  liable  to  the  action  of  ipecacuanha  or 
jalap,  experience  the  emetic  eftects  of  the  former,  or  the  cathartic 
qualities  of  the  latter,  by  merely  smelling  them  for  a  short  time ;  and 
the  majority  of  individuals,  by  pounding  jalap  or  rhubarb,  find  them- 
selves sooner  or  later  more  or  less  afiected.  By  smelling  strong  alco- 
hol for  a  considerable  tiipe,  intoxication  may  be  induced,  as  not  un- 
frequently  happens  to  the  spirit-taster,  who  is  young  in  his  vocation. 
It  has  also  been  asserted,  that  the  constant  application  of  this  sense  to 
the  discrimination  of  teas  in  the  English  East  India  Company's  ware- 
liouses  has  laid  the  foundation  for  numerous  head  affections;  but  the 
report  originated  in  prejudice,  or  in  accidental  coincidences,  and  has 
not  been  found  to  be  accurate. 

In  all  cases  in  which  we  see  medicinal  or  poisonous  effects  actually 
produced  by  substances  inhaled  through  the  nostrils,  we  cannot  attempt 
to  explain  them  by  the  simple  impi-ession  made  by  the  odorous  parti- 
cles on  the  olfactory  nerves.  They  must  be  accounted  for  by  minute 
particles  of  the  medicinal  or  ])oisonous  substance  being  diffused  in  the 
atmosphere,  and  coming  in  contact  with  the  mucous  membrane,  through 
whicli  they  are  absorbed,  and  in  this  manner  enter  the  circulation. 

Odours  have,  likewise,  been  considered  to  possess  nutritive  proper- 
ties; and  this,  chiefly  perhaps,  from  the  eft'ect  known  to  be  produced 

'  Elementa  Physiolog.,  torn.  v.  lib.  xiv.  p.  102,  LansaJin.,  1760. 
-   KleiiU'iits  of  Physiology,  by  Baly,  p.  i:>17,  Luiul.,  1^;;!*. 

^  Pliysiology,  ii.  5G1,  cited  by  Dr.  Carpenter,  art.  l^luel),  in  Cyclopredia  of  Anatomy 
and  Physiology,  pt.  xxxvi.  p.  703,  Lend.,  June,  lb4y^ 
VOL.  I. — 10 


722  SENSIBILITY. 

by  savoury  smells  upon  the  appetite.  It  is  not  probable,  that  absorp- 
tion can  occur  to  a  sufficient  extent  to  account  for  the  apparent  satiation. 
The  fact  can  only  be  explained  by  the  impression  upon  the  nervous 
system,  which  influences  the  appetite  materially,  as  we  see  in  the  effect 
of  various  mental  emotions.  The  first  impact  of  a  nauseous  odour,  or 
even  the  view  of  a  disgusting  object,  frequently  converts  the  keenest 
appetite  into  loathing.  Yet,  anciently,  it  was  believed,  that  life  might 
be  sustained  for  a  time,  by  simply  smelling  nutritious  substances. 
Democritus  is  said  to  have  lived  three  days  on  the  vapour  of  hot 
bread ;  and  Bacon  refers  to  a  man  who  supported  an  abstinence  of 
.several  days  by  inhaling  the  odour  of  a  mixture  of  aromatic  and  alli- 
aceous herbs.  Two  hundred  years  ago  these  notions  were  entertained 
to  a  great  extent ;  and  they  suggested  the  viaticum  for  travellers  pro- 
ceeding to  the  moon,  according  to  the  plan  proposed  by  Dr.  John  Wil- 
kins.  Bishop  of  Chester.^  "  If  we  must  needs  feed  upon  something," 
he  remarks,  "  why  may  not  smells  nourish  us  ?  Plutarch  and  Pliny, 
and  divers  other  ancients,  tell  us  of  a  nation  in  India  that  lived  only 
upon  pleasing  odours;  and  it  is  the  common  opinion  of  physicians  that 
these  do  strangely  both  strengthen  and  repair  the  spirits."  Fuller,^  a 
learned  cotemporary  of  the  bishop  affords  an  amusing  instance  of  liti- 
gation, originally  given  by  Rabelais,^ — whom  he  does  not  cite,  however, 
— arising  from  this  supposed  nourishing  character  of  odours.  A  poor 
man  being  very  hungry,  stayed  so  long  in  a  cook's  shop  who  was  dish- 
ing up  the  meat,  that  his  stomach  was  satisfied  with  the  smell  thereof. 
The  choleric  cook  demanded  of  him  pay  for  his  breakfast ;  the  poor 
man  denied  having  had  any ;  and  the  controversy  was  referred  to  the 
decision  of  the  next  man  that  should  pass  by,  who  chanced  to  be  the 
most  notorious  idiot  in  the  whole  city :  he,  on  the  relation  of  the  mat- 
ter, determined  that  the  poor  man's  money  should  be  put  betwixt  two 
empty  dishes,  and  that  the  cook  should  be  recompensed  with  the  jin- 
gling of  the  money,  as  the  man  had  been  satisfied  by  the  smell  of  the 
cook's  meat. 

It  need  scarcely  be  said,  that  if  the  vapour  from  alimentary  sub- 
stances be  capable,  in  an}'  manner,  of  serving  the  purposes  of  nutrition, 
it  can  only  be  by  passing  into  the  blood-vessels  of  the  lungs. 

3.   PHYSIOLOGY  OF  OLFACTION. 

In  order  that  the  sense  of  smell  may  be  duly  exercised,  it  is  neces- 
sary that  the  emanation  from  an  odorous  body  shall  not  only  impinge 
upon  the  pituitary  membrane,  but  that  it  shall  do  so  with  some  degree 
of  force.  It  must,  in  other  words,  be  drawn  in  with  the  inspired  air. 
Perrault^  and  Lower^  found,  that  by  making  an  opening  into  the  tra- 

'  The  Discovery  of  a  New  Woikl,  or  a  Discourse  tending  to  prove,  that  'tis  possible 
there  may  be  another  Habitable  Workl  in  the  Moon,  with  a  Discourse  concerning  the 
possibility  of  a  passage  thither.     Loud.,  1G38. 

^  Holy'State,  London,  1()40. 

'  The  Works  of  Francis  Rabelais,  ii.  115,  Loud.,  1849.  In  a  note  it  is  stated,  "that 
Bocchoris,  according  to  Plutarch,  gave  a  similar  juilgnient  against  the  courtesan  Tho- 
nis,  who  demanded  in  money  the  price  of  her  favours  from  a  young  spark,  who  had 
enjoyed  them  in  imagination  only." 

■*  Ess.  de  Phys.,  iii.  2i). 

*  Needham,  de  Format.  Foetus,  p.  165 ;  and  Haller,  edit,  cit.,  v.  173. 


PHYSIOLOGY   OF   OLFACTION.  723 

chea  of  animals,  and  preventing  the  inspired  air  from  passing  tlirongli 
the  nasal  fossae,  smell  was  not  effected  ;  and  that  dogs,  which  were  the 
subjects  of  the  experiment,  readily  ate  food  they  had  previously  refused. 

These  experiments  were  repeated  by  Professor  Chaussier,  and  with 
like  results.'  They  explain  why  we  use  effort  to  draw  in  air  loaded 
with  an  odour  that  is  agreeable  to  us ;  and,  on  the  contrary,  arrest  the 
respiration,  or  make  it  pass  entirely  through  the  mouth  when  odours 
are  disagreeable.  Still  they  are  occasionally  so  diffusible  and  expan- 
sible, that  they  reach,  notwithstanding,  the  olfactory  membrane ;  and 
we  are  compelled  to  shut  them  off  by  calling  in  the  aid  of  the  upper 
extremity.  The  air  being  the  ordinary  medium  for  the  conveyance  of 
odorous  molecules,  we  can  understand  why  the  organ  of  smell  should 
form  a  part  of  the  air  passages. 

The  use  of  the  nose  is  to  direct  the  air,  charged  with  odours,  towards 
the  upper  part  of  the  nasal  fossae.  Its  situation  is  well  adapted  for  the 
reception  of  emanations  from  bodies  beneath  it,  and  its  appropriate 
muscles  allow  the  nostrils  to  be  more  or  less  expanded  or  contracted. 
These  uses  assigned  to  the  nose  are  demonstrated  by  the  fact,  that 
they,  whose  noses  are  deformed — especially  the  flat-nosed — or  whose 
nostrils  are  directed  forwards,  instead  of  downwards,  have  commonly 
the  sense  feebly  developed.  The  loss  of  the  nose,  too,  either  by  acci- 
dent or  disease,  has  been  found  to  destroy  the  sense  completely ;  and 
by  no  means  the  least  advantage  of  the  rhinoplastic  operation  is  the 
enjoyment  afforded  by  the  improvement  of  this  sense.  M.  Beclard 
affirms,  that  an  artificial  nose,  formed  of  paper  or  other  appropriate 
materials,  is  sufficient  to  restore  it,  so  long  as  the  substitute  is  attached.'^ 
It  is  proper  to  remark,  however,  that  in  a  case  which  fell  under  the 
author's  observation,  although  the  nose  had  been  lost  by  syphilis,  the 
smell  persisted ;  and  two  cases  of  a  similar  kind  occurred  to  M.  P.  H. 
Berard.' 

The  mode  in  which  olfaction  is  effected  appears  to  be  as  follows : — 
The  inspired  air,  loaded  with  odorous  particles,  traverses  the  nasal 
fossae ;  and,  in  its  passage,  comes  in  contact  with  the  pituitary  mem- 
brane, through  the  medium  of  the  nasal  mucus.  The  use  of  this  mucus 
seems  to  be,  not  only  to  keep  the  organ  properly  lubricated,  but  to 
arrest  the  particles  as  they  pass, — not  by  any  chemical  attraction,  but 
in  a  mechanical  manner.  The  olfactory  nerves  being  distributed  on 
the  membrane,  receive  the  impression  of  the  molecules,  and,  in  this 
manner,  sensation  is  accomplished. 

The  use  of  the  different  spongy  or  turbinated  bones  would  seem  to 
be  to  enlarge  the  olfactory  surface.  According  to  some,  however,  they 
form  channels  to  direct  the  air  towards  the  openings  of  the  sinuses. 
The  sinuses,  themselves,  afford  subjects  for  physiological  discussion. 
By  many  they  are  considered  to  add  to  the  extent  of  olfactory  surfice : 
by  others,  to  furnish  the  nasal  mucus.  No  hesitation  would  be  felt  in 
pronouncing  both  the  spongy  bones  and  sinuses  to  be  useful  in  olfaction, 
were  it  not  that  the  olfactory  nerves  or  first  pair  have  not  been  traced 
on  the  pituitary  membrane  covering  the  middle  and  inferior  spongy 

'  Adelon.  op.  cit.,  i.  335. 

^  Magemlie,  Precis  El-'inentaire,  2(le  I'dit.,  i.  I'M),  Paris,  IS'Zf). 

3  Art.  Olfaction,  Diet,  de  Medecine,  2dc  edit.,  xxii.  9,  Paris,  1840. 


724  SENSIBILITY. 

bones,  or  on  that  lining  the  different  sinuses ; — that  the  sinuses  are 
wanting  in  the  infant,  which,  notwithstanding,  appreciates  odours; — 
that  they  exist  only  in  the  mammalia ; — and  that  experiments  would 
seem  to  show,  that  the  up])er  part  of  the  olfactory  organ  is  more  par- 
ticularly destined  for  the  function,  and  that  the  sinuses,  which,  as  well 
as  the  membrane  covering  the  middle  and  lower  spongy  bones,  are 
supplied  by  filaments  from  the  fifth  pair  of  nerves,  are  not  sensible  to 
odours. 

Messrs.  Todd  and  Bowman' — from  the  fact,  that  on  the  septum  na- 
rium  and  turbinated  bones  bounding  the  direct  passage  from  the  nostrils 
to  the  throat,  the  lining  membrane  is  rendered  thick  and  spongy  by  the 
presence  of  ample  and  capacious  submucous  plexuses  of  both  arteries 
and  veins,  of  which  the  latter  are  by  far  the  larger  and  more  tortuous 
— surmise,  and  Dr.  Carpenter^  thinks,  with  much  probability,  that  the 
chief  use  of  these  may  be  to  impart  warmth  to  the  air,  before  it  enters 
the  proper  olfaetive  portion  of  the  cavity;  as  well  as  to  afford  a  copious 
supply  of  moisture,  which  may  be  exhaled  by  the  abundant  glandulas 
seated  in  the  membrane.  ''The  remarkable  complexity  of  the  lower 
turbinated  bones  in  animals  with  active  scent,  without  any  ascertained 
distribution  of  the  olfactory  nerves  upon  them,  has" — they  remark — 
"given  countenance  to  the  supposition,  that  the  fifth  pair  may  possess 
some  olfactory  endowment,  and  seems  not  to  have  been  explained  by 
those  who  rejected  that  idea.  If  considered  as  accessory  to  the  perfec- 
tion of  the  sense  in  the  way  above  alluded  to,  this  striking  arrangement 
will  be  found  consistent  with  the  view,  which  thus  limits  the  power  of 
smell  to  the  first  pair  of  nerves." 

That  the  upper  part  of  the  nasal  fossae  is  the  great  seat  of  smell  is 
proved  by  the  facts  referred  to  regarding  the  uses  of  the  nose.  Dessault 
mentions  the  case  of  a  young  female,  who  had  a  fistula  in  the  frontal 
sinuses,  and  who  could  not  perceive  an  odorous  substance,  when  pre- 
sented at  the  orifice  of  the  fistula,  because  there  was  no  communication 
with  the  proper  poi'tion  of  the  nasal  foss«,  although  she  was  capable 
of  breathing  through  the  opening.  M.  Deschamps,  the  younger,  relates 
the  case  of  a  man,  who  had  a  fistula  of  the  frontal  sinus,  through  which 
ether  might  be  injected  without  its  odour  being  appreciated,  provided 
all  communication  had  been  previously  cut  off'  between  the  sinus  and 
the  upper  part  of  the  nasal  fossae;  but  if  this  precaution  had  not  been 
taken,  the  sense  was  more  vivid,  when  the  odours  passed  through  the 
fistulous  opening,  than  when  they  reached  the  organ  by  the  ordmary 
channel.  Again; — AI.  Richerand^  found  that  highly  odoriferous  injec- 
tions, thrown  through  a  fistulous  opening  in  the  maxillary  sinus  or 
antrum  of  Highmore,  produced  no  olfactory  sensation  whatever. 

All  these  facts  would  seem  to  lead  to  the  belief,  that  the  upper  part 
of  the  nasal  fossas,  on  which  the  first  pair  or  olfactory  nerves  are  dis- 
tributed, is  the  chief  seat  of  olfaction,  and  that  the  inferior  portions  of 
these  fosstB,  as  well  as  the  different  sinuses  communicating  with  them, 
are  not  primarily  concerned  in  the  function;  but,  doubtless,  offer  se- 
condary advantages  of  no  little  importance.     This  conclusion  would, 

'  Physiological  Anatomy  and  Physiology  of  Man,  ii.  3. 

2  Art.  Smell,  Cyclop,  of  Anat.  and  Physiol.,  pt.  xxxvi.  p.  694,  Lond.,  June,  1849. 

2  Elemens  de  Physiologie.  edit.  13eme  par  Berard,  p.  202,  Bruxelles,  1837. 


PHYSIOLOGY   OF   OLFACTION.  725 

however,  seem  to  admit,  wliat  is  not  by  any  means  universally  admitted, 
that  the  olfaetory  is  the  sole  or  chief  nerve  of  smell.  Especially  diffi- 
cult is  it  to  embrace  this  view,  and  not  to  believe  that  the  spongy  bones 
and  sinuses  on  which  the  fifth  pair  are  distributed,  are  agents  in  per- 
fecting the  sense,  when  we  find  them  so  largely  developed  in  animals 
that  possess  unusual  delicacy  of  smell,  as  the  dog  and  elephant.  It  has 
already  been  remarked,  that  the  ancients  believed  the  olfactory  nerves 
to  be  canals  for  conveying  away  the  pituita  or  phlegm  from  the  brain. 
Diemerbroeck,  also,  maintained  this  view,'  At  the  early  part  of  the 
last  centur}^  however,  the  olfactory  was  supposed  to  be  the  proper  nerve 
of  smell,  and  the  opinion  prevailed,  with  few  dissentient  voices,  until 
within  the  last  few  years.  Inspection  of  the  origin  and  distribution  of 
the  nerve  seems  to  indicate  it  as  admirably  adapted  for  special  sensibility 
connected  with  smell.  It  is  largely  developed  in  animals  in  proportion 
to  their  acuteness  of  the  sense,  and  is  distributed  on  the  very  part  of 
the  pituitary  membrane  to  which  it  is  necessary  to  direct  air,  loaded 
with  odorous  emanations,  in  order  that  they  may  be  appreciated.  M. 
Magendie^  has,  however,  endeavoured  to  show  by  experiment,  that  the 
sense  of  smell  is  in  no  wise,  or  little,  dependent  upon  the  olfactory 
nerve,  but  upon  branches  of  the  fifth  pair.  Prior  to  the  institution  of 
his  experiments,  he  had  observed  with  astonishment,  that  after  he  had 
j-emoved  the  cerebral  hemispheres,  with  the  olfactory  nerves  of  animals, 
they  still  preserved  this  sense.  He  had  noticed,  too,  that  it  continued 
in  lunatics,  who  had  fallen  into  a  state  of  stupor,  and  in  whom  the 
substance  of  the  brain  appeared,  on  dissection,  greatly  disorganized. 
These  facts  induced  him  to  expose  the  olfactory  nerves  on  living  ani- 
mals, and  to  experiment  upon  them;  and  he  found,  in  the  first  place, 
that  the  nerves  were  insensible  to  puncture,  pressure,  and  the  contact 
of  the  most  odorous  substances.  He  afterwards  satisfied  himself,  that 
after  their  division  the  pituitary  membrane  not  only  preserved  its 
general  sensibility,  appreciated  the  contact  of  bodies,  but  also,  strong- 
odours,  those  of  ammonia,  acetic  acid,  oil  of  lavender,  Dippel's  oil,  &c. 
On  the  other  hand,  having  divided  the  fifth  pair  of  nerves  within  the 
cranium,  and  left  the  olfactory  nerves  entire,  he  remarked,  that  the 
pituitary  membrane  had  lost  its  general  sensibility;  was  no  longer  sen- 
sible to  contact  of  any  kind ;  and  had  lost  the  power  of  appreciating 
odours.  From  these  experiments,  he  considered  himself  justified  in 
inferring,  that  the  olfactory  nerve  does  not  preside  over  the  general 
sensibility  of  the  nose;  that  it  has,  at  the  most,  a  special  sensibility  as 
concerns  odours;  and  that  if  the  olfactory  be  the  nerve  of  smell,  it  re- 
<|uires  the  influence  of  the  fifth  pair,  in  order  that  it  may  act.  Lastly; 
lie  asks,  may  not  the  general  and  special  sensibility  be  comprised  in 
the  same  nerve  in  the  sense  of  smell,  as  they  are  in  that  of  taste; — in 
the  fifth  pair? 

These  experiments  are  interesting;  but  they  by  no  means  establish, 
that  the  fifth  pair  is  the  olfactory  nerve.  The  numerous  facts,  already 
mentioned,  attract  us  irresistibly  to  the  first  pair  or  olfacton/^  as  they 
have  been  exclusively  called.     It  has  been  already  remarked,  that  the 

'  Anatome  Corporis  Humani,  lib.  iii.  cap.  8,  Ultraject.,  1672. 
'^  Precis  El.mentaire,  2i.le  edit.,  i,  132. 

46* 


726  SENSIBILITY. 

lifth  is  concerned  in  all  the  facial  senses;  that  it  convej's  to  them  gene- 
ral sensibility  or  feeling;  and  that  some  of  them  are  unquestionably 
supplied  with  nerves  of  special  sensibility; — the  eye  with  the  optic; 
and  the  ear  with  the  auditory;  but  that  neither  perhaps  can  fully 
exert  its  special  functions,  without  the  integrity  of  the  fifth.  The 
olfactory  nerve  is  probably  in  this  category, — is  the  nerve  of  special 
sensibility.  It  is  true,  that  in  the  experiments  of  M.  Magendie  the 
animal  appeared  to  be  affected  by  odorous  substances,  after  the  division 
of  the  first  pair ;  but  a  source  of  fallacy  existed  here,  in  discriminating 
accurately  between  the  general  and  special  sensibility.  Some  of  the 
substances  employed  were  better  adapted  for  eliciting  the  former  than 
the  latter; — ammonia  and  acetic  acid,  for  example.  In  a  case  before 
referred  to,^  whilst  the  olfactory  nerve  was  paralyzed  and  smell  proper 
was  wholly  lost,  the  person  was  able  to  appreciate  the  contact  of  pun- 
gent substances;  and  the  application  of  snuff' to  the  Schneiderian  mem- 
brane occasioned  sneezing,  because  the  ramifications  of  the  nerve  of 
the  fifth  pair  or  nerve  of  general  sensibility  were  unaffected. 

The  immediate  function  of  the  sense  of  smell  is  to  appreciate  odours. 
In  this  it  cannot  be  supplied  by  any  other  sense.  The  function  is  in- 
stinctive; requires  no  education;  and  is  exerted  as  soon  as  the  parts 
have  attained  the  necessary  degree  of  developement.  In  many  respects 
the  sense  is  intimately  connected  with  that  of  taste ;  and  the  impres- 
sions made  upon  each  are  frequently  confounded.  In  the  nutritive 
function,  the  smell  serves  as  a  kind  of  advanced  guard  or  sentinel  to 
the  taste ;  and  warns  us  of  the  disagreeable  or  agreeble  nature  of  the 
aliment;  but  if  a  substance  repugnant  to  the  smell  be  agreeable  to  the 
taste,  the  smell  soon  loses  its  aversion,  or  at  least  becomes  less  disa- 
greeably impressed.  The  smell  is  not,  however,  in  man  so  useful  as  a 
sentinel  to  the  taste,  as  it  is  to  animals:  there  are  many  bodies, — those 
containing  prussic  acid  for  example, — which  are  extremely  pleasing  by 
the  odours  they  exhale,  and  yet  are  noxious  to  man.  In  the  animal 
kingdom,  this  sense  is  greatly  depended  upon,  and  is  rarely  a  fallacious 
H'uide.  It  enables  animals  to  make  the  proper  selection  of  the  noxious 
from  the  innocent; — the  alimentary  from  that  which  is  devoid  of  nutri- 
ment;— the  agreeable  from  the  disagreeable ;  and  the  power  appears  to 
be  instinctive  or  dependent  upon  inappreciable  varieties  of  structure  in 
the  organs  concerned  in  olfaction. 

As  an  intellectual  sense,  smell  is  not  entitled  to  a  higher  rank  than 
taste.  Its  mediate  functions  are  very  limited.  It  enables  the  chemist, 
mineralogist,  and  perfumer,  to  discriminate  bodies  from  each  other. 
We  can,  likewise,  by  it  form  a  slight — but  only  a  slight — idea  regard- 
ing the  distance  and  direction  of  bodies,  owing  to  the  greater  intensity 
of  odours  near  an  odorous  body,  than  at  a  distance  from  it.  Under 
ordinary  circumstances,  the  information  of  this  kind  derived  by  olfac- 
tion is  inconsiderable;  but  in  the  blind;  and  in  the  savage,  who  is 
accustomed  to  exercise  all  his  external  senses  more  than  the  civilized, 
its  sphere  of  utility  and  accuracy  is  largely  augmented.  Of  this  we 
shall  have  to  speak  presently.     We  find  it,  too,  surprisingly  developed 

'  Page  710. 


IMMEDIATE   FUNCTION"   OF   SMELL.  72i 

in  certain  animals;  in  wliicliit  is  considered,  by  the  eloquent  Buffon,  as 
an  eye  that  sees  objects  not  only  where  they  are,  but  where  they  have 
been, — as  an  organ  of  gustation,  by  which  the  animal  tastes  not  only 
Avhat  it  can  touch  and  seize,  but  even  what  is  remote,  and  cannot  be 
attained ;  and  he  esteems  it  a  universal  organ  of  sensation,  by  which 
animals  are  most  readily  and  most  frequently  impressed;  by  which  they 
act  and  determine,  and  recognise  whatever  is  in  accordance  with,  or  in 
opposition  to,  their  nature.  The  hound  amongst  quadrupeds  affords  us 
a  I'amiliar  example  of  the  extreme  delicacy  of  this  sense.  For  hours 
after  the  passage  of  game,  it  is  capable  of  detecting  its  traces;  and  the 
l)loodhound  can  be  trained  to  indicate  the  human  footsteps  with  unerr- 
ing  certainty. 

Until  of  late  years,  it  was  almost  universally  believed,  that  many  of 
the  birds  of  prey  possess  an  astonishingly  acute  sense  of  smell.  Plum- 
l)oldt^  relates,  that  in  Peru,  Quito,  and  in  the  province  of  Popayan, 
when  they  are  desirous  of  taking  the  gigantic  condor — Vultur  grijj)hus 
of  Linnaeus — they  kill  a  cow,  or  horse,  and  in  a  short  time,  the  odour 
of  the  dead  animal  attracts  those  birds  in  numbers,  and  in  places 
where  they  were  scarcely  known  to  exist.  It  is  asserted,  that  vultures 
went  from  Asia  to  the  field  of  battle  at  Pharsalia,  a  distance  of  several 
liundred  miles,  attracted  thither  by  the  smell  of  the  killed!^  Pliny ,-' 
liowever,  exceeds  almost  all  his  contemporaries  in  his  assertions  on  this 
matter.  He  affirms,  that  the  vulture  and  the  raven  have  the  sense  of 
smell  so  delicate,  that  they  can  foretell  the  death  of  a  man  three  days 
beforehand,  and  in  order  not  to  lose  their  prey  they  arrive  upon  the 
spot  the  night  before  his  dissolution!  The  turkey-buzzard  of  the 
United  States  is  a  bird  of  this  class,  and  it  is  surprising  to  see  how 
soon  they  collect  from  immense  distances  after  an  animal  has  died  in 
the  forests.  The  observations  and  experiments  of  the  ornithologist 
Audubon''  would  seem,  however,  to  show  that  this,  bird  possesses  the 
sense  of  smell  in  a  less  degree  than  the  carnivorous  quadruped.  He 
stuffed  the  skin  of  a  deer  with  hay,  and  after  the  whole  had  become 
])erfectly  dry  and  hard,  placed  it  in  an  open  field  on  its  back,  and  in 
the  attitude  of  a  dead  animal.  In  the  course  of  a  few  minutes  a  vul- 
ture was  observed  flying  towards  it,  which  alighted  near,  and  began  to 
attack  it ;  tearing  open  the  seams,  and  pulling  out  the  hay ;  but  finding 
that  it  could  obtain  nothing  congenial  to  its  taste,  it  took  flight.  It 
was  found,  too,  that  when  animals  in  an  advanced  state  of  putridity 
were  lightly  covered  over  so  as  to  prevent  vultures  from  seeing  them, 
they  remained  undisturbed  and  undiscovered,  although  the  birds  re- 
]ieatedly  flew  over  them.  In  some  other  experiments  it  was  found, 
that  birds  of  prey  were  attracted  by  well-executed  representations  of 
dead  animals  painted  on  canvass  and  exposed  in  the  fields, — and  in 
')thers,  that  young  vultnres,  enclosed  in  a  cage,  exhibited  no  tokens  ol' 
their  perceiving  food,  when  it  could  not  be  seen  by  them,  however  near 
them  it  was  brought.  These  results — which  were  obtained,  also,  by 
Dr.  Bachman  in  the  presence  of  a  number  of  scientific  gentlemen  of 

'  Rec.  de  Zoolog.  et  d'Anat.  Comp.,  2de  livr.,p.  73,  Paris,  1807. 

^  Haller,  edit,  cit.,  torn.  v.  lib.  xiv.  j).  LOS. 

3  Hist.  Nat.,  lib.  x.  cap.  «,  p.  230,  Lugd.,  1587. 

■•  Oniitliological  Biography,  p.  33,  Boston,  1835  ;  Loudon's  Mag.  of  Nat.  Hist.,Yii.  1(J7. 


728  SENSIBILITY. 

Charleston,  South  Carolina — are  strange,  inasmuch  as  the  olfactory 
apparatus  of  the  turkey-buzzard,  when  examined  by  the  comparative 
anatomist,  exhibits  great  developement,  and  admirable  adaptation  for 
acuteness  of  smell.  They  are  confirmed,  however,  by  more  recent  expe- 
riments on  the  condor  by  Mr.  Charles  Darwin,^  a  distinguished  natu- 
ralist. He  tied  several  condors  by  ropes  in  a  long  row  at  the  bottom 
of  a  wall ;  and  having  folded  up  a  piece  of  meat  in  white  paper,  he 
walked  backwards  and  forwards  carrying  it  in  his  hand  at  the  distance 
of  about  three  yards  from  them ;  but  no  notice  whatever  was  taken  of 
it.  He  then  threw  it  on  the  ground  within  one  yard  of  an  old  male 
bird,  which  looked  at  it  for  a  moment  with  attention,  but  regardecl  it 
no  more.  With  a  stick  he  pushed  it  closer  and  closer,  until  at  last  the 
bird  touched  it  with  its  beak;  the  paper  was  then  instantly  torn  oft' 
with  fury,  and  at  the  same  moment  every  condor  in  the  long  row  began 
struggling,  and  flapping  its  wings.  "Under  the  same  circumstances, 
it  would  have  been  quite  impossible  to  have  deceived  a  dog." 

As  the  organ  of  smell,  in  all  animals  that  respire  air,  is  situate  at 
the  entrance  of  the  organs  of  respiration,  it  is  probable  that  its  seat,  in 
insects,  is  in  the  mouth  of  the  air  tubes.  This  sense  appears  to  guide 
them  to  the  proper  kinds  of  food,  and  to  the  execution  of  most  of  the 
few  offices  they  perform  during  their  transient  existence.  Occasionally, 
however,  they  are  deceived  by  the  resemblance  between  odours  of 
substances  very  different  in  other  qualities.  Certain  plants,  for  ex- 
ample, emit  a  cadaverous  odour  similar  to  putrid  flesh,  by  which  the 
flesh-fly  is  attracted,  and  led  to  deposit  its  ova  in  places  that  can  furnish 
no  food  to  its  future  progeny. 

As  regards  the  extent  of  the  organ  of  smell,  man  is  undoubtedly 
worse  situate  than  most  animals ;  and  all  things  being,  in  other  re- 
spects, equal,  it  may  be  fair  to  presume,  that  those,  in  which  the  olfac- 
tory membrane  is-  most  extensive,  possess  the  sense  of  smell  most 
acutely.  It  is  curious,  however,  that  certain  animals,  which  have  the 
sense  of  smell  in  the  highest  degree,  feed  on  the  most  fetid  substances. 
The  dog,  for  instance,  riots  in  putridity ;  and  the  birds  of  prey,  to  which 
reference  has  been  made,  but  whose  acuteness  of  smell,  we  have  seen, 
has  been  contested,  have  similar  enjoyment.  The  turkey-buzzard  is 
so  fetid  and  loathsome,  that  his  captors  are  glad  to  loosen  him  from 
bondage ;  and  it  is  affirmed,  that  if  his  ordinary  foetor  be  insufficient  to 
produce  his  release,  he  affords  an  irresistible  incentive,  by  ejecting  the 
putrid  contents  of  his  stomach  upon  them  P 

One  inference  may,  perhaps,  be  drawn  from  this  penchant  of  animals 
with  exquisite  olfactories  for  putrid  substances; — that  the  taste  of  the 
epicure  for  game,  kept  until  it  has  attained  the  requisite /wme^,  is  not 
so  unnatural  as  might  at  first  sight  appear. 

Like  the  senses  already  described,  that  of  smell  is  to  a  certain  extent 
under  the.  influence  of  volition : — in  other  words,  it  can  be  exerted 
actively^  and  passively.  Its  active  exercise — as  when  we  smell  any 
substance  to  enjoy  its  sweets,  or  test  its  odorous  qualities — generally 

'  Joiirnal  of  Researches  into  the  Natural  History  and  Geography  of  the  countries 
visited  during  the  voyage  of  H.  M.  S.  Beagle  rouiul  the  World,  Aiuer.  edit.,  New  York, 
1846. 

^  Wilson's  American  Ornithology,  by  Geo.  Ord,  Philad.,  1803-1814. 


SMELL  IMrROVED   BY   EDUCATION.  729 

requires  prehension,  the  proper  direction  of  the  head  towards  the 
object,  and  more  or  less  contraction  of  certain  muscles  of  the  alae  nasi. 
Doubtless,  here  again,  the  papillas  are  capable  of  being  erected  under 
attention,  as  in  the  senses  of  taste  and  toach.  On  the  other  hand,  we 
can  throw  obstacles  in  the  way  of  the  reception  of  disagreeable  odours  ; 
and,  if  necessary,  prevent  their  ingress  altogether,  by  compressing  the 
nostrils  with  the  upper  extremity. 

Lastly : — like  the  other  senses,  smell  is  capable  of  great  improvement 
by  education.  The  perfumer  arrives,  by  habit,  at  an  accurate  discri- 
mination of  the  nicest  shades  of  odours;  and  the  chemist  and  the 
apothecary  employ  it  to  aid  them  in  distinguishing  bodies  from  each 
other ;  and  in  pointing  out  the  changes  that  take  place  in  them,  under 
the  influence  of  heat,  light,  moisture,  &c.  In  this  way,  it  becomes  a 
useful  chemical  tost.  The  effect  of  education  is  likewise  shown,  by  the 
difference  between  a  dog  kept  regularly  accustomed  to  the  chase,  and 
one  that  has  not  been  trained.  For  the  same  reason,  in  man,  the  sense 
is  more  exquisite  in  the  savage  than  in  the  civilized  state.  In  the 
latter,  he  can  have  recourse  to  a  variety  of  means  for  discriminating 
the  properties  of  bodies ;  and  hence  has  less  occasion  for  acuteness  of 
smell  than  in  the  former ;  whilst,  again,  in  the  latter  state,  numbers 
destroy  the  sense  to  procure  pleasure.  The  use  of  snuff  is  one  of  the 
most  common  of  these  destructive  influences. 

Of  the  acuteness  of  the  sense  of  smell  in  the  savage  we  have  an 
example  on  the  authority  of  Humboldt :  he  affirms,  that  the  Peruvian 
Indian  in  the  middle  of  the  night  can  distinguish  the  different  races  by 
their  smell, — whether  they  are  European,  American  Indian,  or  negro. 
To  the  same  cause  must  be  ascribed  the  delicacy  of  olfaction  generally 
observed  in  the  blind.  The  boy  Mitchell,^  who  was  born  blind  and 
deaf,  and  whose  case  will  have  to  be  referred  to  hereafter,  was  able  to 
distinguish  the  entrance  of  a  stranger  into  the  roonj  by  smell  alone. 
A  gentleman,  blind  from  birth,  from  some  unaccountable  impression 
of  dread  or  antipathy,  could  never  endure  the  presence  of  a  cat  in  the 
apartment.  One  day,  in  company,  he  suddenly  leaped  up  ;  got  upon 
an  elevated  seat ;  and  exclaimed,  that  a  cat  was  in  the  room,  begging 
them  to  remove  it.  It  was  in  vain  that  the  company,  after  careful 
inspection,  assured  him  he  was  under  an  illusion.  lie  persisted  in  his 
assertion  and  state  of  agitation  ;  when,  on  opening  the  door  of  a  small 
closet,  it  was  found  that  a  cat  had  been  accidentally  sliut  up  in  it. 

'  Wanlrop's  History  of  James  Mitcliell,  Loud.,  1813  ;  and  Dugald  Stewart's  Elements 
of  the  Philosophy  of  the  Human  Mind,  iii.  401,  3d  edit.,  Lond.,  1S08. 


END    OF    VOL.    I. 


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